Dentin

“ Disposition to caries shows itself even in the developing tooth in the composition of its enamel, which is undulating, whereas teeth with quite smooth enamel have much greater power of resistance. The enamel appears to be the only tissue in the body which is subject to no metabolism, and which remains quite unchanged. Every alteration in it which is caused by external influences, and every defect of the enamel, remains during the whole of life, and can never be repaired. Dentine also shows differences in structure as regards its disposition to caries. ”

“ When the complex molar cuts the gum, the cement is first rubbed off the digital summits; then their enamel cap is worn away, and the central dentine comes into play with a prominent enamel ring; the digital processes are next ground down to their common uniting base, and a transverse [Pg 271] tract of dentine, with its wavy border of enamel, is exposed; finally, the transverse plates themselves are abraded to their common base of dentine, and a smooth and polished tract of that substance is produced. ”

“ He admits the existence of distinct germs for the enamel and for the dentine. According to him the incisors are formed from three points of ossification, the canines from one, and the molars from three or four. The tooth after its eruption is an extraneous body “with respect to a circulation through its substance, but they have most certainly a living principle by which means they make part of the body, and are capable of uniting with any part of a living body.” The milk teeth, says Hunter, are not shed by a mechanical action of the second teeth, but by an organizing law of Nature. ”

“ The microscropical structure consists of a simple pulp-cavity in the centre of a body of dentine permeated by calcigerous tubes, but with this peculiar modification, that the dentine is traversed by vascular canals, radiating at definite intervals from the pulp-cavity nearly to the periphery of the tooth, and running parallel with the calcigerous tubes; thus constituting a softer and coarser dentine than in the other reptiles, and resembling that which characterizes the teeth of some of the herbivorous mammals. ”

“ The teeth are thus nourished like other parts of the body. The exposure of the delicate pulp to the air, due to the decay of the dentine, gives rise to the pain of toothache.
Surrounding the cavity on all sides is the hard substance known as the dentine, or tooth ivory. Outside the dentine of the root is a substance closely resembling bone, called cement. In fact, it is true bone, but lacks the Haversian canals. The root is held in its socket by a dense fibrous membrane which surrounds the cement as the periosteum does bone. ”

“ They are readily recognized by their large incisors. These teeth grow throughout life, and if they are not constantly worn away by gnawing upon hard food, they become inconveniently long, and may prevent closing of the mouth and cause starvation. The hard enamel is all on the front surface, the dentine in the rear being softer; hence the incisors sharpen themselves by use to a chisel-like edge. ”

“ By this last active agent they have sometimes been reduced to very fantastic forms. In some cases the enamel of the tooth is worn away, in others the dentine: many of the antler-tips have been so sharpened by it that they may readily be mistaken for human implements. ”

“ The denticle consists of dentine, the spine being of a much denser structure than the base. The teeth and the large spines of the fins and claspers are also composed of dentine and may be considered as modified placoid scales. ”

“ The dentine tubes cither run regularly closely side by side, when the teeth have greater power of resistance; or they branch and surround cellular bodies, or even small air-vesicles, when the teeth fall an easy prey to caries. ”

“ A moment's reflection will show the folly of extracting teeth to make room for those out of alignment, and modern dentistry has
proved that such extraction will defeat the object for which it is undertaken, viz., the restoration of the perfect denture. A man who will extract a tooth in regulating may be foolishly clinging to the old tradition, that was spoken of just now, that the unfortunate child had inherited large teeth from one parent, and small jaws from the other. ”

“ These little germs always get into places that are not kept clean, and when they get into the mouth they go to work, like so many little carpenters, with pick and drill, and pick away the [60] outer covering of the tooth and then the tooth decays, and this causes toothache.
We all want to have pretty white teeth like Ned's, do we not? When we are little we must take care of the teeth, and if they begin to decay we must have them filled or treated by the dentist. Let us look at our teeth and see who has the prettiest and the best ones. Has every one a toothbrush? We must each have one. ”

