Use of a self-etching adhesive on previously etched intact enamel and its effect on sealant microleakage and tag formation

Aim This study verified the effects of a self-etching adhesive applied on pre-etched fissures (phosphoric acid 35%) on microleakage, penetration ability and tag formation of a fissure sealant. Methods 80 extracted sound human molar teeth were randomly divided into four groups and bisected in two equal parts, forming two subgroups, denominated A and B. Groups 1 and 2 were etched with phosphoric acid for 60 and 40 s, respectively. Groups 3 and 4 were etched with phosphoric acid (40 and 20 s, respectively) and afterwards treated with Xeno®III (20 s). All the procedures on sealant placement were performed under 90±2% relative humidity. The subgroups A and B were submitted to 1000 and 5000 thermal cycles, respectively. The samples were examined by light microscopy and by confocal laser scanning microscopy (CLSM) after sectioning. Microleakage, penetration ability, fissure type, tag formation quality and tag length were measured. Results Etching with phosphoric acid for 60 s showed statistically significantly lower microleakage when compared to the other groups and significantly better tag formation quality and longer tags compared to 20 s H3PO4 plus Xeno®III. Fissure type and number of thermal cycles were not significant factors on sealant microleakage. The penetration ability of the sealant in the fissure systems was not influenced by the treatment regimes. Shallow fissures showed a significant better tag formation than deep fissures. No significant difference in the prevalence of fissure types was seen among the groups. Conclusion Etching fissures with phosphoric acid for 60 s showed best results. The additional use of Xeno®III did not improve fissure sealing under the conditions of this study.