Ethanol-wet bonding technique: Clinical versus laboratory findings

This study evaluated the microtensile bond strength (μTBS) and nanoleakage (NL) of dentin bonded interfaces produced with ethanol-wet and water-wet bonding protocols under clinical and laboratory conditions.

The sample was composed of forty primary second molars in advanced exfoliation process. Occlusal cavities were prepared leaving a flat dentin surface on the pulpal floor. In half of the teeth, the water-wet protocol was followed using a three-step etch-and-rinse adhesive. In the other half, dentin was dehydrated with ascending ethanol solutions (50%, 70%, 80%, 95% and 3×100%), 15s each for the ethanol-bonding protocol. An experimental hydrophobic primer was used, followed by the neat adhesive application. Resin build-ups were prepared, stored for 24h, sectioned into sticks and tested in tensile mode (0.5mm/min). NL was performed for all groups. The μTBS and NL data were submitted to two-way ANOVA and Kruskall-Wallis tests, respectively (α=0.05).

Under clinical conditions, the highest μTBS was observed for the water-wet bonding while under the laboratory setting, the highest μTBS was obtained for the ethanol-wet bonding. Increased NL was observed in the water-wet bonding groups irrespective of the bonding condition.

The immediate benefits of the ethanol-bonding observed in the laboratory setting was not confirmed when the same protocol was performed in vivo. However, as reduced nanoleakage was seen in adhesive interfaces produced with the ethanol-wet bonding technique, suggests that the hybrid layer may be more resistant to degradation.