Evaluation of heat-cure polymethyl methacrylate reinforced with microcrystalline cellulose in two different weight ratios for compressive strength – An in vitro study

Background: Polymethyl methacrylate (PMMA) is widely used in prosthodontics due to its favorable physical and aesthetic properties. However, its limited mechanical strength remains a concern. This study aimed to evaluate the effect of reinforcing heat-cured PMMA with microcrystalline cellulose (MCC) in two different weight ratios, 5 wt% and 10 wt%, on compressive strength. Materials and Methods: Seventy-five samples were fabricated and divided into three groups ( n = 25 each): Group 1 (control – unmodified PMMA), Group 2 (PMMA + 5 wt% MCC), and Group 3 (PMMA + 10 wt% MCC). Compressive strength was measured using a universal testing machine. Data were statistically analyzed using one-way analysis of variance (ANOVA), followed by Tukey’s post hoc test, with significance set at P < 0.05. Results: The mean compressive strength values were highest for the control group (11.908 MPa), followed by the 5 wt% MCC group (10.981 MPa), and lowest for the 10 wt% MCC group (10.243 MPa). One-way ANOVA revealed a statistically significant difference among the groups ( P = 0.000). Post hoc Tukey’s analysis confirmed significant differences between all pairwise comparisons ( P < 0.05). Conclusion: The incorporation of MCC into PMMA significantly reduced its compressive strength in a dose-dependent manner. While MCC offers a natural and potentially sustainable reinforcement option, its concentration must be carefully optimized to maintain the mechanical integrity of denture base materials.