Effect of curing method and thermocycling on flexural strength and microhardness of a new composite resin with alkaline filler

Abstract

Background: Cention N has been introduced as an alternative material for amalgam. The purpose was to investigate the flexural strength and microhardness of this material in self-cure and dual-cure modes before and after thermocycling. Materials and Methods: In this experimental study, 40 samples of Cention N were prepared in order to determine and compare the microhardness. Half of the samples were set by self-cure method and the other half with dual-cure method. The Vickers microhardness test was performed once after 24 h and again after 10000 thermocyclings. Three-point flexural test was used to determine and compare the flexural strength of 52 rod-shaped samples. Half of the samples were set by self-cure method and the other half with dual-cure method. Among 26 samples in each group, 13 samples were randomly selected and three-point flexural test was performed after 24 h and for another 13 samples after 10,000 thermocyclings. Data were analyzed using two-way ANOVA and paired samples t-test (P 0.05]). However, the mean flexural strength without thermocycling (85.98 ± 21.74) was higher than that of the thermocycled group (64.24 ± 6.40) (P < 0.001). Conclusion: The microhardness of Cention N in dual-cure mode was higher than that of self-cure mode, but the flexural strength of dual-cure was not significantly different from that of self-cure. Thermocycling had a significant effect on the microhardness and flexural strength.

Keywords

• aging
• composite resins
• flexural strength
• hardness
• self-curing of dental resins