Flexural properties of eight flowable light-cured restorative materials, in immediate vs 24-hour water storage

This study evaluated the flexural strength, flexural modulus, modulus of resilience and water sorption of eight flowable light-cured restorative materials compared with two conventional restoratives (as control). Forty specimens of each material were made. Twenty specimens were immediately flexural tested, while the remaining 20 were weight-measured and immersed in distilled water in a 37 degrees C incubator. After 24 hours, the samples were weight-measured again to identify water sorption and they were flexural tested. The findings were statistically analyzed using t-test, one-way ANOVA, Tukey test and Pearson's Product-Moment Correlation. The results of the flexural strength test were also analyzed using Weibull statistic. All flowable light-cured restorative materials except Palfique Estelite Low Flow exhibited immediate flexural strength values between the conventional ones. All flowable light-cured restorative materials showed 24-hour flexural strength values between the conventional ones. The Weibull modulus for immediate flexural strength of the materials varied from 6.37 to 15.23, while for 24-hour flexural strength, the strength varied from 8.10 to 14.30. In both conditions, all flowable light-cured resin composites showed lower flexural moduli but higher modulus of resilience than the conventional ones. The water sorption of all resin composites was lower than the flowable light-cured compomer. There was a distinct relation (r=-0.84, p<0.01) between the increasing ratio in modulus of resilience and the amount of water sorption.