Assessment of Flexural and Impact Strengths in Polymethyl Methacrylate Denture Base Resin Reinforced with Short E-glass Fiber

Abstract

Polymethyl methacrylate (PMMA) is the predominant material for denture base construction, however its low flexural and impact strengths contribute a high rate of clinical failure. This study aimed to evaluate the reinforcing effect of silane-treated short E-glass fiber (SEGF) incorporated into heat-polymerized PMMA at different concentrations (0%, 2%, 4%, 5%, 7%, and 9 wt.%). A total of 180 specimens, fabricated according to ISO 1567, were subjected to three-point bending and Charpy impact tests to determine flexural and impact strengths. Statistical analysis using one-way ANOVA followed by Tukey's post-hoc test (α = 0.05) revealed a highly significant improvement in both properties with SEGF incorporation. Flexural strength increased progressively, reaching its maximum at 7 wt.% (106.47 ± 5.78 MPa), followed by a slight decline at 9 wt.% was recorded, likely due to fiber agglomeration and increased void formation. In contrast, impact strength showed a consistent and significant increase across all concentrations, with the highest value at 9 wt.% (12.80 ± 0.33 kJ/m²). These enhancements are attributed to improve interfacial bonding provided by silane treatment, which promotes effective stress transfer and crack-bridging. Within the limitations of this study, SEGF incorporation particularly in the 5-7 wt.% range offers optimal mechanical reinforcement. In conclusion, silane-treated SEGF represent a practical and effective strategy for improving the durability and fracture resistance of PMMA-based prostheses.