Does etching time affect the in vitro performance of a sealant material?

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.