. A manual of mechanical dentistry and metallurgy . ly all of the wax rim will be em-bedded in the upper portion of the flask. \\dien the necks of the teeth are to rest upon the naturalgum, as shown in Fig. 19, the investing plaster shouldextend to the cutting edges of these teeth so as to retainthem in the lower section of the flask. This is illustratedin Fig\ 21. ^^hile the plaster is setting, trim the surface up to theshape or slant desired, avoiding undercuts, leaving it assmooth as possible. After it is thoroughly set, varnishthis surface with shellac, and when dry give it a thin coatof o
. A manual of mechanical dentistry and metallurgy . ly all of the wax rim will be em-bedded in the upper portion of the flask. \\dien the necks of the teeth are to rest upon the naturalgum, as shown in Fig. 19, the investing plaster shouldextend to the cutting edges of these teeth so as to retainthem in the lower section of the flask. This is illustratedin Fig\ 21. ^^hile the plaster is setting, trim the surface up to theshape or slant desired, avoiding undercuts, leaving it assmooth as possible. After it is thoroughly set, varnishthis surface with shellac, and when dry give it a thin coatof oil or the soap solution. Care should be taken not toallow the varnish or oil to come in contact ^vith the teeth. The ring or upper section of the flask should now^ be 46 MECHANICAL DENTISTRY AND METALLURGY. placed on the lower portion which contains the teeth. Aperfect joint should l>e secured between these two sections,the plaster should be mixed as before, and poured into thisring while in position, jolting the flask at the same time Fig. to induce the plaster to run around the teeth perfectly andto force the air out. After the flask is well filled, the toppiece should be placed in position and forced home, whichw^ill drive out any surplus plaster; this pressure should becontinued until the plaster has thoroughly set. Fig. 22.
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Keywords: ., bookcentury1900, bookdecade1900, bookidman, booksubjectmetallurgy
