ABSTRACT
The aim of this study was to evaluate the effect of glass-fiber on the flexural strength of composite resins. The study was done experimentally in which flexural strength of glass - fiber reinforced composite resins were assessed with a three-point load test on 22 samples. 11 samples of composite resin blocks and 11 samples of composite resins reinforced with glass - fiber were prepared in a mold of 25x6x2 mm and stored in 100% of moisture for one month, until they were ready for testing in an Instron Universal Testing Machine using a crosshead speed of 1 mm/min. Student t test was used for statistical analysis. Flexural strength in the first group was 22.39 +/- 3.38 MPa and in second group was 29.74 +/- 2.36 MPa. According to test analysis, the difference between the two groups was statistically significant. [P<0.01]. The results of this study suggest that the flexural strength of the fiber-reinforced composite made from glass - fibers was more than composite resin