RESUMO
STATEMENT OF PROBLEM: Implant overdenture prostheses are prone to acrylic resin fracture because of space limitations around the implant overdenture components. PURPOSE: The purpose of this study was to evaluate the influence of E-glass fibers and acrylic resin thickness in resisting acrylic resin fracture around a simulated overdenture abutment. MATERIAL AND METHODS: A model was developed to simulate the clinical situation of an implant overdenture abutment with varying acrylic resin thickness (1.5 or 3.0 mm) with or without E-glass fiber reinforcement. Forty-eight specimens with an underlying simulated abutment were divided into 4 groups (n=12): 1.5 mm acrylic resin without E-glass fibers identified as thin with no E-glass fiber mesh (TN-N); 1.5 mm acrylic resin with E-glass fibers identified as thin with E-glass fiber mesh (TN-F); 3.0 mm acrylic resin without E-glass fibers identified as thick without E-glass fiber mesh (TK-N); and 3.0 mm acrylic resin with E-glass fibers identified as thick with E-glass fiber mesh (TK-F). All specimens were submitted to a 3-point bending test and fracture loads (N) were analyzed with a 2-way ANOVA and Tukey's post hoc test (α=.05). RESULTS: The results revealed significant differences in fracture load among the 4 groups, with significant effects from both thickness (P<.001) and inclusion of the mesh (P<.001). Results demonstrated no interaction between mesh and thickness (P=.690). The TN-N: 39 ±5 N; TN-F: 50 ±6.9 N; TK-N: 162 ±13 N; and TK-F: 193 ±21 N groups were all statistically different (P<.001). CONCLUSIONS: The fracture load of a processed, acrylic resin implant-supported overdenture can be significantly increased by the addition of E-glass fibers even when using thin acrylic resin sections. On a relative basis, the increase in fracture load was similar when adding E-glass fibers or increasing acrylic resin thickness.
