Comparison on the Transverse Strength of Heat Cure Polymethylmethacrylate Denture Base Resin Repaired with Different Surface Treatments and Surface Design Modifications

Abstract

Introduction: Fracture of denture being most common clinical complain in daily Prosthodontic practice, results in great inconvenience to patient and humiliation to Prosthodontist. A satisfactory repair should be cost-effective, simple to perform, match the original color and not cause distortion to the existing denture. Objective: The aim of the present study is to investigate the effect of different surface treatments and surface design modifications on the transverse strength of repaired heat cure polymethylmethacrylate denture base resin Materials and Methods: A total of 135 rectangular specimens measuring 65 x 10 x 2.5 mm were made from heat cure PMMA resin using standardized mould. They were further divided into following 5 groups with 27 specimens in each group with simple random sampling method. Group A: control, Group B: 45° bevel of the edge, Group C: rounded contour of the edge, Group D: dichloromethane application at the edge and Group E: sandblasting of the edge. The repair index was fabricated with poly vinyl siloxane (putty). The specimens in each sample group were sectioned in the center to form 2 parts with approximately 3mm gap in between them. The sectioned surface of each sample group was modified according to their group specification and repaired using autopolymerizing acrylic resin. All the repaired specimens were tested for transverse strength in universal testing machine by subjecting them to 3-point bend test and the value at which the fracture of specimen occurred were noted. Data were analyzed with one-way ANOVA for multiple group comparisons followed by Tukey post hoc for group comparison (p<0.05). Results: Transverse strength of original specimen was higher than that of repaired specimen. Transverse strength of specimen repaired with surface design modification with rounded contour of the edge was higher than chemical and mechanical treatment and 45 bevel of the edge Conclusion: Within the limits of the study, irrespective of the method of repair, the transverse strength of surface design modification with rounded contour of the edges was significantly higher than the group repaired with surface design modification 45 bevel of the edge, chemical treatment with dichloromethane application at the edge and mechanical treatment by sandblasting of the edge.