Method: Ninety bovine teeth had their roots cut and the buccal enamel worn to expose and standardize the dentin. The specimens were embedded in acrylic resin and then were randomly divided into 3 groups, according to pre-treatment: Control group (CG) there was no pre-treatment, the SEAS was used according to manufacturer's recommendations; Group L, Er:YAG-laser application (60 mJ energy and 2Hz frequency, 30s) before the SEAS application; Group A, total-etching application before the SEAS application. The L and A groups were subdivided in 4 subgroups: (LDA, LDP, LHA, LHP) (ADA, ADP, AHA, AHP) N=10, according to hydration (Dry/Humid) and the SEAS application form (Active/Passive). All samples were restored with the composite P-90 (3M-Espe, USA). Artificial aging was performed with thermomechanical cycling machine. The specimens were sectioned into 1x1x10mm sticks and stressed to failure using a universal testing machine at cross-head speed of 1mm/min. Remaining teeth in each groups were used for Scanning Electron Microscopy to illustrate the fractured area.
Result: Data were subjected to three way ANOVA test, Tukey test and Dunnett test. Results (mean± SD; in Mpa) were, in descending order: AHA (20,24±3,79); AHP (19,97±3,25); LDA (19,56±1,51); LDP (15,75±2,84); LHA (15,70±2,49); ADA (12,78±1,70); LHP (12,54±1,72); CG (11,77±1,85); ADP (11,29±2,33). There were no significant difference between surface treatment (P=0.7510), however the hydration (P<0.001) and the SEAS application form (P<0.001) were affected.
Conclusion: The humid dentin and the SEAS active application showed higher figures of dentin bond strength. The groups LDP, LDA, LHA, AHP and AHA presented better bond strength values than the control group.