Two=part crown for tooth - is mfd. by forming via mould using plastics which leaves no residue when burnt

摘要

The method is for prodn. of a crown to fit the stump of a tooth. A layer of wax (6) is placed around the stump (4) and a cap (1) is fitted over the wax. This cap (1) is made from a type of plastics which when burnt leaves no residue. The cap (1) together with the wax (6) is removed from the stump and enclosed in plaster of Paris. When the plaster has hardened it is heated to melt the wax (6) and burn away the plastics cap (1) so that a hollow space is formed inside the plaster. This hollow space serves as a mould for casting a two-part crown which can form part of a dental bridge. USE - Prodn. of crown to fit over stump' of tooth.