RESUMO
PURPOSE: To evaluate the effect of intra-radicular cleaning protocols after post-space preparation (PSP) on marginal adaptation of a luting agent to root dentin. METHODS: Eighty bovine incisors were sectioned transversely to obtain 18-mm-long root sections. The roots were prepared with ProTaper instruments and filled using Tagger's hybrid technique. PSP was performed at a length of 14 mm using #3-5 Largo drills. The roots were distributed into eight groups according to the chelating solution used (17% EDTA or 0.2% Chitosan) and the chelating activation/delivery method employed (conventional needle irrigation [CNI], EndoActivator [EA], XP-Endo Finisher [XPF] or passive ultrasonic irrigation [PUI]). The fiber posts were cemented using self-adhesive resin cement, and the roots were sectioned to obtain three discs from each root third. The dentin discs were observed under an optical microscope at ×40 magnification to assess marginal adaptation. The different protocols were compared considering the frequency of the marginal adaptation scores using the Kruskal-Wallis test, followed by the Dwass-Steel-Critchlow-Fligner test (α = 5%). RESULTS: The use of 17% EDTA resulted in better marginal adaptation (P < 0.001). PUI yielded results that were similar to those for EA (P = 0.949) and superior to those for XPF (P = 0.020). The combination of 17% EDTA + PUI provided a greater number of interfaces without marginal gaps (P < 0.001). CONCLUSION: The cleaning protocol influenced the marginal adaptation of resin cement to root dentin.