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Saliva and Dental Caries ppt Saliva and Dental Caries arthritis

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Saliva and Dental Caries ppt Saliva and Dental Caries arthritis Powered By Docstoc
					Saliva and Dental Caries

        Dr. Oula Al-Saeed
   BDS, MSc, Jordanian Board of
           Endodontics
             Introduction
Saliva is produced by major and minor salivary
glands
Ninety percent of saliva is produced by the three
pairs of major salivary glands
At mealtimes, salivary flow increases (stimulated
saliva)
At rest, there is a constant slow flow of saliva
which provides protection to the teeth, tongue,
and mucous membranes (resting saliva)
At night, the flow rate virtually stops
         Salivary flow rates
Resting (unstimulated) rate: 0.3-0.5 ml/min.
Stimulated rate:1-2 ml/min.
Xerostomia comes from the greek words xeros,
which means dry, and stoma, which means
mouth
Hyposalivation, or reduced salivary secretion
rate (SSR) is different from xerostomia, the latter
more reflecting the end result of the process of
inflow of pure saliva, evaporation, adsorption to
the oral mucosa and outflow of saliva
Causes of reduced salivary flow
 Acute/chronic inflammation of salivary glands
 Benign/malignant tumors of salivary glands
 Radiotherapy
 Drugs
 Systemic disorders
 Aging
 Decreased masticatory activity (liquid diet, soft
 food)
 Other causes of dry mouth
    Mouth breathers
    Smoking
            Radiotherapy
Severe reduction in salivary flow (<0.1 ml/min)
When parotid gland is involved, saliva becomes
higher in protein content resulting in thicker
saliva
May be temporary or permanent
Secretory cells, blood supply, and nerves may
be affected
Serous cells are more sensitive than mucous
cells
            Radiotherapy
Saliva changes into viscous, white, yellow,
or brownish fluid with reduced pH, reduced
buffering capacity and altered electrolyte
and protein content
Irradiation also increases the numbers of
acidogenic, cariogenic microorganism
Caries occurs at sites relatively resistant to
dental caries (lingual and incisal surfaces)
               Drugs
Antidepressants     Diuretics
Antipsychotics      Antiparkinsonians
Antihypertensives   Antidiarrheal
Anxiolytics         Anticholinergics
Chemotherapeutics   Anorectics
Antihistamines
        Systemic disorders
Sjögren’s syndrome
Rheumatoid arthritis (15-30% of patients with
rheumatoid arthritis also have Sjögren’s
syndrome)
Psychogenic factors: depression, anorexia
nervosa
Malnutrition, dehydration, frequent fasting
Severe immunodeficiency (AIDS)
Other conditions; cystic fibrosis, hormonal
changes, DM, HT
                 Aging
Age per se has little effect on salivary flow,
esp. parotid glands
Drugs and health conditions rather reduce
saliva
Submandibular glands may suffer some
atrophic changes, parotid not affected in
healthy individuals
         Signs and symptoms
Patients may complain of a sensation of dryness
   Hypofunction of minor salivary glands
   Little correlation between subjective feeling of
    dryness and SSR
Dryness of the lining oral tissues
Thin, pale oral mucosa with loss of glossy sheen
Tongue depressor or mirror may adhere to oral
mucosa
Increase in dental caries
         Signs and symptoms
Increase in oral infections, esp candidiasis and angular
cheilitis
Fissured tongue
Swelling of salivary glands may be noted
Non-oral signs: decreased lacrimation, pharyngitis,
laryngitits, dry cough, nasal dryness, epistaxis, reflux
esophagitis, heartburn, and constipation
Reduced SSR
Tests
   Infrared light
   Mechanical friction measurements
 Diagnosis of hyposalivation
Stimulated SSR
Resting SSR
History of the patient (drugs, systemic
diseases)
Examination of the patient
Patient’s symptoms (difficulty speaking
and/or swallowing, soreness of oral
mucosa
Axelsson P. Diagnosis and risk prediction of dental caries. 1st ed. Illions: Quintessence Publishing Co, Inc;2000: p.241
Gupta et al. Hyposalivation in Elderly Patients. J Can Dent Assoc 2006; 72(9):841–6
Consequences of hyposalivation
Oral mucosa is more prone to traumatic
ulceration and infection
Alteration in taste
Difficulties in chewing swallowing, and speaking
Extreme sensitivity to heat and cold, esp. if
dentin is exposed
Loss of retention of dentures
Higher plaque retention leading to gingivitis
Changes in plaque composition favoring
Candida, Streptococcus mutans, and Lactobacilli
        Composition of saliva
Saliva is a complex secretion mainly composed
of water
Whole saliva consists of
   Secretions from major and minor salivary glands
   Gingival crevicular fluid
   Serum
   Blood cells
   Bacteria and their products, viruses, and fungi
