Scanning electron microscopic study of the interface of glass ionomer cement sealers and conditioned bovine dentin

This in vitro study characterized the interface of glass ionomer cement root canal sealers and dentin conditioned by common endodontic irrigants. The interface of Ketac-Endo and two experimental glass ionomer cement sealers (KT-308 and ZUT) with bovine dentin--conditioned with either distilled water, 2.6% NaOCl, or 17% EDTA, followed by 2.6% NaOCl--was investigated. Cylinders of each of the sealers were formed on the conditioned dentin surface and allowed to set for 90 min. They were first shear tested to failure to determine their adhesive bond strength. Then three dentin specimens from each group were processed for scanning electron microscopic study. The test-failed surface of the strongest and weakest bonded specimens was examined. A third specimen, of intermediate bond strength, was cross-sectioned and the interface was also examined. Failures in all of the specimens were found to be mainly cohesive in nature. Specimens conditioned with 2.6% NaOCl only revealed the presence of a hybrid layer at the interface composed of dentin and whichever of the sealers were tested.