DENTAL CARIES AND RELATED FACTORS

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					           DENTAL CARIES AND RELATED FACTORS

 IN THE FIRST AND SECOND ACADEMIC YEAR MEDICAL

STUDENTS IN THAIBINH MEDICAL UNIVERSITY, VIETNAM




                          Ms. Pham Thi My Hanh




          A Thesis Submitted in Partial Fulfillment of the Requirements
for the Degree of Master of Public Health Program in Health Systems Development
                       College of Public Health Sciences
                            Chulalongkorn University
                              Academic Year 2007
                     Copyright of Chulalongkorn University
Thesis Title     DENTAL CARIES AND RELATED FACTORS IN THE FIRST

                 AND SECOND ACADEMIC YEAR MEDICAL STUDENTS IN

                 THAIBINH MEDICAL UNIVERSITY, VIETNAM

By               Pham Thi My Hanh
Field of Study   Health Systems Development
Thesis Advisor Robert Sedgwick Chapman, M.D., M.P.H.


       Accepted by College of Public Health Sciences, Chulalongkorn University in
Partial Fulfillment of the Requirement for the Master’s Degree


           …………….………………..Dean of College of Public Health Sciences
           (Professor Surasak Taneepanichsakul, M.D.)


THESIS COMMITTEE



           ……………………………………………….Chairperson
           (Assistant Professor Ratana Somrongthong, M.A., Ph.D.)



           ………………………………………………..Thesis Advisor
           (Robert Sedgwick Chapman, M.D., M.P.H.)



           ………………………………………………..External Member
           (Siriwan Pitayarangsarit, D.D.S., M.P.H., Ph.D.)
                                                                                    iii

PH 072480:    MAJOR HEALTH SYSTEMS DEVELOPMENT
KEY WORDS : DENTAL CARIES./DMFT./ORAL HYGIENE./FLUORIDE
      SUPPLEMENT./EATING HABIT./ MEDICAL STUDENT
      PHAM THI MY HANH: DENTAL CARIES AND RELATED FACTORS IN
      THE FIRST AND SECOND ACADEMIC YEAR MEDICAL STUDENTS IN
      THAIBINH MEDICAL UNIVERSITY, VIETNAM. THESIS ADVISOR:
      ROBERT SEDGWICK CHAPMAN, M.D., M.P.H., 108 pp.

        A population based cross-sectional analytical study was conducted among 365
first- and second- year medical students in Thaibinh Medical University, Vietnam.
The study had two main purposes: first to describe prevalence of dental caries by
using the decayed, missing and filled teeth (DMFT) index, identify oral hygiene
practice, fluoride supplements, eating habit and perception on oral health problem
among these students; second to characterize associations between these factors and
dental caries. Data were collected in January 2008 by using a structured questionnaire
and dental clinical examination. All students in 9 academic units (classes) randomly
selected from the list of 11 units were invited to take part in the study. Frequencies,
percentages, means, and standard deviations were used to describe the data. To assess
associations between dependent and independent variables, non-parametric statistics
(Chi-square tests, Spearman’s correlations, Mann-Whitney tests and Kruskal-Wallis
tests) were used.
        The prevalence of dental caries (DMFT ≥ 1) was 70.4 and the mean DMFT
was 2.28 ± 2.18. Mean filled teeth marked low (only 0.005 ± 0.46). There was only
limited prevalence of ever visiting a dentist (56.7%) and a very small prevalence of
visiting for dental checkup (13.5%). All the students brushed their teeth every day and
most brushed twice or more per day (83.5%). Just above 50% of participants had ever
used one type of fluoride supplement, not including fluoridated toothpaste, and 53.6%
stopped using such supplements before the study. No significant association was seen
between dental caries and fluoride supplements. The study revealed good eating habit
among this population; with most frequent food intake was healthy food. Significant
associations were found between dental caries experience and increased intake of
unhealthy foods, especially sweetened milk, gel and chocolate. Perception on oral
health problem in terms of pain, chewing, bad odor, tooth damage, tooth color,
smiling, communication, and school absence were 57.1%, 35.5%, 17.2%, 9.9%, 9.3%,
6.5% and 4.5% respectively. A significant positive association was found between
perceived tooth damage and dental caries experience.
        Study findings indicate a need for more education on oral health promotion,
especially regarding tooth brushing schedule and reduction of unhealthy food
consumption. Regular dental check-ups and early caries treatment are also needed to
improve dental health status of this population. Time relationships between dental
caries occurrence and perceived dental health-related problems should also be further
characterized.

Field of Study   Heath System Development       Student’s signature

Academic year       2007                        Advisor’s signature
                                                                                   iv


                           ACKNOWLEDGEMENTS

       I would like to express my sincere gratitude and deep appreciation to my

advisor, Dr. Robert S. Chapman, for his invaluable supervision, guidance, kindness,

constructive criticism and tremendous assistance throughout my study. I also would

like to express my appreciation and gratitude to Dr. Ratana Somrongthong and Dr.

Siriwan Pitayarangsarit for their guidance, invaluable advice which has enabled me to

develop this thesis.

       My acknowledgement and thankful are also expressed to all of the teachers in

College of Public Health Sciences for giving me valuable knowledge during my study

in the College.

       I want to acknowledge and thank to Colombo-Plan and Thailand International

Cooperation Agency for generous financial support for all expenses of my graduate

education, to all my teachers and my colleagues in Thaibinh Medical University,

especially to Associate Professor Pham Van Trong, the Dean of Faculty of Public

Health and Dr. Bui Van Han, the Dean of Department of Odontology for their kindly

help and supporting me throughout this study. My acknowledgement is also given to

all my friends in College of Public Health Sciences for their support and assistance

during the study course.

       Finally, I could not pursue the MPH degree without love, support and

encouragement from my dear family.
                                                                                                                         v


                                 TABLE OF CONTENTS

                                                                                                                    Page

ABSTRACT…………………..………………………………………………………iii

ACKNOWLEDGEMENTS..........................................................................................iv

TABLE OF CONTENTS...............................................................................................v

LIST OF TABLES........................................................................................................ix

LIST OF FIGURES ......................................................................................................xi

LIST OF ABBREVIATION ........................................................................................xii

CHAPTER I INTRODUCTION....................................................................................1

   1. Background and significance of the problem ........................................................1

   2. Research question of the study ..............................................................................4

   3. Hypotheses of the study .........................................................................................4

   4. Purpose of the Study ..............................................................................................4

   5. Benefits of the study ..............................................................................................5

   6. Brief description of the study area .........................................................................5

   7. Variables in the study.............................................................................................6

      Independent variables ............................................................................................6

      Dependent variables...............................................................................................7

   8. Conceptual Framework..........................................................................................8

CHAPTER II LITERATURE REVIEW .......................................................................9

   1. Dental caries overview...........................................................................................9

   2. Dental caries – definition and related factors: .....................................................12

      2.1 Definition of dental caries..............................................................................12

      2.2 Related factors to dental caries ......................................................................13
                                                                                                                         vi

                                                                                                                     Page

         2.2.1 Social-economic status related to dental caries ...................................... 14

         2.2.2 Oral hygiene practice relates to dental caries ......................................... 15

         2.2.3 Eating habits related to dental caries ...................................................... 16

         2.2.4 Tobacco smoking related to dental caries............................................... 17

         2.2.5 Fluoride supplement related to dental caries .......................................... 18

CHAPTER III RESEARCH METHODOLOGY ........................................................20

  1. Research design ...................................................................................................20

  2. Study population ..................................................................................................20

  3. Sample size calculation........................................................................................20

  4. Sampling method .................................................................................................23

  5. Research Instruments and measurements ............................................................23

  6. Data collection: ....................................................................................................31

  7. Data Analysis .......................................................................................................31

     7.1 Data entry and editing....................................................................................31

     7.2 Statistical technique: ......................................................................................31

  8. Ethical Considerations .........................................................................................32

CHAPTER IV RESEARCH RESULTS......................................................................33

  1. General characteristics of the medical students in the first and second

     academic years .....................................................................................................33

  2. Oral hygiene practice, fluoride supplement, eating habits and perception of

     oral health problem ..............................................................................................39

     2.1 Descriptive data of oral hygiene practice: .....................................................39

     2.2 Description of fluoride supplements..............................................................43
                                                                                                                             vii

                                                                                                                         Page

       2.3 Description of eating habits ...........................................................................45

       2.4 Description of perceived oral health problems ..............................................50

   3. Relationship between dental caries and general characteristics, oral hygiene

       practice, fluoride supplements, eating habits and perception of oral health

       problem. ...............................................................................................................52

   3. Relationship between perception of oral problems and DMFT score .................67

CHAPTER V DISSCUSION, CONCLUSION, AND RECOMMENDATIONS.......70

   1. Discussion ............................................................................................................70

       1.1 Social-demographic characteristics and dental status of respondents ...........70

       1.2 Oral hygiene practices....................................................................................72

       1.3 Fluoride supplement.......................................................................................73

       1.4 Eating habits...................................................................................................74

       1.5 Perception of dental health problems.............................................................75

       1.6. Scope and limitation .....................................................................................76

   2. Conclusion ...........................................................................................................77

   3. Recommendation .................................................................................................78

       3.1 For policy .......................................................................................................78

       3.2 For further study ............................................................................................78

REFERENCES ............................................................................................................79

   APENDICES............................................................................................................83

   APPENDIX A Examination form (English version) ..............................................84

   APPENDIX B Examination form (Vietnamese version)........................................95

   APPENDIX C Schedule activities ........................................................................106
                                                                                                          viii

                                                                                                        Page

   APPENDIX D Administration cost.......................................................................107

CURRICULUM VITAE............................................................................................108
                                                                                                                            ix


                                            LIST OF TABLES

                                                                                                                       Page

Table 1: The average DMFT by age and geography, Vietnam, 2002..........................12

Table 2: Occurrence of root caries by type of a subject’s dental health behavior .......22

Table 3: Codes for the dentition status of primary and permanent teeth .....................25

Table 4: General characteristic of subjects ..................................................................34

Table 5: Parental occupation and education ................................................................36

Table 6: Dental status of the subjects ..........................................................................37

Table 7: Tests of Normality of DMFT.........................................................................38

Table 8: General oral hygiene practice of medical students ........................................40

Table 9: Time of brushing............................................................................................41

Table 10: Visits to dentist by subjects .........................................................................42

Table 11: Reasons for going to dentist (may choose more than 1)..............................43

Table 12: Fluoride supplementation in medical students by fluoride source ..............44

Table 13: Number of fluoride supplement in medical students...................................45

Table 14: Food intake in medical students ..................................................................47

Table 15: Intake of individual unhealthy food items ...................................................48

Table 16: Tests of normal distribution for food variables ...........................................49

Table 17: Perception of oral health problem................................................................50

Table 18: Relationship between general characteristics and DMFT score..................53

Table 19: Relationship between DMFT score and parental occupation and

             education ......................................................................................................54

Table 20: Relationship between brushing behavior and DMFT category ...................55
                                                                                                                      x

                                                                                                                 Page

Table 21: Relationship between brushing time and DMFT category ..........................56

Table 22: Relationship between fluoride use and untreated decay (DT).....................57

Table 23: relationship between fluoride use and DMFT category ..............................57

Table 24: Relationship between each type of fluoride supplement with

          DMFT score .................................................................................................58

Table 25: Relationship between fluoride supplement parent occupations...................59

Table 26: Relationship between fluoride supplement and parent education ...............60

Table 27: Spearman correlations of DMFT score with food intake variables.............61

Table 28: Relationship between DMFT category and food intake variables...............63

Table 29: Relationship between DMFT category and unhealthy foods ......................64

Table 30: Relationship between brushing behavior and snacks consumption.............66

Table 31: Relationship between perception of oral health problems and

          DMFT score .................................................................................................67

Table 32: Relationship between perception of oral health problems and

          DMFT score .................................................................................................68
                                                                                                               xi


                                        LIST OF FIGURES

                                                                                                           Page

Figure 1: Conceptual Framework ..................................................................................8

Figure 2: Tooth decay over the US residents’ Lifespan ..............................................10

Figure 3: The prevalence of dental caries DMFT in Vietnam, 2002 ...........................11
                                           xii


          LIST OF ABBREVIATION

WHO    World Health Organization

DMFT   Decayed, Missing and Filled Teeth
                                     CHAPTER I

                                 INTRODUCTION


1. Background and significance of the problem

       The two most common oral diseases which hinder the achievement and

maintenance of oral health are dental caries and periodontal disease and these affect

all age groups, not only children (Thean et al., 2007). WHO pointed that the global

problems of oral diseases still persists despite great improvements in the oral health of

populations in several countries. Dental caries is one of major public health problems

worldwide. WHO also claimed that poor oral health may have a profound effect on

general health as well as quality of life, and several oral diseases are related to chronic

diseases. The experience of pain, problems with eating, chewing, smiling and

communication due to missing, discolored or damaged teeth have a major impact on

people’s daily lives and well-being. Furthermore, oral diseases restrict activities at

school, at work and at home causing millions of school and work-hours to be lost each

year throughout the world (Petersen et al., 2005)

       At present, the distribution and severity of dental caries vary in different parts

of the world and within the same country or region. It is affecting 60-90% of

schoolchildren and the vast majority of adults. It is also a most prevalent oral disease

in several Asian and Latin American countries. However it is expected that the

incidence of dental caries will increase in the near future in many developing

countries (Petersen et al., 2005)
                                                                                       2

       Nowadays, as a consequence of high prevalence of dental caries, the treatment

need is increase. However, treatment cost for dental disease is normally high. In the

United States annual treatment costs are estimated to be at least $4.5 billion (Aligne et

al., 2003). Therefore, treatment for all community is not feasible due to limited

resources such as time, person and money. On the other hand, prevention is more

affordable. Through many years, prevention of dental caries program has become one

important policy of Ministry of Health in many developed and developing countries.

However, most of such programs are focusing on children and lack of program which

is particularly for adults, especially for young adults. The same situation comes when

we mention to research field. I searched from PubMed with “dental caries” and

“children” in title as key word then I found that there were 12644 articles related to

that topic, with key word “dental caries” and “adults” in title, total number of articles

was only 6398 but with narrower key word “dental caries” and “young adults” in title,

total number of articles was only 130 (search on 12/30/07). The healthy permanent

dentition is also very important because it must last for a lifetime. Therefore, “Oral

health is essential to general health and well-being at every stage of life” is

significantly pointed out in a “National Call to Action to Promote Oral Health” of the

U.S Department of Health and Human Service which was published in May, 2003.

       Vietnam is one of the developing countries facing a high prevalence of dental

caries. A nationwide survey of oral health conducted by Ministry of Health

cooperated with Adelaide University of Australia in 2002 pointed that caries disease

affected more than 50% of Vietnamese population, in which people aged 18-34 held

75.2% of tooth decay prevalence (Tran et al., 2002).
                                                                                      3

         Dental caries is one of the most prevalence diseases in the Red river Delta of

Vietnam and exists as a major public health problem. The “school dental health

promotion and preventive program” is the largest preventive program which has been

running for 10 years but only is limited in 6 provinces and focus only on primary

schoolchildren. Young adults who are at the age of 18-25 have not taken much dental

health care or dental health promotion. Besides, many of them are suffering from such

disease. If left untreated, tooth decay can result in substantial morbidity due to pain,

dysfunction, poor appearance, and possibly problems with speech development.

Toothaches are the most common pain of the mouth or face reported by adults. This

pain can interfere with vital functions such as eating, swallowing, and talking. Some

researches related to dental caries in Vietnam were carried out but I could find none

of them addressed to such disease in young adults.

