Abstract
Self-curing acrylic resins for pattern have been recently developed and applied in clinics. However, the inadequate dimensional stability caused by curing shrinkage has been reported concerning the various applications of resins for pattern.
The purpose of this investigation was to examine the effects of residual monomer, production temperature of pattern, water absorption, thermal expansion and pattern shape on dimensional change after polymerization of resin. Three commercial acrylic resins, in which the amount of residual monomer of set materials was markedly different were used. And three cylindrical specimens of different diameter and full crown shaped specimen were prepared.
According to the increase of the surface area per unit mass of pattern, the amount of residual monomer and linear shrinkage increased. And when the production temperature of pattern was high, the linear shrinkage after setting time decreased. The absorbed water increased with elapsed time and all patterns showed expansion when water was absorbed. The heat-treated pattern expanded proportionaly. And the coefficient of thermal expansion of resin for pattern was less than that of wax.
