[Three dimensional changes of the denture base of the complete denture following polymerization]

The objective of this study was to clarify some of the dimensional change patterns of the denture base of the complete denture following polymerization. Dimensional changes of three polymerization method types were compared. The complete dentures were measured by using the three dimensional measurement system. The results obtained were summarized as follows. 1. Dimensional changes from the original model immediately after polymerization of complete upper and lower dentures were recorded and all three polymerization methods produced shrinkage on all three axes toward the center. Heat cured resin samples and microwave cured resin samples showed the same shrinkage with pour type resin samples only showing 1/2 that amount. 2. The gradual dimensional changes occurring after polymerization up until 4 weeks were also recorded. The heat cured resin samples showed no additional changes but remained in its shrunken state. The pour-type resin samples began to enlarge until almost all of them reached the original model size within 4 weeks. The microwave cured resin samples began to enlarge but only slightly and then soon stopped changing. 3. All polymerization method types showed more dimensional change in the lower plate than in the upper plate.