         University students play a significant role in public life. As the education of

the medical student progresses, he or she is expected to be a role model for his or her

patients, becoming a teacher of hygiene practice. Many of them might be dentists in

the future and will be expected to perform a healthy oral health lifestyle. Patterns of

oral hygiene in medical students are therefore particularly significant. However, little

attention has been paid to the context in which medical students undergo motivational

and behavioral changes with respect to their oral self-care regimens (Komabayashi,

2005).

         Thaibinh is one of Northern Provinces of Vietnam, on where Thaibinh

Medical University is located. Until now, there is no available data of dental health

status in young adult in this province. Thaibinh Medical University’s students also

have never been recruited for any study related to oral health.
                                                                                    4

       For these reasons we conducted the study: The relationship between dental

caries status and associated factors in medical students in ThaiBinh Medical

University in academic year 2007-2008.


2. Research question of the study

       Is there any relationship between dental caries and social-economic status oral

hygiene practices, eating habit, tobacco smoke exposure and fluoride supplement

among medical students?


3. Hypotheses of the study

   − Better oral hygiene practices associate with lower dental caries.

   − Healthy eating habits associate with lower dental caries.

   − More tobacco smoke exposure associate with higher dental caries.

   − There is an association between dental caries and fluoride supplement.

   − Low social-economic status associates with high dental caries.


4. Purpose of the Study

   − General objective:

       To identify the relationship between social-economic statuses, oral hygiene

       practices, eating habits and fluoride supplement with dental caries among

       medical students.

   − Specific objectives of the Study.

       1. To describe dental caries status.

       2. To measure social-economic status, oral hygiene practice, eating habits,

          tobacco smoke exposure and fluoride supplement.
                                                                                        5

       3. To characterize the relationship between oral hygiene practices and dental

           caries

       4. To characterize the relationship between eating habit and dental caries

       5. To characterize the relationship between tobacco smoke exposure and

           dental caries

       6. To characterize the association between fluoride supplement and dental

           experience

       7. To characterize the association between social-economic status and dental

           experience.


5. Benefits of the study

       The present study provided information about risk factors of dental caries in

Thaibinh Medical University’s students for further program planning implementation

and evaluation in public dental health service.


6. Brief description of the study area

       Thaibinh is a purely agricultural province located in the Red river Delta in the

north of Vietnam. The province is about 100km far from the capital. Thaibinh is in the

center of region and has a convenient transportation to other provinces. The disease

pattern in this province is also typical for the disease pattern in the region. Because of

these reasons, Thaibinh was chosen to place Thaibinh medical university in June

1979. Thaibinh Medical University is training both doctors of medicine and

pharmacists with many codes of graduates of medicine and pharmacology, post

graduates of medicine and pharmacists at high school level. Training doctor of

general medicine is the most important task of the university. The university recruits
                                                                                        6

about 200 new students each year for this course. The present number of students at

the university is over 3000, in which 1852 is the number of medical student, including

228 first-year students and 279 second-year students. These medical students all came

from 8 provinces in Red river Delta. The academic duration for this type of training is

6 years. On two first years, students are trained gathering in class. From the third year,

students both learn in class and practice at hospital. Odontology is taken by students

at the fifth year.


7. Variables in the study


Independent variables

 − General characteristics

        Gender

        Social-economic status

        Accordance with the minimum wage established by Vietnam government in

        2006, the minimum wage was 500 thousand Vietnamdong/cap/month,

        (approximate 1000 Thai Bath).

 − Oral hygiene practice

          Frequency of tooth-brushing

          Frequency of dental visit

 − Eating habit

          Type of food

          Frequency of food intake

 − Tobacco smoke exposure

          Frequency of smoking
                                                                                       7

        Frequency of passive smoking

− Fluoride supplement

        Type of fluoride supplement

        Time used


Dependent variables

        Dental caries refers to a pathological condition of tooth with localized

destruction enamel and dentine by micro organism. The indicator will be measured in

this study using DMFT indicator (decayed, missing and filled teeth), which describes

prevalence of dental caries in permanent teeth in an individual. DMFT reflects

numerically express of caries prevalence and are obtained by calculating the number

of:

        D: decayed of permanent tooth

        M: missing permanent tooth

        F: filled permanent tooth

        The missing component (M) and filled component (F) indicates those teeth

missing or filled as a result of caries.

DMFT score was calculated as follow:

                                           ∑D + ∑M + ∑F

        Mean DMFT          =

                                    Number of students examined

        Teeth (T) are thus used to get an estimation illustrating how much the

dentition until the day of examination has become affected by dental caries. It is either

calculated for 28 (permanent) teeth, excluding 18, 28, 38 and 48 (the "wisdom" teeth)

or for 32 teeth.
                                                                                     8


8. Conceptual Framework

                    Independent variables                      Dependent variables




                             Oral hygiene practice:
                                  Frequency of tooth-
                                  brushing
                                  Dental check-ups.




                              Eating habits:
                                   Type of food
                                   Frequency of food


 General
                                                                    DECAYED,
 characteristics:
                                                                     MISSING,
                                                                  FILLED TEETH
    Gender
    Social-
    economic               Tobacco smoke exposure:
    status                       Frequency of active
                                 smoking
                                 Frequency of passive
                                 smoking




                             Fluoride supplements:
                                  Type of fluoride
                                  supplement (toothpaste,
                                  gel, tablet, vitamin,
                                  mouthrinse)
                                  Time used



                              Figure 1: Conceptual Framework
                                    CHAPTER II

                            LITERATURE REVIEW


1. Dental caries overview

       In the Alma Ata conference in 1978, WHO informed that the percentage of

population affected with dental caries in the world was very high (90%), they began

to work for program for dental health care (Petersen et al., 2005). But until now, this

program has depended on social-economic condition and ability of each country,

therefore, the result of this program been varied. WHO reported that dental caries

experience in children is relatively high in the America (DMFT = 3.0) and in the

European Region (DMFT = 2.6) whereas the index is lower in most African countries

(DMFT = 1.7). In most developing countries, the levels of dental caries were low until

recent years but prevalence rates of dental caries and dental caries experience are now

tending to increase. The main reason for this trend is the increasing consumption of

sugars and inadequate exposure to fluorides. In contrast, a decline in caries has been

observed in most industrialized countries over the past 20 years or so. This result was

explained by the effectiveness of fluorides together with changing living conditions,

lifestyles and improved self-care practices. This report also pointed that the

prevalence of dental caries among adults is high as the disease affects nearly 100% of

the population in the majority of countries (Petersen et al., 2005).

       According to the National Center for Chronic Disease Prevention and Health

Promotion, tooth decay affects more than one-fourth of US. People aged 20 – 39 hold
                                                                                      10

an 87% lifetime prevalence of tooth decay (National Center for Chronic Disease

Prevention and Health Promotion, 2007) as shown in Figure 2.



     100%                                                 95%       93%
                                                87%

        80%
                                      68%

        60%
                            50%

        40%
               28%

        20%


        0%
                2–5         12–15     16–19    20–39     40–59      ≥60



                       Figure 2: Tooth decay over the US residents’ Lifespan



        In India, the prevalence of dental caries in 12-15 years-old children, whom

have permanent dentition, ranged from 80 to 87 percent. The mean DMFT was 3.03 ±

2.52 in the 12-years and 3.82 ± 2.85 in the 15-years. In there, the decay component

contributed 94% and 97%, missing and filled components were almost negligible

(Goyal et al., 2007)

        Among young Israeli army, Shenkman found that the total DMFT and DMFS

(decayed, missing and filled surfaces of teeth) were 6.09 +/- 5.29 and 10.18 +/-10.28,

respectively. Active caries-free patient rate, represented by D=0, was 38.7%. Caries

lesions were mostly moderate hold a percentage of 68.25 (Shenkman & Levin, L.,

2007)

         Caries prevalence was 66.7% and the mean DMFT value was 10.3 in Iasi

adults aged 35 to44. Significant statistical differences in dental caries prevalence were
                                                                                   11

found by sex, province, location ( urban and rural) and family income (Murariu et al.,

2007).

         In a sample of 200 Vietnamese refugees in Norway, which was divided into

four age groups, Selikowitz found that the mean score of DMFT ranged from 8.7 in

the youngest age group to 11.5 in the oldest and the high prevalence of caries was

seen in the permanent first molars in all age groups (Selikowitz, 1984).

         In Vietnam, the nationwide oral health survey conducted by Ministry of

Health showed that the prevalence of dental caries is 75.2 (DMFT = 3.29) in the 18-

34 year old population (Figure 3) (Tran et al., 2002).


         100
                                                                       89.7
                      Percent                                 83.2
          80                                         75.2
                                             68.6
                                     64.1
          60                54.6

          40
                25.4
          20

           0
                6-8        9-11    12-14    15-17   18-34    35-44     45+


           Figure 3: The prevalence of dental caries DMFT in Vietnam, 2002


         The average number of teeth with cavities (DT) in 18-34 year old population

range from 1.15 to 4.92 (Table 1).
                                                                                         12

Table 1: The average DMFT by age and geography, Vietnam, 2002

                                                              DMFT
 Region
                                          DT           MT          FT         DMFT

 The Northern Highland                    2.68         0.24        0.02       2.94

 The Red River Delta                      1.15         0.17        0.22       1.54

 The Coastal Northern Center              1.46         0.24        0.10       1.80

 The Coastal Southern Center              4.92         1.71        0.35       6.98

 The Highland Center                      1.45         0.35        0.09       1.89

 The East South                           2.94         1.12        0.42       4.48

 The Mekong River Delta                   2.17         1.42        0.22       3.81


Source: Nationwide Oral Health Survey 1999-2001 (Tran et al., 2002)


2. Dental caries – definition and related factors:


  2.1 Definition of dental caries

      Dental caries is a decalcification of enamel and dentine by the action of bacteria

on particles of carbohydrate (particular sugar) and associated with the time for

developing lactic acid dissolving tooth structure. Therefore it can be prevented by

controlling the development of bacteria as well as having a healthy diet for teeth

(Thylstrup et al, 1994). According to Bader, dental caries is a chronic infectious

disease caused by a complex interaction of oral microorganisms in dental plaque, diet,

and a broad array of host factors ranging from societal and environmental factors to

genetic and biochemical/immunologic host responses (Bader et al., 2001).

       So, the cause of dental caries can be described by a reference which comprises

two parts, one is like biological factor and the other is social circle. In the oral cavity,
                                                                                     13

a microbial deposit will cover most tooth surfaces, which are normally present in the

mouth. The bacteria convert all foods especially sugar and starch into acids. Bacteria,

acid, food debris and saliva combine in the mouth to form sticky substance called

plaque that adheres to the teeth. The acid in plaque dissolves the enamel surface of the

tooth and creates holes in the tooth (cavity). Plaque and bacteria begin to accumulate

within 20 minutes after eating. Scheie has documented that S. mutans prevalence was

highest in plaque over caries lesions and from fissures, and lowest in plaque from

smooth surfaces in immigrant Vietnamese children (Scheie et al., 1984). Caufield

surmised from his study’s results that lactobacilli associated with dental caries are

likely exogenous and opportunistic colonizers, arising from food or other reservoirs

outside the oral cavity (Caufield et al., 2007). Tare of saliva flow, buffer capacity,

sugar, diet, fluoride are factors closely related with dental caries. They play the role

influencing bacteria to destroy enamel of tooth to become tooth decay. Others

important factors at the outer circle as mentioned before is social factors, such as

education, knowledge about dental health care, behavior and attitudes of people. They

play as potential factors affecting to oral disease in general or dental caries in

specialty.


  2.2 Related factors to dental caries

      Risk factor was defined by Beck and adopted for the World Workshop on

Periodontics in 1996 as “an environmental, behavioral, or biologic factor confirmed

by temporal sequence, usually in longitudinal studies, which if present directly

increases the probability of a disease occurring, and if absent or removed reduces the

probability. Risk factors are part of the causal chain, or expose the host to the causal

chain. Once disease occurs, removal of a risk factor may not result in a cure.” (Beck,
                                                                                      14

1998). Recent decades, the most frequent risk factors of dental caries have pointed out

by numbers of scientific evidences is social-economic status, oral hygiene, eating

habit and fluoride supplement. Tobacco smoke exposure has also documented as a

related factor to dental cavity. However, the agreements are different from study to

study.


         2.2.1 Social-economic status related to dental caries

              The socio-behavioral risk factors have been found to play significant roles

in the occurrence of dental caries in both children and adults worldwide (Petersen et

al., 2005)

               Other social factors relating to dental caries also were concluded in

Basto’s study that low level of schooling, low maternal schooling and low monthly

family income were statistically associated with dental caries. He found that

individuals with eight or less years of study (OR 8.1: CI95% 1.9-34.7), raised by

mothers with eight or less years of study (OR 2.9 : CI 95% 1.7-5.0) were more likely

to have dental caries. Subjects whose families earned less than six Brazilian minimum

wages per month were also more likely to have dental caries (OR 2.3 : CI95% 1.4-

3.8) (Bastos et al., 2007).

               On the other hand, Browns’ study indicated that there was no different of

DMF permanent teeth between 6-to-18-year children who were at or below poverty

level and those at above poverty level (DMFT = 1.87 for the former and 1.89 for the

latter). However, children at or below poverty level has the average of 59.7 filled

permanent teeth compare with the 75.4 higher of this indicator in their counterpart.

Poverty level in this study was defined as the ratio of family income to the federal

poverty line (Brown et al., 2000). In the early 1990s, children above the poverty level
                                                                                      15

and children at or below the poverty level experienced about the same level of caries

with number of DMFT of 2.28 and 2.57 teeth, respectively. Older children (12 – 18

years of age) exhibited more caries than their younger counterparts whose age was

from 6 to 11 years. Their DMF permanent teeth are 6.65 and 1.67, respectively. This

is because older children have more permanent teeth that have been at risk for a longer

time and because caries is a cumulative disease whose damage is irreversible at the

stage it is measured in epidemiologic surveys (Brown et al., 2000)

       In Vietnam, the association between social-economic status and dental caries

in children was documented in few studies. Bui’s studied in 25-36 month aged

children has indicated that the prevalence of dental caries of those whose mother’s

occupation is farmers is significant higher than those whose mother are officers. The

prevalence is 71.9% for the former and is 42.5% for the latter (Bui, 2006)


      2.2.2 Oral hygiene practice relates to dental caries

            A number of studies in recent decades have emphasized the positive

effects of healthy behavior of individuals on improving oral health in general as well

as dental health in specific (Hugoson et al., 2007). Vehkalahti et al. conducted a study

in 1988 to find out if there is a relationship between the occurrence of untreated root

caries and a subject's dental health habits, such as the frequency of tooth-brushing, the

avoidance of sugar, and regularity of dental visits. The result shows that a high

frequency of tooth-brushing was strongly related to a low occurrence of root caries for

both men (OR = 4.3, p value < 0.001) and women (OR = 4.1, p value < 0.001).

Regular dental check-up behavior was also strongly related to an infrequent

occurrence of root caries. For those who check-up at least once in two years (OR =
                                                                                       16

3.4, p value < 0.001) in women and (OR = 4.5, p value < 0.001) in men (Vehkalahti &

Paunio, 1988).

            Some dental health programs which focused on improving oral hygiene

habit positively results in the improvement of oral cleaning, particularly plaque

cleaning (Hugoson et al., 2007)


      2.2.3 Eating habits related to dental caries

            Eating habit refers sweet is a risk factor of dental caries in children was

proved by many researches (Goyal et al., 2007; Pitayarangsarit, 1996). This factor

also has documented as a risk factor of dental caries in adult in some studies. The use

of sugar in coffee or tea was a common habit in Vehkalahti’s findings, both in women

(48%) and in men (72%). Root caries occurred more frequently among the users

(20%) than the non-users (12%). This habit was associated with root caries

occurrence, showing an odds ratio of 2.2 among men . Every third subject reported

some use of sweets. This habit was moderately related to root caries occurrence in

men (OR = 0.8, p value < 0.05) but not in women (OR = 1, p value > 0.05)

(Vehkalahti & Paunio, 1988).