   Desquamated epithelial cells
   Food debris
   Fluoride
   Some bronchial secretions
       Composition of saliva
Saliva is composed of
   99% water
   1% divided as follows
      Large organic molecules (proteins, glycoproteins,
      and lipids)
      Small organic molecules (glucose and urea)
      Electrolytes (Na+, Ca2+, Cl-, PO43-(
      Saliva and dental caries
It reduces the rate of plaque accumulation and increases
the rate of carbohydrate clearance
It increases the thickness of the acquired pellicle and
thus retarding the demineralization process of enamel
The carbonic acid-bicarbonate buffering system,
ammonia and urea components all neutralize the pH fall
from bacterial byproducts
Antimicrobial properties
   Non-immunological components: lysozyme, lactoperoxidase,
    lactoferrin
   IgA secreted by plasma cells
It harbors Ca2+, PO43-,OH-, and F- ions which reduce
solubility of enamel and aid in remineralization
Clearance of carbohydrates and
       microorganisms
The most important function of saliva in
caries prevention
Clearance is from the mouth to the
digestive tract
Clearance rate depends on
   SSR
   Site
 Role of organic components
Mucins and other glycoproteins
   Lubrication and maintenance of a moist mucosal surface
   Aggregation of oral bacteria
   Inhibition of bacterial adhesion to tooth surface
Statherin and acidic proline-rich proteins
   Inhibition of spontaneous precipitation of calcium phosphate
    salts, maintaining a protective and reparative environment for
    teeth
Amylase
   It splits starch into maltose, maltotriose, and dextrins
   Role of modulating the adhesion of bacterial on oral surfaces?
Other organic components with antimicrobial properties
      Antimicrobial properties
Lysozyme
   A strongly cationic protein which can activate
    bacterial autolysins
   Muramidase activity
Lactoferrin
   High affinity for iron and expropriation from
    pathogenic microorganisms
Peroxidase
   Antimicrobial activity
   Protection of host proteins and cells from hydrogen
    peroxide toxicity
IgA, IgG, IgM
      The buffering system
The sugar clearance effect of saliva reduces the
formation of plaque acids
The buffering action of saliva, however, is mainly
dependant on the carbonic acid/bicarbonate
system
Less importantly, the macromolecular proteins
have some buffering capacity
At the sites of carious attacks, i.e, within the
plaque, buffering mechanisms are different from
those in saliva
          The role of calcium
Calcium is bivalent, and can bind to chelating agents
(eg. citrate in citric acid found in citrus fruits or juices)
Depending on the pH, calcium is distributed in saliva in
ionized and bound forms
Ionized calcium is especially important in the carious
process, because it participates in establishing the
equilibrium between the calcium phosphates of the
dental hard tissue and its surrounding liquid
The pellicle layer contains a higher concentration of
calcium than saliva
After sugar intake, bound calcium is liberated; and as pH
slowly increases, an equilibrium is reached
The role of inorganic phosphate
Inorganic orthophosphate in saliva consists of
phosphoric acid (H3PO4), the primary (H2PO4-),
secondary (HPO42-), and tertiary (PO43-)
inorganic phosphate ions
The concentration of total inorganic phosphate
decreases with increasing SSR
Inorganic phosphate participates in the
maintenance of the tooth structure
Buffering role
Phosphate is a nutrient for the oral microflora
          The role of fluoride
Concentration is dependant on fluoride in the
environment, esp. drinking water
Fluoride diffuses from the saliva into the plaque
causing an elevation in the plaque fluoride level
Fluorides acts by
   Inhibits demineralization of enamel and enhances
    remineralization
   Its uptake by demineralized enamel forms an enamel
    structure which is more resistant to acids
   It affects the activity of cariogenic bacteria
         Salivary stimulation and
               substitution
Stimulation is the optimal approach for a patient with
some remaining glandular function
   Systemic
       Pilocarpine hydrochloride
       Adequate water intake
   Local, eg.
       Fiber-rich, well-flavored diet
       Fluoride chewing gum
For patients with negligible function, treatment is
symptomatic
   Saliva substitutes (artificial saliva)
   Frequent sips of water
   Petroleum jelly application to dry lips
Preventive programs for patients
      with hyposalivation
Strict oral hygiene maintenance, by
mechanical and chemical plaque control
Professional scaling at needs-related
intervals
Use of fluorides
Thank you

				
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