HISTOLOGICAL AND HISTOCHEMICAL STUDY OF
PILOCARPINE AS SALIVARY GLAND RADIOPROTECTANT
AGENTIN RAT PAROTID GLAND
e;;e:tU bti ii",L:i) ",iI $ , & 4 iii M U Iii lac
",', a gilnY,1
*Aisha G.M. Areibi
Treatment oforal' dryness that usually accompany head and neck irradiation is a perplexing problem for
practitioner. Today. management of patients with dry mouth are ineffective or inadequate in addition to subjected
complaints. The patient with salivary gland dysfunction is susceptible to increase with caries. oral pain, frequent
infection. difficulty in !>lJe~king, chewing and swallowing. Pilocarpin is an alkaloid that was first isolated from south
American plant-of the genus pilocarpus in nineteen century. It junctions primarily as muscarcinic cholinergic agent
and has potent effect on hoth smooth muscle and exocrine tissues as salivary glands. Twentyfour albino rats (weighting
170 ± 10 gm each) were divide into three groups: Group 1 as control gpo Group 2 was exposed to head and neck
irradiation procedures. Group 3 received 24h prior to irradiation 5 mglkg pilocarpine nitrate intruperiotonelly for
three weeks. At the end ofthe experimental period all animals were scarified and the specimens ofparotid gland were
subjected to cryostat and paraffin sectionsfor demonstration ofacid phosphatase enzyme, Bromphenol blue and H & E
stains. The result revealed that Pilocarpine administration 24 h prior to irradiation protects the salivary glands from
the degenerative changes a/irradiation.
P ost irr.adiation damages in salivary glands playa very
important role in the development of radiation caries
and radiation xerostamia which is responsible for rampant
tissues among them lacrimal, salivary, gastric and
intestinal glands (Green Span and Daniel, 1979).
It has been demonstrated that in persons with
caries and subsequent early loss of teeth in irradiation normal salivary function low dosage of pilopcarpine
(Stein et al.. 1970). results in transient marked increase in salivary flow. In
Treatment of oral dryness that accompanies some studies the composition of pilocarpine stimulated
diminished salivary gland function is perplexing problem saliva was compared with the of saliva elicited by
for practitioner. Today, management of patients with. a gustatory stimulation with citrate. It was found to be
dry mouth is ineffective or inadequate (Mandel I-D and similar to submandibular secretions but somewhat
Wotmans., 1976). Osaki et al. (1977) irradiated the head different from parotid secretions (Dawes, 1980).
region of rats using cobalt 60 teletherapy machine with Mouchira Set al., (1984) used Thiola as radioprotectant
doses ranging between 400 and 2900 rads. They noticed agent for orodental structures. They found that salivary
sever degeneration of serous acini with pyknotic nuclei gland alveoli showed more degeneration without
and decreased chromatin. The cytoplasm was protection, while it still showed some degeneration with
disorganized, the interlobular duct also showed sever protection, but mostly remained with n0011al characters.
damage with disappearance of striations and granules and The ducts showed degeneration only in cases without
vasculation too, mucous cells and goblet cells did not protection.
show visible degeneration. The use of pilocarpine to treat salivary gland
A ttia Hassan and Salah El Din (1980) described hypofunction is not a noval idea. They recommended the
much similar post irradiation effect of 1000 and 2000 R use of drug stimulate parotid and whole salivary gland
on the salivary glands of mice, and reported that mucous function 24 hours after cessation of pilocarpin or placebo
accini are less affected by irradiation than serous accini. treatment (Philip et al., 1986).
The importance of saliva in maintenance of oral health Treatment prior to irradiation with cyilotidins or
and normal oral functions becomes apparent when pilocarpin led to salivary gland protection with no redox
salivary secretion is decreased due to irradiation, drugs or activity of iron and copper cons was detected recorded for
diseases involving the salivary gland tissues or the parotid and submandibular gland (Naglar, 1990).
neurosecretory functions. The taste activity is decreased, Xerostomia or oral dryness is one of the most
extensive progress of caries, periodontitis, dysfunction of common complaints experienced by patients who have
mastication, swallowing and speech may occur (Spielman radiotherapy of the oral cavity and neck region. The
et 01., 1981). hallmarks of radiation-induced damage are accinar
Pilocarpine is on alkaloid that was first isolated altraphy and chronic inflammation of salivary function.
from south American plants of the genus pilocorpus. It Oral administration of pilocarpin 5-10 mg three times day
functions primarily as a musicarinic-cholinergic agonists is effective in increasing salivary flow and improving the
and has potent effect on both smooth muscle and exocrine symptoms of xerostomia (Guchelear et al., 1994).
