Caries may be produced by food impaction, size of food particles being an important factor. L. acidophilus alone is not responsible for all carious processes, but many different acidogenic bacteria, including various streptococci and bacilli other than lactobacilli, may participate. Dental structure, and subsequent resistance or non-resistance to caries, are not influenced by the nutrition of the pregnant mother unless the deficiency of mineral salts is such as markedly to reduce the tidal calcium and phosphorus available to the fetus. Nature compensates for deficiency by adjusting demands, by decreasing size of offspring and, in case of severe deprivation, by effecting structural changes.
Various mouth-inhabiting acidogenic bacteria may act in symbiosis to increase pH and amounts of active acid end-products. Bacteria in the mouth produce not only lactic acid, but also acetic, butyric, citric, formic, oxalic, propionic, pyruvic, succinic, etc. Proteolytic and putrefactive bacteria, by their action in breaking down food proteins to ammonium carbonate and other alkaline products, may so markedly inhibit the action of acidogenic bacteria that the former types of oral organisms become antibiotic, their antibiosis in turn retarding the carious process. Salts in saliva and food, etc., may also alter the chemical reactions in the mouth to a point where such acids as acetic are broken down to carbon dioxide (carbonate) and water. Bacterial action may be accelerated, or chemical products of their growth changed, by enzymes produced by the bacteria themselves.
References: J. Am. Den. Assoc., 1935, 1936, 1938; Den. Items Int., 1935.