The relationship of the teeth to general health and efficiency was appreciated in a general way long before vitamins or focal infections had been heard of. Toothaches used to be as inevitable as colds; and slave buyers and horse traders inspected the teeth of their prospective purchases before buying. But only in recent times has attention been given to the care and preservation of the teeth.
Early studies of the cause and prevention of dental caries suggested that there might be a single causative factor but further results show that the problem is a complex one, with diet, heredity, internal secretions, mechanical factors, and oral hygiene of greatest importance OIls by Jane.
Diet and Dental Caries
There is now general agreement that diet probably is the most important single factor in the maintenance of sound, healthy teeth, and that an adequate diet is most essential during the period of most rapid growth. McCullum and Simmonds conclude from an experimental study that rats which are kept on a deficient diet during a part of the growing period have inferior teeth and early decay, even though an adequate diet is provided later. In the days before viosterol had been developed and before cod-liver oil was widely used, McCullum also reported that at the age of entering school 9 per cent of children who had been breast-fed for at least 6 months had dental caries, 22 per cent of children who were fed on cow’s milk or on milk mixtures, and 27 per cent who were fed on oatmeal water and other prepared foods. This would indicate that the foundation of dental health is laid very early in life, but it now appears that the prenatal period is also of great importance in this regard. Consequently emphasis is now being placed upon a proper diet during pregnancy.
Important though diet admittedly is, there does not seem to be any single dietary factor which is responsible for dental caries. Calcium and phosphorus, the two minerals found in bones and teeth, and vitamin D, which regulates the utilization of these minerals by the body, are clearly essential. Of these, calcium and Vitamin D were first thought to be of greatest importance: but the more recent work seems to indicate that phosphorus is of as great if not greater importance than calcium. Milk, certain vegetables, and fish foods are rich sources of both calcium and phosphorus. Vitamin D is very likely to be deficient in natural foods during the winter months but is easily administered in the form of cod-liver oil, vitamin D milk, or viosterol.
Children have long been denied candy because of the belief that sugar is related to dental decay, and certain studies carried out in institutions for orphans where the diet is strictly controlled suggest that the prevalence of dental caries is directly related to the amount of carbohydrate in the diet. Cereals from which the hull of the grain has been removed seem to have an unfavorable influence upon the development of the teeth, and several investigators believe that oatmeal contributes directly to the formation of caries.
Divergent opinions concerning the relation of diet to dental health leave one rather confused. Apparently no one dietary factor is responsible for resistance to caries, but various elements are necessary for the proper development and continuing soundness of the teeth. For practical purposes a well-rounded diet, containing liberal amounts of milk, orange juice, fresh fruits, vegetables, and for children cod-liver oil or some other form of vitamin D, may be depended upon to supply the nutritional requirements of the teeth.
It is frequently said that “a clean tooth never decays.” Whether or not this is true depends upon the definition of cleanliness. If cleanliness implies freedom from bacteria, the statement probably is correct. But with bacteria constantly present in the mouth and in the food we eat, it is impossible to have the teeth bacteriologically clean.
The mechanism of decay is through the action of acids produced by bacterial decomposition of food, first upon the enamel and then upon the softer dentine of the tooth. The action of this acid upon the tooth structure may begin in any crevice, irregularity, or break in the enamel. The amount of decomposition and acid formation is greatest when there are gross accumulations of food substances. In fact, it is between the teeth, where it is difficult to prevent accumulations of food that decay most frequently begins. Hence, although cleanliness of the teeth is hot the only factor in the prevention of dental decay, or even the most important one it is not without significance.
Some clarification of this aspect of the problem has been given by recent studies of the bacteria found in the mouth. If a particular germ called Lactobacillus acidophilus occurs in quantity caries develop with great rapidity. This is because these bacteria act upon carbohydrates, particularly sugars, on and around the teeth to form acids which dissolve the enamel and the dentine. These studies have also shown that if persons have excessive number of lactobacilli in their mouths, the amount of caries can be reduced by the elimination of sugars and other easily fermentable carbohydrates from the diet.
It now appears that certain chemicals applied to the teeth will neutralize the acids formed by the action of bacteria upon carbohydrates and therefore reduce caries. Some of these chemicals are now being included in so-called “ammoniated” toothpastes.