* Lecturer ofOral Biology Oral Blology Department, Facultv ofDental Medicine, GarY01mis University (Libya)
Pilocarpine certainly is not a treatment for all xerostomic B) Irradiated proup (Fig. 2)
patients, but persons must have some stimulated gland Some degenerative changes in the wall of the
functions with appropriate selection. However, pilocarpin accinar cells and some accini showed vaculations. while
is an effective, easily administrated and safe therapy for others appeared smaller size and widely spaced. The
the oral dryness that accompanies salivary gland intercalated ducts as well as striated ducts showed
hypo function (Yun~ionttoet ul.. 1995). dilatation with deeply stained irregularly arranged nuclei.
Comoarative observations of the effect of cholinereic and Trabecular fibrosis and inflammatorv cells were detected.
adreiergic agonists such as pilocarpine, phenylephyne and
isoproternal on the secretion of salivary fluid in Tokyo
Daruma frog were made by light and electron'microscope
.The effect of pilocarpine on loss of cytoplasm in both
lingual epithelium and lingual glands was The strongest
and that of isoproternal was the weakest (lnvusoki el of.,
AIM OF THE STUDY:
The present study was undertaken to determine the effect
of pilocarpine as parasympathetic drug on the structure of
salivary gland histologically and histochemically .
MATERIALS AND METHODS:
Twenty five albino rats (weighting 170 10 gm each) * Fig. (2): Photomicrograph of' salivary lobules o f rat parotid glands from
were divided into three groups: irradiated group showing histological alterations in thc accini and ducts.
Group I : 5 rats as control group. IlH 8;'E. O r ~ gMag. X 200).
Group 11: 10 rats were exposed to head and neck C) Protected group (Fig. 3)
irradiation procedure carried out with cobalt 60 therapy The lobules of the parotid gland were clearly
machine, with a single shot of I-750R. separated by empty spaces and the accini showed
Group 111: 10 rats received 24 hours pi-ior to shrinkage and boundaries were ill distinct but with notmal
irradiation exposure 5 mgfkg pi locarpinenitrate
itraperitoneally, weekly for three weeks. sta~rirng.
All animals were maintained under the same 'l'he nuclei showed normal basal sites and normal
laboratory conditions and they were fed standard diet arid staining. Few accini showed degeneration but mostly with
water at libitum. notmal characters.
.At the end of experimental period (three weeks)
all animals were scarified and the parotid glands were
excised and specimens were immediately frozen and
cryostat sections were prepared up to 10- 12 microns for
enzymatic demonstration of acid pllosphatase enzyme
The rest of parotid specimens were fixed in 10%
neutTa1 formal and paraffin sections 5 u were stained with
Flairs haematoxyline and eosin for general study and
Bromphenol blue for demonstration of total proteins.
I. Histo~atholo~ical Chanaes:
A) Controi eroue (Fig. 1). f:ig. 43): Photomicrograph o f salivary lobules of rat parotid glands frorn
Histological sections stained bv Haris rllc protected irradiated group showrng nearly normal histological
haematoxyline Fhowed normal lobulated serous gland fcnturcs. ( H & E. Orig. Mag. X 200).
with well defined accinar form and normal size cells. The
nuclei appeared deeply stained at the basal part of the 2. (Bromphenol Stain)
cells. The leumen was narrow and the intercalated duct as A) Control group (Fig. 4)
well as striated duct were seen normal with deeply stained There were Positive bromphenol blue reaction in
nuclei. No inflammatory cells were detected either both accinar and ductal cells and tilore intense the nuclei
between the accini or in the connective tissue trabecullae. which indicated Increase content of total proteins.
Fig. (4). Photomicmgraph o f salivary l o b u l e m t parotid glands from
Fig. ( I ) : Photomicrograph o f salivary lobules of rat parotid glands o f
thc contml group showing positive Brompllenol reaction. (Bromphcnol.
con11 group showing normal histological characters. (H & E. Orig.
Orrg May. X 300).
