Effect of adjunctive application of epigallocatechin-3-gallate and ethanol–wet bonding on adhesive–dentin bonds

ObjectivesTo determine the effect of the combined use of epigallocatechin-3-gallate (EGCG) and ethanol–wet bonding (EWB) on resin–dentin bonds.MethodsSixty molars were sectioned, polished, and randomly divided into six groups (n = 10) according to the following pretreatments: group 1, water–wet bonding (WWB); group 2, WWB with 0.02% (w/v) EGCG; group 3, WWB with 0.1% EGCG; group 4, EWB; group 5, EWB with 0.02% EGCG; and group 6, EWB with 0.1% EGCG. An etch-and-rinse adhesive was then used, followed by the resin composites building. The microtensile bond strength (MTBS), failure modes and interfacial nanoleakage were separately determined after 24 h water storage or 10,000 runs of thermocycling.ResultsBoth pretreatment method (P < 0.05) and thermocycling (P < 0.05) significantly influenced bond strength and nanoleakage. Irrespective of thermocycling, the 0.02% EGCG/ethanol (group 5) pretreated adhesive–dentin interfaces showed higher MTBS than the control group (P < 0.05). Nanoleakage expression of all groups increased after thermocycling (P < 0.05) except group 5. Adhesive failure was the main fracture pattern in all groups.ConclusionThis study showed that pretreatment with 0.02% EGCG/ethanol solutions can effectively improve immediate bond strength and bond stability of etch-and-rinse adhesives on dentin.Clinical significanceThe adjunctive application of EGCG and EWB provides a new strategy for dentists to obtain the desired bond effectiveness during adhesive restoration in clinical practice.