Influence of storage temperature on vickers microhardness of resin composite

Abstract

Objectives: The aim was to assess the effects of the pre-heating or pre-cooling resin composite on surface hardness. Methods: Sixty test specimens (TS) were made of resin composite Z250, using a steel matrix 3mm x 5mm, light cured with an XL3000 light cure appliance. The TS were divided into 6 groups of 10 specimens, altering the light cure time (CT), 20 or 40s, and the resin composite temperature (TEMP), 5oC, 24oC or 54oC. The TS were stored in distilled water at 37oC for 24 hours and the Vickers microhardness analysis was performed. Both the TS top and bottom were analyzed. Results: The results of two-way ANOVA showed that the temperature had a significant effect on microhardness. At the top, higher microhardness values were observed for the temperature of 54oC, while the temperature of 5oC and 24oC presented no significant differences. Conclusion: It was concluded that pre-heating resin composite significantly increased the resin microhardness, the light cure time of 40 s improved top microhardness for the use of resin at 24 oC or 5 oC.