Page:The New International Encyclopædia 1st ed. v. 06.djvu/168

* DENTISTRY. i;u DENTISTRY. filling cavities in teeth; but tlic only reference to the subject in liis works is his reeoiiiuuMulii- tion to stuir with lead . but was little used until its application to dental purposes was patented, and its working quality improved by A. J. Watt, of Itiea, N. Y., in 18.53. In ISoo Ur. Artlnir. of Baltimore, reconnnended the use of cohesive gold lor tilling teeth, and this variety is more used at present than any other. The use of mallet force in tilling teeth with gold was first recom- meiulcd by Dr. William 11. Atkinson, of Xew York. I'laliiium has been tried as a tilling ma- terial, but was found to l>e too luirsli, and to have too little ductility and plasticity to make it valuable for that purpose. It is .sometimes used in combination with gold foil or rolled gold for a tilling exposed to severe stress. .S'l/rc;' is not used alone for fillings, because of its ten- dency to oxidize, and because of its stillness and want of ductility. Tin. in the form of foil, has Ix'en used for tilling teeth since 178;!, and is still used for certain kinds of cavities. The advan- tages of tin are that it is soft, pliable, easily condensed and adapted to cavity walls, a poor conductor of heat, and, in cases of disintegra- tion, yields salts that seem to possess antiseptic jiroperties. Yet its softness, its almost com- ing discolored in the mouth, and its disintegra- tion under chemical and mechanical inlluences, also constitute serious disadvantages. Owing to the dilliculties in i)roperly manipu- lating the simple metals in tilling teeth, etVorts were early made toward discovering some ma- terial of greater adaptability, and. as a result, we have the plastics so extensively used at the present day. The earliest of these materials were preparations of the gum resins, .such as ethereal or alcoholic solutions of mastic, sanda- rac, daniar. or copal. Then fusible metals were employed, until, in IS2(i or thereabouts. Taveau. of Paris, inti(du<cd the use of aniiitiidiiis. . amalgam is a combination of one or more metals with nu'reury. and that first tried was an amal- gam of pure silver. The next amalgam to be used was one of coin-silver. The amalgams as made at present usually consist of a combina- tion of three or more metals with mercury. Such amalgams, manipulated by improved modern methoils. constitute the only plastics that can be considered as pernianent filling materials. The other plastics used at present incluile: (iiitta pereha (introduced in 1847-48) ; "Hiirs stopping* (a mi-xtiire of gutta-percha with harder mate- rials) ; oxy-chloride of zinc (oxide of zinc, with n solution of zinc chloride) ; zinc phosphate (ox- ide of zinc, with a solution of phosphoric acid) : oxy-pho-phate of coppei*: aluminum phosphate; «>xy-sul|>hate of zinc; and other varieties of the cements. Kach of these cements has its definite uses and advantages, but all have the disadvan- tage of serving only as temporary fillings. The fitlinii of pulp-rnnnli) in devitalized teeth was believed to have been introduced bv Mavnard and Haker, of Washington, 1). C. It has been shown, however, that this operation was prac- ticed by Bourdel and Kauchard, in Paris, as far back as the middle of the eighteenth century; and, iiceording to liourdet, had liecn practiced, by others many years before. The C(i/i/)iii;/ (cov- ering over) of cxponiil jiulps is said to have been first recommemled by Koecker. The diiitiil iiiyiiu: in its original form, was introduced by JJr. .Morrison, of Saint l.ouis. Mo., in IS4li: in its various improved forms, it has become one of the most useful of dental appliances. The use of the rubber ilain for the purpose of excluding mois- ture from cavities during the operation of tilling teeth was first suggested by Ur. S. C. liarnum, of Xew York, and this iiuiovation has been as great a boon to dentistry as the intri>duetion of the Esinarck bandage has been to general surgery. Inlay Wohiv. One of the latest innovations in the art of dentistry is inlay work. i. e. the ise of plugs of porcelain, glass, gold, vulcanized rubber, and similar materials, which are ce- mented into a tooth-cavity in such form and shape as to fit it exactly. With the improved methods and nuiterials for making porcelain in- lays, this mode of filling carious cavities is becoming more and more popular, and when per- fected will undoubtedly cause the abolition of gold fillings in the anterior teeth. It may l>e interesting to observe that inlays of green jade, l)laced in the teeth probably for ornamentation, have been found in the ruins of t'opan. llonilu- ras. and of Yucatan. IsKS OF Ki.iccTHU'iTY. Electricity has its jirac- tical applications in dentistry as well as in the arts, and is utilized not only for the control of various mechanical ai)pliances emi)loyed by the operative and prosthetic dentist, but in the form of the electric mouth-lami). the cataphoric current, etc., is used for diagnostic and thera- peutic purposes as well. Cnlupliorcsis. or the method of forcing drugs into the tissues b.v means of the galvanic current, was first jiroposed by Dr. B. W. Richardson as far back as 1857. but has come into general use only within recent years. The X-rays, or Roentgen rays, are now- put to practical u.se in dental as well as in gen- eral surger,v. and as a means of diagnosis are sometimes of very gi-eat assistaiu'c. For the ))nrpose of detecting unerupted or inipa<'led teeth, abnormal growths on or about the teeth, ini|H'rfeet root -canal fillings, resorption of roots, fractures of the jaw, or the presence of foreign bodies in the alveoli of the teeth, the Xray* are of great value and frcipicntly utilized. Theatmknt of Loose Tkktii. The teeth fre- quently become loosened from their attachments ill consequence of hx'al or constitutional dis- turbances, and the treatment of this conditicm is still a somewhat knotty problem. When due to local catises. such as deposits of salivary cal- culus, or ordinary tartar, the treatment is prin- cipally loi'al, and consists in first removing the deposits, getting the teeth as smooth as possible, and then adtqiting i)roper therapeutic and pro- phylactii' nn'asures, with a view to inducing a healthy condition of the soft tissues and prevent- ing a return of the de|iosit. The constitutional cause, which is more often concerned than any other in bringing about the loos4'ning of teeth. i» the .so-called 'goiitv' or 'rheumatic' condition.
 * )U'te lack of cohesiveness, its pro|H'rtj of becom-