Page:The New International Encyclopædia 1st ed. v. 06.djvu/167

* DENTISTRY. 133 DENTISTRY. dentistry in 1728, and Houiilet in 1757. John Hunter in 1771 published his Treatise on the Natural History of the Human Teeth, and in 1778 A I'raetical Treatise on Diseases of the Teeth, as a ^;uI)I)Ionlont to his former work. Not being a dental speiialist, liowever, he wrote ana- foniically and philosophically, rather than prac- tically. W'ool'endale's I'ruetival Obscriatioiis on the Human Tntli were puhlished in London in 1783. Blake wrote on dentistry in 1798 or 1801. •Since the beginning of the nineteenth century a considerable amount of original research has been carried on in all branches of dental science, and a large and increasing number of treatises have been devoted to dentistry exclusively. Histology. d Developmekt. The micro- scope has done much to improve the ])raetice of modern dentistry. Leeuwenhoek was the first to give an intelligent idea of the histological structure of the teeth (C.1GS2). The main work, liowever, on the embryology, histology, and path- olog)" of the teeth, was done during the nineteenth century. The first rational theory of the evolu- tion of the teeth was advanced by Goodsir in 1837. In 1800 ^obin and Magitot brought forth a better theory in regard to the mode of develop- ment of the teeth, and their theory, with very- little moditication, is accepted at the present time. See Teeth. Abtifici.vl Dentures. Prior to the discovery of the method of making porcelain teeth, the dentist made use of human teeth, animal teeth (those of cattle and sheep), hippopotamus tusks, elephant and other ivories, and bone. The human and animal teeth were fastened in the mouth by ligatures of gold or silver wire, tm- bleached thread, sea-grass, or silkworm gut. The hippopotamus or elephant ivory, or the common bone, was carved in single teeth or blocks, and perhaps in the shape of full or partial dentures, to replace the lost natural teeth. The objections to this method of restoration were the difficulty of getting accurate adaptation in the mouth, and the tendency, because of the porosity of the material, to absorb moisture, to become oiTensive, and ultiniatelv to decay. The use of porcelain as a material for artificial teeth was first pro- posed by Fauchard in 1728; but the manufacture ••f porcelain teeth was first actually begun by Duchateau. a French cliemist, assisted by Du- bois, a dentist of Paris, somewhere between 1774 and 177G. The date of the introduction of metal bases in prosthetic dentistry is not definitely known. It is believed, however, that gold was the first metal used as a base for artificial teeth, and that Dr. Gardette, of Philadelphia, was the first to use the gold base in this country, in or before 1787. Among the other metals which have been used as bases for artificial dentures are silver, platinum, aluminum, tin, and various metallic alloys: but at the present time gold and platinum are the only metals in general use for that |)urpose. Ontta pcrrhii as a base was introduced in England by Edwin Trueman, about 1851. In 18.11. also. Xelson Goodyear discovered a method of making a hard rubber compoimd, since named rnlrnnii''. and in IS'i.') Charles Good- year, .Ir., obtained a patent in England for making a dental plate of hard rubber, in which the teeth were secured before the compound was vulcanized. Rosr-penrl. a preparation of collo- dion, was next experimented with .ns a base, but, owing to the dilliculty of manipulating it, and to its lack of durability, it fell into disuse. Cellu- loid was the ne.xl material tried, but, being more porous and less durable than vulcanite, it is seldom used at present. Porcelain and a com- bination of jilatinum and porcelain have lieen used as bases for artiliiial dentures. Porcelain alone <li(l not come into general use because of the dilli- culty of manufacture, brittleness, and danger of shrinkage or vari)ing during the process of firing. The combination of porcelain and platinum (continuous gum) is made as follows: A base of platinum is swaged to fit the mouth, the arti- ficial teeth are lined with metal and soldered to the platinum base; a porcelain body of the proper shade is next molded about the necks and root portion of the artificial teeth, as well as upon the exposed surfaces of the platinum, and carved and colored to imitate the natural mucous membrane of the mouth : the entire piece is then put in an oven and baked long enough and often enough to fuse the porcelain properly. This method of inserting artificial teeth is one of the best at our command, so far as beauty, cleanliness, durability, and correct imitation of nature are concerned. Crown and Bridge Work. Jlodern bridge- work (or the insertion of artificial teeth by means of bands, springs, or artificial crowns attached to the crowns or roots of natural teeth) is but a modification of methods pursued by the ancients many centuries before the Christian Era. The use of bridges is not infrequently car- ried to extremes, and bulky bridges are some- times attached to teeth which are incapable of bearing the strain for any length of time. Poorly nuide or improperly adapted bridges are fre- quently inserted, and are prolific sources of pol- lution of the secretions of the mouth ; and some cases of movable or immovable bridges require considerable sacrifice of natural tooth structure, or perhaps devitalization of the pulp, in order that the bridge may be properly adjusted. It is sometimes a diflicult matter to determine the best means of restoration or prosthesis in these cases, but the conservative dentist will hesitate, and perhaps prefer a partial denture, rather than resort to the sacrifice of those tissues for the sake of introducing a bridge. Gold shell crowns, for the purpose of covering teeth too badly broken down to be amenable to the operation of filling, are supposed to be of quite recent invention, but it is claimed that their use was suggested by il. Mouton. of Paris, as far back as 1746. It is said also that Mouton advised enameling the exposed surfaces of such crowns. Gold crown -work has been abused even more than bridge-work, and we frequently find gold crowns jilaced on the anterior teeth to pro- tect them when injured or diseased, or to serve as abutments for bridges when crowns of porce- lain or porcelain-faced crowns would answer the l)urpose as well, and he much more sightly. Many patients will insist on a dentist placing fi gold cap or shell crown on a tooth, when a filling of some sort would Ix? very much better and nuich more artistic. Fortunately, the laify, as well as the dentist, are beginning to appreciate the enor- mity of this oficnse against good taste. Fri.r.iNcs, etc. The filling of teeth is now fonietimes called nhturnlion. Before the intro- duction of gold, lead foil was used as the ma- terial for filling teeth. Celsus (li.c. 100) is sometimes referred to as the first to have advised