PMMA Denture Base Composites Reinforced by Nitrile Rubber and Ceramic Fillers

Poly(methyl methacrylate) (PMMA) denture base composites were fabricated by incorporating nitrile butadiene rubber (NBR) particles and ceramic fillers (Al2O3, YSZ, and SiO2). PMMA powder was mixed with liquid methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) as crosslinking agents. The different types of ceramic fillers were fixed at 5 wt.% and NBR particles in proportions of 5, 7.5 and 10 wt.%, respectively, mixed with PMMA. The impact strength (IS) increased and the fracture toughness (K-IC) decreased with the increase of NBR content in PMMA matrix. The composites with Al2O3 showed better IS and K-IC when compared to YSZ and SiO2 particles. It has been demonstrated that the combination of 10 wt.% NBR/5 wt.% Al2O3 produced the optimum density (1.049 g/cm(3)), IS (7.41 KJ/m(2)), K-IC (2.45 MPa.m(1/2)) and statistically the values was significantly increased (p < 0.05).