Effects of Immediate Coating on Unset Composite with Different Bonding Agents to Surface Hardness.

Objectives:  This study evaluated the surface microhardness of composite, affected by surface coating with different dental adhesive systems.

Materials And Methods:  A total of 100 composite discs were divided into five groups. Group 1 was uncoated (control group C), and groups 2 to 5 were coated with different adhesive systems (OptiBond FL: FL, OptiBond SOLO Plus: SOLO, OptiBond XTR: XTR, and OptiBond All in one: AIO, respectively). The Vickers microhardness (VHN) was measured without and with 500 thermocycles.

Statistical Analysis:  The data were analyzed using two-way ANOVA and Tukey's posthoc test at the 95% confidence level.

Results:  At 24 hours, the VHN of C (59.96 ± 3.68) and FL (59.83 ± 4.54) were significantly higher than SOLO (51.73 ± 4.63) and AIO (51.45 ± 4.11). The VHN of XTR (54.96 ± 3.68) was not significant compared with that of C and all other groups. After thermocycling, VHN were significantly decreased in all groups. However, there were no significant differences among all groups.

Conclusions:  At 24 hours, composite coated with different adhesive systems have different effects to VHN. Thermocycling all adhesive resin systems coated on composite surface significantly decreased the VHN.