Fig. (7): Photorn~crograpli of salivary lobules of rat
B) Irradiated moue (Fig. 5) parotid glands from the control group showing cl :ak
TIie bromphenol blue reactions of the accini and enzyme activity. (Acid Phosphatase. Orig. Mag. X 3 0 I ) .
ducts were less than normal, with faintly blue staining due
B) Irradiated p r o u ~
to decreased amount of total proteins. The accinar boundaries. cytoplasm, nuclei show
intense enzyme reaction. There was no differentiation
Fig. (5): Photo~iiicrograph of salivaly lobules of rat
parotid glands from the irradiated group mild
Bromphenol. (Bromphenol. Orig. Mag. X 300). Fig. (8): Photomicrograph of salivary lobules of rat
parotid glands from irradiated group showin? strong
C) Protected prom (Fig. 6): enzyme activity. (Acid Phosphatase. Orig. Mag. X 300).
The accini, ducts, cell boundaries and nuclei
bromphenol reaction more than normal.
showed slro~ig C) Protected prom (Fig. 9):
Thc cnzyme reaction in the protected group was
mild in most accini and moderate in some few group. The
ducts cells showed negative reaction.
Fig. (6): Photomicrograph of salivary lobules of rat
parotid glands from the protected irradiated group
showing stlowing strong Bromphenol. (Bromphenol.
Orig. Mag. X 300).
Fig. (9): Photomicrograph of salivary lobules of rat
3. Acid Pltosplzntase Enzvme chanjies :
parotid glands from protected irradiated group showing
A) Control group (Fig. 7) ~iioderateenzyme activity. (Acid Phosphatase. Orig. Mag.
TIie serous accini of parotid gland showed mild
reaction from apical to basal end of the cells. while the
duct and connective tissue stronia showed negatlve
rraction. The need for a saliva substitute in patients with
salivary gland dysfunction has long been realized. Efforts
have been directed toward providing a solution wit11
content and viscosity similar to normal human whole
saliva, to be used especially in patients undergoing
Synthetic saliva solution containing fluorides has
been developed in an attempt to resist caries which is
common in these patients by increasing teeth
microhardness (Shannon et al. 1977 and Gravenniande et
Others agent have been used as salivary -
- - gland
radioprotectant as Brornhcxine Citric acid, TI~iola,
Placebo and WR-2721. (Tapper Jones et al 1980,
Areibi; A. A..G.M. Histological and histochemical study 0/philocarpine as salivarygland radioprotectant
Donatsky et aJ., 1982, Mouchira et al., 1984, Speilman et 6. Greenspan D., Daniel T.E. (1979): The use of
al., 1981 and Abdel Azeim 1989). pilocarpine in post irradiation xerostomia. J. Dent. Res.
Head & neck irradiation - induces hypofunction 58: 426 (Abs. !J19).
of the salivary glands due to degenerative effect of the 7. Guchelear H.J., Vermes A. and Meerwaldt J.H.
accini, ducts and also some nuclear changes as (1994): Radiation induced xerostomia; pathology, clinical
enlargement and hyperchromatism as observed in the course and supportive treatment. Support. Care. Cancer 2:
present study which is in agreement with (Mouchira et al., 281-288.
1984, Abdel Axim 1989, Greenspan and Daniel, 1979). 8. Iwasaki, S., Iwabuchi, Y. and Sami T. (19960:
The present study demonstrates that the systemic Histological and ultrastructural study of the effects of
administration of Pilocarpine is effective in improving cholinergic and adrenergic agonists on salivary glands
salivary glands dysfunction by irradiation which is secretion from lingual glands of Tokyo Daruma Frog.
documented by histological, histochemical and enzymatic Tisue - cell 28: 323 w338.
activity. This Pilocarpine stimulation resulted in 9. Kestov, A.C., Weeb, J. and Latt, D. (1981):
production of saliva which is similar to Citrate but Treatment of xerostomia: A double blind trial in 108
without irritating effect on the oral mucosa as the Citric patients with sjogren syndrome. Oral Surg., Oral Med.,
acid (Kestove et al., 1981 and Tanzer et al., 1995). Oral Pathol. 5\: 594-599.
