Methods: After endodontic treatment, thirty-two extracted human teeth with single root and root canal were prepared for post space. The teeth were randomly divided into four groups (n=8) after etching and rinsing for rewetting: Group 1: Water-wet bonding, Group 2: Water-wet bonding with 2% chlorhexidine, Group 3: Ethanol-wet bonding, Group 4: Ethanol-wet bonding with 2% chlorhexidine. The rewetting agent was applied for 60 seconds. Two coats of primer (50 wt% of 100% ethanol and 50 wt% of hydrophobic resin) followed by hydrophobic resin application were applied to root dentine and light-cured for 40 seconds. The fiber post was subsequently luted to bonded root dentine using dual cure resin cement. After 24 hr, five bonded roots from each group were subjected to push-out bond strength testing and subsequent failure mode analysis. Bond strength data were evaluated using two-way ANOVA and Tukey’s test (α=0.05). Three teeth from each group were sectioned and interfacial nanoleakage was examined using a field-emission scanning electron microscopy and analyzed using chi-square test (α=0.05).
Results: Groups 3 and 4 showed significantly higher bond strengths and significantly lower interfacial nanoleakage, when compared to Groups 1 and 2. Addition of 2% CHX to ethanol-wet bonding did not alter the bond strength of hydrophobic adhesive to intraradicular dentine. No significant difference in bond strength was found at different root regions.
Conclusions: Ethanol-wet bonding with a hydrophobic adhesive improved bond strength of fiber post luted to radicular dentine. The addition of 2% CHX to ethanol-wet bonding did not have any adverse effect on bond strength to radicular dentine.
(This study was supported by HKU GRF 784410M)