Effect of Finishing Time on Microleakage at the Composite-Repair Interface

BACKGROUND Repair is a conservative treatment of defective composite restoration. Sealing the repair interface is a critical factor to achieve successful repaired restorations. OBJECTIVE The aim of this study was to evaluatethe effect of three finishing times on the microleakage at the composite-repair interface. METHOD Eighty composite specimens (Z250) were made and aged for eight weeks in water. They were randomly divided into four groups. In the control group, repairing was done with no surface treatment and using bonding agent. In groups 2 to 4, the specimens were repaired following roughening, etching and use of Adper Single Bond, and finished immediately, after 20 minutes and after 24 hours, respectively. After thermocycling, the microleakage at the repair interface was assessed using dye-penetration technique. The results were analyzed using Kruskal-Wallis and Mann-Whitney tests (α=0.05). RESULTS There was a significant difference among the four groups (P<0.001). The control group with the highest leakage showed a significant difference with the other groups (P<0.05). Immediate finishing showed a significantly higher leakage compared to 20-minute and 24-hour delayed finishing time (P<0.001). The two latter groups had no difference. CONCLUSION Immediate finishing of the repaired restorations negatively affect the sealing at the repair interface, while 20-minute and 24-hour delayed finishing had no adverse effect on the interface sealing.