The purpose of this study was to investigate the influence of ultrasonic washing with 70% ethylalcohol on the resin adhesion to the bovine dentin.
The labial surfaces of 46 bovine mandibular incisors extracted and frozen in physiologic saline were used. Two adhesive treatment groups were prepared: the AB 2 Group (All-Etch, Primer A and B, Dentin/Enamel Bonding Resin: Bisco Inc. ), the SDL Group (10-3 solution, Superbond Primer, Superbond D Liner: Sunmedical Co. ). The composite resin used in this study was Clearfil Photo Anterior (Kuraray Co. ). Final polishing of the dentin surface was carried out with 600-grit wet silicon carbide paper. The cleaning efficacy of the one-minute ultrasonic washing with 70% ethylalcohol on the ground and polished dentin surfaces was observed in the SEM. The shear bond strength was tested and the test surfaces of the dentin and the resin specimens were observed in the SEM. Data were compared with the results on the nonalcohlol-washed dentin which were previously reported.
1. After the one-minute ultrasonic washing with 70% ethylalcohol, some of the dentinal tubules were found to be opened.
2. In the comparison of the bond strengths of the non-thermal cycled groups with those of the thermal cycled groups, in the AB 2 non-alcohol-washed groups, the bond strength of the thermal cycled group was significantly higher than that of the non-thermal cycled group.
3. In the comparison of the bond strengths of the non-alcohol-washed groups with those of the alcoholwashed groups, in the AB 2 non-thermal cycled group and the SDL thermal cycled group, the bond strengths of the alcohol-washed groups were significantly higher than those with the non-alcoholwashed groups.
4. As for the fracture modes between the dentin and resin, in the AB 2 thermal cycled groups, the percentage of the adhesive fracture of the alcohol-washed group was significantly higher than that of the non-alcohol-washed group and the percentage of the mix fracture of the non-alcohol-washed group was significantly higher than that of the alcohol-washed group.
5. There was the tendency to increase the bond strength by the one-minute ultrasonic washing with 70% ethylalcohol on the ground and polished dentin. In addition to the cleaning efficacy, the effects of the dehydration and the fixation of the dentin by alcohol might be considered.