Abstract:
Flexural strength is one of the most significant test to evaluate mechanical performance of dental restorative materials because it combines compression, tension and shear stresses. These stresses will affect the restoration during mastication in a great similarity to the real oral situation. Many brands of Bulk-fill composites are being introduced to the dental market in the last few years which enable the dentist to place a restoration of 4 mm in thickness as a single composite increment. It's important to test the flexural strength of bulk-fill composites to have an idea about their clinical performance in the oral cavity and consequently the durability of the restoration. This study was designed to evaluate flexural strength values of Tetric EvoCeram bulk-fill composite in comparison with three different traditional composites.This study investigates the flexural strength of four different composites with A3 shade: Tetric EvoCeram Bulk fill (Ivoclar-Vivadent), Nanoceram-Bright (DMP), Ceram.X one (Dentsply), Estelite Sigma Quick (Tokuyama Dental). Ten samples from each composite material were prepared in a metal mold with dimensions of 2 mm x 2 mm x 25 mm and were photo-cured for 20 seconds. The samples were in a bar shape of the same mold dimensions. Flexural strength was evaluated by three-point bending test using universal testing machine after incubation of the samples in 37°C saline for 24 hours. Data were analyzed by one-way ANOVA and post hoc Tukey’s test at 5% level of significance.One-way ANOVA test revealed that, there was a statistically significant difference between the four composite groups being tested (P≤0.05). The highest mean flexural strength value was obtained for NANOCERAM-BRIGHT (116.75 MPa) followed by Tetric EvoCeram Bulk Fill (116.09 MPa), CERAM.X ONE (101.12 MPa) and ESTELITE SIGMA QUICK which exhibited the lowest mean flexural strength value (97.40 MPa).It was concluded that composition of dental composite materials significantly affects their flexural strength. Composites with higher fillers content will have better flexural strength. Tetric EvoCeram Bulk Fill successfully passed the flexural strength test and can serve clinically as a successful posterior restoration.
