DISEASES OF TUE TEETH.—The dangers to which infants and children are exposed during the process of teething, are noticed in the article DENTITION; and we shall there fore here confine our remarks to the affections of permanent teeth, of which the follow ing are the most important: 1. Caries of the teeth, usually commences in the dentine immediately below the enamel, a yellow or brown spot being observed on the surface of the tooth over the affected part. The tissue soon becomes softened, and a small cavity is formed, which, after a time, presents an external opening, in consequence of the unsupported enamel giving way. The substance of the tooth now decays more rapidly, and the caries grad ually approaches the central or pulp cavity, which at length is opened. Hitherto, there has been little or no suffering, but now pain is experienced under the action of irritant substances, heat, cold, etc. Inflammation proceeding to suppuration takes place; the pulp is gradually destroyed by ulceration; and the body of the tooth, thus deprived of its nourishment, decays and leaves nothing but the outer coating of enamel, which then breaks away by degrees, till nothing but the fangs of the tooth remain, and these usually cease to give pain. Caries is not only a common cause of toothache, but frequently gives rise to obstinate headache, pain in the ear, deafness, squinting, impossibility of bearing the light (photophobia), and other anomalous symptoms, which immediately disap pear upon the removal of the diseased tooth. Iu these cases, the tooth may never have ached, but will be found painful when pressed up or smartly struck. The primary cause of caries is constitutional, and it especially occurs in scrofulous and ill-nourished persons, or in those whose health is broken down by too frequent pregnancies, pro longed lactation, the abuse of mercury, etc. The direct or exciting causes are usually described as: (1) Such as destroy the integrity of the enamel, and thereby expose the dentine to the influence of irritant substances; or (2) such as operate upon the vital sus ceptibilities of the dental tissues. Among the former are acids and other corrosive sub
stances taken into the mouth, sour eructations, the attrition of opposing surfaces of the teeth, and all kinds of mechanical violence; while among the latter may be mentioned hot and cold drinks, especially when taken in quick alternation. The excessive use of sugar is also commonly regarded as a cause of the disease. Many of the best dentists, however, deny that acids (when taken medicinally) or the abrasion of the enamel can give rise to caries.
With regard to treatment, it may be observed that if the caries be slight and recent, the decayed portion must be removed, and the cavity filled up with gold, as described in the article DENTISTRY. " But," says Dr. Druitt, who on dental matters always quotes the opinion of Mr. Tomes, one of the greatest scientific authorities on the diseases of the teeth. " if the decay has advanced far toward the pulp cavity, or has laid that open, it may he necessary first to employ aperients and tonics, and use some application to deaden the sensibility of the tooth, so as to enable it to bear the stopping, and to protect it mean while from contact with food and saliva." Many a useless visit to the dentist might be avoided, if the patient would take au aperient dose of epsom salts two or three consecu tive mornings; and after cleansing out the cavity with dry cotton-wool, would insert twice a day a plug of that substance, moistened in eau de cologne, or still better, in either of the following solutions : (1) Mastic solution, formed by dissolving a dram of mastic in an ounce and a half of can de cologne; or (2) Ethereal tincture of tannin, formed by dissolving a dram each of tannin and mastic in an ounce and a half of sulphuric ether. By these means a painful tooth may be often brought into a state in which it will bear stopping. The patient's sensations will warn him against drinking very hot or cold, or sweet or acid fluids, and against exposure to cold draughts of air. Whenever the teeth exhibit a tendency to rapid decay, general tonic treatment is indicated.