            There is a general consensus today that the consumption of fermentable

carbohydrates has been a key etiological factor behind caries ever since prehistoric

times. However, it is difficult to specify this factor’s precise role in modern society in

epidemiological and clinical data, and to determine a clear link between sugar intake

and caries at population level. This is partly due to the large variations that occur in

sugar intake. Our diet has become more complex. The consumption of pure sugar is

progressively decreasing, while consumption of sugary drinks and foods is on the rise

(Lingstrom, 2006).
                                                                                   17

            According to Lingstrom, food intake frequency plays an important role in

development of dental caries. A high intake frequency means longer periods of

demineralization and only short periods when teeth have a chance to remineralise

(Lingstrom, 2006).


      2.2.4 Tobacco smoking related to dental caries

            Arbes reported that environmental tobacco smoke (ETS) has been shown

to be associated with periodontal disease in adults. Exposure to ETS at home only,

work only, and both was reported by 18.0%, 10.7%, and 3.8% of the study population

of 6611 persons 18 years and older who had never smoked cigarettes or used other

forms of tobacco, respectively. Besides, the adjusted odds of having periodontal

disease were 1.6 (95% confidence interval = 1.1, 2.2) times greater for persons

exposed to ETS than for persons not exposed (Arbes et al., 2001).

            Tobacco smoke contains agents which can impair immune system. Thus

it would be a risk factor for development of tooth decay, which is an oral infectious

disease (Edwards et al., 1999).

            In addition, environment tobacco smoke is associated with decreased

serum vitamin C levels and decreased levels of vitamin C are associated with growth

of cariogenic bacteria (Tribble et al., 1993). In children, after adjusting for age,

gender, vitamin C intake, and multivitamin use, environmental tobacco exposure

remained significantly associated with lower levels of serum ascorbic acid in children

who were exposed to both high and low levels of (Strauss, 2001).
                                                                                    18


       2.2.5 Fluoride supplement related to dental caries

             In the study of Goyal, 80.2% Chandigarh school children examined still

were using non-fluoridated toothpastes and 99% did not know the importance and

effect of fluorides on teeth in spite of the regular advertisements on TV regarding the

importance of using fluoridated toothpaste by the dentifrice manufacturing

companies. Lack of awareness on role of fluoride on dental caries prevention and the

increasing of sugary stuff consume results in the high prevalence of tooth decay in

this population (Goyal et al., 2007)

             Yoder at el., found that the majority of Indian dental professionals

surveyed had misunderstood of fluoride’s predominant posteruptive mode of action

through remineralization of incipient carious lesions. The researchers also suggested

that educational efforts was needed to promote the appropriate use of fluoride (Yoder

et al., 2007).

             In Vietnam, according to the Natiowide Oral Health Survey from 1999 to

2000, most of province in northern part of Vietnam has low fluoride concentration in

underground water, from 0.4 – 0.8 ppm (Tran et al., 2002). WHO suggested the

standard level of fluoride in drinking water is 0.7ppm. Dao reported that in Vietnam,

Hochiminh city was the first city that applied water fluoridation with fluoride

concentration in drinking water ranging from 0.7 ppm to 0.1 ppm. After running the

program for 4 years, the prevalence of dental caries reduced from 76% to 30% (Dao,

1995). The most common source supply fluoride in Vietnam is from toothpastes.

Other fluoride supplements are fluoride gel, fluoride tablet and fluoride vitamin but

they are not common sources of supplement.
                                                                                  19

            The fluoridated drinking water program in Vietnam is being run in only

two province of southern part. None of these provinces, the study subjects came from.

Because of limitation of time and other resource, fluoride concentration measuring in

drinking water was not included in the survey.
                                     CHAPTER III

                       RESEARCH METHODOLOGY


1. Research design

       This study design was a cross-sectional analytical study. The goals were to

ascertain dental caries status, oral hygiene practice, fluoride supplements, eating habit

and perception on oral problems. The other main purpose of this study was to

characterize the relationships between dental caries and these factors in students of the

first and the second academic year in Thaibinh Medical University.


2. Study population

       The population of this study was medical students who were studying in the

first or second academic year in Thaibinh medical university. Most of these students

came from 8 provinces in the Red river Delta of Vietnam. Some of them were foreign

students who came from Lao or Cambodia.


3. Sample size calculation

       A sample size calculation for measuring the prevalence of dental caries was

performed under the following formula:

                                           Z2 (1 - α/2) p (1 - p)

                                  n = ----------------------------

                                                 d2

       n = sample size

       α = level of significant
                                                                                        21


       Z1 - α/2 = reliability of coefficient based on level of significance. With α = 0.05,

       Z1 - α/2 = 1.96

       p = 0.75: proportion of dental caries of 18-34 year olds reported by the

         Nationwide Oral Health Survey 1999-2001 in Vietnam.

       d=0.05: acceptable difference.

       Therefore:

                         (1.96)2 (0.75)(1 – 0.75)

                    n=   ---------------------------- = 288

                               (0.05)2

       A sample size calculation for exploring the association between some risk

factors and dental caries was performed under the results from Vehkalahti’s study.The

Table 4 in her study showed the associations between root caries and dental health

behaviors (reproduced in table 2 below).
                                                                                        22

Table 2: Occurrence of root caries by type of a subject’s dental health behavior

                                    Number of subjects, % with Root Caries (%RC), and
                                            Odds Ratio (OR) for Having RC
          Elements of Dental              Women                         Men
            Health Behavior        n       %RC      OR*       n       %RC      OR*
     Tooth-brushing: frequent
     Sugar in coffee or tea: no    781     6.8               317      5.7
     Dental check-up: regular
     Tooth-brushing: frequent
     Sugar in coffee or tea: yes   520     6.5      1.0      538      8.9      2.1
     Dental check-up: regular
     Tooth-brushing: frequent
     Sugar in coffee or tea: no    437     16.5     2.7      237      16.5     3.3
     Dental check-up: irregular
     Tooth-brushing: frequent
     Sugar in coffee or tea: yes   527     18.8     3.2      707      25.0     5.5
     Dental check-up: irregular
     Tooth-brushing: infrequent
     Sugar in coffee or tea: yes   121     28.1     5.4      522      39.1     10.7
     Dental check-up: irregular
     Tooth-brushing: infrequent
     Sugar in coffee or tea: no    36      38.9     8.7      125      23.2     5.0
     Dental check-up: irregular
     Other combinations            19      5.3               111      10.9
     Cases with missing data       19                        11
     Total                         2460    12.5              2568     20.1
*
    Compared with subjects following all three recommendations.

             The table showed six behavior groups, in which, the first group was one

which had the entirely good dental health behavior. Other groups had at least one of

unhealthy behaviors.

             From that table, we had total of 1098 (=781+317) subjects in first group.

Thus, the prevalence for both sexes in this group was 6.4% (=(0.068*781

+0.057*317)/1098).

             By the same way, we had the prevalence for both sexes in the group 3,

which had good behavior of tooth-brushing and sugar intake but unhealthy behavior
                                                                                    23

of dental check-ups, is 16.4%. Based on this prevalence and under the assumption that

confidence level is 95% and power of study is 80%, we calculated the desirable

sample size for finding the association between dental caries and eating habits is 354.

Because the prevalence in other behavior groups 4, 5 and 6 is higher than group 3 so

the sample size calculated based on group 3 also was appropriate to see the

association between dental caries and other supposed related factors.

          All sample size calculations were done with Stacalc component of EpiInfo

software for cohort and cross-sectional study.


4. Sampling method

       At the time the study was conducted, the number of students in Thaibinh

Medical University were 279 second-year ones and 228 first-year ones. There were 6

class units for first year students and 5 class units for second year students.

       The randomly sampling method was applied to choose 5 from 6 classes in the

first years and 4 from 5 classes in the second years. Total students in chosen classes

were invited participate in the study, in which 365 students participated in both oral

examination and answering questionnaire.


5. Research Instruments and measurements

   •   The data about social-economic status, oral hygiene practice, eating habits,

fluoride supplement and perception on oral problem was gathered by structured

questionnaire.

   •   A clinical examination was carried out to collect data about dental health

status. The WHO caries diagnostic criterion for decayed, missing, and filled teeth

(DMFT) was used to measure the dental health status. Method of assessing dental
                                                                                   24

caries followed instructions of “Oral Health Surveys - Basic methods, 1997”.

Examinations were performed in a spacious environment. The individuals to be

examined remained seated on a dental chair and the examiner stood. The examiners

were properly and professionally vested with mask, cap and gloves (the latter were

changed at each examination) and made use of periodontal probes (CPI Probe) and

flat dental mirrors, previously sterilized. All the biosafety norms were followed.

Examiners adopted a systematic approach to the assessment of dentition status. The

examination proceeded in an orderly manner from one tooth to the adjacent tooth. A

tooth was considered present in the mouth when any part of it is visible. Considerable

care was taken by examiners while diagnosing tooth-colored fillings, which was

extremely difficult to detect.

   •   Radiography for detection of caries was not recommended because of the

impracticability of using the equipment in all situations. Likewise, the use of fiber

optics was not recommended also. Although it was realized that both these diagnostic

aided would reduce the underestimation of the need for restorative care, the extra

complication and frequent objections to exposure to radiation outweigh the gains to be

expected.

The Criteria for diagnosis and coding are presented in table 3.
                                                                                       25

Table 3: Codes for the dentition status of primary and permanent teeth (crowns and

           roots)

   Code
   Crown Root                 Condition/Status
       0            0         Sound
       1            1         Decayed
       2            2         Filled, with decay
       3            3         Filled, no decay
       4            -         Missing, as a result of caries
       5            -         Missing, any other reason
       6            -         Fissure sealant
       7            7        Bridge abutment, special crown or veneer/implant
       8            8        Unerupted tooth (crown)/unexposed root
       T            -         Trauma (fracture)
       9            9         Not recorded
  Source: “Oral health survey – Basic method”, (WHO, 1997).

Sound crown (code 0)

       A crown is recorded as sound if it shows no evidence of treated or untreated

clinical caries. The stages of caries that precede capitation, as well as other conditions

similar to the early stages of caries, are excluded because they cannot be reliably

diagnosed. Thus, a crown with the following defects, in the absence of other positive

criteria, will be coded as sound:

   •   white or chalky spots;

   •   discolored or rough spots that are not soft to touch with a metal CPI probe;

   •   stained pits or fissures in the enamel that do not have visual signs of

       undermined enamel, or softening of the floor or walls detectable with a CPI

       probe;
                                                                                     26

   •   dark, shiny, hard, pitted areas of enamel in a tooth showing signs of moderate

       to severe fluorosis.

   •   lesions that, on the basis of their distribution or history, or visual/tactile

       examination, appear to be due to abrasion.

Sound root (code 0)

       A root is recorded as sound when it is exposed and shows no evidence of

treated or untreated clinical caries. (Unexposed roots are coded 8.)

Decayed crown (code 1)

       Caries is recorded as present when a lesion in a pit or fissure, or on a smooth

tooth surface, has an unmistakable cavity, undermined enamel, or a detectably

softened floor or wall. A tooth with a temporary filling, or one which is sealed (code

6) but also decayed, will also be included in this category. In case where the crown

has been destroyed by caries and only the root is left, the caries is judged to have

originated on the crown and therefore scored as crown caries only. The CPI probe will

be used to confirm visual evidence of caries on the occlusal, buccal and lingual

surfaces. Where any doubt exists, caries will not be recorded as present.

Decayed root (code 1)

       Caries is recorded as present when a lesion feels soft or leathery to probing

with the CPI probe. If the root caries is discrete from the crown and will require a

separate treatment, it will be recorded as root caries. For single carious lesions

affecting both the crown and the root, the likely site of origin of the lesion will be

recorded as decayed. When it is not possible to judge the site of origin, both the crown

and the root will be recorded as decayed.
                                                                                     27


Filled crown, with decay (code 2)

       A crown is considered filled, with decay, when it has one or more permanent

restorations and one or more areas that are decayed. No distinction is made between

primary and secondary caries (i.e., the same code applies whether or not the carious

lesions are in physical association with the restoration(s)).

Filled root, with decay (code 2)

       A root is considered filled, with decay, when it has one or more permanent

restorations and one or more areas that are decayed. No distinction is made between

primary and secondary caries.

       In the case of fillings involving both the crown and the root, judgment of the

site of origin is more difficult. For any restoration most likely site of the primary

carious lesion is recorded as filled, with decay. When it is not possible to judge the

site of origin of the primary carious lesion, both the crown and the root will be

recorded as filled, with decay.

Filled crown, with no decay (code 3)

       A crown is considered filled, without decay, when one or more permanent

restorations are present and there is no caries anywhere on the crown. A tooth that has

been crowned because of previous decay is recorded in this category. (A tooth that

has been crowned for reasons other than decay, e.g. a bridge abutment, is coded 7)

Filled root, with no decay (code 3)

       A root is considered filled, without decay, when one or more permanent

restorations are present and there is no caries anywhere on the root.

       In the case of fillings involving both the crown and the root, judgment of the

site of origin is more difficult. For any restoration involving both the crown and the
                                                                                       28

root, the most likely site of the primary carious lesion is recorded as filled. When it is

not possible to judge the site of origin, both the crown and the root will be recorded as

filled.

Missing tooth, as a result of caries (code 4)

          This code is used for permanent or primary teeth that have been extracted

because of caries and is recorded under coronal status. For missing primary teeth, this

score will be used only if the subject is at an age when normal exfoliation would not

be a sufficient explanation for absence.

          The root status of a tooth that has been scored as missing because of caries

will be coded "7" or "9".

          It may be difficult to distinguish between unerupted teeth (code 8) and missing

teeth (code 4 and code 5). Basic knowledge of tooth eruption patterns, the appearance

of the alveolar ridge in the area of the tooth space in question, and the caries status of

other teeth in the mouth may provide helpful clues in making a differential diagnosis

between unerupted and extracted teeth. Code 4 will not be used for teeth judged to be

missing for any reason other than caries.

Permanent tooth missing, for any other reason (code 5)

          This code is used for permanent teeth judged to be absent congenitally, or

extracted for orthodontic reasons or because of periodontal disease, trauma, etc. As

for code 4, two entries of code 5 can be linked by a line in cases of fully edentulous

arches.

          The root status of a tooth scored 5 will be coded "7" or "9".
                                                                                       29


Fissure sealant (code 6)

       This code is used for teeth in which a fissure sealant has been placed on the

occlusal surface; or for teeth in which the occlusal fissure has been enlarged with a

rounded or "flame-shaped" bur, and a composite material placed. If a tooth with a

sealant has decay, it will be coded as 1.

Bridge abutment, special crown or veneer (code 7)

       This code is used under coronal status to indicate that a tooth forms part of a

fixed bridge, i.e., is a bridge abutment. This code can also be used for crowns placed

for reasons other than caries and for veneers or laminates covering the labial surface

of a tooth on which there is no evidence of caries or a restoration.

       Missing teeth replaced by a bridge are coded 4 or 5, under coronal status,

while root status is scored 9.

       Implant This code is used under root status to indicate that an implant has

been placed as an abutment.

Unerupted crown (code 8)

       This classification is restricted to permanent teeth and used only for a tooth

space with an unerupted permanent tooth but without a primary tooth. Teeth scored as

unerupted are excluded from all calculations concerning dental caries. This category

does not include congenitally missing teeth, or teeth lost as a result of trauma, etc. For

differential diagnosis between missing and unerupted teeth, see code 5.

