Analysis of surfaces and adhesive interfaces of enamel and dentin after different treatments.

Purpose: The purpose of this study was to analyze, by Scanning Electron Microscopy (SEM), the surface topography and the morphology of the adhesive interfaces of enamel and dentin after different treatments.
Materials and Methods: The enamel-dentin discs were randomly assigned into three groups according to the surface treatment: I-37% phosphoric acid; II-air-abrasion; III-air-abrasion followed by 37% phosphoric acid. After surface treatment, discs were divided in two: one hemi-disc was separated for surface analysis; the other hemi-disc received the Single Bond/Filtek Z-250 restorative system. The restored sections were bisected perpendicularly to the surface and prepared for interface analysis.
Results: Results disclosed that when the surface treatment was performed by air-abrasion, irregularities were observed at the enamel surface; microcracks and occluded tubules at dentin surface and lack of hybrid layer at adhesive/dentin interface. The air-abrasion treatment followed by acid etching provided an enamel etching pattern similar to the acid etching; microfissures and open tubules at dentin surface, and formation of hybrid layer at adhesive-dentin interface.
Conclusion: It may be concluded that the treatment with air-abrasion followed by acid etching is an effective procedure to obtain an adequate surface for resin adhesion.