The Microshear Bond Strength of Repaired Composite as Affected by Different Surface Treatments

Abstract

The aim of this study was to test the micro-shear bond strength of aged and repaired nanofilled resin composite under different surface treatments, different intermediate agents and different storage periods. Two hundred and eighty specimens of a nanofilled resin composite were fabricated and stored in artificial saliva for 1 or 3 months prior to the following surface treatment: roughening using course finishing disc, diamond bur or air abrasion. After each surface treatment, three different intermediate agents were applied. The same nanofilled resin composite was applied to be tested for micro-shear bond strength. Then, all specimens were stored in artificial saliva for 1 week, 1 month or 3 months. Ten specimens were subjected to immediate placement of repair composite without any aging, mechanical surface treatment or intermediate agent application to be used as a control (n=10). The µSBS results revealed that, all tested surface treatments and intermediate agents showed significant difference compared to control. The evaluated bond strength was decreased by pre-repair aging time intervals. We concluded that, flowable composite combined with air abrasion or diamond bur surface treatment is considered a viable repair protocol for optimized durability of repaired resin composite restoration.