Fracture toughness of self-curing denture base resins with different polymerizing conditions

Jeong, Soo Yang; Kim, Ji Hye; Yang, Byung Deok; Park, Ju Mi; Song, Kwang Yeob

Abstract

PURPOSE
The intent of this study was to evaluate the effects of curing conditions on selfcuring denture base resins to find out proper condition in self-curing resin polymerization. MATERIALS AND METHODS: In this study, 3 commercial self-curing denture base resins are used: Vertex SC, Tokuso Rebase and Jet Denture Repair Acrylic. After mixing the self curing resin, it was placed in a stainless steel mold(3x6x60mm). The mold containing the resin was placed under the following conditions- in air at 23 degrees C, or in water at 23degrees C; or in water at 23degrees C under pressure(20psi); or in water at 37degrees C under pressure(20psi); or in water at 50degrees C under pressure(20psi); or in water at 65degrees C under pressure(20psi), respectively. Also heatcuring denture base resin is polymerized according to manufacturers' instructions as control. Fracture toughness was measured by a single edge notched beam(SENB) method. Notch about 3mm deep was carved at the center of the long axis of the specimen using a dental diamond disk driven by a dental micro engine. The flexural test was carried out at a crosshead speed 0.5mm/min and fracture surface were observed under measuring microscope. RESULTS AND CONCLUSION: The results obtained were summarized as follows : 1. The fracture toughness value of self-curing denture base resins were relatively lower than that of heat-curing denture base resin. 2. In Vertex SC and Jet Denture Repair Acrylic, higher fracture toughness value was observed in the curing environment with pressure but in Tokuso Rebase, low fracture toughness value was observed but there was no statistical difference. 3. Higher fracture toughness value was observed in the curing environment with water than air but there was no statistical difference. 4. Raising the temperature in water showed the increase of fracture toughness.