Unexposed root (code 8)

       This code indicates that the root surface is not exposed, i.e. there is no gingival

recession beyond the CEJ.
                                                                                    30


Trauma (fracture) (code T)

       A crown is scored as fractured when some of its surface is missing as a result

of trauma and there is no evidence of caries.

Not recorded (code 9)

       This code is used for any erupted permanent tooth that cannot be examined for

any reason (e.g. because of orthodontic bands, severe hypoplasia, etc.).

       This code is used under root status to indicate either that the tooth has been

extracted or that calculus is present to such an extent that a root examination is not

possible.

       Information on the Decayed, Missing, and Filled Teeth Index (DMFT) were

calculated base on clinical files recorded by using the WHO caries diagnostic criteria,

1997 as described above. The D-component included all teeth with codes 1 or 2.

WHO caries diagnostic criteria, the M-component comprised teeth with code 4 in

subjects under 30 years of age, and teeth coded 4 or 5 for subjects 30 years and older,

i.e. missing due to caries or for any other reason. In my study, all participants were

less than 25 years of age, so M-component comprised only teeth with code 4. The F-

component includes only teeth with code 3. There was 47.7 percent of my researched

population with non wisdom teeth. The rest part of population has the number of

wisdom teeth varies from 1 to 4. Because of the diversity of number of wisdom teeth

in the population, these teeth are not concerned in further analysis of DMFT score.

Therefore, the basis for DMFT calculations is 28, with all permanent teeth excluding

wisdom teeth. Teeth coded 6 (fissure sealant) or 7 (bridge abutment, special crown or

veneer/implant) were not included in calculations of the DMFT.
                                                                                 31


6. Data collection:

       Data collection process of this research had the details as follow:

   •   The researcher introduced the rector and the chief of Training Management

       Department of Thaibinh medical university the objectives of this study and

       details of data collection procedure as well as for cooperation in collecting

       data.

   •   The researcher had meeting with monitors of all chosen classes to explained

       and informed the objectives of this study and details of data collection

       procedure as well as for cooperation in collecting data and sat the date and

       time to collect the data.

   •   The researcher trained the assistants to use the structured questionnaire and

       examiner to perform physical examination.

   •   Data collection was done everyday from 7.00 a.m. to 17.00 p.m. from January

       24 – 28, 2008.


7. Data Analysis

  7.1 Data entry and editing

       Data was coded and entered twice by using Epi Data software.

  7.2 Statistical technique:

       Data analysis was done by using SPSS software.

       Descriptive statistic includes frequency distribution and mean were used to

describe dental caries experience (DMFT). Frequency distribution will be used to

describe the general characteristic, oral hygiene practices, eating habits, fluoride

supplement and perception of oral problem.
                                                                                       32

       Chi-square was used to test the association between oral hygiene practices,

fluoride supplement, eating habits and dental caries prevalence when both dependent

and independent variables were categorical.

       To test the DMFT score and dichotomous variables, the Mann-Whitney tests

were employed. The Kruskal-Wallis tests were used, due to the stratification in more

than two categories. The choice of non-parametric tests is justifiable, since the caries

index utilized (DMFT) was not present a normal distribution. A 5% level of statistical

significance was adopted.


8. Ethical Considerations

       Purpose of the study was explained to all prospective subjects. The verbal

consent was taken from each participant before interview and examination.

       Prospective subjects were free to refuse to participate and they could also

withdraw through out the interview or examination. If, during the examination, a

potentially fatal condition or one that demanded immediate care was identified, the

case was referred to a pertinent public oral health center.

       The present study was submitted to the Ethics in Research Committee,

Thaibinh Medical University, and received a favorable.
                                   CHAPTER IV

                            RESEARCH RESULTS


       This chapter describes the results of the study in 3 parts. The first part addresses

general characteristics of first and second year medical students in Thaibinh Medical

University. General dental status of these subjects is included in this part. Descriptive

data of oral hygiene practice, fluoride supplements, eating habits and perception of oral

health problem are presented in part 2. The third part presents associations between

dental caries, as measured by DMFT score (continuous variable) and DMFT category

(presence or absence of non-zero DMFT), and general characteristics, oral hygiene

practice, fluoride supplements, eating habits and perception of oral health.

It was originally proposed to evaluate tobacco smoking. However, very few people

smoked (4%), and a substantial percentage, 20.3% could not estimate how much time a

day they exposed to tobacco smoke. Therefore, effects of smoking could not be

analyzed with confidence.


1. General characteristics of the medical students in the first and second

   academic years

       General subject characteristics are presented in table 4. A total of 365 medical

students at first year (67.4%) and second year (32.6%) in Thaibinh Medical

University received dental examination and were interviewed. 55.1% of respondents

were male, and 44.9% were female.
                                                                              34

Table 4: General characteristic of subjects

Characteristics                                      Number of subjects (%)
                                                     or Mean ± SD
Academic year (n = 365):
       First year                                    246 (67.4)
       Second year                                   119 (32.6)
Age
       17 – 19                                       266(72.9)
       20 - 24                                       97(26.6)
Gender (n = 365):                                    201 (55.1)
       Male                                          164 (44.9)
       Female
Nationality (n = 365):
       Vietnamese                                    329 (90.1)
       Non-Vietnamese                                36 (9.9)
Residence before admitted to university (n = 358):
       Rural area                                    259 (72.3)
       Urban area                                    99 (27.7)

Current residence while at university (n = 364):
       Outside campus                                216 (59.3)
       On campus                                     148 (40.7)

Monthly expenditure (VND/in thousand)                753.35 ± 313.86
(n = 361)
       < 500,000 VND/month                           91 (25.2)
       ≥ 500,00 VND/month                            270(74.8)

Perception of monthly expenditure: (n = 361)
       Satisfied                                     238 (65.9)
       Unsatisfied                                   123 (34.1)
                                                                               35

       Most of participants were Vietnamese (90.1%), only few of them (9.9%) come

from Lao and Cambodia. Mean of monthly expenditure of all participants was 753.35

thousand VND, higher than minimum wage established by Vietnam government in

2006, which was 500 thousand VNDs per month (one thousand VNDs is about 0.062

USD, approximates 2 Thai Bath). Even so, about 25% of subjects spent less than 500

thousand VND per month. There were about two thirds of participants satisfied with

amount of money they have to spend every month. 59.3% of the students were living

outside campus at the time of study.
                                                                                 36

Table 5: Parental occupation and education

 Parental occupation and        Fathers (%)               Mothers (%)

 education

 Occupation                     n = 361                   n = 364

    Farmer                      210 (58.2)                236 (64.8)

    Government employee             45 (12.5)               33 (9.1)

    Private business                32 (8.9)                38 (10.4)

    General worker                  25 (6.9)                -

    Teacher                         17 (4.7)                27 (7.4)

    Other jobs                      32 (8.9)               30 (8.2) (includes
                                                            general worker)

 Education                      n = 360                   n = 362

    Primary or no education     120 (33.3) (include       29 (8.0)
                                secondary)
    Secondary                   -                         130 (35.9)

    High school                 146 (40.6)                133 (36.7)

    Occupation training             31 (8.6)                25 (6.9)

    College or higher               63 (17.5)               45 (12.4)



       As shown in table 5, more than half of students have father or mother or both

being farmers. 7.4% of mothers were teachers and only 4.7% of fathers were teachers.

As for government employee which did not include teacher, 45 fathers (12.5%) and

33 mothers (9.1%) were taking these positions. Private business, general worker and

other jobs take not over one-fourth of the total parental occupations. Table 5 also

shows that most of parents’ education are high school level or lower. Fathers and
                                                                                   37

mothers who had occupational training account for 31 (8.6%) and 25 (6.9%),

respectively. There are more fathers (17.5%) having college or higher degrees than

mothers (12.4%).


Table 6: Dental status of the subjects

 Dental status                                          Frequency    Mean score

 (n = 365)                                                 (%)*          ± SD

 Unerupted wisdom teeth

   Percentage of population with no erupted teeth                    2.48 ± 1.62
                                                        174 (47.7)
   Percentage of population with at least one erupted
                                                        191 (52.3)
   wisdom teeth

 DMFT                                                   257 (70.4)   2.28 ± 2.18

 DT                                                     254 (69.6)   2.16 ± 2.09

 MT                                                     17 (4.7)     0.07 ± 0.36

 FT                                                     8 (2.2)      0.05 ± 0.46

*prevalence of non-zero measurements only, for example 2.2 is prevalence of FT > 0

       Table 6 shows the students' tooth status. There was 47.7 percent of this

population with no erupted teeth. The number of visible wisdom teeth in the rest of

the subjects varied from 1 to 4. In view of these findings, wisdom teeth were not

considered in data analysis. Dental caries prevalence was assumed as the proportion

of individuals with DMFT > 0. As revealed in table 6, dental caries affected 70.4%

(257 subjects) of population, in which 69.6 % of population with untreated decayed

teeth (represented by DT). Mean number of DMFT in this population was 2.28, in

which mean number of D component, M component was 2.16 and 0.07, respectively.
                                                                                  38

F, the last component of DMFT, which summarizes treatment for decay, had a mean

of only 0.05.


Table 7: Tests of Normality of DMFT

                                    Kolmogorov-Smirnov(a)

                                    Statistic      df               p-value

Decay teeth                         .156           365              < .001

Filled teeth                        .526           365              < .001

Missing teeth                       .529           365              < .001

DMFT                                .149           365              < .001

(a) Lilliefors Significance Correction

       According to table 7 and figure 3, the distribution of DMFT in the population

was non-normal. Hence, further statistic tests involving this measure will be done in

terms of non-parametric tests.
                                                                                          39


    Frequency

        120



        100



         80



         60



         40


                                                                      Mean = 2.28
         20
                                                                      Std. Dev. = 2.188

                                                                      N = 365
          0
              0                         5                      10   DMFT


                  Figure 3: Histogram of DMFT score



2. Oral hygiene practice, fluoride supplement, eating habits and perception of

  oral health problem

   2.1 Descriptive data of oral hygiene practice:

       Brushing behaviors of medical students in this study were measured by

questionnaire with 4 items: frequency of brushing, frequency of changing toothbrush,

forgetting to brush for 7 or more days and brushing model. These three first behaviors

are shown in table 8. Most of the students brushed their teeth twice or more a week

(83.5%). Only 31 students used their brush until it broke or wore out, accounts for

8.1%. 6.8% reported they had ever forgotten to brush their teeth for 7 days. All

participants brushed their teeth everyday. Thus, the proportion was 100% not

presented in the table.
                                                                                     40

Table 8: General oral hygiene practice of medical students

 Brushing behaviors                              Frequency         Percent

 Frequency of brushing per day (n = 364)

              once or less                       60                16.5

              twice or more                      304               83.5

 Toothbrush change (n = 365)

              once 3 month                       273               74.8

              once 6 month                       61                16.7

              breaks or wears out                31                8.5

 Ever forgot to brush (n = 365)

              never                              340               93.2

              ever                               25                6.8



       7.1% of subjects reported that they had no regular brushing schedule, followed

by brushing after breakfast with 11.6%. About 80 percent brushed after getting up and

around 72 percent brushed before going to bed. However, in the population of the

research, there was not more than 12 percent brushing their teeth after breakfast (table

9).
                                                                                  41

Table 9: Time of brushing

 Time of brushing                                   Frequency        Percent

 Brushing, no regular schedule (n = 364)

              No                                    338              92.9

              Yes                                   26               7.1

 Brush after getting up (n = 364)

              No                                    74               20.3

              Yes                                   290              79.7

 Brush after breakfast (n = 363)

              No                                    321              88.4

              Yes                                   42               11.6

 Brush before going to bed (n = 364)

              No                                    99               27.2

              Yes                                   265              72.8



       More than half of the students surveyed said that they had ever visited a

dentist, specifically 207 in total of 365 people. 40.3% had never gone to see dentist

and only very few (3.0) said they did not remember whether they had done or not. In

207 people who had visited dentist, there were over one third had their most recent

visits more than two years ago. 35 people (16.9%) had most recent dental visit

between last year and the year after last year. Nearly half of these 207 students

reported they had most recent dental exam last year. (See table 10 below).
                                                                                    42

Table 10: Visits to dentist by subjects

                                              Frequency             Percent

 Visit history (n = 365)

     ever                                     207                   56.7

     never                                    147                   40.3

     don't remember                           11                    3.0

 Most recent visit (*)

     less than 6 months                       46                    22.2

     6 months to 1 year                       55                    26.6

     1 year to 2 years                        35                    16.9

     more than 2 years                        71                    34.3

(*) in total of 207 those who ever visited dentist

       As for reasons for going to dentist, extraction, scaling and pain were the three

most frequent reasons; followed by filling with 19.8% reported, as shown in table 11.

Each of these three reasons counted for 21.3% of total reasons for dental visiting in

sample of 207 medical students who had ever gone to see dentist. There were 14.0%

said that they did not remember why they had to see dentist as shown in table 11. Our

analysis revealed that all students who did not remember the reason for dental visiting

had the most recent visit more than 2 years ago (data not shown).
                                                                                   43

Table 11: Reasons for going to dentist (may choose more than 1)

  Reasons (n = 207)                   Frequency                   Percent

  Extraction                          44                          21.3

  Scaling                             44                          21.3

  Pain                                44                          21.3

  Filling                             41                          19.8

  Checkup                             28                          13.5

  Bleeding                            17                          8.2

  Other treatments                    15                          7.2

  Do not remember reason              29                          14.0



    2.2 Description of fluoride supplements

         Regarding to fluoride supplements in medical students in Thaibinh Medical

University, some types of fluoride supplements were listed to ask. These included

fluoride mouth rinse, fluoride gel and other source of fluoride supplement such as

fluoride vitamin or fluoride tablet. Fluoride in tooth paste was not included in these

questions. The “yes” answers for these questions related to using fluoride never

exceeded 50% of the whole study sample. 43.3 % reported that they had ever used

fluoride mouth rinse. 20.9% said that they had ever used fluoride gel and only 11.2 %

of sample answered they had ever used other sources of fluoride supplements. 196

students (53.7%) said that they had ever used at least one type of fluoride supplement

(table 12).
                                                                                  44

Table 12: Fluoride supplementation in medical students by fluoride source

 Fluoride supplements                    Frequency           Percent

 Ever used Fluoride mouth rinse (n = 365)

              yes                        158                 43.3

              never                      183                 50.1

              don't remember             24                  6.6

 Ever used Fluoride gel (n = 363)

              yes                        76                  20.9

              never                      253                 69.7

              don't remember             34                  9.4

 Ever used other Fluoride sources (n = 365)

              yes                        41                  11.2

              never                      272                 74.5

              don't remember             52                  14.2

 Ever used any Fluoride supplement       196                 53.7



       We summed all fluoride supplements in Thaibinh medical students to see how

many sources of supplement the students could access. This data is presented in table

13. The very few of students supplement their teeth with fluoride from all source

(3.8%). Otherwise, the figure for those who never used any type of fluoride

supplement was quite high with 46.3 percent; follow by 35.9 percent of those who had

ever used only one source of fluoride supplement. Among subjects who had ever used

fluoride supplements, more than half were not using them at the time of survey

(53.6%). Some people were using two or three types of fluoride at that time with 7.7%
                                                                                    45

for the former and 3.1% for the latter. There were around 36 percent using one source

of fluoride supplement when data were collected.


