Do different dentin tubular patterns of primary molars affect the bond strength of total-etching and self-etching adhesive systems?

Abstract

Aims: To evaluate the tensile bond strength of self-etching and total-etching adhesive systems to the different dentin surfaces of primary molars and to analyze the resin-dentin interface.

Methodology: In this in vitro study, dentin samples 35 to 65% distant from the pulp (intermediate dentin) were obtained from buccal and lingual surfaces at the middle third of the crown of first and second primary molars. Dentin surfaces were prepared with 400 and 600-grit silicon carbide paper. Three adhesive systems (Prime & Bond NT, AdheSE and Clearfil SE Bond) were tested on the first and second primary molar surfaces (n=15); inverted truncated cones of resin composite with a 2.0 mm bonding diameter were built. After 24 hour storage in distilled water at 37°C, the specimens were submitted to the tensile bond strength test. To analyze the resin-dentin interface under scanning electron microscopy, samples were prepared with the same three adhesive systems (n=5).

Results: No differences between first and second primary molar dentin substrates could be observed in mean bond strength values (ANOVA; p>0.05). The following mean bond strength values (MPa) were obtained: 15.65±3.70 (Prime & Bond NT), 19.47±7.09 (AdheSE) and 17.14 ±5.35 (Clearfil SE Bond). There were no statistically significant differences between the self-etching adhesive systems. The presence of hybrid a layer and tags were observed in all groups.

Conclusions: Contemporary adhesive systems showed similar behaviors on both dentin tubular surfaces of primary molars. Follow-up studies of the clinical performance of these materials are needed.