Understanding of the etiology and pathogenesis of dental caries is necessary for its successful prevention and treatment, so dentists have to be familiar with the theory of caries. There are many theories of dental caries, among them are the theories of historical value; a number of theories reflect only some aspects of caries development. Modern theory of caries allows us to understand this process taking into account many factors that cause its development.
MILLER'S CHEMO-PARASITIC THEORY OF CARIES (1884)
Not long ago, the chemo-parasitic theory of caries served as the basis for the modern concept of dental caries pathogenesis. In accordance with this theory, the carious process has two stages: the first stage - demineralization of hard dental tissues. Carbohydrate fermentation results in production of lactic acid. It dissolves inorganic base enamel and dentin. The second stage involves destruction of the organic matrix of dentin by proteolytic enzymes of microorganisms. In addition to factors such as microorganisms and acids, Miller took into account the presence of predisposing factors. He pointed out the role of the quantity and quality of saliva, food and drinking water quality, emphasized the importance of hereditary factors.
Drawbacks of the theory
Demineralization of enamel occurs as a result of presence of acid salts and acids in the oral fluid (mixed saliva) that have a devastating effect on a tooth as a result of lowered pH of saliva. It is now known that demineralization of enamel surface takes place at pH ≤4.5. And oral fluid normally has a neutral medium (pH = 7.0), and even when using large amounts of sugar and decom-pensated degree of caries activity, mixed saliva pH reduction occurs before the critical factors that can cause demineralization of tooth enamel.