Effect of Silane Coupling Agent Content on Mechanical Properties of Hydroxyapatite/Poly(methyl methacrylate) Denture Base Composite

In removable prosthodontics, poly(methyl methacrylate) is the most suitable for the construction of denture bases. Intra-orally, the subjected stress intensity during the function accelerate the fracture of acrylic resin denture bases. Extra-orally, fracture occurs when dentures are accidentally dropped on a hard surface. The aim of the current study was to investigate the effect of coupling agent concentration on the mechanical properties of Hydroxyapatite/Poly(methyl methacrylate) denture base composite. The HA treated with four different ratios (i.e. 0, 5, 7 and 10 wt%) of γMPS silane coupling agent was added into the PMMA matrix. The mechanical performance of the composite was evaluated by conducting fracture toughness, flexural and tensile tests. An improvement of 13.83% and 9.62% in the tensile and flexural strength respectively, was achieved. The tensile and flexural modulus of the composite increased by 19.04% and 12.5% respectively. A significant improvement of 29.26% in the fracture toughness was observed at 10 wt% of γ-MPS . 10 wt% of γ-MPS is the optimum amount of coupling agent for obtaining a balanced mechanical properties.