Table 13: Number of fluoride supplement in medical students

Fluoride supplements               Frequency                 Percent

Ever used fluoride (n = 365)

            Never                  169                       46.3

            Used one type          131                       35.9

            Used two types         51                        14.0

            Used all               14                        3.8

Using fluoride at present (n = 196)

            Not using now          105                       53.6

            Using one type         70                        35.7

            Using two type         15                        7.7

            Using all              6                         3.1



   2.3 Description of eating habits

       For the questions related to food intake, we gave three score for three level of

intake. 1, 2, 3 score were respectively given to food which was never or rarely taken

(0-10% of days such food is taken), sometimes taken (10-50% of days such food is

taken) or often taken (more than 50% of days such food is taken). To get the total

score for each food item I summed all score of each food items given by each

individual in the whole sample. It means that for each food the lowest score might be

365 and the highest score might be 3 x 365 = 1095. Thus, the score closes to the
                                                                                    46

lowest score means the food is rarely consumed. Inversely, the food had score closes

to the highest score is most frequent consumed. Then, we divided total of 32 food

items into 6 groups, namely protein, grain, vegetable, fruit, beverages and snack.

Protein group consisted of beef, pork, chicken, egg, tofu, and fish. Grain group

included rice, bread, and noodles. Vegetable group was carrot, morning-glory,

cabbage, tomato, and other vegetable. Fruit group included banana, orange, pineapple,

and other fruits. In beverage group there were soft carbonated drinks, fruit juice, and

yoghurt drinks. Snack group consisted snacks, cookies, cake, candy, chocolate and

gel. Sweetened milk and unsweetened milk has documented having inverse role in

causing dental caries. Hence, these two kinds of milk were not combined. Sweetened

milk, snack and beverage were put together in one new group namely “unhealthy

food” according to the classification by Le, T.H. (Le, 2002). Other foods included

protein, grain, vegetable, fruit, and unsweetened milk were considered as healthy

food. To get the score for each food group, we summed all score of each food item in

the group. Table 14 shows mean score and adjusted mean of each food group.

Adjusted means were calculated by dividing mean of each food group by number of

its food item. Among 8 food groups (include unsweetened and sweetened milk) grain

was the most frequently consumed, followed by other healthy food group that were

protein, vegetable and fruit. Beverage and snacks and unsweetened milk were at the

end of the list of intake frequency of 7 food groups. In comparison, unhealthy food

was less consumed than healthy food with adjusted mean = 1.49 comparing with 1.95.
                                                                                   47

Table 14: Food intake in medical students

                                  Number of       Range                 Adjusted
Food group                                                    Mean
                                  food items      score                 mean*
Grain (n = 364)                   3               3-9         6.66      2.22

Protein (n = 362)                 6               6-18        12.94     2.16

Vegetable (n = 363)               6               6-18        11.58     1.93

Fruit (n = 363)                   5               5-15        8.83      1.77

Unsweetened Milk (n = 362)        1               1-3         1.40      1.40

Sweetened milk (365)              1               1-3         1.64      1.64

Beverage (n = 364)                3               3-9         4.54      1.51

Snack (n = 363)                   6               6-18        8.90      1.48

Unhealthy food (n = 363)          9               9-27        13.42     1.49

Healthy food (n = 360)            22              26-66       43.05     1.95

* Overall mean divided by number of questions used to calculate the score.
                                                                                48

Table 15: Intake of individual unhealthy food items

                                       Total score in
 Order         Food items                               N         Mean score*
                                       whole sample

    1.         Candy                   602              364       1.65

    2.         Sweetened milk          599              365       1.64

    3.         Snack                   582              365       1.59

    4.         Cookies                 567              363       1.56

    5.         Fruit juice             530              365       1.45

    6.         Soft drink              523              365       1.43

    7.         Cake                    509              364       1.40

    8.         Gel                     498              364       1.37

    9.         Chocolate               483              364       1.33

* mean score = total score/N

         Table 15 shows the total score of each unhealthy food items in order of

descending of intake level. Candy was consumed most frequently and chocolate was

consumed least frequently. However, there were not much differences of food intake

within the unhealthy food group.
                                                                                  49

Table 16: Tests of normal distribution for food variables

                                                  Kolmogorov-Smirnov (a)

 Food group                               Statistic         df        p-value

 Protein score                            .101              359       < .001

 Grain score                              .161              359       < .001

 Vegetable score                          .119              359       < .001

 Fruit score                              .100              359       < .001

 Beverage score                           .201              359       < .001

 Snack score                              .147              359       < .001

 Unsweetened milk score                   .407              362       < .001

 Sweetened milk score                     .293              362       < .001

 Unhealthy food score                     .138              359       < .001

 Healthy food score                       .056              359       .008

(a) Lilliefors Significance Correction

       Tests of normality for food variables are given in table 16. The table shows

that none of food variables were distributed normally. Therefore, the analysis used

non-parametric tests to test the associations between these variables and DMFT.
                                                                         50


   2.4 Description of perceived oral health problems

Table 17: Perception of oral health problem

Perception of oral health problem               Number of subjects (%)
Pain n = 354
                     Present                    54 (15.3)
                     Past only                  202 (57.1)
                     Never                      98 (27.7)
Chewing n = 352
                     Present                    26(7.4)
                     Past only                  125 (35.5)
                     Never                      201 (57.1)
Smiling n = 356
                     Present                    48 (13.5)
                     Past only                  33(9.3)
                     Never                      275 (77.2)
Communication
n = 353              Present                    32 (9.1)
                     Past only                  23 (6.5)
                     Never                      298 (84.4)
Tooth color
n = 354              Present                    109 (30.8)
                     Past only                  35 (9.9)
                     Never                      210 (59.3)
Tooth damage
n = 355              Present                    95 (26.8)
                     Past only                  61 (17.2)
                     Never                      199 (56.1)
Bad odor
n = 354              Present                    62 (17.5)
                     Past only                  71 (20.1)
                     Never                      221 (62.4)
School absence
n = 356              Present                    8 (2.2)
                     Past only                  16 (4.5)
                     Never                      332 (93.3)
                                                                                    51

       72.4% of population reported they have ever had oral pain, in which 54 people

said they were suffering from such symptom, as shown in table 17. Following pain

problem were chewing, bad odor and tooth damage with 35.5%, 20.1% and 17.2%

respectively of population had it in the past. Smiling and tooth color hold the similar

frequency with 9.3% for the former and 9.9% for the latter. School absence is

reported as lowest frequency for both past (4.5%) and at present (2.2%).
                                                                                     52


3. Relationship between dental caries and general characteristics, oral hygiene

  practice, fluoride supplements, eating habits and perception of oral health

  problem

       The DMFT score variable and group food scores are continuous variable with

non-normal distribution as indicated in previous tables. Thus, the relationships

between DMFT and general characteristic, oral hygiene practice, fluoride supplement,

eating habits and perception of oral health problem were examined by non-parametric

Mann-Whitney test, Kruskal-Wallis test or Spearman correlation. Chi- square test was

used to determine the association between DMFT category and the examined factors.

The level of significance for relationships among these variables was set at α = 0.05.

Table 18 shows the relationship between DMFT score and general characteristics.

Significantly higher mean ranks of DMFT can be seen in second years, in older

subjects, in females, in non-Vietnamese, in those whose hometown was urban area

and in those who was living on campus at the time of survey. Only monthly

expenditure showed no significant between higher and lower expense group.
                                                                              53

Table 18: Relationship between general characteristics and DMFT score

                                                             Mann-Whitney U
                                  N          Mean Rank       Z (p-value)
  Academic year (n = 365)

        First year                246        171.09          -3.162 (.002)

        Second year               119        207.63

  Age

        17 -19                    266        174.35          -2.345 (.019)

        20 – 24                   97         202.98

  Gender (n = 365)

        Male                      201        172.90          -2.065 (.039)

        Female                    164        195.38

  Nationality (n = 365)

        Vietnamese                329        177.72          -2.948 (.003)

        Non-vietnamese            36         231.28

  Hometown (n = 364)

        Rural area                259        172.81          -2.018 (.044)

        Urban area                99         197.00

  Recent residence (n=364)

        Outside campus            216        173.02          -2.117 (.034)

        On campus                 148        196.33

  Monthly expenditure (n=361)

        < 500,000 VND/month       91         169.04          -1.289 (.198)

        ≥ 500,00 VND/month        270        185.03
                                                                                 54

Table 19: Relationship between DMFT score and parental occupation and education

                             Fathers                      Mothers
 Occupation and levels
 of education                          Mean                      Mean
                             N                 p-value* N                p-value*
                                       Rank                      Rank
 Occupation                                    .512                      <.001

 Farmer                      210       177.4              236    163.6

 Government employee         45        205.4              33     217.2

 Private business            32        192.1              38     221.3

 General worker              25        181.5              30     211.1

 Teacher                     17        170.2              27     218.2

 Other jobs                  32        163.8              -      -

 Total                       361                         364

 Education                                     .412                      .092

 Primary or no education     120       172.6              29     193.9

 Secondary                   -         -                  130    167.0

 High school                 146       178.9              133    179.1

 Occupation training         31        180.3              25     199.3

 College or higher           63        199.2              45     212.6

 Total                       360                          362

* Kruskal-Wallis test

         For parent occupation, the table mentioned that the higher DMFT, the better

occupation of parents. The highest DMFT score can be seen in subjects whose parent

were private businessman and lowest DMFT score was in subjects whose parent were
                                                                                      55

famer (exclude jobs which was not specified). The association was strongly

significant in mother occupation.

         Parent education shows the inverse association with dental caries. Among

students whose father was more educated had more teeth affected by caries. No

educated mothers or high educated mothers were more likely to have children affected

by caries than those whose schooling was secondary or high school. The lowest

DMFT score was in those whose mother education was secondary or high school

level.


Table 20: Relationship between brushing behavior and DMFT category

                                    DMFT category            Pearson Chi-Square
  Brushing behavior                 DMFT = 0 DMFT > 0        Value (df)     p-value
  Brushing frequency per day
                                                               .004 (1)        .951
  (n = 364)
         Once or less               18 (30.0)   42 (70.0)                 OR = 1.01
         Twice or more              90 (29.6)   214 (70.4)   95%CI = (0.55 – 1.86)
  Changing toothbrush
                                                               .614 (2)        .736
  (n = 365)
         Once 3 month               80 (29.3)   193 (70.7)
         Once 6 month               17 (27.9)   44 (72.1)
         breaks or wears out        11 (35.5)   20 (64.5)
  Ever forgot to brush
                                                               .529 (1)        .467
  (n = 365)
         Ever                       9 (36.0)    16 (64.0)                 OR = 0.73
         Never                      99 (29.1)   241 (70.9)    95%CI = (0.31-1.70)



         Table 20 showed the relationship between brushing behavior and DMFT

category. It was shown that there was no significant association between frequency of
                                                                                  56

brushing and DMFT category (p-value = 0.951). The proportion of non-zero DMFT

among those who brushed their teeth twice or more than twice per day was not too

much difference from this figure among those who did not (70.4% compare within

70.4%). Similarly, frequency of changing toothbrush and ever forgetting to brush

were not associated with DMFT category.


Table 21: Relationship between brushing time and DMFT category

                                  DMFT category          Pearson Chi-Square
   Brushing time              DMFT = 0 DMFT > 0 Value(df)            p-value
   Brush, no regular
                                                         4.302 (1)         .038
   schedule (n = 364)
          Yes                 3 (11.5)     23 (88.5)          OR = 3.40
          No                  104 (30.8)   234 (69.2)   95%CI = (1.01 – 11.60)
   brush after getting up
                                                         4.912 (1)         .027
   (n = 364)
          Yes                 93 (32.1)    197 (67.9)         OR = 0.49
          No                  14 (18.9)    60 (81.1)    95%CI = (0.26 – 0.93)
   Brush after breakfast
                                                          .734 (1)         .392
   (n = 363)
          Yes                 10 (23.8)    32 (76.2)          OR = 1.38
          No                  97 (30.2)    224 (69.8)   95%CI = (0.65 – 2.93)
   Bush before going to
                                                          .081 (1)         .776
   bed (n = 364)
          Yes                 79 (29.8)    186 (70.2)         OR = 0.92
          No                  28 (28.3)    71 (71.7)    95%CI = (0.55 – 1.54)



       There was significant association between unfixed brushing behavior,

brushing after getting and DMFT category (p-value = 0.38 for the former and p-value

= 0.27 for the latter) as shown in table 21. In those who did not brush their teeth
                                                                                      57

regularly, the prevalence of non-zero DMFT score was higher than those who did.

Students in “brush after getting up” group had lower non-zero DMFT score

prevalence than “not brush after getting up” group. Brushing at other times of day was

not significantly associated with this index (p≥0.392).


Table 22: Relationship between fluoride use and untreated decay (DT)

                                          DT                  Pearson Chi-Square
  Ever used any fluoride
                             DT = 0          DT > 0       Value (df) p-value

  Never                      60 (35.5)       109 (64.5)   3.856 (1)       .050

                                                                      OR = 1.56
  Ever                       51 (26.0)       145 (74.0)
                                                              95%CI = (.99 – 2.45)



Table 23: relationship between fluoride use and DMFT category

                                         DMFT category         Pearson Chi-Square
  Ever used any        Mean
                                                               Value
  fluoride          DMFT ± SD DMFT = 0           DMFT > 0                   p-value
                                                               (df)

  Never             2.13 ± 2.208 58 (34.3)       111 (65.7)    3.38 (1)     .066

                                                                       OR = 1.52
  Ever              2.41 ± 2.167 50 (25.5)       146 (74.5)
                                                               95%CI = (.97 – 2.39)



         Tables 22 and 23 show the relationship between using any fluoride and dental

caries. In table 22, the association was determined between untreated decay

(represented by non-zero DT score or DT score > 0) and fluoride use. P-value = 0.05

revealed the marginal significant difference between prevalence of untreated decay
                                                                                  58

teeth in those who had never used any type of fluoride supplement and in those who

had ever used. The difference between prevalence of non-zero DMFT score in “never

used” group and “ever used” group was not significant with p-value = .066 (table 23.

OR in these two tests were higher than 1 showing the association between DMFT

category and fluoride supplement but 95% confidence interval of OR in these two

cases included 1 confirming the associations not being significant. However, the

direction of the association goes in the way that prevalence of non-zero DMFT score

was higher in subjects who had used fluoride than in those who had not.

       When looking at relationship between DMFT score and each fluoride

supplements, there was also no significant association. The association went in the

same way for all three supplements of fluoride that DMFT score was higher in those

who ever used and lower in those who never used or did not remember ever used or

not (table 24).


Table 24: Relationship between each type of fluoride supplement with DMFT score

Fluoride supplements           N            Mean rank of DMFT       K-W test p-value
Fluoride mouth rinse
     Yes                              158                  185.84
                                                                                  .364
     Never                            183                  177.33
     Don’t remember                    24                  207.56
Fluoride gel
     Yes                               76                  183.51
     Never                            253                  182.80                 .857
     Don’t remember                    34                  172.69
Fluoride from other source
     Yes                               41                  210.27
     Never                            272                  180.52                 .187
     Don’t remember                    52                  174.48
                                                                                     59




Table 25: Relationship between fluoride supplement parent occupations

 Parent occupation                    Fluoride supplement               Chi-square

                                      Never            Ever              (p-value)

 Mother’s     farmer                  121 (51.3)       115 (48.7)       9.220 (.056)

 occupation private business          10 (26.3)        28 (73.7)

              government
                                      13 (39.4)        20 (60.6)
              employee

              teacher                 12 (44.4)        15 (55.6)

              general worker,
                                      13 (43.3)        17 (56.7)
              housewife, others

 Father’s     farmer                  107 (51.0)       103 (49.0)       5.460 (.362)

 occupation government
                                      17 (37.8)        28 (62.2)
              employee

              private business        11 (34.4)        21 (65.6)

              fisherman, soldier,
                                      14 (43.8)        18 (56.3)
              others



       The relationship between fluoride use and parents’ occupation is shown in

table 25. The table states that subjects whose mother’s occupation was high income

job had had more access to fluoride than those whose mother’s occupation was not.

