No abstract

The purpose of the present study was to evaluate the bond strength and the interaction morphology of self-adhesive resin luting cements (SLCs) to dentin prepared with different methods. Four SLCs were used: RelyX U100 ® , RelyX U200 ® , Clearfil SA Luting ® , and SmartCem2 ® . A flat dentin surface of 40 human molars was exposed and each tooth was sectioned in four tooth-quarters, which were distributed into four groups according to the SLC used to cement indirect resin composite restorations. The tooth-quarters of each group were then distributed in four subgroups according to the method used for dentin preparation: flat-ended cylindrical fine-grit diamond, flat-ended cylindrical median-grit diamond, flat-ended cylindrical plain-cut tungsten carbide, or abraded with #600-grit SiC paper (control). The restored toothquarters were sectioned to obtain beams (0.8 mm 2 ) and submitted to the microtensile bond strength test (n = 10). The results were analyzed using two-way ANOVA/ Tukey (α = 0.05). Forty-four additional teeth were used for micromorphological investigation of the SLC/dentin interface and of the topographic aspect of the dentin surfaces after application of the SLCs. Only the bond strength of RelyX U200 was significantly influenced by the surface preparation. No interference was identified on the micromorphological aspect of the bonding interfaces. The topographic investigation of the dentinal surfaces showed that the SLCs were not able to effectively remove the smear layer and etch the underlying dentin, irrespective of the preparation method. So, the interference of the dentin preparation on the bond strength of SLCs is material dependent, but don't influence the micromorphologic aspect of the interaction zone.

Dentin is the largest substrate available whenever restorative procedures are implemented on the exposed crown or root of teeth. In endodontics, restorative/obturating procedures are practically restricted to dentin. It is well recognized that the incidence of fracture in endodontically treated teeth is intrinsically related to the amount of remaining dentin. Ideally, it is expected that a gap‐free, solid interface can be formed between the restorative/obturating materials and root dentin, providing an impervious seal and, simultaneously, fracture resistance to root‐filled teeth. Over the past years, a number of new obturating biomaterials have been launched in the market, bringing to endodontists the expectation of achieving consistent sealing/reinforcing of the root canal system. However, the successful sealing of root dentin remains one of the greatest challenges in restorative dentistry. This article will focus on reviewing some factors that affect the formation and integrity of dentin–biomaterial interfaces from the perspective of the dentin substrate. Because other articles in preceding issues of Endodontic Topics have already covered dentin structure and composition, the objective here is not to review these aspects. Specific attention is given, however, to depicting how chemical treatments affect existing root filling/restorative mechanisms and how some microbial and host‐related aspects can compromise the interaction of dentin with new biomaterials.