Microhardness of provisional fixed prosthodontic materials

Statement of problem. Provisional restorations play a critical role in the success of restorative treatment. Thus, the provisional restoration must maintain its surface integrity throughout the restorative process. Purpose. This study evaluated the microhardness of 5 prosthodontic provisional materials. Material and methods. Cylindrical samples of 3 bis-acryl resin composites (Integrity, Protemp Garant, Temphase) and 2 methyl methacrylate acrylic resins (Tet, Temporary Bridge) were fabricated (n = 5 per material). Specimens were wet sanded through 600 grit abrasive and stored in artificial saliva at 37 degrees C for a total of 14 days. Baseline Knoop hardness (KHN) was measured 24 hours after specimen fabrication. Three microhardness measurements were obtained from each specimen. Knoop hardness ass again recorded after 14 days of storage. Results. ANOVA and Duncan's tests (P<.05) indicated a significant difference between the methyl methacrylate: type resins and the bis-acryl resin composites at both time intervals. Conclusion. The hardness of most materials (Integrity, Protemp Garant, Tet) decreased over time. All of the bis-acryl resin composite materials exhibited superior microhardness over traditional methyl methacrylate (Tet, Temporary Bridge) resins.