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

Purpose: To compare the microtensile bond strength (μTBS) 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. Methods: Sealant and adhesive systems were applied under manufacturers’ specifications with or without previous saliva contamination. After storage in distilled water at 37oC for 24 hours, the specimens were longitudinally sectioned perpendicularly to the adhesive interface to obtain sticks (0.6 mm) 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 μTBS of each tooth. Results: No association between failure mode and the values of μTBS 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 μTBS (34.5 ± 2.2 MPa and 45.1 ± 3.2 MPa, respectively) which are significantly higher than the corresponding average μTBS 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). (Am J Dent 2007;20:114-120). CLINICAL SIGNIFICANCE: Except for the conventional sealant, all adhesive systems showed similar performance on dry and contaminated primary enamel surface. However, the total etch two-step adhesive system provided the highest resinenamel bond strength values on the occlusal surface of primary molars and seemed to be the best option for fissure sealing. : Prof. Dr. Rosa Helena Miranda Grande, Department of Dental Materials, Faculty of Dentistry, University of Sao Paulo, Avenida Lineu Prestes, 2227 – Cidade Universitaria, 05508-000 Sao Paulo, SP, Brazil. E: grande@usp.br