“ It is plain enough that ninety per cent, of dental work might have been avoided; just as ninety per cent, of the sickness and premature death in the world is needless and could be prevented. The dentists have made the astonishing discovery that they can alter and enlarge the jaws of any child by simple means and they have found out, moreover, that the teeth themselves and their arrangement are the pattern from which the jaw takes its shape. ”

“ Provided, that the lower jaw and the tongue and lips are strong and well developed, made so by sufficient chewing, especially from the years of two to six, in a child's life. If the child's education in chewing, however, has been neglected, the dentist can and does spread the jaw as already stated, so that it will have room enough for all the teeth. In other words, orthodontia does what nature would accomplish unaided were her simple laws of development properly observed.
A full set of teeth forms a beautiful arch, no stone of which should be missing. ”

“ In cases of difficult dentition, the best remedy, according to Musitano, for facilitating the eruption of the teeth consists in friction of the gums, once, or at most twice, with blood drawn fresh from the comb of a cock!249 If, however, even this remedy fails to produce the desired effect, it will then be necessary to lance the gum at the point where the tooth is to erupt, or to press it hard with the thumb, that the tooth may the easier come through. ”

“ The brain of the hare can, by being rubbed on the gums and jaws, serve for two important purposes, since it has not only the virtue of facilitating dentition, but also of making teeth grow again to those who have lost them! The brain of a partridge applied to a carious tooth makes it fall in pieces!
The treatment of odontalgia embraces, according to Gaddesden, both general and special means of cure. To the former belong purgatives, bloodletting, scarifications of the labial and sublingual mucous membrane, leeches, the application of scarified cuppings under the chin. ”

“ We do not, of course, know how often the question has applied to the actual and complete loss of the teeth, or only to some interference with the teeth cutting the gum, occasioned by a limitation of the necessary space. However, it must be remembered that the shortening of the jaw stands in direct correlation with the reduction of the dentition. A prediction of the man of the future is given us by Cope: the lower races of men will retain the dentition of the present day, incisors , canines , premolars , molars ”

“ Great care is required in compounding dentifrices and mouth-waters, and special attention must be paid to the correct selection of the material. The substances used must be chemically pure, and no caustic or sharp or grating materials, such as pumice, sand, ossa sepiæ, etc., should be employed, they destroying the enamel of the teeth.
The coloring substances used to give the dentifrices and mouth-waters a pleasing appearance should under no condition be injurious or poisonous, such as, for instance, brilliant rosa, cinnabar, aniline, chrome yellow, picric acid, etc. ”

“ The development of the profession of dentistry has made possible the preservation of the teeth, even when naturally poor, as long as one has need of them. To preserve the teeth they must be kept clean. They should be washed at least once a day with a soft-bristled brush, and small particles of food, lodged between them, should be removed with a wooden pick. The biting of hard substances, such as nuts, should be avoided, on account of the danger of breaking the enamel, although the chewing of tough substances is considered beneficial. ”

“ An artificial dentifrice will certainly keep the teeth white, but that does not prevent their premature decay; disuse gradually softens their substance, till one fine day the hash-eater snaps his best incisor upon an unexpected piece of bone. Every old dentist knows hundreds of city customers whom the daily use of a tooth-brush did not save from the necessity of applying, before the end of the fortieth year, for a complete "celluloid set." ”

“ Butter, either alone or with honey, is very useful for children; and is very helpful, especially during dentition, in the diseases of the gums, and to cure the ulcers of the mouth. To prevent the disorders that generally accompany dentition, it is a useful thing that the child should wear a wolf’s tooth, or one of the first teeth lost by a horse. ”

“ Then a deep groove is made in the middle of the upper teeth, crossing them all, and itself cutting through at least one-fourth of the whole thickness of the teeth, so that the enamel is cut quite through, a fact which we Europeans, who are taught by our dentifricators that any damage done to the enamel is mortal to the tooth, find it difficult to believe. ”

