GB866118A - Improvements in or relating to the preparation of individual tooth prostheses - Google Patents

Abstract

866,118. Moulding an aid for making a tooth crown. LANGENSCHEIDT, A. Aug. 12, 1957 [Feb. 18, 1957], No. 25445/57. Class 87(2). [Also in Group VI] A device for use in preparing an individual tooth crown comprises a shell to be accommodated in and secured against rotation in a plaster work model and a pin having a head on which the crown is to be modelled and a tail which is a snug fit in the shell in such a manner that it is prevented from rotating about its longitudinal axis in the shell. The shell 1 and the tail of the pin 2 are both of circular crosssection and each has a projection or detent to prevent its rotation in the plaster model and the shell respectively. Alternatively, the shell and the tail of the pin are of irregular polygonal cross-section. An impression of the tooth stump which is to receive a crown, is made in moulding material 8 in a copper ring 7 over which a larger impression 6 of the patient's mouth is made. The cavity 9 formed in the moulding material 8 by the tooth stump is filled with modelling compound into which is pressed the head of the pin 2 which may have the shape of a tooth crown on a reduced scale. The mouth impression containing the pin 2 and shell 1 is then filled with plaster. After setting, the plaster model containing the shell 1 and the pin 2 which carries a model of the stump formed by the cavity 9, is removed from the impressions, the pin 2 being readily detached from the model for the shaping of the crown.