Flexural strength and hardness of resins for interim fixed partial dentures.

ABSTRACT

Context Materials used for the fabrication of interim restorations must satisfy biological, esthetic, and functional needs. Strength and wear resistance are two important physical properties contributing to clinical efficiency. Aim: The objective of this in vitro study was to evaluate and compare the flexural strength and hardness of five resins used for the fabrication of interim fixed partial dentures. Materials and Methods: Five groups containing ten specimens of each material were fabricated in customized brass split molds with dimensions 65×10×2.5 mm. The materials subjected to this study were Revotek LC™ (group RLC), Protemp II™ (group PSC), Acry-lux V™ with regular monomer (group AHC), Acry-lux V™ with self-cure monomer (group ASC), DPI™ self-cure tooth molding powder (group DSC). The specimens were polymerized according to the manufacturers' instructions and were evaluated for flexural strength using a universal testing machine and for hardness using a microhardness tester. Statistical Analysis: The mean of the five groups was compared using one way analysis of variance (ANOVA) and pair-wise comparison was done using Tukeys honesty significance difference (HSD) test. P≤.05 was considered to be statistically significant. Results: Flexural test results showed that group AHC (79.8950 MPa) had the highest flexural strength followed, in descending order, by group PSC (77.9700 MPa), group ASC (63.7150 MPa), group RLC (58.8110 MPa), and group DSC (51.9840 MPa). Statistically, the difference was found to be highly significant among all the groups. The hardness tests showed that group AHC (17.6900 KHN) had the highest hardness value followed, in descending order, by group PSC (15.9400 KHN), group RLC (12.6000 KHN), group ASC (11.2500 KHN), and group DSC (8.7700 KHN). Statistically, the difference was found to be highly significant among all the groups. Conclusion: Group AHC, representing a heat-polymerizing resin, showed the highest flexural strength and hardness values as compared to auto-polymerizing resins and light-polymerizing resin.