A practical treatise on the technics and principles of dental orthopedia and prosthetic correction of cleft palate . combinationin the flask for subsequent castings; the exposed surfaces to be poured against beingcovered with a thin coating of plumbago. If the first pouring of the metal cast Ais found to be perfect, it can be immediately replaced in the flask with the Invest-ment E (if not broken) and without further drying (if it is still hot) the second halfof the cast A can be poured. When the two pieces which form the metal duplicates of the model A aresecured, the next castings to be obta
A practical treatise on the technics and principles of dental orthopedia and prosthetic correction of cleft palate . combinationin the flask for subsequent castings; the exposed surfaces to be poured against beingcovered with a thin coating of plumbago. If the first pouring of the metal cast Ais found to be perfect, it can be immediately replaced in the flask with the Invest-ment E (if not broken) and without further drying (if it is still hot) the second halfof the cast A can be poured. When the two pieces which form the metal duplicates of the model A aresecured, the next castings to be obtained are the duplicates of the original nasaland palatal models B and C, which surroimd the model of the obturator. Fig. 31. The Metal Casts of the Original Plaster Models B and C It makes no difference which of the two remaining models of the original setis cast first, though it is usually easier to duplicate the nasal cast B last. In thisdescription, however, the nasal cast B is made first, i. e.: Place the right and leftmetal castings A in the flask with the original plaster nasal model B, Fig. 37. Fig. Before doing this secure a perfect coaptation of the contact surfaces of the metal castsand plaster model, especially along the border y which may be understood asrepresenting the entire border of the nasal portion. The interferences to the perfectcoaptation of the plaster and metal pieces are commonly due to imperfections of themetal castings at their outer borders next to the flask where they have followedslight fractures of the investment model. The fitting is usually done outside of theflask, either by cutting away the metal or the plaster at interfering points. Finally,see that the surface of the plaster model B is well coated with lubricants, and thenasal cover of the flask secured in place to prevent the slightest pour investment G jogging it so that it will flow and completely fill to theirvery outer borders the deep interspaces, which represen
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Keywords: ., bookcentury1900, bookdecade1920, bookidpracticaltre, bookyear1921
