There is a definite relationship between progress of caries and density of tooth structure, but none between incidence of caries and tooth density. Vitamins A and C are possible, but not important, factors in incidence of caries. They influence principally tooth density or structure. The carbohydrate in such starchy foods as potato, taro, and banana, is not a factor in caries, for these foods do not adhere to teeth. Refined cereal foods lower the ptyalin level of saliva and increase oral fermentation. The ptyalin level is an important factor, especially when cereal starch is high. The greater the acidity of fermenting cereals on a tooth surface, the higher the salivary buffer-value necessary to prevent destructive action. A ” dry mouth “—one in which the amount of saliva is less than the average—contributes to causation of caries. Normal buffer-value of saliva neutralizes acids of fermentation. The pH of saliva does not run parallel with buffer value, and therefore is not a constant influence. The inorganic minerals—salts of potassium, sodium, calcium, magnesium, chlorine, sulphur, phosphorus and iron—influence buffer value of saliva. Vitamins D and B (complex) affect incidence of caries by influencing calcium, phosphorus and ptyalin levels in saliva. Sugar is an indirect factor in caries. It satisfies the caloric requirements before mineral needs are met, and thus may reduce assimilation of calcium. Sugar and all refined carbohydrates tend to lower the salivary ptyalin-level. Meat and animal proteins are preventive factors by raising the phosphorus level, which is low in caries in children. Fats and oils increase or decrease caries according to the influence they exert on the calcium/phosphorus level and acid/base balance. Fruit and vegetable juices increase or decrease caries through their influences on the mineral level, and buffer value, of saliva. Other contributing factors, of different degrees of importance, are inheritance, principally as influencing assimilation and tooth structure; diseases or conditions that impair functions of liver and pancreas (normal assimilation of calcium and phosphorus being largely controlled by these glands), or interfere with elimination through the kidneys (as affecting acid/base balance) ; basal metabolic rate, by preventing normal calcium assimilation if too negative, or loss of calcium through the urine if too high ; hydrochloric acid in the stomach, assimilation of calcium and phosphorus being dependent thereon.
References: J. Den. Res., 1931; Nutr. Den. Health, 1937.