Precision investment casting appts - dental restorations produced using wax surrounding plastic material casting tree

摘要

A precision investment casting tree used e.g. for making dental crowns and caps, rings etc. formed of relatively high m.pt. plastics material surrounded by a lower m.pt. wax is built to support a number of small wax patterns. The tree is supported by a base and surrounded by investment material. The plastics members are hollow so that on heatint the wax melts and runs out of the investment material leaving a cavity within the material. On heating again to a higher temp. the plastic melts and runs out of the investment material leaving a sprued investment material which will ensure high quality casting.