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.
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. Consequential emphasis is now being placed upon a proper diet during pregnancy.
Important though diet is admittedly is, there does not seem to be any single diet 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 seemed to indicate that phosphorus is of 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 administrated 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 suggesting that the prevalence of dental caries is directly related to the amount of carbohydrates in the diet. Cereals from which the hull of the grain has been removed seem to have an unfavorable impact 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. Almost no one diet 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 dependent 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 implications 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 decide most often begins. Here, despite cleanliness of the teeth is 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 bacterium found in the mouth. If a particular germ called Lactobacillus acidophilus occurs in quantity caries develop with great rapidity. This is due to 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.
Fluorine and Dental Caries
During the past several years investigations have taken another turn. It was determined that the only chemical difference between carious and non-carious teeth is that carious teeth contain less fluorine, a chemical element which is present in minute amounts in the bones and teeth. This was followed by an investigation of the fluorine content of the drinking water in areas in which dental caries are rare and areas in which they are prevalent. Here again a difference in fluorine content was found. From these studies it has been concluded that the presence of approximately 1 part of fluorine per 1,000,000 parts of drinking water results in a decreased prevalence of caries. Incidentally fluorine in this amount causes some mottling of the teeth.
Proceeding on the basis of this information, several investigators have experimented with the application of fluorine to the surface of the teeth of children. In this study Knutson and Armstrong reported that the application of 2 per cent sodium fluoride solution to the teeth resulted in 40 per cent less caries over a period of a year in 289 children than developed in 326 untreated controls. No healing effect was noted on teeth in which caries exhausted. This use of fluorine for the prevention of dental caries is a promising line of investigation but it is still in the experimental stage.
Other exceedingly important studies are those in which sodium fluoride in minute amounts is being added to the water supplies of several cities which have low fluoride content. If this should prove effective in preventing caries, it will be a great step forward in the control of this most widespread of human diseases.
That other factors play a part in determining the health of teeth is evident from the fact that some persons remain immune from caries no matter how unbalanced the diet or howclean the mouth, while others develop caries even though the diet, so far as we can tell, is entirely adequate and the care of the mouth perfect. One of these additional factors is probably heredity, and the functioning of the glands of internal secretion may be another.
The so-called "apical abscesses" which develop around the roots of teeth are the most dangerous type of mouth infection. Infective organisms usually reach these areas by traveling from deep cavities down the pulp of the tooth and along the root canal. On the other hand, abscesses occasionally occur around the roots of apparently healthy teeth.
An infection at the root of a tooth begins as a small inflammatory area in the bone in which the tooth is embedded. Without an abscess forms and works its way to the surface, becoming a so-called "gum boil," these infections can not drain. The result is that their toxic products and even the bacteria themselves may be absorbed into the blood and lymph stream to be circulated through the body. The toxic products cause fatigue, lassitude, and various aches and pains, while bacteria which are absorbed may set up infections in the joints, kidneys, or heart valves. Abscesses at the roots of certain teeth of the upper jaw may extend directly into the antrum, producing one of the most different types of sinus infection. The development of these root abscesses is usually accompanied by pain, but they may develop, particularly at the roots of "dead" teeth, without any warning whatever. The only satisfactory treatment is free drainage obtained by the removal of the tooth.
Gingivitis and Pyorrhea
Gingivitis means an inflammatory condition of the gums; While Pyorrhea implies that actual pus is present. The normal gums are pink or light red in color, thin and firm. If they become bright red or purplish, soft, swollen, and spongy, or bleed easily, they should receive attention. The causes of an unhealthy condition of the gums may be faulty diet, mechanical irritation, or bacterial infection.
Vitamin C seems to be the dietary factor most directly related to the health of the gums. In scurvy, the disease due to vitamin C deficiency, a spongy, bleeding condition of the gums is a predominant symptom. Hanke reported that the addition of a pint of orange juice and the juice of one lemon to the daily diet lead to an almost complete disappearance of gingivitis.
Mechanical injury to the gums may result from the faulty use of the toothbrush or from the accumulation of tartar lime like deposits on the teeth at the gum margin. Such mechanical injury causes irritation and is frequently followed by secondary infection.
Exercise and massage of the gums by biting and chewing assist in the maintenance of an adequate circulation and a healthy condition. For this reason it is important that teeth be kept in proper repair so that they will be used regularly and uniformly. Missing teeth and poor fillings prevent the proper use of the teeth in chewing. Gentle massage of the gums with the fingers or the toothbrush, using a stroke toward the gum margin, is helpful in maintaining good circulation.
