Evaluation of the enamel etching pattern of self-etching adhesives

Abstract

Objectives: To evaluate the capacity of seven self-etching adhesives (SEAs) to demineralize ground enamel in comparison with traditional phosphoric acid etchant (PAE) using SEM and statistical analysis. Materials and methods: 80 caries-free extracted human third molars were divided into 8 groups ( n = 10). Enamel bur-cut surfaces were prepared and, strictly following the manufacturers’ instructions, treated with three priming agents of two-step self-etching adhesives: Aqua Resulcin Prime (Group 1); Peak™ (Group 2); Clearfil Protect Bond (Group 3); four one-step self-etch (all-in-one) adhesives, G-Bond (Group 4); Artegral One (Group 5); Clearfil S3 Bond (Group 6); Adper Easy Bond (Group 7); and phosphoric acid etching (Control group). The etch patterns for the SEA systems were determined by rinsing off the material with water, acetone and alcohol. A minimum of 15 specimens was used for each group. Morphology matches were made between each SEA system and PAE by means of ultrastructural SEM analysis and were computed using the Kruskal–Wallis test ( P Results: SEM images showed that two-step-self-etching adhesives (Groups 1–3) produced a regular pattern over a considerable surface area and depth, not concerning, however, the prismless layer of enamel in the fissure space; one-step self-etch adhesives (Groups 4–7) demonstrated similar morphological features; an uneven demineralization pattern was observed in the PAE group with un-etched prismless enamel in the depth of the fissures. The Kruskal–Wallis test demonstrated no statistically significant difference among the groups ( P = 0.43). Conclusions: Despite the enamel etching pattern being similar for all SEAs used, two-step self-etching systems containing phosphate derivative monomers were the most efficient self-etching agents with a more homogeneous and regular pattern of demineralization when compared to the traditional PAE.