Effect of chlorhexidine and ethanol-wet bonding with a hydrophobic adhesive to intraradicular dentine.

To evaluate the effect of adjunctive application of ethanol-wet bonding and chlorhexidine (CHX) with a hydrophobic adhesive on bond durability of fibre posts to intraradicular dentine. Ninety-six extracted human teeth with a single root and root canal were prepared for post placement after endodontic treatment. The teeth were randomly divided into four groups (n=24) after etching and rinsing for rewetting: Group 1: water-wet bonding, Group 2: water-wet bonding with CHX, Group 3: ethanol-wet bonding and Group 4: ethanol-wet bonding with CHX. Teeth in Groups 1 and 2 were treated with either distilled water or distilled water with 2% CHX for 60 s; while teeth in Groups 3 and 4 were treated with either 100% ethanol or 100% ethanol with 2% CHX. Two coats of primer, followed by neat resin were applied and light-cured for 40 s. Fibre posts were luted to bonded root dentine using dual-cure resin cement. Bonded roots were subjected to push-out bond strength testing and interfacial nanoleakage evaluation after 24 h, 6 and 12 months of storage. Data were analyzed using 3-way ANOVA (rewetting solutions, time and post space regions) and SNK tests. Groups 3 and 4 showed significantly (p<0.05) higher bond strengths and lower nanoleakage than Groups 1 and 2 after 12 months of ageing. Addition of 2% chlorhexidine to ethanol-wet bonding with a hydrophobic adhesive did not further improve the bonding of a fibre post to intraradicular dentine, when compared to ethanol-wet bonding alone after 12 months of ageing. Ethanol-wet bonding with a hydrophobic adhesive alone could improve the bond durability of fibre post to intraradicular dentine and therefore would increase the success rate of post and core restorations of endodontically treated teeth.