The effectiveness of pilocarpine in increasing 10. Mandel I.D., and Wotman S. (1976): The
salivary flow and the known phannalogic properties of salivary secretions in health and diseases. Oral Sci. Rev.
the drug suggest that Pilocarpine acts predominately 8: 25-47.
directly on muscarinic receptors at the end organ sites as a II. Mouchira Sala £1 Din, Maged M.S. Gridly,
parasympathomimetric agent. It also has some activity via Anwar Ahmed Zaky & Medhat Mouamed Mouhamed,
acetylcholine released by preganglionic stimulation (1984): Chemoprotection on irradiated orodental
leading to an increased secretary rate of the accinar cells structures. Egypt. J. Hostol. 7: 61-70.
this is in agreement with (Philip et al., 1986, Naglar et al., 12. Naglar R., marmary Y., Fox P., Baum B., Har E
1990 and Guchelear et al., 1994). and Chevion M (1990): Irradiation induced damage to the
CONCLUSION: salivary glands. The role of redox-active iron and copper.
The results of this study concluded that: Radial res. 138 : 468-476.
1. Radiotherapy of head and neck with single dose 13. Osakai, T., Takeshi, H., Ogawa, T., and
1750r causes biological damage to parotid accini and less Tamimoto, K. (1977): The effect of irradiation to salivary
to ducts. glands of rats. Histological changes of salivary glands.
2. Administration of 5 mglkg Pilocarpine 24 hours Oral J. Yonugo Med. Assoc. 28 (5): 409-423.
prior to radiotherapy protects parotid glands and 14. Philip C. Fox, Peter F. Van, Bruce J. Baum and
decreases degeneration of the alveoli, prevent the Irwin D. mandel (1986): Pilocarpine for the treatment of
shrinkage of the lumen, duct alteration and preserves xerostomia associated with salivary gland dysfunction.
salivary secretion. Oral Surg., Oral Med., Oral PathoJ. 61: 243-248.
3. No clinical side effects or irritating 15. Shannon LL., Mecary B.R. and Starcke E.N.
manifestations except mild lacrimal flow were detected. (977): A saliva substitute for use of xerostomia patients
REFERENCES: undergoing radiation therapy of head and neck. Oral
1. Abdel Aziern, A. (1989): Comparative study of Surg., 44: 656~661.
autoradiography and histopathology in the evaluation of 16. Spielman A., Ben-Aryeh H. and Gutman D.
the effects of modern radiotherapy on selected (1981): Xerostomia - diagnosis and treatment. Oral Surg.,
unprotected versus chemically protected oral tissues with Oral Med., Oral Pathol., 51: 144-147.
S-2 (3 aminopropyl amine ethyl phosphorothioic acid). 17. Tanzer, J.M., Kramer, P.A., Schulman, P. and
(WR 2721). Thesis for Doctoral Degree in Oral and Willard A.K. (1995): Apharmacokinetic and
Dental Medicine, Cairo University. pharmacodynamic study of intravenous pilocarpine in
2. Atria, M.A., Hassan, G.A. and Salah EI Din humans. J. Dent. Res. 74 (12): 1845-1849.
(1971): Effects of single irradiation dose on the tongue 18. Tapper ~ Jones L.M., Aldred H. and Cadogan
and salivary glands of mice (unpublished article). S.J. (1980): Sjogren syndrome treated with bromhexine.
3. Dawes C. (1980): the effect of flow rat and Br. Med. 1. 1: 1365.
length of stimulation on protein concentration in human 19. Yamamoto, H., Ishibashi, K., Nakagwa, J. and
parotid saliva. Archs Oral BioI. 25: 337-342. Moeda, N, (1995): Detection of alteration in the levels of
4. Dontasky, 0., Johnsen, T., Holmostrup, P. and neuropeties and salivary glands responses in the none
Bertram U. (1982): Effect of saliment on parotid gland obese Diabetic mouse model for autoimmune
secretion and on xerostomia. Scand. J. Dent. Res. 90: 175- sialoadenitis. Scand. 1. ImmunoJ. 41: 55·61.
5. Gravenmade R1., Raukema P.A. and Panders
A.K. (1974): Effect of mucine containing artificial saliva
in sever xerostomia.Int, 1. Oral Surg., 3: 435 w439.
