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This in vitro study evaluated the adhesive interface of intraradicular fiber glass posts and root dentin using scanning electron microscopy (SEM). Forty-eight single-rooted premolars were randomly divided into 6 groups consisting of chemical, dual, or light cured adhesive systems combined with either chemical or dual cure resin cements. Scanning electron microscopic analysis showed the best results for continuity, density and morphology of the hybrid layer and resin tags for the combination of a self-cure adhesive with self-cure cement resin, followed by a dual-cure adhesive with self-cure cement resin, and finally a light-cure adhesive with self-cure cement. For the dual-cure resin cement, the same relation may be observed. The apical third was the most critical region for evaluated the criteria for all combinations of materials (Kruskal-Wallis and Friedman tests; p<0.001). Generally, the simplification of steps in the adhesive system and the polymerization reaction of resin adhesives and cements produced a direct effect on the quality of the adhesive post/dentin substrate interface.

The purpose of the present study was to evaluate the influence of short course topical application of carbamide peroxide on proliferating cell nuclear antigen (PCNA) immunohistochemical expression in the oral tongue mucosa of rats. Twelve male Wistar rats were submitted to topical application of 10% carbamide peroxide on one side of the dorsal tongue once a week for three consecutive weeks. Only distilled water was applied on the control side. The animals were killed on days 0, 10, and 20 after the last application. The tongue was fixed in buffered formalin for 24 h and embedded in paraffin. Tissue blocks (3 µm) were subjected to the biotin-streptavidin amplified system for identification of PCNA. The percentage of epithelial-positive basal cells in each side of the tongue mucosa was calculated. The results demonstrated that topical application of 10% carbamide peroxide increases PCNA immunohistochemical expression on the basal layer of the oral mucosa epithelium of rats on day 0 after treatment. In conclusion, short-course use of carbamide peroxide induces transient epithelial cell proliferation of the oral mucosa of rats.

A delayed post preparation of the root space, following the root canal filling, is recommended.