Microtensile bond strength of sealant and adhesive systems applied to occlusal primary enamel

To compare the microtensile bond strength (muTBS) of a self-etch adhesive system (OptiBond Solo Self-Etch Adhesive System), two total etch adhesive system (OptiBond FL; OptiBond Solo), and a conventional sealant (Clinpro) applied to the occlusal surface of primary molars under saliva contamination.

Sealant and adhesive systems were applied under manufacturers' specifications with or without previous saliva contamination. After storage in distilled water at 37 degrees C for 24 hours, the specimens were longitudinally sectioned perpendicularly to the adhesive interface to obtain sticks (0.6 mm2) which were tested under a tensile load of 0.5 mm/minute. The bond failure modes were evaluated via scanning electron microscope. Repeated measures ANOVA followed by multiple comparisons using Bonferroni's technique was used to evaluate the effects of adhesive system and saliva contamination. The pre-test debonded specimens were included in the computation of the pTBS of each tooth.

No association between failure mode and the values of muTBS was observed (P = 0.3605). The majority of fractures were of mixed type; no cohesive failure of enamel or composite resin was observed. No significant effect of saliva contamination was detected (P = 0.2044). OptiBond FL and Clinpro had equivalent average muTBS (34.5 +/- 2.2 MPa and 45.1 +/- 3.2 MPa, respectively) which are significantly higher than the corresponding average muTBS for OptiBond Solo Plus and OptiBond Solo SE which may also be considered equivalent (19.1 +/- 2.3 MPa and 9.8 +/- 2.3 MPa, respectively).