Cairo Dental Journal 356 Volume 20 (2) pan2: 353·356.2004
THE PREVALENCE OF TRAUMATIC DENTAL INJURIES
AMONG THE LIBYAN SCHOOL CHILDREN
tfumrr?A. OraJi* C;uzulu K Algalr **
This puper ainzed to ~ietrrminethe pretfcrlrnce o f (lentul injuries clmmilg the Lihyrrn
school children. Ozrt o 1586 child prewnted to fhc drprrrtmenf qf Paedo~Iontir. Ucnghazi Dental School 360 hrl~l
~u~st~rined injuries. The prevulence was 22.7% t o the totcrl number. Libyun hoj}s ore ntore prone t t ~ r l ~ n t ~ r l
irzjuries lhan the girls; male were 68.1% cvhile ,female M:ErE 3 1.9%. The mean crgc was 10.3 yeurs. Morle wus 10 and
nirdian was 10. Thc maxilluly cenlrals n 7 r nmost romntonly c!f/ii,.fed t e ~ t h 76.8% lrnd the crown frurtz~resM ' C ~ Lntor'c
commorz. Elli's class / V tlte mcczrrrcd more,frequentlJ;(-77.H%)~fr,ll<)wed E(li'.s ~~1us.s (28.4%) and Llli :s cluss VII
(16.6%). lncrea.sed over jer ~ ~ 1 ' 1 protl-usion of upper iinrisor.~ insuflici~nt closza-r lzveresignificant predispo.sing
Jz urtd lips
fuclors to the lrazitnaric denlul injzrrie,~ 17.8%. Sqfi tissue injury us more,li.equen/ (Y3.1'34) whilc mtindihuIr~r,fir~c'h~rc~.s
MJL'rlA4.9% and tempromandihulur joint fhrqture was onlj~ 2.(1?6. I'd1 down cvu.s the ntain reason jbr dentul im~rmrr
45.6% ,fi)llowed h,y Jght 10.3% and sport 9.2%. Most r!f'thp children ~jc.r*e injured ur ~ h ~ rholnes 23.9% [crud 12.204
were injured ut tlteir ,scltool and on!v 17.5 were injtrred al the streets.
The * a m c e of a dentition mutilated by fracture or
loss of teeth may no longer be socially acceptable-
Attempls have been made to assess the factors that make
Total number of pat~ents
was 1586, off then, 360 rcccived
some ~ndividuals Inore pronc to injury than others. Females were 1 15 (42.81%) and males were 245 (68.2%).
Thc gencr:il rcsponse of soft and mineral~zcdtissucs to
surgical and traumatic injurics is a scnsltivc proccss,
wherc cven minor changes in the treatment procedure
may have an impact upon the rate and quality of healing.
Dcntal tissues are uiiique in comparison to other tissues in
the body due to their marked capacity of regenerationi.
The aim of this study is to determine the prevalence of
traumatic dental Injuries among the Libyan school
children, mean age, sex distribution, incidarlce and type of
0 .x 1
. - _"-
I teeth injured, site of injury, the predisposing fhctors and
the aetiology of the trauma. Fig. 1. Sex distribution In the sample.
Patients and Materials
I T h ~ sprospective study co~nprisingthe school chlldren
that sustained dental injuries and attended from thc first of
January 1996 to the end of may 1999. The age group was
from 6-14 years. The total patients attendcd the
department of Paedodontic of Bmghazi Dental School
were 1586, off them 362 complained of dental ~njuries: :-8*
two male patlents were excluded because of tncon~plctc i
inforn~ntlons. Trauma sheet was prcpared for the ; \-,
collcctlon of thc data and informations. Radiographs were i 1 -
- -- - z
taken as necessary. V~talitytests; cold or thermal, wcrc
also needed for sonle cases. t.,lli's classtficat~onwas used
Fig. 2. Address of the pts.
In thls study. No st;ttlstlcal analysls was needed because
all results wcre descr~pt~ve.
Orofi: H. A, & Algal): G. K The prevalence oftraumatic dental injuries among the libyan school children
Table 1. Prevalence of traumatic dental iniuries
Total ts Pts who received trauma
Mean age: 10.27. Mode: 10. Median 10.
tvnes 0 fh e tee th imjunes.
Ta ble 2 T t
Elli's Classification CII (In CIUI CUV CI.V C1.VI CI.VII CI.VIlI
No. of teeth 13 161 57 214 21 3 94 3
Incidence% 2.3 28.4 10.1 37.8 3.7 0.53 16.6 0.53
Total teeth 566
T a ble 3 Th e injure d teet.
