Effects of Addition of Aluminum Oxide on Flexural Strength and Hardness of Acrylic Resins

Purpose: Acrylic dentures frequently fracture during service due totheir poor strength characteristics. The aim of this study was to evaluate the effects of adding 5%, 10% and 15% aluminum oxide powder on the flexural strength, surface hardness of a conventional heat-polymerized acrylic resin. Materials and methods: One of the commonly used conventional heat cure denture base resin (DPI) and high impact heat cure denture base resin(lucitone) with incorporation of three different percentage of aluminum oxide concentration was studied in 4 groups of 10 samples each. A standard mould measuring 65 x 10 x 3mm3 (ISO 1567 standard) was obtained for the fabrication of 40 specimens that were divided into 4groups; group-A was unmodified denture base resin (Control group), groupB, group-C and group-D were modified denture base resin with 5%, 10%and 15% by wt. aluminum oxide powder respectively.All specimens were stored in distilled water at 37o C for 7 days. The flexural strength of thespecimens was measured using 3-point bending test in a Universal Testing Machine.Hardness testing was conducted using shore hardness tester. Conclusion: Reinforcement of the conventional heat-cured acrylic resin(DPI) and high impact heat cured acrylic resin(LUCITONE) with 15% by wt.% Aluminum oxide powder significantly increased its flexural strength and hardness with no adverse effects.