Comparison between physico-mechanical properties of three types of composite resins

The aim of this research was to evaluate the shear punch strength and creep for nano-composite, nanohybrid and low shrinkage composite. A total number of 126 resin composite specimens were used. They were divided into three groups (n=42) according to the type of resin composites (silorane {Filtek P90}), (nanohybrid{Filtek Z250XT}),& (nanofilled{Filtek Z350 XT}, each group was subdivided into two subgroups (n=21) for each laboratory test (shear strength & creep).The two main subgroups were further subdivided into three equal categories(n=7)according to immersion time in distilled water(24 hours, one week& one month). The aesthetic light-cured resin composite specimens were cured by using LED light-curing unit. Shear strength& creep tests were done by using universal testing machine. The data were subjected to statistical analysis using two-way ANOVA& one- way ANOVA followed by pair- wise Duncn post- hoc tests were performed to detect level of significance of 5% between subgroups. Comparison was made using the Tukey test with level of significance of 5%. Statistical analysis was performed using Aasistat 7.6 statistics software for Windows (Campina Grande, Paraiba state, Brazil). P values ≤ 0.05 are considered to be statistically significant in all tests. Statistical no difference was observed in shear strength between all groups for different periods (24-hour, one week &one month). Statistical no difference in polymerization shrinkage between silorane & nanofilled composites. Statistical no difference in creep between nano-hybrid & nanofilled composites, while siloran composite recorded statistically significant lowest creep. In conclusion, the nanofilled composite showed significantly higher shear strength than the other composites. The nano-hybrid composite showed significantly higher creep than the other composites.