Clinical Relevance Salivary contamination before and after priming could significantly reduce the enamel bond strength of self-etching adhesives. Proper isolation should be performed before and during application of the adhesives and placement of the resin composite. Thorough water-spraying could significantly improve the μTBS of saliva-contaminated enamel. SUMMARY Objective: This study evaluated the effect of saliva contamination on the bovine enamel microtensile bond strengths (μTBS) of four self-etching adhesives. Materials and Methods: The labial enamel surfaces of extracted non-carious bovine incisors were serially wet ground. The enamel surfaces were not contaminated (Group A), contaminated with saliva before/after priming (Groups B/C) or they were water-sprayed after salivary contamination occurred before/after priming (Groups D/E). Four self-etching adhesives and the corresponding resin composites from the same manufacturer (Clearfil SE Bond + Clearfil AP-X, Kuraray Co; Xeno III + Ceram X, Densply; Frog + Ice, SDI; FL Bond II + Beautifil II, Shofu Inc) were applied onto the enamel surfaces. The μTBS tests were performed with a micro tester (BISCO, Inc). The enamel surface was analyzed with AFM (Atomic Force Microscopy) before/after salivary contamination occurred or after the saliva-contaminated enamel was water-sprayed. The data were analyzed using one-way ANOVA, factorial design ANOVA and post hoc Tukey's HSD multiple comparisons. Results: Salivary contamination significantly reduced the μTBS of all the adhesives in the current study ( p <0.001). Thorough water-spraying could significantly restore the μTBS of saliva-contaminated enamel to some degree ( p <0.05) or fully restore it for Clearfil SE Bond, but it could not remove some proteins adsorbed on the enamel surface. Conclusion: Hydrophilic self-etching adhesives are negatively influenced by salivary contamination. Thorough water-spraying could significantly improve the μTBS of the saliva-contaminated enamel. Proper isolation should be performed before and during application of the adhesives and during placement of the resin composite.