A practical treatise on artificial crown- and bridge-work . a- much as possible in size, and additional investing material,composed of two parts marble-dust and one of plasterV^pplieduntil all of the bridge is covered except the space along thebackings and crowns where they are to be united in the solder-:ing. To prevent fracture during the process of soldering, which yv au,V COXSThUTloX OF BRIDGE-WORK. 159 Fig. 308. might readily occur from contraction in so large an investment,an iron wire or a narrow horse-shoe shaped strip of sheet ironshould be placed in the investment so as to encircle t
A practical treatise on artificial crown- and bridge-work . a- much as possible in size, and additional investing material,composed of two parts marble-dust and one of plasterV^pplieduntil all of the bridge is covered except the space along thebackings and crowns where they are to be united in the solder-:ing. To prevent fracture during the process of soldering, which yv au,V COXSThUTloX OF BRIDGE-WORK. 159 Fig. 308. might readily occur from contraction in so large an investment,an iron wire or a narrow horse-shoe shaped strip of sheet ironshould be placed in the investment so as to encircle the teethand crowns about one-fourth of an inch from their exterior sur-face (Fig. 307). In fibe spaces between the backings pieces ofgold or platinum plate or wire, about one-eighth of aii inchlong, are placed lengthwise, and the joints well soldered V(wi20-carat gold sokler. The soldering is best done with a gas blow-pipe on a piece of charcoal with a concave depression. When thebridge is removed for finishing, the joints of the backings andcrowns are fi
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherphila, bookyear1889
