Publication

Abstract : The objective of this study was to evaluate the effect of artificial accelerated aging on the flexural strength of three heat-cure PMMA formulations: conventional, high-impact, and glass fiber-reinforced heat-cure PMMA. Thirty rectangular specimens were fabricated in accordance with ASTM D790 standards and divided into three groups (n = 10 per group). Subgroups (n = 5) were tested either immediately after polymerization or after artificial accelerated aging for 1008 h (this included cyclic UV light exposure (60 ± 3 °C) and dark condensation (45 ± 3 °C). Flexural strength was determined using a three-point bending test. Before aging, mean flexural strengths were highest for high-impact PMMA (79.92 ± 0.51 MPa), followed by conventional PMMA (76.46 ± 0.68 MPa) and glass fiber-reinforced PMMA (72.21 ± 0.70 MPa). After aging, all groups showed statistically significant reductions (p = 0.043). Conventional PMMA exhibited the greatest loss of flexural strength (−21.21 MPa), whereas high-impact PMMA (−12.04 MPa) and glass fiber-reinforced PMMA (−3.74 MPa) retained greater strength. Statistical analysis revealed significant intergroup differences both before and after aging (p < 0.001). It was noted that after artificial accelerated aging, both reinforced materials outperformed conventional PMMA, with no significant difference between the flexural strength of high-impact and glass fiber-reinforced PMMA groups after aging (p = 0.579). The results demonstrate that aging adversely affects the flexural strength of all tested PMMA types; however, reinforcement strategies mitigate this effect. High-impact PMMA provided the greatest initial strength advantage, likely due to elastomeric modifiers, while glass fiber reinforcement offered superior retention of strength after aging compared to other two groups, attributed to effective stress transfer within the resin matrix. Glass fiber reinforced heat cure PMMA showed acceptable performance post-aging, supporting its clinical use as a more durable alternative to conventional PMMA for denture base fabrication.