Abstract
The purpose of this study was to examine the polymerization method suitable for the microwave-curing type denture base resin depending on the adaptability and physical properties of the resin while varing microwave irradiation conditions.
Under condition of microwave irradiation at 500 W, the resin was exposed to themicrowave for 2, 3, 4 and 5 minutes. And also under condition at 90 W, the resin was exposed to the microwave for 10, 15, 20, and 25 minutes. Irradiation was directed to mucosal side, occlusal side, and both sides. For two-stage polymerization, irradiation was first carried out at 90 W for 13 minutes and then at 500 W for 1.5 minutes from the mucosal side.
The results were as follows:
1. Better adaptability was obtained by irradiation at 90 W and two-stage polymerization than irradiation at 500 W.
2. Surface roughness of the resin was smoother in irradiation at 90 W and two-stage polymerization than irradiation at 500 W.
3. Irradiation at 500 W and two-stage polymerization produced high transverse strength and Knoop hardness than irradiation at 90 W.
4. Fewer internal poroes were observed with irradiation at 90 W and two-stage polymerization than irradiation at 500 W.
5. Low residual monomer was obtained by irradiation at 500 W and two-stage polymerization than irradiation at 90 W.