The association is almost significant with p-value = .056.
                                                                                     60




Table 26: Relationship between fluoride supplement and parent education

 Parent education                               Fluoride supplement      Chi-square

                                                 Never       Ever        (p-value)

 Mother’s       Cannot read or write,
                                                 16 (55.2)   13 (44.8) 10.70 (.030)
 education      primary school

                Secondary school                 73 (56.2)   57 (43.8)

                High school                      53 (39.8)   80 (60.2)

                Occupation trainings             10 (40.0)   15 (60.0)

                Graduated                        16 (35.6)   29 (64.4)

 Father’s       Cannot read or write,

 education      primary school, secondary        60 (50.0)   60 (50.0)     .96 (.809)

                School

                High school                      67 (45.9)   79 (54.1)

                Occupation training              14 (45.2)   17 (54.8)

                Graduated                        27 (42.9)   36 (57.1)



       Table 26 shows the relationship between fluoride supplement and parent

education. The prevalence of using fluoride among students whose mother was highly

educated was significantly higher than among students whose mother was not. This

trend was not as strong in relation father’s education.
                                                                                     61

Table 27: Spearman correlations of DMFT score with food intake variables

 Food groups                               Correlation Coefficient (p-value)

 Protein score (n = 362)                   -.012 (.823)

 Grain score (n = 364)                     .055 (.295)

 Vegetable score (n = 363)                 -.015 (.770)

 Fruit score (n = 363)                     .111 (.034)

 Beverage score (n = 364)                  .056 (.285)

 Snack score (n = 363)                     .096 (.068)

 Unsweetened milk score (n = 362)          .076 (.150)

 Sweetened milk score (n = 365)            .146 (.005)

 Unhealthy food score (n = 363)            .109 (.039)

 Healthy food score (n = 360)              .044 (.403)



       Spearman correlations of food intake-related scores with DMFT score are

given in table 27. This table consisted two parts. The first part listed 8 separate food

groups in association with DMFT score and second part looked at the association

between DMFT score and the group of unhealthy foods, which include beverage,

snack and sweetened milk, and between DMFT score and healthy foods, which

include the rest of 31 foods listed in the survey. Protein and vegetables were

negatively correlated with DMFT score and these correlations were not significant. 5

of 8 food groups were positively correlated with DMFT score in which fruit, which

was treated as healthy food but showed significant positive correlation (p-value =

.034), sweetened milk showed highly significant correlation (p-value = .005). Snack

score was almost significant with p-value = .068. The overall score for unhealthy
                                                                                62

foods was positively and significantly correlated with DMFT score (=0.039). The

healthy food score was not significantly correlated with DMFT score.

       Then we used DMFT category to further assess the relationship between this

measurement and food intake and we found that only sweetened milk and unhealthy

food showed the significant association with DMFT category, p-value = 0.011 and

0.03, respectively (table 28). Other food groups were not significant at all.
                                                                         63

Table 28: Relationship between DMFT category and food intake variables

DMFT category                 N       Mean Rank Mann-Whitney Z (p-value)
Protein score                                       -.069 (.945)
(n = 362)         DMFT = 0    107     182.07
                  DMFT > 0    255     181.26
Grain score                                         -1.352 (.176)
(n = 364)         DMFT = 0    107     171.29
                  DMFT > 0    257     187.17
Vegetable score                                     -.299 (.765)
(n = 363)         DMFT = 0    107     184.52
                  DMFT > 0    256     180.95
Fruit score                                         -1.632 (.103)
(n = 363)         DMFT = 0    107     168.23
                  DMFT > 0    256     187.76
Beverage score                                      -1.391 (.164)
( n = 364)        DMFT = 0    108     171.06
                  DMFT > 0    256     187.33
Snack score                                         -1.910 (.056)
(n = 363)         DMFT = 0    107     165.93
                  DMFT > 0    256     188.71
Unsweetened milk score                              -943 (.346)
(n = 365)         DMFT = 0    107     174.85
                  DMFT > 0    255     189.29
Sweetened milk score                                -2.531 (.011)
(n = 362)         DMFT = 0    108     163.53
                  DMFT > 0    257     191.18
Unhealthy food score                                -2.168 (.030)
(n = 363)         DMFT = 0    107     163.63
                  DMFT > 0    256     189.68
Healthy food score                                  -.790 (.430)
(n = 360)         DMFT = 0    106     173.80
                  DMFT > 0    254     183.30
                                                                                  64




Table 29: Relationship between DMFT category and unhealthy foods

  Food items                              DMFT category            Chi-square

                                          DMFT = 0 DMFT > 1 (p-value)

  Snacks           often                  6 (14.6)    35 (85.4)    5.705 (.058)

                   sometimes              39 (28.9)   96 (71.1)

                   never or rarely used   63 (33.3)   126 (66.7)

  Cake             often                  6 (28.6)    15 (71.4)    .748 (.688)

                   sometimes              27 (26.2)   76 (73.8)

                   never or rarely used   74 (30.8)   166 (69.2)

  Candy            often                  8 (21.6)    29 (78.4)    1.206 (.547)

                   sometimes              50 (30.5)   114 (69.5)

                   never or rarely used   49 (30.1)   114 (69.9)

  Chocolate        often                  3 (23.1)    10 (76.9)    6.695 (.035)

                   sometimes              18 (19.4)   75 (80.6)

                   never or rarely used   86 (33.3)   172 (66.7)

  Gel              often                  7 (43.8)    9 (56.3)     11.788(.003)

                   sometimes              17 (16.7)   85 (83.3)

                   never or rarely used   83 (33.7)   163 (66.3)

  Sweetened milk often                    7 (19.4)    29 (80.6)    6.424 (.040)

                   sometimes              41 (25.3)   121 (74.7)

                   never or rarely used   60 (35.9)   107 (64.1)
                                                                               65

        Among unhealthy foods, the trend that the more frequent intake, the higher

prevalence of non-zero DMFT score could be seen in snacks, chocolate and

sweetened milk. Chocolate and sweetened milk revealed significant association with

DMFT category. Snacks revealed marginal significance. In 5 of 6 unhealthy food

items, DMFT prevalence went in the way that “sometimes” user had equal or a little

bit higher prevalence of non-zero DMFT score in comparison with “often” user but

had marked higher prevalence of non-zero DMFT score than “never or rarely” user

(table 29).
                                                                                  66

Table 30: Relationship between brushing behavior and snacks consumption

                                                      Mean         Mann-Whitney
                                            N         Rank         Z (p-value)
  Brushing frequency per day (n = 362)

                 once or less                    59       204.02      -1.829(.067)

                 twice or more                  303       177.12

 Ever forgot to brush (n = 351)

                 Ever                            12       188.58       -.443(.658)

                 Never                          339       175.55

 Brushing, no regular schedule (n = 362)

                 no                             337       180.57       -.626 (.531)

                 yes                             25       193.98

 Brushing after getting up (n = 362)

                 no                              73       186.74       -.485(.628)

                 yes                            289       180.18

 Brushing before going to bed (n = 362)

                 no                              99       194.03      -1.415(.157)

                 yes                            263       176.78



       Even there was not any brushing behavior significantly associated with snacks

consumption, there was still a trend that snacks consumption was higher among those

who brushed their teeth less than twice per day, who had ever forgot to brush for 7

days, who had no regular brushing schedule. The consumption level was lower among
                                                                                67

those who usually brushed after getting up and those who usually brushed before

going to bed (table 30).


3. Relationship between perception of oral problems and DMFT score


Table 31: Relationship between perception of oral health problems and DMFT score

          (DMFT is considered as outcome)

Oral Health Problems           Frequency (%) of DMFT            Chi-square
                               DMFT = 0       DMFT > 0            p-value
Pain                 Never     35 (35.7)      63 (64.3)
                                                              2.877 (.090)
(n=354)              Ever      68 (26.6)      188 (73.4)

Chewing              Never     62 (30.8)      139 (69.2)
                                                              .568 (.451)
(n=352)              Ever      41 (27.2)      110 (72.8)

Smiling              Never     79 (28.7)      196 (71.3)
                                                              .635 (.426)
(n=356)              Ever      27 (33.3)      54 (66.7)

Communication        Never     86 (28.9)      212 (71.1)
                                                              .334 (.563)
(n=353)              Ever      18 (32.7)      37 (67.3)

Color                Never     62 (29.5)      148 (70.5)
                                                              .005 (.942)
(n=354)              Ever      42 (29.2)      102 (70.8)

Tooth damage         Never     76 (38.2)      123 (61.8)
                                                              17.299 (< 0.01)
(n=355)              Ever      28 (17.9)      128 (82.1)

Odor                 Never     66 (29.9)      155 (70.1)
                                                              .067 (.796)
(n=354)              Ever      38 (28.6)      95 (71.4)

School absence       Never     101 (30.4)     231 (69.6)
                                                              2.036 (.154)
(n=356)              Ever      4 (16.7)       20 (83.3)
                                                                                      68

Table 32: Relationship between perception of oral health problems and DMFT score

           (Oral health problems are considered as outcomes)

  Oral Health Problems               Frequency (%) of Problems          Chi-square
                                     Never             Ever               p-value
  Pain                DMFT = 0       35 (34.0)         68 (66.0)
                                                                       2.877 (.090)
  (n=354)             DMFT > 0       63 (25.1)         188 (74.9)

  Chewing             DMFT = 0       62 (60.2)         41 (39.8)
                                                                       .568 (.451)
  (n=352)             DMFT > 0       139 (55.8)        110 (44.2)

  Smiling             DMFT = 0       79 (74.5)         27 (25.5)
                                                                       .635 (.426)
  (n=356)             DMFT > 0       196 (78.4)        54 (21.6)

  Communication       DMFT = 0       86 (82.7)         18 (17.3)
                                                                       .334 (.563)
  (n=353)             DMFT > 0       212 (85.1)        37 (14.9)

  Color               DMFT = 0       62 (59.6)         42 (40.4)
                                                                       .005 (.942)
  (n=354)             DMFT > 0       148 (59.2)        102 (40.8)

  Tooth damage        DMFT = 0       76 (73.1)         28 (26.9)       17.299 (<

  (n=355)             DMFT > 0       123 (49.0)        128 (51.0)      0.01)

  Odor                DMFT = 0       66 (63.5)         38 (36.5)
                                                                       .067 (.796)
  (n=354)             DMFT > 0       155 (62.0)        95 (38.0)

  School absence      DMFT = 0       101 (96.2)        4 (3.8)
                                                                       2.036 (.154)
  (n=356)             DMFT > 0       231 (92.0)        20 (8.0)



         Relationships between perceived dental health-related problems and dental

caries are presented in tables 31 and 32. Time relationships between these variables

are not clear, that is, it is not clear whether occurrence of dental caries preceded the
                                                                                    69

perceived problems or vice versa. Therefore, in data analysis the researcher

considered both possibilities. Table 31 shows the relationships between dental caries

and perception of oral health problems as though the problems preceded the caries

(caries considered to be the dependent variable). In this table, except smiling and

communication, others problems show the higher prevalence of non-zero DMFT

when the problems were reported (shown in bold). Inversely, table 32 shows the same

relationship but perception of oral health problems were considered as dependent

variables. However, in this case, the similar results were repeated. Except smiling and

communication, the higher prevalence of problems reported in non-zero DMFT group

comparing with the lower prevalence of problems reported in zero DMFT group

(shown in bold). Highly significant and marginally significant associations can be

seen between dental caries and perceived tooth damage and pain, respectively. For

each specific perceived problem, the strength of association with dental caries, as

measured by the X2 statistic and the corresponding p-value, was the same in tables 31

and 32.
                                  CHAPTER V

   DISSCUSION, CONCLUSION, AND RECOMMENDATIONS


1. Discussion

       In this study, the findings were presented in 5 aspects which need to be further

discussed. Those are:

       − Social-demographic characteristics and dental status of respondents

       − Oral hygiene behavior

       − Fluoride supplement

       − Eating habits

       − Perception of dental health problems

  1.1 Social-demographic characteristics and dental status of respondents

       Under the main purpose of determining the prevalence and risk factors of

dental caries in Thaibinh medical students, a population based cross-sectional study

on a sample of 365 first year and second year medical students of Thaibinh Medical

University was conducted. The prevalence of dental caries found by 70.4% almost

equal to dental caries prevalence among 18-year-old males from Florianopolis, Santa

Catarina, Brazil in 2003 (Bastos et al., 2005) and was lower than the prevalence

among 18-34 year old people living in Red river delta, the area most subjects of my

study came from, reported by the Nationwide Oral Health Survey 1999-2001 in

Vietnam, which was 89.9%. This result is also consistent with the findings of Seibert

in African-American youth and adults (Seibert et al., 2004). The lower prevalence of

the study can be explained that over duration of 9 year from 1999 to 2008, the
                                                                                      71

development of social, economic resulted in improved quality of life made people

might concern more about their dental health as well as the improvement of dental

health care by non-government organization and government health care system and

the popular of dental health communication by mass media. Furthermore, the study

emphasized that medical students might be much more concern about health than

other group at the same age, such as farmers, economics students, constructive

students, etc because they had sense of their future work being a model of healthy

behavior and healthy life for population.

       However DMFT of my population is 2.28, nearly double that of 18-34 year

old Red river delta residents established by the Nationwide Oral Health Survey

(DMFT = 1.54) but it is a little bit lower than mean DMFT index of 18-year-old

Brazilian males (Amaral et al., 2005; Bastos et al., 2005). It was about three times

lower than mean DMFT of young Israeli adults which was 6.77 (Levin, 2004). If we

look at detail of each components of DMFT, we see that mean of DT component

which was 2.16 is much higher than this figure of Nationwide Oral Health Survey

(mean dt of the survey = 1.15) and is higher than this among young Brazilian males

(mean DT = 1.8) (Bastos et al., 2005). Meanwhile, means of FT components of these

students population, which is 0.05, is much lower in comparison with National Survey

(DT = 0.22) and Bastos’ study (DT = 1.2) (Bastos et al., 2005) as well as Levin’s

findings among young Israeli adults (Levin, 2004). It means that in the population of

medical students, a predominant group of these students had healthy dental status but

in other smaller group, they were suffering very poor dental health with many

untreated cavities (active caries) on their teeth. The noticeable low mean of 0.05 filled

teeth strongly said that dental treatment in those who had dental caries was poor.
                                                                                      72

        Association between general characteristic and DMFT pointed out that DMFT

was significant higher in second year students and in older age group even this survey

involved only two academic levels. It raises a question that whether there is a fast

development of dental caries at the beginning of student life among these medical

students or not. Say in other words, whether student’s life in university develops

dental caries or not. To answer this question, a longitudinal study which follows

students from the beginning to the end of their course in university is necessary. The

association between dental caries and subjects’ age and subjects’ sex indicated in this

study is consistent with the finding of author Pitayarangsarit (Pitayarangsarit, 1996).

In relation to socioeconomic level, a tendency for worse dental health to be associated

with higher socioeconomic status could be seen in this population. The higher

prevalence of caries can be seen among students whose mothers’ and fathers’ job

were well-paid or whose parent were high educated (table 21). Even so, most

associations between socioeconomic indicators and students' dental health were not

statistically significant.

  1.2 Oral hygiene practices

        Healthy oral hygiene practice in terms of brushing, frequency of brushing and

time of brushing revealed the marked high proportion. 100 percent of sample brushed

their teeth every day and more than 80 percent of them brushed twice a day or more.

