A comparative study to check fracture strength of provisional fixed partial dentures made of autopolymerizing polymethylmethacrylate resin reinforced with different materials: An in vitro study

AIM: The purpose of the study was to evaluate the fracture strength of provisional fixed partial dentures made of autopolymerizing polymethylmethacrylate (PMMA) resin using different types of reinforcement materials to determine the best among them. MATERIALS AND METHODS: Fifty samples were made (10 samples for each group) with autopolymerizing PMMA resin using reinforcement materials (stainless steel wire: looped and unlooped and glass fiber: loose and unidirectional) as 3-unit posterior bridge. The test specimens were divided into five groups depending on the reinforcing material as Group I, II, III, IV, and V; Group I: PMMA unreinforced (control group), Group II: PMMA reinforced with stainless steel wire (straight ends), Group III: PMMA reinforced with stainless steel wire (looped ends), Group IV: PMMA reinforced with unidirectional glass fibers, and Group V: PMMA reinforced with randomly distributed glass fibers. Universal testing machine was used to evaluate and compare the fracture strength of samples. Comparison of mean ultimate force and ultimate stress was done employing one-way analysis of variance and Tukey's post hoc tests. RESULTS: The highest and lowest mean ultimate force and mean ultimate stress were of Group IV and I, respectively. Tukey's post hoc honestly significant difference multiple comparison for mean ultimate force and stress shows the increase in strength to be statistically significant (P < 0.05) except for the samples reinforced with randomly distributed glass fibers (P > 0.05). CONCLUSION: Unidirectional glass fibers showed the maximum strength, which was comparable to mean values of both stainless steel wire groups. Low cost and easy technique of using stainless steel wire make it the material of choice over the unidirectional glass fiber for reinforcement in nonesthetic areas where high strength is required.