Objectives . The objective of the present study was to evaluate the effect of aging on the adhesion of total-etched and self-etched fissure sealants to ground enamel of bovine teeth using thermocycling and micro-tensile tests.

Materials and methods . The labial surface of 6 bovine incisors were flattened and assigned to 3 groups of 2 according to the sealants applied. The materials studied were: (1) Ultraseal XT (US-Ultradent); (2) 35% phosphoric acid + Enamel Loc (Premier Dental); and (3) Adper Prompt L-Pop + Clinpro(3 M). Composite build-up was then fabricated for microtensile bond testing. All samples were cut to beam-shaped specimens of about 0.8 mm × 0.8 mm in cross-section using a low-speed diamond saw. Half of the specimens from each group were tested for their micro-tensile bond strengths after 24 h storage in 37 °C water. The other half was tested after 5000 thermal cycles (5–55 °C; dwell time of 30 s). Each specimen was examined under a microscope after testing, and only those with a fracture surface lying entirely or partially within the enamel–sealant interface were considered as valid results.

Results . The highest mean bond strength was obtained for specimens with Ultraseal XT applied (39.38 MPa). The self-etched adhesive system of Adper Prompt L-Pop with Clinpro sealant resulted in bond strengths 31.82 MPa which was not significantly different from that of pre-etched group with Enamel Loc (34.08 MPa). After 5000 thermal cycles, the bonding strengths of these three groups were not significantly decreased (35.08 MPa, 28.90 MPa and 33.10 Mpa respectively).

Conclusions . Application of the self-etched adhesive system Adper Prompt L-Pop with the Clinpro sealant resulted in bond strengths comparable to those of total-etched sealants and demonstrated stability after 5000 thermal cycles.