Properties improvement of acrylic resin for denture application: effect of single and hybrid types of fillers with different weight loadings

This research aims to identify the suitable and optimum filler loading to improve the polymethyl methacrylate (PMMA) properties for denture application. Mechanical properties were determined based on the flexural, fracture toughness, hardness and impact strength. The first stage investigated the effect of different weight loadings of hydroxyapatite (HA) and beta-tricalcium phosphate (beta-TCP). The addition of 2 wt-% HA in PMMA composites increased the flexural and fracture toughness when compared with beta-TCP composites. The addition of beta-TCP in PMMA composites increased the mechanical properties at higher filler loading; 4 and 6 wt-%. The second stage investigated the effect of hybrid fillers; HA/polylactic acid (PLA) microsphere and HA/alumina (Al2O3). HA/PLA microsphere in PMMA showed 5% and 23% improvement on the fracture toughness and impact strength if compared to PMMA/2 wt-% HA. HA/Al2O3 in PMMA showed higher flexural strength. The mechanical properties of a single filler can be further improved by hybrid fillers.