“ The tooth pushes thru the gum; and as it goes by, the cells at the sides of the pocket and on top plaster it with a coating of enamel. Therefore, as most of us find out to our cost, this enamel once destroyed, can never grow again. Once clear of the pocket where it was formed, it has to last us the rest of our lives; and little boys and girls who don’t keep their teeth clean when they are young, have to put up with something not nearly so good when they are grown up. ”

“ In general, when the permanent teeth are irregular, one or more should be removed. If the teeth are crowded and irregular, in consequence of the jaw being narrow and short, or when they press so hard upon each other as to injure the enamel, remove one or more to prevent their looking unsightly, and in a few months the remaining teeth, with a little care, will fill the spaces. ”

“ Thus they all have the same number of teeth as man—possessing four incisors, two canines, four false molars, and six true molars in each jaw, or 32 teeth in all, in the adult condition; while the milk dentition consists of 20 teeth—or four incisors, two canines, and four molars in each jaw. They are what are called catarrhine Apes—that is, their nostrils have a narrow partition and look downwards; and, furthermore, their arms are always longer than their legs, the difference being sometimes greater and sometimes less ”

“ I. All men's teeth are naturally in a state of total decay or caries, and, therefore, no man can bite until every one of them is extracted and a new set is inserted according to the principles of dentistry adopted by this Society.
I, for one, should want to discuss that before signing my name to it, and I should say this:—Why, no, that isn't true. There are a good many bad teeth, we all know, but a great many more good ones. You mustn't trust the dentists; they are all the time looking at the people who have bad teeth, and such as are suffering from toothache. ”

“ And between the lips were teeth that had never known nor needed the dentist's care. They were white and strong and regular, he decided, as he looked at them. But as he looked, he began to be troubled. Somewhere, stored away in the recesses of his mind and vaguely remembered, was the impression that there were people who washed their teeth every day. They were the people from up above--people in her class. She must wash her teeth every day, too. What would she think if she learned that he had never washed his teeth in all the days of his life? ”

“ Each tooth has a biting part or crown covered by enamel, a neck Where the gum surrounds it, and one or more roots or fangs fitting into sockets (alveoli) in the jaw bone. For surgery of the teeth see Dentistry.
There are thirty-two permanent teeth in man, sixteen in the upper and sixteen in the lower jaw; they are also arranged in symmetrical sets of eight teeth on each side. ”

“ Leeks must not be eaten, as such a food, by its own nature, is injurious to the teeth. (8) The teeth must be cleaned, at once, after every meal, from the particles of food left in them; and for this purpose must be used thin pieces of wood somewhat broad at the ends, but not sharp pointed or edged; and preference should be given to small cypress twigs, to the wood of aloes, of pine, rosemary, of juniper, and similar sorts of wood which are rather bitter and styptic; care must, however, be taken not to search too long in the dental interstices and not to injure the gums or shake the teeth. ”

“ The teeth are a fruitful source of suffering and of disease; and are, with truth, styled "our first and our last plagues." Dentition is the most important period of a child's life, and is the exciting cause of many infantile diseases; during this period, therefore, he requires constant and careful watching. When we consider how the teeth elongate and enlarge in his gums, pressing on the nerves and on the surrounding parts, and thus how frequently they produce pain, irritation, and inflammation ”

“ Fig. 303.—Dental plates of Dipterus valenciennesi, nat. size. A, Upper jaw; B, lower jaw. n, Position of the nostrils; p.p, palatine dental plates; p.pt, palato-pterygoid bones; sp, splenial teeth. (From Smith Woodward, after Traquair.)
Fam. 1. Ctenodontidae.—Body fusiform. Tail heterocercal or apparently diphycercal. Excluding the anal fin, which is always distinct, the remaining median fins are either distinct or continuous. Dental plates traversed by radiating transverse ridges terminating in rows of conical denticles (ctenodont dentition, Fig. 303) . Vomerine teeth not known. ”