Of all the substances which are injurious to the teeth, acid saliva, as a primary factor, plays the most important rôle. This condition may be brought about by certain articles of food, such as sugar (Holz), which increase the acidity in the cavities of the teeth, injurious results following. A plentiful meat diet will also cause acid saliva. In addition to its other prejudicial effects upon the substance of the teeth themselves, acid saliva favors the formation of tartar. When the tartar extends under the gum, the latter becomes loosened, and a pocket is formed which constitutes a welcome nidus for a variety of small organisms, suppuration therefore occurring around the neck of the tooth. This may cause the tooth to be irrevocably lost. It is precisely in persons who have the prettiest and most regular teeth that we most frequently see this most terrible disease of the teeth, pyorrhoea alveolaris.
According to Hermann, there may exist a predisposition to this affection, in the sense that it most frequently occurs in diabetics and those suffering from gout. Now, these diseases are very often the result of overnutrition,overfeeding upon meat,so that here also the acid property of the saliva plays a rôle.
If one wishes to protect the teeth, one must always wash out the mouth immediately after eating sugar, honey, acid fruits, fruit acids, grapes, or other fruits, and this is best done with a fluid containing some alkali, e.g., with some alkaline mineral water, or water to which bicarbonate of soda has been added. Toothpastes containing alkalies may also act very favorably.
With a meat diet, it should be remembered that particles of the meat which remain between the teeth may easily become decomposed. A toothpick must then be carefully used; con-forming with good manners, this is best done when one is alone. Antiseptic mouth-washes, odol, for instance, or, even better, hydrogen peroxide, can destroy the bâcteria of decompositions. It is important to cleanse the teeth with a somewhat hard toothbrush after each meal.
The saliva itself exerts a cleansing effect on the buccal cavity and the teeth. Food substances giving rise to much saliva, such as hard bread, may also have a useful action upon the teeth. When much saliva is secreted, the acid resulting from the previous use of sugar, for instance, may be counter-acted through the alkaline property of the saliva. Chewing forms a splendid gymnastic exercise for the teeth, which are correspondingly strengthened by all such foods as require considerable mastication. Hard, black bread, rye bread, is particularly recommended by Roese for keeping the teeth in good condition. He also takes into account the mineral salts, such as lime, contained therein. I feel impelled to remark, however, in this connection that the action of the black rye bread in the intestine is not favorable, and that a rather large proportion of the nutritive salts, and consequently of the lime, is lost. The discovery of Roese, that drinking-water containing lime in-creases the. alkalinity of the saliva, is worthy of note.
The amount of lime contained in the food is of the greatest importance in keeping the teeth in good condition,especially during the period of growth, since the teeth are principally formed of lime and magnesia. According to Roese, as stated above, drinking-water containing lime may act well here; he also mentions the interesting fact that, wherever such water is consumed, the population has fine teeth-yellowish-white teeth are the strongest; where the water is soft, on the other hand, one finds universally poor teeth. By the free use of lime-containing drinking-water, as well as of food substances containing much lime, such as milk, much good may be accomplished in the way of retention of the teeth.
The secretion of saliva is greatly stimulated by chewing, and this is not only beneficial for the teeth, but for the throat as well. In persons who have large tonsils these organs frequently become inflamed; the inflammatory condition, in turn, has a deleterious effect upon the throat, and consequently a chronic inflammation is developed. The secretion of a large quantity of saliva may hère be of much benefit; it is helpful in these cases to use special chewing tablets, such as are much employed in the United States, where gum is prepared with sugar and the various fruit extracts for this purpose, and used in very large quantities. I wish that I could create here a sentiment which would encourage the Austrian and German industries in the manufacture of this “chewing gum” ; this would not only have a beneficial influence upon the throat and the tonsils, but upon the teeth as well, for which it would, with the increased flow of saliva, act as a cleansing agent. It would be necessary, however, that only pure ingredients, and in no case injurious substances, should be used. The use of chewing gum probably originated with the old Aztecs. I found in the British Museum, in the records of the Dominican monk, P. Bernardius Sahagun, who accompanied the Spanish conquerors to Mexico, that the prostitutes, in particular, continually chewed gum (“chicle”). They also had wonderfully beautiful teeth.
The various substances injurious to the teeth, especially acids, may be hurtful to the throat. Alkaline mineral waters are very useful, especially those of the nature of Ems water.
Of the acids, only the very acid fruits act injuriously; those less sour may, unless taken in very large quantities, be advantageous, since they act as a preventive against inflammation of the tonsils.
Certain fruits, such as the bilberry and the blackberry, are good for the throat, and they can be used combined with glycerin in the manner of the English “glycerin and black-currant lozenges” with much benefit. They are especially good for dryness of the throat, and also have a favorable action upon the voice.
A similar effect is produced by all of the mucilaginous and fatty food substances in general, such as glycerin, various oils and fats. The action of raw eggs is well known. Coarse and irritant foods, of a sandy or corn-like consistency, such as nuts, chestnuts, etc., are, on the contrary, injurious.
Honey, and sugar in various forms, e.g., candy, while not exerting a good influence upon the teeth, act favorably upon the pharynx and the voice, especially when, as in the glycerin lozenges, the sugar is added to glycerin. The mucilaginous constituent of many pastilles, as, for instance, those made with Iceland moss, acts very favorably. Such mucilaginous lozenges, of a gummy consistency, may be made of the various algæ, and be employed for lubricating the throat when it is unduly dry, as well as for keeping the throat and voice in good condition. Malt bonbons likewise have a good effect by virtue of their expectorant properties.
Many articles of food, e.g., cheese, act unfavorably upon the voice. Many singers do not drink beer for this reason.
Tobacco, and especially cigarettes, have a most injurious effect upon the throat and voice, and yet great singers like Caruso smoke. I have frequently seen Dalmores smoking cigarettes.
Alcohol is also injurious to the voice when taken in large amount. It may, on the contrary, when greatly sweetened with sugar, especially in the form of Swedish punches,but only of the better kinds, not the “Banco,”act quite advantageously upon the “timbre” of the voice, and make it clearer. At least, I have several times observed this effect. I certainly do not wish to imply, however, that the magnificent voices of the Swedish students’ chorus and their masterly singingprobably the best among the students’ choruses of the worldbear any relationship to their enjoyment of the national punch.