Flexural Strength of Glass and Polyethylene Fiber Combined with Three Different Composites

Statement of problem: the flexure of the fiber- reinforced composites (frc) which can be generally used instead of fixed metal- framework prostheses have been more advocated due to the enormous demands for the conservative and esthetic restoration. the flexure of the fiber should be well-fitted to its covering composite. no study has been reported the comparison of the combination of glass and polyethylene fiber with particulate filled composite and fiber reinforced composite yet. purpose: this study compared the flexural strength of two types of fibers combined with three types of composites. materials and method: sixty-six specimens were prepared in a split mold (25×2×2 mm). the specimens were divided into six groups according to the type of resin and the fiber (n = 11): group 1: z250 composite + polyethylene fiber; group 2: build it composite + polyethylene fiber; group 3: nulite f composite+ polyethylene fiber; group 4: glass fiber + z250 composite; group 5: glass fiber + build-it composite and group 6: glass fiber + nulite f. the mean flexural strengths (mpa) values were determined in a 3- point bending test at a crosshead speed of 1 mm/min by a universal testing machine (zwick/roell z020, germany). the results were statistically analyzed, using one and two- way anova and lsd post-hoc tests (p< 0.05). results: the highest flexural strength was registered for glass fiber in combination with z250 composite (500 mpa) and the lowest for polyethylene fiber in combination with build-it composite (188 mpa). one-way anova test revealed that there was no statistically significant difference between polyethylene fiber combinations (p= 0.62) but there was a significant difference between glass fiber combinations (p= 0.0001). two- way anova revealed that the fiber type had a significant effect on flexural strength (p= 0.0001). conclusion: the choice of fiber and composite type was shown to have a significant positive influence on the flexural properties of the fiber-reinforced composite. glass fiber has a significant influence on the flexural properties of directly- made specimens.