• Dental caries is defined as a chronic infectious disease which results from the demineralization of the inorganic portion and destruction of the organic portion of the tooth. 
• Epidemiology of dental caries can be studied under the following heading: Host, agent and environment All these factors should react over a period of time for dental caries to occur. 
• CARIES FORMATION 
  • Substrate (sugar) + microorganism (s.mutans in plaque) = lactic acid = causing demineralization
  • Remineralization = fluoride, calcium, phosphate
    1. Fl = dentifrice
    2. Ca and PO4 = teeth and saliva
• HOST FACTORS
  • TEETH 
    1. 80% of caries occur on occlusal surfaces
    2. Lower incisors are the least affected teeth 
    3. Malaligned rotated = bristles cannot reach and clean leading to increased caries 
    4. Dentinogenesis and amelogenesis imperfecta = hypoplastic teeth and pitts = more prone to caries
    5. Caries is considered to be bilateral 
  • SALIVA 
    1. COMPOSITION
       1. rich in calcium phosphate and fluoride = decrease in caries
       2. Rich in carbonate = increase in caries attack
    2. pH = 
       1. unstimulated pH is slightly acidic 
       2. High flow rate = pH increases
       3. pH of saliva = main is bicarbonate content 
       4. Sialin, phosphate and ammonia = also determines pH of saliva
    3. QUANTITY 
       1. Normal secretion = 700-800 ml/day 
       2. Aplasia of glands and xerostomia = increase in rampant caries
    4. VISCOSITY 
       1. Mucin responsible for viscous saliva  
       2. Viscosity does not influence caries 
    5. ANTIBACTERIAL PROPERTIES 
       1. Lactoperoxidase = this prevents early microbial colonization of tooth 
       2. Lysozyme = it is a positive enzyme that catalyzed the degradation of negatively charged peptidoglycans matrix of microbial cells 
       3. Lactoferrin = iron binding protein = needed for microbial growth
       4. IgA = inhibits adherence and thereby prevents colonization on mucosal surfaces and teeth by organisms, facilitating their removal of swallowing 
  • AGE = 3 peaks for caries development
    1. 4-8 years = manual dexterity is less
    2. 11 – 19 years = adolescents
    3. 55 – 65 years = root caries
  • Gender = Reasons 
    1. Early eruption of teeth 
    2. More fondness of sweets
    3. Hormonal variations
    4. Morphological differences
  • Familial hereditary 
    1. Good or bad teeth seen in the family 
    2. Morphology, occlusion, salivary flow
  • Emotional disturbances 
    1. Increase stress = decrease salivary flow = increased caries in oral hygiene is not followed 
  • Socio-economic status 
    1. Low SES = increases decayed and increased missing 
    2. High SES = increased filling 
    3. Overall low SES = increase dental caries
    4. Reason = affordability for prevention and treatment 
    5. Caries is considered as disease of poverty
  • TIME FACTOR FOR DEVELOPMENT OF CARIES
    1. Peak susceptibility = 2-4 years after eruption 
• Agent factors
  • Diet 
  • Organisms = S.mutans = pioneer = acidogenic, aciouric, eat/consume sugar 
    1. Extracellular = dextrans and fructans. Responsible for adhesion on tooth
    2. intracellular polysaccharide = glycogen
  • Lactobacilli = secondary organisms, when caries have reached dentin. It kills all S.Mutans creates an environment of very low pH
  • Veillonella = anti caries organism = consumes acid as food = produced by S.Mutans for demineralization

DIET OF DENTAL CARIES

1. Diet = it is defined as type and amount of food eaten daily by an individual
2. Nutrition = defined as seen of the processes by which an individual takes in and utilizes food
3. Carbohydrates

1. Organic compound containing carbon, hydrogen and oxygen 
2. Physical nature of diet = form, clearance, time, retention, oral hygiene
3. Frequency of carbohydrate diet  
4. Types 
   1. Monosaccharides = glucose, galactose, fructose
   2. Disaccharides = sucrose [ glucose+fructose]
   3. Polysaccharides = starch, glycogen 
   4. Polyols of alcohol = xylitol, mannitol and sorbitol

Classification of sugars 

Total sugars 

1. Intrinsic sugar
   1. Sugar molecules inside the cell

1. Fruit and vegetable
2. Extrinsic sugar 
   1. Sugar molecules outsides the cell 
   2. Milk sugar = found in dairy products = lactose
   3. Non milk sugar = honey, fruit juices, table sugar = responsible for the caries