. The science and practice of dental surgery. triturated together in a mortar, paUadium and mercury do not combine at once; whenthe union does occur, it is somewhat sudden,and a certain amount of heat is generated,indicating a chemical union. Palladium amalgam sets rapidly,yielding a plug that exliibits a largedegree of expansion, which continuesfor a fairly long period. In the mouththe fiUmg becomes jet black in colour;it does not, however, stain tlie toothtissue. The Mixing of Dental Amalgams.—Ithas already been indicated that theamount of mercury required to make amass that is easily
. The science and practice of dental surgery. triturated together in a mortar, paUadium and mercury do not combine at once; whenthe union does occur, it is somewhat sudden,and a certain amount of heat is generated,indicating a chemical union. Palladium amalgam sets rapidly,yielding a plug that exliibits a largedegree of expansion, which continuesfor a fairly long period. In the mouththe fiUmg becomes jet black in colour;it does not, however, stain tlie toothtissue. The Mixing of Dental Amalgams.—Ithas already been indicated that theamount of mercury required to make amass that is easily manipulated andthat may be condensed without diffi-culty varies with the constitution,character, and method of preparationof the primary alloy. Some excess ofmercury over and above what is neces-sary to satisfy the chemical affinities ofthe constituent metals is required, asotherwise the mass cannot be renderedsufficiently plastic; but the limitationof this excess to a uniform minimum, as wellas evenness m its distribution, are matters of. Fig. 456.—TuUochs amalgam alloy measure. (Trans. Odont. Soc.) the first importance. Amalgamation is effectedin various ways : by trituration with pestleand mortar; by shakmg the finely divided alloy 393 and mercury together iii a test tube; or bymerely rubbing tliem together ui the palm ofthe hand. The first of these is the methodmost generally adopted and is the best; further,the mortar should be warmed. The filings having been incorporated withthe mercury, it is a common practice to expresssome of the excess mercury by squeezing it outthrough a cloth or piece of chamois a procedure cannot but lead to a lackof uniformity in the results achieved. Ifsome of the expressed mercury Is exammed,and a globule of it made to roll do«ii a smoothincline, it will at once be observed that it iscontanimated by some other metal, as evidencedby the fact that, when rolling, it does not main-tain the form of a perfect sphere. With themercury
Size: 1475px × 1694px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectdentistry, bookyear19
