Comparative Evaluation of the Flexural Strength and Hardness of Provisional Polymethyl Methacrylate Incorporated With Different Concentrations of Ultra-High-Molecular-Weight Polyethylene - An Invitro Study

PURPOSE: To evaluate the impact of varying concentrations of UHMWPE filler particles on provisional self-cure PMMA’s mechanical properties by analyzing the flexural strength and hardness of the specimens along with the scanning electron microscopic analysis. MATERIALS AND METHODS: Four groups of specimens (n=16 per group) were prepared using PMMA incorporated with different concentrations of UHMWPE - Control group (Pure PMMA), 10% UHMWPE group, 20% UHMWPE group, 30% UHMWPE group. Flexural strength was measured using a Universal Testing Machine under a three-point bending setup while hardness was evaluated using the Shore A hardness testing machine and the surface of fractured samples was analyzed using a scanning electron microscope (SEM). One-way statistical ANOVA test was done to find the difference between groups, followed by Tukey’s post hoc test for multiple pairwise comparison. RESULTS: The highest flexural strength was reported in 10% UHMWPE group followed by the Control PMMA group, 20% UHMWPE group and 30% UHMWPE group. Higher concentrations of UHMWPE (20% and 30%) showed a decline in flexural strength, with values similar to or lower than the control group. In contrast, Shore A hardness values increased progressively with UHMWPE concentration, with 30% UHMWPE group achieving the highest values (92.8 ± 0.73). SEM evaluation showed uniformly dispersed UHMWPE filler particles in PMMA matrix at 10% UHMWPE group. CONCLUSION: Within the limitations of this study, it is concluded that: 1) The incorporation of 10% UHMWPE significantly enhances flexural strength. 2) Increase in UHMWPE content to 20% and 30% led to a decline in flexural strength. 3) A consistent increase in Shore A hardness was observed with increasing UHMWPE concentration. The highest hardness values were recorded at 30% UHMWPE.