IV. MULTIFACTORIAL CONCEPT OF CARIES ETIOLOGY
Dental caries – a multifactorial disease – interplay of 3 primary factors plus time.Presence of bacteria and a suitable substrate on a tooth surface at a given time is not enough to cause caries.
So, variations in caries incidence occur because of number of indirect factors ( CONTRIBUTING FACTORS ).
• dental caries to occur :
• bacterial biofilm has to accumulate on a tooth surface.• The bacteria within the biofilm metabolize dietary sugar substrates producing acids.
• acids, over time, lead to demineralization of the tooth tissue.
• Clinically, this is not the case.
• Some tooth surfaces that are frequently covered with plaque do not develop caries
• whereas other tooth surfaces covered with plaque in the same mouth develop caries .
Many other factors, such as:
• dietary habits,• fluoride and saliva
• impact upon the disease process
• which is complex and dynamic in
• nature.
From the earliest stage, continued demineralization can be stoped and lesion arrest is possible by simply disrupting the plaque biofilm on the surface of the tooth at regular intervals.
Very early lesions which are not detected clinically may therefore not progress to clinically detectable white spot lesions.
CONTRIBUTING FACTORS - TOOTH
• 1. COMPOSITION OF TOOTH: -• Structure & composition of a tooth determines initiation and rate of progression of caries.
• Surface enamel more mineralized than subsurface enamel and is more resistant to caries. It also accumulates more fluoride, zinc, lead ions than subsurface enamel.
• Therefore in initial carious lesions, the subsurface enamel shows marked demineralization even though the outer enamel is relatively intact.
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• 2. MORPHOLOGIC CHARACTERISTICS: -
•CONTRIBUTING FACTORS – TOOTH
• 3. POSITION: -
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CONTRIBUTING FACTORS - DIET
• 1.PHYSICAL FORM: -• Very important factor responsible for difference between caries incidence of primitive and modern man.
• Already explained that diet of primitive man contained plenty of roughage which mechanically cleansed the teeth of any adhering to the teeth.
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• Also, the coarse nature of the diet induced early attrition of occlusal and proximal surfaces leading to reduction in food entrapment.
• Diet of modern man in contrast is soft and lacking in roughage. As a result, food sticks to teeth and is not cleansed mechanically.
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• 2. CARBOHYDRATE CONTENT OF DIET: -
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• 3. LIPID CONTENT OF DIET: -
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• 4. VITAMIN CONTENT OF DIET: -
•• 5. CALCIUM & PHOSHORUS CONTENT:-
• 6. FLUORINE CONTENT: -•
• 1. COMPOSITION: -
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CONTRIBUTING FACTORS –
SALIVA• 2. pH OF SALIVA: -
The “critical” pH at which the inorganic material of tooth begins to dissolve is about 5.5, since above this pH, saliva is supersaturated with Ca and Po4 ions.
Although much has been discussed about buffering capacity of saliva, its relation with caries incidence is not so simple!
Acid production during caries occurs at a localized site on tooth, which in initial stages at least, is covered by dental plaque. This plaque prevents a free exchange of ions.
• 3. QUANTITY OF SALIVA: -
•• 4. VISCOSITY OF SALIVA: -
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• 5. ANTIBACTERIAL PROPERTIES: -
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CONTRIBUTING FACTORS – SYSTEMIC FACTORS
• 1. HEREDITY: -• Prepared by Dr Sundeep S Bhagwath