This in vitro study evaluated the shear bond strength (SBS), failure mode and microleakage of fissure sealing materials in relation to different etching times on aprismatic and prismatic enamel. Ninety-six healthy human third molars were randomly allocated to the following groups: 1) prismatic or aprismatic enamel; 2) etching: 15, 30, 45, 60 s. After 5,000-fold thermocycling SBS, failure mode and microleakage were measured. Statistical evaluation included Mann-Whitney-U-test and linear regression analysis. In the aprismatic enamel group, an increasing etching time resulted in higher SBS. The linear regression model revealed that 60 s of etching time led to a significant increase in SBS. Microleakage was found to be low in all test groups. This study indicated that 60 s of etching time showed to a significantly better SBS. When considering the small differences of SBS, failure modes and microleakage between 30 and 60 s etching time, 30 s acid etching seems to also be justifiable.
Keywords: Acid etching; Enamel pretreatment; Microleakage testing; Pit and fissure sealing; Shear bond strength.