title: Micro-CT Evaluation of Root Filling Removal after Three Stages of Retreatment Procedure.
abstract: The aim of this study was to quantify the residual filling material after filling removal, re-preparation with rotary or reciprocating files and passive ultrasonic irrigation (PUI). Twenty maxillary molars were prepared using ProTaper instruments up to F1. The teeth were filled with AH Plus and ProTaper gutta-percha points using the single-cone technique. Thereafter, the specimens were scanned using a micro-computed tomography system (Micro-CT #1). Then, the root canal filling was removed using ProTaper Retreatment files, and a new scan was performed (Micro-CT #2). The specimens were divided into two groups according to the instrument used for re-preparation: ProTaper rotary or WaveOne reciprocating files (Micro-CT #3). Finally, PUI was performed, and a new micro-CT scan was performed (Micro-CT #4). Intragroup and intergroup analyses were performed using Friedman and Dunn's post hoc test and the Kruskal-Wallis and Dunn post hoc tests, respectively. Palatal canal presented the highest volume of residual filling material in all stages of endodontic retreatment (p<0.05). The main reduction of filling volume was achieved after using ProTaper Retreament (p<0.05). The amount of remaining filling material after using ProTaper Retreatment was similar to that achieved with rotary and reciprocating files and after PUI (p>0.05). Rotary and reciprocating files achieved similar removal of the root canal filling (p>0.05). The greatest reduction in filling material was achieved after using ProTaper Retreatment files. Rotary and reciprocating instruments and PUI did not improve the removal of root canal filling materials.
authors.affiliation: Department of Conservative Dentistry, UFRGS - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Ricardo Abreu
authors.initials: RA
authors.lastname: Da Rosa
authors.affiliation: Department of Conservative Dentistry, UFRGS - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Manuela Favarin
authors.initials: MF
authors.lastname: Santini
authors.affiliation: Department of Endodontics, Dental School of Bauru, USP - Universidade de São Paulo, Bauru, SP, Brazil.
authors.forename: Bruno Cavalini
authors.initials: BC
authors.lastname: Cavenago
authors.affiliation: Department of Prosthodontics, Dental School, UNISUL - Universidade de Santa Catarina do Sul, Tubarão, SC, Brazil.
authors.forename: Jefferson Ricardo
authors.initials: JR
authors.lastname: Pereira
authors.affiliation: Department of Endodontics, Dental School of Bauru, USP - Universidade de São Paulo, Bauru, SP, Brazil.
authors.forename: Marco Antônio Húngaro
authors.initials: MA
authors.lastname: Duarte
authors.affiliation: Department of Conservative Dentistry, UFRGS - Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Marcus Vinícius Reis
authors.initials: MV
authors.lastname: Só
mesh_terms: D006801:Humans; D012086:Reoperation; D012387:Root Canal Filling Materials; D012390:Root Canal Therapy / Q000379:methods*; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D012387:Root Canal Filling Materials