Tensile bond strength of filled and unfilled adhesives to dentin.

ABSTRACT

PURPOSE: To determine the tensile bond strength of three filled and two unfilled adhesives applied to bovine dentin. MATERIALS AND METHODS: Fragments of the labial dentin of bovine incisors were embedded in PVC cylinders with self-cure acrylic resin, and ground flat using 200 grit and 600 grit sandpaper. The following adhesive systems were tested (n=10) Prime & Bond NT, Prime & Bond NT dual cure, Prime & Bond 2.1, OptiBond Solo and Single Bond. A 3 mm-diameter bonding surface was delimited using a perforated adhesive tape. After etching with 37% phosphoric acid and adhesive application, a resin-based composite truncated cone (TPH, shade A3) was built. Tensile test was performed after 24 hrs storage in distilled water at 37 degrees C. Failure mode was accessed using a x10 magnification stereomicroscope. RESULTS: Weibull statistical analysis revealed significant differences in the characteristic strength between Single Bond and Prime & Bond NT dual cure, and between Single Bond and Prime & Bond 2.1. The Weibull parameter (m) was statistically similar among the five groups. Single Bond and Prime & Bond NT showed areas of dentin cohesive failure in most of the specimens. For OptiBond Solo, Prime & Bond NT dual cure and Prime & Bond 2.1 failure was predominantly adhesive.