In Vitro Study of Transverse Strength of Fiber Reinforced Composites

Reinforcement with fiber is an effective method for considerable improvementin flexural properties of indirect composite resin restorations. The aim of this in-vitrostudy was to compare the transverse strength of composite resin bars reinforced with preimpregnatedand non-impregnated fibers.Materials and Methods: Thirty six bar type composite resin specimens (3×2×25 mm)were constructed in three groups. The first group was the control group (C) without anyfiber reinforcement. The specimens in the second group (P) were reinforced with preimpregnatedfibers and the third group (N) with non-impregnated fibers. These specimenswere tested by the three-point bending method to measure primary transverse strength.Data were statistically analyzed with one way ANOVA and Tukey's tests.Results: There was a significant difference among the mean primary transverse strength inthe three groups (P<0.001). The post-hoc (Tukey) test showed that there was a significantdifference between the pre-impregnated and control groups in their primary transversestrength (P<0.001). Regarding deflection, there was also a significant difference amongthe three groups (P=0.001). There were significant differences among the mean deflectionof the control group and two other groups (PC&N<.001 and PC&P=.004), but there was nosignificant difference between the non- and pre-impregnated groups (PN&P=.813).Conclusion: Within the limitations of this study, it was concluded that reinforcement withfiber considerably increased the transverse strength of composite resin specimens, but impregnationof the fiber used implemented no significant difference in the transversestrength of composite resin samples.