Pyorrhea is a more severe infection of the gums which demands expert treatment. There is no mouthwash, toothpaste, or powder that will cure it.
A severe form of gingivitis which received special study during the First World War has been called "trench mouth." This is caused by a specific germ and is easily communicated from one person to another, either directly or indirectly through drinking glasses or eating utensils. The treatment of trench mouth is a problem for a physician or a dentist.
Care of the Mouth and Teeth
Cleanliness of the mouth and teeth is important from an aesthetic as well as from a hygienic point of view. It is difficult to keep the mouth clean in view of the irregularities in the shape of the teeth and the crevices between them. Neverheless, by the regular use of the toothbrush and dental floss the teeth may be kept relatively free from deposits of food and mucus. The mouth should be cleansed upon rising in the morning, after each meal, and before retiring.
A small or medium-sized brush with a straight or slightly convex brushing surface looks to give the best results. The bristles should be reliably short and stiff, with the tufts broadly separated and containing bristles of different lengths. The expense of the brush is not necessarily a criterion of its value.
Cold water should be used in brushing the teeth, for hot water softens the bristles. After using a brush, it should be washed and hung where it will become thoroughly dry before before use. It is well to have several brushes which may be used alternately.
The teeth should be brushed on all surfaces which the brush can reach. Other surfaces should be cleaned with dental floss. A technique recommended for brushing the teeth is to place the brush against the teeth with the bristles slanting away from the gums. Then with a gentle, rotary motion work the bristles between as well as over the surface of the teeth. If there is a tendency for the gum margins to recede, the gums should be massed with the brush when cleaning the teeth, using a gentle stroke toward the edge of the gum margin.
Tooth Pastes and Powders
The chief merit of dentifrices is that they are pleasant to use and encourage regularity in the care of the teeth. They contribute but little to the cleaning and nothing to the preservation of the teeth. Nor do they prevent pyorrhea and gingivitis. And the use of some dentifrices is actually worse than nothing at all, for they contain abrasive, gritty substances which wear down the enamel of the teeth. For practical purposes, finely precipitated chalk or bicarbonate of soda with or without flavoring is an inexpensive, safe, and satisfactory dentifrice. The recently developed ammoniated dentifrices may prove to have real value in preventing caries.
The only merit which can be attributed to Mouthwashes is that they give a pleasant sensation of cleanliness. They have no antiseptic properties of any consequence. If the mouth is healthy, they are unnecessary; and if not, they are valueless.
There is some suggestion that the persistent use of some of the popular "antiseptic gargles" may be harmful. Whether or not this is correct, it is unintelligent for people to be cajoled into spending money for such preparations by the writers of advertising copy who knows nothing about health and careless.
The selection of a competent dentist is of first importance in the care of the teeth. Cheap, incompetent dentistry usually means one of several things: decay left under fillings to infect the pulp and give rise to apical abscesses, poorly prepared cavities from which fillings easily become loose, poorly fitting fillings which permit of decay around their edges, difficult work neglected , and good teeth sacrificed to poor judgment. In dentistry as in other things one does not get something for nothing. The ultimate cost of poor dentistry is much greater than the cost of good work in the first place.
A publication of the American Dental Association states that dental research has as yet found no way to prevent caries. The only satisfactory method of combating the disease is to fill affected teeth during the early stages of decay. Without this is done, the teeth attacked by caries will be lost in almost every instance. Thus, the only logical present method of meeting the dental health need of school children is to fill all carious permanent teeth.
Teeth should be cleaned and examined at regular intervals of 6 or better still, 3 months. The thorough cleaning aids in the prevention of decay and the examination discloses cavities when they are just beginning and as yet of minor importance. If cavities are properly filled when small, the progress of decay is arrested and the structure of the tooth saved. To postpone or neglect necessary dental work is no economy. To be most effective, routine dental care should begin at the age of two. Dentistry is expensive, and even the most skillful reconstructive work is not nearly as satisfactory as sound, natural teeth.
Disagreeable odor of the breath may come from decay teeth, from collections of decomposing food between the teeth, from infections in the nose or sinuses, from plugs in the crypts of the tonsils, or from malodorous volatile substances eliminated from the blood stream through the lungs . The conditions affecting the teeth can be corrected by dentistry and dental hygiene; nose and throat infections, by medical care. The excretion of unpleasant odors from the lungs can be reduced if not eliminated by diets of low fat content. Mouthwashes may temporarily mask unpleasant odors but they never really eliminate the odor or remove its cause.