Evaluation of the effect of different fiber reinforced composite resins on the flexural strength of Bulk Fill composite resin

Aims: The aim of this study was to evaluate the effect of reinforcing a Bulk Fill composite resin material with different fiber reinforced composite resins (FRCRs) on flexural strength. Methods: For the flexural strength test, 60 specimens were prepared using 4x4x8 mm polymethyl methacrylate (PMMA) blocks in accordance with the standards and the specimens were divided into four study groups [Bulk Fill composite resin (group 1), Bulk Fill composite resin+glass fiber in braided structure (group 2), Bulk Fill composite resin+polyethylene fiber in leno woven structure (group 3), Bulk Fill composite resin+short glass fiber reinforced composite resin (group 4)]. The specimens were soaked in distilled water at 37°C for 24 hours and subjected to three-point bending test with Universal Test device. Data were statistically analyzed using Mann-Whitney U and Kruskal Wallis-H tests. Results: The average bending resistance values were 654.72 Newton (N), 682.33 N, 643.87 N and 1003.91 N in groups 1, 2, 3 and 4, respectively. The effect of short glass fiber reinforced composite resin+Bulk Fill composite resin group on bending resistance was statistically significantly higher than all other groups (p>0.05). There was no statistically significant difference between the other groups in terms of flexural strength. Conclusion: Within the limits of this in vitro study, it was concluded that short glass fiber reinforced composite resin increases the flexural strength of Bulk Fill composite resin as a base material.