Evaluation of dentin intraradicular changed by endodontic retreatment on the bond strength of resin cements

Abstract

Evaluating the effect of the bond strength of resin cements to radicular dentin weakened by endodontic retreatment and its penetration into dentinal surface, this study intends to verify the quality of adhesion through the "push out" mechanical testing, confocal laser microscopy and scanning electron microscopy. Will be used 24 human tooth roots in pilot testing to define the sample size of each group: G1- Endodontic treatment and cementation with RelyX ARC; G2- Endodontic treatment and cementation U200; G3- Endodontic retreatment and cementation RelyX ARC; G4- Endodontic retreatment and cementation with U200. The groups with conventional endodontic treatment will be filled with AH plus (G1 and G2) and the groups that will suffer endodontic retreatment will be filled, primarily, with Endofill and, after, with AH Plus. The fiber glass posts will receive as a previous treatment, an alcohol 70% cleaning, and application of silane and for groups G1 and G3 adhesive application. For analysis in confocal laser microscope, will be added to the the primer adhesive system and the self-adhesive cement, the fluorescent dye rhodamine B isothiocyanate RITC 0.01%. to Each root thirds will be pass for the "push-out" test, with a speed of 0.5 mm / min and to verify the penetration and adaptation of the cement in the root dentin analysis will be made under confocal laser scanning microscopy. Subsequently each of the specimens will be analyzed in scanning electron microscopy, the failures are classified (AD) between dentin and adhesive resin cement; (PA) between pin adhesive fiberglass and resin cement; (MI) mixed; (CO) cohesive in resin cement. For statistical analysis of the results, will be selected two criteria: the tests two-way ANOVA and the Tukey test (± <0,05). (AU)