Additionally, the similarly high proportion can be seen in behavior of brushing after

getting up and brushing before going to bed. However, the results showed that there

was no association between daily frequency of brushing and DMFT (p-value = .951)

as well as between frequency of changing toothbrush and DMFT (p-value = .736). On

the other hand, statistical test revealed the significant association between brushing
                                                                                     73

time and DMFT in terms of brush after getting up with p-value = 0.027. Furthermore,

among students who had no regular brushing schedule, DMFT was significant higher

than DMFT among those who brushed their teeth regularly. It takes us to a thought

that only brushing twice per day and changing toothbrush every 3 months or 6 months

does not help much to prevent dental caries. Time of brushing appears more likely to

protect teeth from cavity, especially brushing after getting up. Besides, methods of

brushing, which was not measured in this study might have some impacts on dental

caries protection. Therefore, recommendation for further study is that it should look at

the all sides of brushing behavior: frequency, time and method so it can give the

whole picture of influence of brushing behavior on dental caries.

  1.3 Fluoride supplement

       The findings pointed out that DMFT in “ever used any type of fluoride” group

was higher than in “never used” group. The association went in the same way when

we looked at individual supplements of fluoride. It is widely accepted that fluoride

need time to affect on teeth. Subjects with a lifetime exposure to fluoridated water had

lower dental caries experience than subjects with no exposure to fluoride had been

documented by many researches (Hopcraft & Morgan, 2003). In this study, fluoride

use was generally short-term, not long-term. Most students had ever used fluoride

stopped using now. As stated in the literature review that until now there are only 2

provinces in Vietnam using fluoridate drinking water and none of the study’s subjects

came from these provinces. Otherwise, in Vietnam market, all adult toothpaste is

fluoridated. Thus, it can be concluded with confidence that all subjects were exposed

to fluoride in toothpaste. This might have confounded the observed relationships

between fluoride supplements and dental caries experience in the present study.
                                                                                   74

       Three type of fluoride listed in the study was not popular in the market.

Fluoride mouth rinse was provided freely in some schools where performing school

dental care program. Other fluoride supplements such as fluoride gel, fluoride table,

fluoride vitamin were available in supermarkets or drugstores in big city but not

available in small provinces where most subjects came from. Therefore, it was not

easy for poor people even to know about such products. People who had good social

economic status were more affordable and more comfortable to assess these kinds of

fluoridated products. This point can be reasonable explained by the finding presented

in table 25 and 26.

  1.4 Eating habits

       Grain was the food most frequently consumed in medical students. The most

frequent grain consumed was rice. This is because rice was very popular in Vietnam

and in Vietnamese eating manner; rice is the main source of providing calories in

Vietnamese meal. In terms of nutrition, these medical students have good eating habit

because in the top most consumed food list, grain is in the top, followed by protein

foods such as pork, egg, fish, and tofu. Vegetable and fruit also were consumed more

frequently than beverages and other highly concentrated sugar foods. Sugary food has

been documented as a high risk factor for dental caries by a huge of researches

(Lingstrom, 2006). Snacks, candy, cake, chocolate, gel, sweetened milk are popular

food with high concentration of sugar, consumed by youths. Even so, these foods

were not frequent foods consumed by studied subjects but in relationship with caries

experience, many of these foods showed the significances. They were gel, chocolate

sweetened milk with p-value < 0.05. For snack, the relationship with caries

experience also is almost significant with p-value = .058. Our results were consistent
                                                                                    75

with the findings of the other Vietnamese authors on association between sugary

foods and dental caries (Le, 2002).

       In 4 over 6 unhealthy food items, DMFT went in the way that DMFT of

“sometimes” user is equal or a little bit higher DMFT of “often” user but marked

higher than this in “never or rarely” user. These foods are very high content of sugar

and sticky foods. It could come and leave in teeth surface if the takers did not clean

their teeth well after eating. This theoretical point was confirmed by the result shown

in table 30 that students consumed more snacks performed poorer brushing behavior

meanwhile students consumed less snacks performed better brushing behavior.

Sweetened milk stood second in the list of frequency of unhealthy food intake and had

significant association with dental caries meanwhile unsweetened milk was less

consumed and revealed no significant relationship with dental caries. This statement

could be seen in many dental related studies in children (Bui, 2006; Le, 2002).

  1.5 Perception of dental health problems

       Dental pain is the most common symptom of oral problem. The prevalence of

students who had had was 15.3%. Similar results were found in Toronto, Canada,

with the prevalence reported in the previous four weeks was 18.0% among 14-20-year

old male and female (Clarke et al., 1996). Another survey showed 21.2% of dental

pain prevalence for young male adults from southern Brazil (Bastos et al., 2005).

However, in this study pain did not showed significant association with dental caries

experience. It is might be pain symptom was asked in terms of perception of subject

and they may not notice mild cavity which causes as not much pain as moderate or

severe cavity and can be ignored. Dental health related school absence also revealed

significant association with dental caries.
                                                                                      76

       Most dental problems considered were related to social life of individuals.

Trouble with smiling, tooth color change, bad odor can make people feel unconfident

about their appearance and can limit their social activities. Pains, chewing problem or

tooth damage are not only physical dysfunction but also obstruct social daily

activities. If people suffer it for long time, they can be lead to stress or even

depression. Hence, the tendency for prevalence of dental caries to be higher when

problem was reported mentioned to the thing that dental caries might not only

influence on physical health but also influence on mental health. Therefore, assessing

dental caries treatment needs to early prevention dental caries from getting worse in

this population is recommended.

  1.6 Scope and limitation

       A sufficiently large sample size and the probability sampling design can

assure good representativeness of the study sample, and reasonable generalizability of

study findings. However, the study also revealed some limitations. Firstly, missing

data can be seen in some variables. Secondly, the statistical analysis did not involve

multivariable techniques such as logistic regression, linear regression. Thus, it was not

able to fully test the relative importance of independent variables as well as fully

identify confounding among these variables. Thirdly, a cross-sectional study design

cannot give thoroughly explain the dental caries status (DMFT) because of

cumulative characteristics of dental caries. Even so, epidemiologic data of dental

caries still use DMFT and cross-sectional survey still is acceptable to define the dental

caries status in population because of feasibility of finance and gathering sample.

       The study limited in medical students in Thaibinh Medical University in first

and second academic year, therefore the results cannot be applied to all students in the
                                                                                    77

university as well as to medical students in Vietnam. Nevertheless, the results of this

study are expected to be useful as baseline data in planning dental caries education

and prevention program for medical students.


2. Conclusion

       The population based cross-sectional analytical study involved 365

participants. Data analysis included two components: descriptive data and analytical

data. For data description, these techniques were used: frequency, percentage, means,

and standard deviation. To assess association between dependent and independent

variables, the following statistical test were used: Chi-square tests, Spearman’s

correlation coefficients, Manwhitney tests and Krusal-Walis tests.

       The research found that the prevalence of dental caries (DMFT ≥ 1) was 70.4

and the mean DMFT was 2.28 ± 2.18. Mean filled teeth marked low (only 0.005 ±

0.46). There were limited proportion of ever visiting dentist (56.7%) and the very

small proportion of visiting for dental checkup (13.5%). All the students brushed their

teeth everyday in which almost students brushed teeth twice or more twice a day

(83.5%). There were just above 50% of participants had ever used one type of fluoride

supplement, not included fluoridated toothpaste, and 53.6% stopped using now. No

significant association could be found between dental caries and fluoride

supplements. The study revealed good eating habit among this population with most

frequent food intake was healthy food. Significant associations were found between

dental caries experience and unhealthy foods, especially sweetened milk, gel and

chocolate. Perception on oral health problem in terms of pain, chewing, bad odor,

tooth damage, tooth color, smiling, communication, and school absence were 57.1%,
                                                                                      78

35.5%, 17.2%, 9.9%, 9.3%, 6.5% and 4.5% respectively. Significant association was

found between tooth damage and dental caries experience.


3. Recommendation

  3.1 For policy

       Base on findings of this study, the following policies are recommended:

       1. Organize educational programs for early prevention dental caries. The

           concept of education should focus on brushing practice, especially

           frequency and time of brushing. The program also should focus on

           knowledge of using fluoride supplement such as the supplement should be

           long-term, as well as focus on healthy eating habit, such as cut down

           unhealthy food in diet. Besides, the program also should communicate to

           the population the necessary of regular dental check-up.

       2. Open primary care dental office in campus so that students can easily

           assess dental service and get consultancies as well as basis treatments.

           Encouraging students take their dental check-up and dental treatment in

           public and private odonto-clinics.

  3.2 For further study

       A comprehensive study on students with many backgrounds, not only medical

students should be conducted to see the whole picture of dental status and dental

caries risk in this important population. Further research is also needed to characterize

time relationships between dental problems as perceived by subjects and dental caries

as measured externally.
                                                                                        79


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       Vehashinayim. 24(3), 12-16, 53-54.
                                                                                82

Strauss, R. S. (2001). Environmental Tobacco Smoke and Serum Vitamin C Levels in

       Children. Pediatrics. 107(30), 540-542.

Thean, H., Wong, M. L., & Koh, H. (2007). The dental awareness of nursing home

       staff in Singapore - a pilot study. Gerodontology. 24(1), 58-63.

Thylstrup, A. & Fejerskov, O. Textbook of clinical cariology. (Eds.). (1994).

       Copenhagen, Munksgaard.

Tran, V. T., Lam, N.A., Trinh, D.H. (2002). Nationwide Oral Health Survey. Hanoi.

       Vietnam Medical Publishing.

Tribble, D. L., Giuliano, L. J., & Fortmann, S. P. (1993). Reduced plasma ascorbic

       acid concentrations in nonsmokers regularly exposed to environmental

       tobacco smoke. Am J Clin Nutr. 58(6), 886-890.

Vehkalahti, M. M., & Paunio, I. K. (1988). Occurrence of root caries in relation to

       dental health behavior. J Dent Res. 67(6), 911-914.

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       Geneva. WHO.

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       use of fluoride among Indiana dental professionals. J Public Health Dent.

       67(3), 140-147.
APENDICES
                                                                                     84


                                     APPENDIX A

                      EXAMINATION FORM (English Version)

Form code: _____________

Date: ______/____/___(Day/Month/Year)

Examiner: __________________________________

   A. Subject information:

                       1. Name: ________________________

                       2. Gender:        . Male           . Female

                       3. Date of birth: _____/_____/______(Day/Month/Year)

   B. Dental status

 18 17      16   15      14   13    12   11   21     22   23   24    25   26   27   28




 48 47      46   45      44   43    42   41   31     32   33   34    35   36   37   38



Code for dental status

0 = Sound                                     5 = Missing any other reason

1 = Decayed                                   6 = Fissure sealant

2 = Filled and decay                          7 = Bridge abutment

3 = Filled without decay                      8 = Unerupted tooth, (crown)/unexposed

4 = Missing as a result of caries             root

                                              9 = Not recorded
                                                                                    85

The wisdom teeth are invisible because of:

                         Unerupted        Extracted as a          Extracted for other

                                          result of caries             reasons

       Tooth 18

       Tooth 28

       Tooth 38

       Tooth 48



        DENTAL CARIES RELATED FACTORS QUESTIONNAIRE

Form code: _______

Date : ______/____/___(DD/MM/YY)

   A. Subject information:

       1. Name: _______________________

       2. Year:                        . First year          . Second year

       3. Gender:                      . Male          . Female

       4. Date of birth: _____/_____/______( DD/MM/YY)

       5. Province student comes from:

              1. Thai Binh            4. Ninh Binh                    7. Nghe An

              2. Ha Nam               5. Ha Tay                       8. Ha Tinh

              3. Nam Đinh             6. Thanh Hoa                    9. Others

       5. Residence before amitted to university is:

                             1. City or town

                             2. Rural area
                                                                            86

   6. Current residence while at university:

                         1. Dormitory on campus

                         2. Outside the campus

B. Social-economic status:

   B1. Mother’s occupation:

   1. Government employee              5. Housewife

   2. Teacher                          6. Private business

   3. General worker                   7. Other (specify)

   4. Farmer                      ________________________

   B2. Father’s occupation:

   1. Government employee               5. Fisherman

   2. Teacher                            6. Soldier

   3. General worker                     7. Private business

   4. Farmer                             8. Others (specify) _________________

   B3. Mother’s education:

   1. Cannot read or write              4. High school

   2. Primary school                    5. Occupation training

   3. Secondary school                   6. Undergraduated, postgraduated


   B4. Father’s education:

   1. Cannot read or write              4. High school

   2. Primary school                    5. Occupation training

   3. Secondary school                   6. Undergraduated, postgraduated
                                                                           87

   B6. Your monthly expenditure: ………………… (thousand VND)

   B7. Do you think that amount of money is enough for you?

                 1. Yes

                 2. No

C. Oral hygiene practice:

   1. Do you brush your teeth?

                 1. Yes

                 2. No (skip to C7)

   2. How often do you brush your teeth?

                          1. Not everyday

                          2. Once everyday

                          3. Twice everyday

                          4. More than twice everyday

   3. How often do you change your toothbrush?

                          1. Once 3 month

                          2. Once 6 month

                          3. Only when it breaks or wears out

   4. Have you ever forgotten to brush your teeth in previous of 7 days?

                 1. Never

                 2. One time

                 3. Two times

                 4. More than two times
                                                                  88

5. When do you brush your teeth? (You may check more than one)

              1. Not fixed

              2. After getting up

              3. After breakfast

              4. Before going to bed

6. Do you use toothpaste to brush your teeth?

               1. Yes

               2. No

7. Have you ever gone to the dentist?

               1. Yes

               2. No (skip to D1.1)

               3. Do not remember (skip D1.1)

8. When the most recent you visit to dentist?

               1. 6 months or less

               2. More than 6 months up to one year

               3. More than 1 year up to two years

               4. More than 2 years

9. Why did you go to the dentist? (You may check more than one)

               1. Check up

               2. Extraction

               3. Filling

               4. Scaling

               5. Gum bleeding

               6. Dental pain
                                                            89

                 7. Other (please specify)……………………………………

                 8. Do not remember.

D. Fluoride supplement

   D1. Fluoride mouth rinse

   1. Have you ever used fluoride mouth rinse?

                 1. Yes

                 2. No (skip to D2.1)

                 3. Don’t remember

   2. Are you using now?

                 1. Yes

                 2. No

   3. How long have you been using?

                 1. Six month or less

                 2. More than 6 months up to one year

                 3. More than one year up to two years

                 4. More than two years

   4. Who provided to you?

                 1. Dentist

                 2. You bought from drug store

                 3. Others (please specify)……………………………………

   D2. Fluoride gel

   1. Have you ever used Fluoride gel?

                 1. Yes

                 2. No (skip to D3.1)
                                                        90

              3. Don’t remember

2. Are you using now?

              1. Yes

              2. No

3. How long have you been using?

              1. Six month or less

              2. More than 6 months up to one year

              3. More than one year up to two years

              4. More than two years

4. Who provided to you?

              1. Dentist

              2. You bought from drug store

              3. Others (please specify)…………………………………….

D3. Any other source of fluoride

1. Have you ever used fluoride from any other source?

              1. Yes

              2. No (skip to E.1)

              3. Don’t remember

2. Are you using now?

              1. Yes

              2. No

3. How long have you been using?

              1. Six month or less

              2. More than 6 months up to one year
                                                                                                             91

                              3. More than one year up to two years

                              4. More than two years

          4. Who provided to you?

                              1. Dentist

                              2. You bought from drug store

                              3. Others (please specify)……………………………………

   E. Tobacco use

   E1. Do you smoke?

                              1. Yes (skip to E4)

                              2. Already given up (skip to E2)

                              3. No (skip to E6)

   E2. You used to smoke from ………….to…………...

   E3. How many cigarettes per day did you use to smoke at that time? ………. (skip

to E6)

   E4. How long have you been smoking? ………years………months

   E5. What is the average number of cigarettes you smoke per day? ……………

   E6. How much time per day do you spend in the presence of other people who

   smoke?

