Abstract
The impact properties of polymethyl methacrylate (PMMA) denture base resins were examined using an impact testing machine. Within the range of specimen cross-sectional area from 3.2mm2 to 7.2mm2, the impact strength, resilience and toughness increased markedly according to an increase in the cross-sectional area without the V-notch portion. However, these three properties decreased linearly with an increase in distance (span) between the supporting points of the specimen. In the case of a cold cured resin, the modulus of rupture and resilience increased slightly with time after the polymerization, and the impact strength and toughness showed a slight decrease.
