Effect of adding aluminum oxide on the flexural strength of heat-cured poly (methyl methacrylate) denture base resin

Abstract

Background: Apart from its numerous advantages, poly (methyl methacrylate) (PMMA) has certain limitations such as its low strength, brittle on impact, poor thermal conductivity, and resultant low flexural strength. This study is, therefore, planned to investigate the flexural strength of heat-cured PMMA denture base resin with the addition of different percentage of aluminum oxide powder. Materials and Methods: A total of 120 specimens of PMMA (DPI® Heat Cure) of standard dimension (64mm x 10mm x 2.5mm) as per the American Dental Association specification No. 12/International Standards Organization specification No. 1567 for the determination of flexural strength were prepared: 30 for each of the four study groups. Aluminum oxide powder was added in specific percentage (5%, 15%, and 25% by weight) to the polymer component of heat-cure denture base resin as per the different subgroups. Results: The results of this study showed that the highest mean flexural strength was for specimens in Subgroup A, i.e., PMMA reinforced with 5% aluminum oxide powder by weight, with a mean value of 124.39 Mpa. Conclusions: Among the experimental group, the highest mean flexural strength of 124.39 Mpa was found with Subgroup A (5%) followed by Subgroup B (15%) which was 116.83 Mpa. The least flexural strength of 95.81 Mpa was found with Subgroup C (25%).