         (Please specify)..……………..............................................................................
                                                                              92


   Eating habits.

   How often do you eat each of the following foods?

                                                                      Often
                                       Never or        Sometimes
                                                                    (more than
                 Food                  rarely (0-      (10-50% of
                                                                     50% of
                                     10% of days)        days)
                                                                      days)
F1. Protein
F1.1   Beef
F1.2   Pork
F1.3   Chicken
F1.4   Egg
F1.5   Tofu
F1.6   Fish
F2. Cereal and grain
F1.1   Rice
F2.2   Bread
F2.3   Noodles
F3. Vegetables
F3.1   Carrot
F3.2   Morning – glory
F3.3   Cabbage
F3.4   String bean
F3.5   Tomato
F3.6   Other vegetable
F4. Fruit
F4.1   Banana
F4.2   Watermelon
F4.3   Orange
F4.4   Pineapple
F4.5   Other fruit
                                                         93


F5. Beverages
F5.1   Soft carbonated drinks
       (coca, pepsi)
F5.2    Fruit juice (orange juice)
F5.3   Yoghurt drinks

F6. Snacks, cake, candy

F6.1   Snacks (bim bim)
F6.2   Cookies, crackers
F6.3   Cake
F6.4   Candy
F6.5   Chocolates
F6.6   Gel
F7. Milk
F7.1   Sweetened milk
F7.2   Unsweetened milk



F8. Do you usually eat vegetables at the end of meals?

                       1. Yes

                       2. No
                                                                                        94


  G. Perceptions about dental health:

  Have you ever had a problem with your teeth for each of the items listed below? If so,

  do you have a problem now?

                                                    In the past              Now
                     Items
                                                  Yes       No         Yes         No
Pain
Chewing difficulty
Smiling
Communication/talking
Tooth color
Tooth damaged/broken
Bad odor
School absence because of tooth problems



                             Thank you so much for your cooperation!
                                                                                    95


                                    APPENDIX B

                   EXAMINATION FORM (Vietnamese version)

Mã phiếu: _____________

Ngày khám: ______/____/___ (Ngày/Tháng/Năm)

Người khám: __________________________________

     C. Thông tin chung:

                      1. Họ tên: ________________________

                      2. Giới:      . Nam         . Nữ

                      3. Ngày tháng năm sinh: ___/____/___ (Ngày/Tháng/Năm)

     D. Tình trạng sâu răng

18    17    16   15    14     13   12   11   21     22   23   24     25   26   27   28




48    47    46   45    44     43   42   41   31     32   33   34     35   36   37   38



     Mã tình trạng răng

0 = Răng lành                           5 = Mất răng vì lý do khác
1 = Sâu răng nguyên phát                6 = Trám bít rãnh
2 = Răng đã trám có sâu lại             7 = Trụ cầu, cầu đặc biệt hoặc veneer/implant
3 = Răng đã trám không có sâu lại       8 = Răng chưa mọc
4 = Mất răng do sâu răng                T = Chấn thương
                                        9 = Không ghi nhận được (vì đeo hàm nắn,
                                        hoặc nhiều cao răng….)
                                                                               96


Răng khôn không quan sát được là do

                       Chưa mọc       Đã nhổ do sâu răng    Đã nhổ do nguyên
                                                               nhân khác
     Răng 18
      Răng 28
      Răng 38
      Răng 48



                 QUESTIONNAIRE FORM (Vietnamese verion)

Mã phiếu: _______

Ngày điều tra: ______/____/___(ngày/tháng/năm)

   E. Thông tin chung:

      1. Tên: _______________________

      2. Khối:                        . Y1           . Y2

      3. Giới:                        . Nam          . Nữ

      4. Ngày sinh: _____/_____/______( ngày/tháng/năm)

      5. Bạn đến từ tỉnh:

             1. Thai Binh             4. Ninh Binh              7. Nghe An

             2. Ha Nam                5. Ha Tay                 8. Ha Tinh

             3. Nam Đinh              6. Thanh Hoa              9. Others

      6. Hiện tại bạn ở:

                            1. Trong ký túc xá

                            2. Ngoài ký túc xá

   F. Tình trạng kinh tế xã hội:

      B1. Nghề nghiệp của mẹ:
                                                                           97

   1. Viên chức nhà nước              5. Nội trợ
   2. Giáo viên                        6. Kinh doanh
   3. Công nhân                        7. Khác (ghi rõ) _____________________
   4. Nông dân



   B2. Nghề nghiệp bố:

   1. Viên chức nhà nước             5. Ngư dân
   2. Giáo viên                      6. Bộ đội
   3. Công nhân                      7. Kinh doanh
   4. Nông dân                       8. Khác (ghi rõ) __________________
   B3. Trình độ của mẹ:

   1. Mù chữ                         4. Trung học phổ thông (Cấp III)
   2. Tiểu học (Cấp I)               5. Trung cấp/ học nghề
   3. Trung học cơ sở (Cấp II)        6. Cao đẳng, đại học, sau đại học


   B4. :Trình độ của bố

    1. Mù chữ                         4. Trung học phổ thông (Cấp III)
    2. Tiểu học (Cấp I)               5. Trung cấp/ học nghề
    3. Trung học cơ sở (Cấp II)       6. Cao đẳng, đại học, sau đại học



   B6. Hàng tháng bạn tiêu: …………………(Nghìn đồng)

   B7. Số tiền đó có đủ cho nhu cầu của bạn không?

                  1. Có

                  2. Không

G. Thực hành vệ sinh răng miệng:

   10. Bạn có chải răng hàng ngày không?

                  1. Có
                                                                             98

              2. Không (chuyển câu C7)

11. Bạn chải răng:

                       1. Ngày chải ngày không

                       2. Mỗi ngày một lần

                       3. Mỗi ngày hai lần

                       4. Mỗi ngày trên hai lần

12. Bạn thường thay bàn chải mới:

                       1. Ba tháng một lần

                       2. Sáu tháng một lần

                       3. Khi bị gãy hoặc quá mòn



13. Đã bao giờ bạn quên chải răng trong khoảng thời gian từ 7 ngày trở lên

   chưa?

              1. Chưa bao giờ

              2. Đã từng một lần

              3. Đã từng hai lần

              4. Đã từng trên hai lần

14. Bạn thường chải răng khi nào? (Có thể lựa chọn nhiều câu trả lời)

              1. Không cố định

              2. Sau khi ngủ dậy

              3. Sau khi ăn sáng

              4. Trước khi đi ngủ

15. Bạn có dùng kem đánh răng khi chải răng không

               1. Có
                                                                       99

                  2. Không

   16. Bạn đã bao giờ đi khám nha sĩ chưa?

                  1. Đã từng

                  2. Chưa bao giờ ( chuyển câu D1.1)

                  3. Không nhớ (chuyển câu D1.1)

   17. Lần gần đây nhất bạn đi khám nha sĩ là:

                  1. Dưới 6 tháng

                  2. Trong khoảng 6 tháng đến một năm

                  3. Trong khoảng 1 đến 2 năm

                  4. Trên 2 năm

   18. Bạn đã đi khám nha sĩ vì: (có thể lựa chọn nhiều câu trả lời)

                  1. Kiểm tra định kỳ

                  2. Nhổ răng

                  3. Hàn răng

                  4. Cao răng

                  5. Chảy máu lợi

                  6. Đau răng

                  7. Lý do khác (ghi rõ lý do) …………………………………

                  8. Không nhớ.

H. Câu hỏi về bổ sung Fluoride

   D1. Nước súc miệng Fluoride.

   5. Bạn đã bao giờ sử dụng nước súc miệng có chứa Fluoride chưa?

                  1. Đã từng

                  2. Chưa bao giờ (chuyển câu D2.1)
                                                                100

               3. Không nhớ

6. Hiện bạn có đang dùng không?

              1. Có

               2. Không

7. Bạn đã dùng nước súc miệng đó được bao lâu rồi?

               1. Dưới 6 tháng

               2. Trong khoảng từ 6 tháng đến một năm

               3. Trong khoảng từ 1 năm đến hai năm

               4. Trên hai năm

8. Nước súc miệng đó là do: (có thể khoanh nhiều mã số)

               1. Nha sĩ bán cho bạn

               2. Bạn tự mua

               3. Nguồn cung cấp khác (ghi rõ nguồn cung cấp)……………



D2. Fluoride gel

1. Bạn đã bao giờ sử dụng gel Fluoride chưa?

               1. Đã từng

               2. Chưa bao giờ (chuyển câu D3.1)

               3. Không nhớ

2. Hiện bạn có đang dùng không?

               1. Có

               2. Không (chuyển câu D3.1)

3. Bạn đã dùng loại gel đó được bao lâu rồi?

               1. Dưới 6 tháng
                                                                         101

               2. Trong khoảng từ 6 tháng đến một năm

               3. Trong khoảng từ 1 năm đến hai năm

               4. Trên hai năm

4. Loại Fluoride đó là do: (có thể khoanh nhiều mã số)

               1. Nha sĩ bán cho bạn

               2. Bạn tự mua

               3. Nguồn cung cấp khác (ghi rõ nguồn cung cấp)……………

D3. Các nguồn bổ sung Fluoride khác

1. Bạn đã bao giờ bổ sung Fluoride bằng các nguồn khác (ví dụ Fluoride

   vitamin, viên Fluoride) chưa?

               1. Đã từng

               2. Chưa bao giờ (chuyển câu E.1)

               3. Không nhớ

2. Hiện bạn có đang dùng không?

               1. Có

               2. Không (chuyển câu E.1)

3. Bạn đã dùng loại gel đó được bao lâu rồi?

               1. Dưới 6 tháng

               2. Trong khoảng từ 6 tháng đến một năm

               3. Trong khoảng từ 1 năm đến hai năm

               4. Trên hai năm

4. Loại Fluoride đó là do: (có thể khoanh nhiều mã số)

               1. Nha sĩ bán cho bạn

               2. Bạn tự mua
                                                                                102

                       3. Nguồn cung cấp khác (ghi rõ nguồn cung cấp)……………

   E. Câu hỏi về phơi nhiễm với khói thuốc lá

   E1. Bạn có hút thuốc lá không?

                       1. Có (chuyển câu E4)

                       2. Đã từng nhưng hiện tại đã bỏ (chuyển câu E2)

                       3. Chưa bao giờ (chuyển câu E6)

   E2. Bạn đã hút thuốc được bao lâu rồi? (ghi rõ) ………năm…………tháng

   E3. Trung bình một ngày bạn hút bao nhiêu điếu? (ghi rõ)

   …………………………………………………………………...(chuyển câu E6)

   E4. Bạn đã hút thuốc được bao lâu? ………năm………tháng

   E5. Trung bình một ngày bạn hút bao nhiêu điếu? ……………

   E6. Khoảng bao nhiêu giờ mỗi ngày bạn phải tiếp xúc với khói thuốc lá từ người

   xung quanh (ghi rõ) ……………………………………………………………...

   F. Câu hỏi về thói quen ăn uống.

   Bạn có thường xuyên ăn/uống những thức ăn/uống sau không?

                                                            Thỉnh        Thường
                                         Hiếm khi ăn
                                                          thoảng ăn      xuyên ăn
                 Thức ăn                  (0 -10% số
                                                         (10 – 50%       (trên 50%
                                               ngày)
                                                          số ngày)       số ngày)

F1. Thịt và các thức ăn cung cấp

Protein

F1.1      Thịt bò

F1.2      Thịt lợn
                                    103


F1.3   Thịt gà

F1.4   Trứng

F1.5   Đậu phụ

F1.6   Cá

F2. Ngũ cốc và tinh bột

F2.1   Gạo (tẻ/nếp)

F2.2   Bánh mì

F2.3   Mì tôm

F3. Rau

F3.1   Cà rốt

F3.2   Rau muống

F3.3   Cải bắp

F3.4   Đậu tây (đậu đũa?)

F3.5   Khoai tây

F3.6   Các loại rau khác

F4. Hoa quả

F4.1   Chuối

F4.2   Dưa hấu

F4.3   Cam

F4.4   Dứa

F4.5   Các loại hoa quả khác

F5. Đồ uống

F5.1   Nước ngọt (coca, pepsi...)
                                                           104


F5.2   Nước hoa quả (sinh tố)

F5.3   Sữa chua

F6. Bánh kẹo

F6.1   Bim bim

F6.2   Bích quy, bánh quy giòn

F6.3   Bánh (bánh dẻo, bánh nướng)

F6.4   Kẹo

F6.5   Sô cô la

F6.6   Kẹo dẻo (kẹo chíp chíp)

F7. Sữa

F7.1   Sữa có đường

F7.2   Sữa không đường



F8. Bạn có thường xuyên ăn rau để kết thúc bữa ăn không?

                      1. Có

                      2. Không
                                                                               105


G. Các rắc rối liên quan đến bệnh răng miệng:

Bạn đã bao giờ gặp những rắc rối liên quan đến sức khỏe răng miệng được kể ra dưới

đây chưa? Nếu có, hiện tại bạn có gặp vấn đề đó không?

                                              Trước đây             Hiện tại
 Các rắc rối liên quan đến răng miệng
                                             Có      Không       Có       Không

Đau

Khó nhai


Ngại cười


Ngại giao tiếp

Màu sắc răng


Răng hỏng


Hơi thở hôi

Nghỉ học do các rắc rối của sâu răng gây

nên.




                      Cảm ơn bạn đã tham gia với chương trình.
                                                                                    106


                                           APPENDIX C

                                       SCHEDULE ACTIVITIES

                                November December January February March April  May
No Activities
                                1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4
1    Writing proposal
2    Submit first draft
3    Revise first draft
4    Submit for proposal exam
5    Proposal exam
6    Revise proposal
7    Pretest questionnaire
8    Revise questionnaire
     Conduct structured
9
     interview
10   Data management
11   Data analysis
12   Report writing
13   Submit for final defense
14   Thesis exam
15   Revision
     Submit as the final
16
     product
                                                                                                                      107


                                                  APPENDIX D

                                       ADMINISTRATION COST

   No                    Activities                         Unit             Price            Unit              Total

                                                                          (baht)            (number)           (Baht)

  1.       Pre-testing

           - Photocopy                                    Quest.         8              30                    240

           - Stationery                                   Set            300/set        1                     300

  2        Air fare : BKK - HCM - BKK                     Trip           7.000/tr       2 x Trip              14,000

  3        Data Collection

           - Photocopy                                    Quest.         0.5            8 x 100               400

           - Interviewers per diem                        Person         500/p/d        4 pr x 5 day          10,000

           - Examination per diem                         Person         500/p/d        8 pr x 4day           16,000

           - Data Processing                              Person         200/p          2 pr x 10day 4,000

  DATA COLLECTING PROCESS

  4        Document Printing

           - Paper + Printing                             Page          5/page          600 pages              3,000

           - Photocopy                                    Page          0.5/pag         10 x 300               1,500

           - Stationery                                   Set           300/set         1 set                  300

           - Binding Paper (exam)                         Set           100/set         5 set                  500

           - Binding Paper (submit)                       Set           200/set         5 set                  1,000

  THESIS DOCUMENT PROCESS                                                                                        6,300

  TOTAL                                                                                                        57,540

Note: a half of this expenditure will be provided by “Comlombo Plan-Thailand International Cooperation Agency” Scholarship.
                                                                          108


                      CURRICULUM VITAE

Name             : Ms. Pham Thi My Hanh

Date of Birth    : 11 July 1980

Place of Birth   : Vietnam

Address          : Thaibinh, Vietnam

Education        : Bachelor of Medicine, Thaibinh Medical University, Vietnam

                 (2005)

Current Office   : Department of       Epidemiology, Faculty of Public Health,

                 Thaibinh Medical University, Vietnam

				
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