[Polymerization shrinkage and fitness of denture (author's transl)].

Polymerization shrinkage causes dimensional change of denture during the processing. We can not control the amount of shrinkage but can control the initiation points and the direction of polymerization. Heat conductivities of dough and mould, the distance from heating or cooling place, and amount of MMA etc. have influence on the polymerization. Polymerization shrinkage mainly appears on the point where polymerize last. In the case of heat processing the shrinkage mainly appeared on the point where heat supply was slow. On the other hand in that of self-curing resin, the polymerization starts at the center of the mass when the mould is immersed in an ice water bath and the shrinkage appeared on the surface of mass. Dentures were prepared by heat processing resin conventionally heated in a water bath, heated from mucous side only on a heat plate, and self-curing fluid resin. An amount of filled light body silicone impression materials between the denture and cast was minimum in the case of the one side heat processed denture. That was middle in the self-cured. The maximum case was conventional heat cured denture.