DOI: https://doi.org/10.36347/sjams.2026.v14i02.007

Pages: 144-149

Background: Heat-cured polymethyl methacrylate (PMMA) acrylic resin is widely used as a denture base material, yet fracture remains a common clinical problem. Processing variables, particularly curing duration at high temperature, may influence internal defects and fracture behavior. Scanning electron microscopy (SEM) provides valuable insight into fracture surface morphology and failure mechanisms. Aim: The aim of this study was to evaluate and compare the fracture surface characteristics of heat-cured PMMA acrylic resin cured at 100 °C for different durations using SEM analysis. Methods: In this in vitro experimental study, 60 PMMA secimens were prepared and cured at 100 °C for 20, 40, and 60 minutes. Specimens were fractured using a three-point bending test, and the fracture surfaces of 30 samples were examined under SEM at 50× and 100× magnifications. Results: Specimens cured for 20 minutes showed predominantly brittle fractures with smooth surfaces and frequent microvoids. The 40-minute group exhibited mixed fracture patterns, while the 60-minute group demonstrated predominantly ductile fracture characteristics, with reduced porosity and increased crack deflection and branching. Conclusion: Longer curing duration at 100 °C improves fracture surface characteristics of heat-cured PMMA, indicating enhanced resistance to crack propagation.