comparision of the preheating effect on the flexural strength of giomer and nano-hybrid composite

Abstract

Background: Considering the ever-increase use of preheating procedure by the clinicians and an increase in the use of newly introduced resin-based materials for the restoration of teeth, this in vitro study was designed to evaluate the effect of preheating on the flexural strength of giomer and compare of that with nano-hybrid composite. Materials and methods: Two different types of restorative materials, Beautifil II giomer, and Alpha III nano-hybrid composite resin, were evaluated in the current study. Thirty bar-shaped samples were prepared from each restorative material, totaling 60 samples, and assigned to two groups: with and without preheating procedures (n=15). In the subgroups with a preheating procedure, giomer and nano-hybrid composite tubes were preheated at 68 °C for 15 minutes prior to sample preparations. In the non-preheated subgroups, giomer and nano-hybrid composite tubes were stored at room temperature (at 25 °C) prior to sample preparations. Then the flexural strengths of the samples were determined. Two-way ANOVA was used to compare the flexural strengths of the samples. Statistical significance was set at P<0.05. Results: There were significant differences in the flexural strengths in terms of the preheating (P<0.001), with significantly higher flexural strength in the subgroups with a preheating procedure. Furthermore, the mean flexural strengths were significantly different in terms of the restorative material (P<0.001) with significantly higher flexural strength in the giomer groups compared with nano-hybrid composite groups. Conclusion: It was concluded that preheating significantly increased the flexural strengths of Beautifil II giomer and Alpha III nano-hybrid composite resin. There was significantly higher flexural strength in the giomer groups compared with nano-hybrid composite groups, irrespective of the use or no use of preheating.