Flexural fatigue of denture base polymer with fiber-reinforced composite reinforcement

Flexural fatigue of denture base polymer with various fiber reinforcements was investigated. The test specimens (3×5×50 mm3, n=6) were made of autopolymerized polymethylmethacrylate (PMMA). The following fiber reinforcements, referred to as partial fiber reinforcements, were embedded into the denture base resin: ribbon polyethylene fibers, unidirectional dimethacrylate-impregnated glass fibers, dimethacrylate-PMMA-impregnated glass fibers and PMMA-preimpregnated glass fibers. Number of cycles to failure was measured in water by the constant deflection fatigue test with a maximum of 100,000 cycles of the test specimens with partial fiber reinforcement placed at various locations, namely, on the compression or tension side. Magnitude of deflection was 1 mm and loading frequency 2.0 Hz. The number of loading cycles needed to cause a fracture in the test specimen was considered the fatigue failure of the specimen. The results of this study suggest that the fiber reinforcements that allowed even fiber distribution in the cross-section or were placed on the tensile side reinforced the test specimens of PMMA most effectively. The PMMA-preimpregnated glass-fiber reinforcements resulted in a higher number of loading cycles (maximum 100,000) than polyethylene fiber ribbon (2886 cycles in compression, 23,220 in tension).