Type of teeth No. of teeth Percentage
URCI 227 40.1
ULCI 208 36.7
LRCI 38 6.7
LLCI 28 4.9
URLJ. 24 4.2
ULLI 21 3.7
LRLl 10 [,8
LLLI 7 1.2
URC 1 0.2
ULC 1 0.2
LRC 0 0
LLC 1 0.2
URCI: upper right central incisor ULCl: upper left central incisor LRCI: lower right central incisor
LLCI: lower left central incisor URLI: upper right lateral incisor ULLI: upper left lateral incisor
LRLI: lower right lateral incisor URC: upper right canine ULe: upper left canine
LRC: lower right canine LLC: lower left canine
T able 5 Causes 0 f t he miunes
Causes of the injuries Pts no. (%)
Fall down 164 (45.6)
Fight 37 ( 10.3)
Sport 33 (9.2)
Road traffic accident 18 (5.0)
Others 16 (4.4)
Not recorded 92 (25.5)
Total patients 360
Ta ble 6• Pre di
Occlusion No. of pats. (%)
Adequate lips& n. occlusion 201 (55.8)
Inadequate lips & incisal protrusion 64 (17.8)
Eoileotic I (0.3)
Not recorded 94 (26.1)
Total 360 (100)
Table 7. Pace 0 fh e eruurv
Place of the iniurv Patients no. (%)
Home 86 (23.9)
School 44 (122)
Street 63 (17.5)
Others 4 (Ll)
Not recorded 163 (45.')
Cairo Dental Journal 358 Volume 20 (2) pari]: 357· 360, ]004
Orr~fi; A. LC Algoli; G. K.
If. Tilo pri:~*rrlr~nce denlcrl
~~'truu~ucrlic U~&rie.vmmong the lib)wjz .~c:hoc)l
Fig. 6. Endodontic Treatment
to 33% as opposed to 4 to 19% in girls which was related
to a fact that boys are more active participate in contact
games and sports3, Probably for the same reason Libyan
boys are more prone to the dental injuries than the g~rls;
males wcre 68. l '% while females were 3 1.9%. The lncan
age was 10.3 years. Previous studies showed that the
majority of dental injuries involved the antenor teeth,
especially the maxillary central incisors, while the
mandibular centrals and the maxillary laterals are less
frequently involved4.' and the largest proportion of injuries
affecting the permanent dentition presented by crown
fracture^^.^.', This was also corrclatcd to this finding where
the maxillary centrals were most commonly affected teeth
(76.8%) and the crown fractures were morc common.
.. - - Elli's class IV is more frequently occurred 37.8%
Fig. f,& o ~ v ~ *, , L ,
P 2 :s '-'I. IV followed by Elli's class T (28.4%) then Elli's class VII
(16.6'h). ~ a h a b u k aFK etal"' found that enamel fracture
was 67% and enamel-dentine fracture was 26%. Increased
over jet with protrusion of upper incisors and insufficient
lips closure arc significant prcdispostng factors to
traumatic dental inj~ries"~'~.". Among the Libyans it also
comprised 17.8%. Soft tissue injury (93.1%) was morc
frequent whrlc mandibular fractures were 4.9% and
tempromandlbular joint fracture was only 2.0%. Fall down
was the main reason for tr-auma 45.6% followed by fight
10.3% and sport 9.2%. Most of the children were ~njurcd
at their homes 23.9% and 12.2% were injured at their
school and only 17.5 were lnjured at the streets. One must
emphasize the development of preventive programs
promoting parent awareness of the importance of looking
for prompt carc.
- - 1
Fig. 5-Cewicai roo: . -ac"uve ., , .V (Nonvital)
Discussion The authors thank Dr Mohammed Mammad and Dr
The frequency of traumatic dental injuries varies. Sulilnan Omar for their help and support.
This variation reflects a number of factors, such as
difference in the sampling criteria, as difference in age References
and sex. In a prospective study where all dental injuries
occurring from birth to thc age of 14 years werc carefully 1- Andreasen J. 0. and Andreasen F.M. (1 994)
registered, it was found thar 22% of the children had Chapter 1 . Wound Healing Subsequent to Injury.
sustained injuries to ;he permanent dentition: The In Textbook and Color Atlas of Traumatic
prevalence in this study was 22.7% to the total age group. injuries to the Teeth by J. 0.Andreasen and F.
The prevalence of dental trauma in boys ranged from 12 M. Andreasen, Munksgaard, Copenhagen, 3rd
edition, pp 13.
Cuiro DenralJovrnal 359 Volume 20 (3parr?: 357 - 360, 2004
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Int. J. Oral. Surg. 1972; 1:235~9. 9- Holland T., O'Mullane D., Clarkson J., Hickey
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4- Gutz D.P. Fractured permanent incisors in a Prevalence of teeth with untreated dental trauma
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Cairo Denial Journal 360 Volume 20(2) partl: 357.360. ]004