Micro-CT Evaluation of Root Filling Removal after Three Stages of Retreatment Procedure.

Ricardo Abreu Da Rosa,Marcus Vinícius Reis Só,Manuela Favarin Santini,Bruno Cavalini Cavenago,Jefferson Ricardo Pereira,Marco Antônio Húngaro Duarte

doi:10.1590/0103-6440201300061

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.

Highlights

Persistent apical periodontitis is primarily caused by intracanal microorganisms that survive primary root canal treatment
The intra-group analysis showed that the greatest reduction of filling material was observed after using ProTaper Universal Retreatment files (p
After using ProTaper F2 and WaveOne Primary files, the volume of residual filling was similar to that observed after using ProTaper Universal Retreatment files (p

Summary

Introduction

Persistent apical periodontitis is primarily caused by intracanal microorganisms that survive primary root canal treatment. Nonsurgical endodontic retreatment is indicated to remove filling material from the root canal and to regain access to the apical foramen. Such procedure can be accomplished with hand, rotary and ultrasonic instruments (1,2), with or without solvents and heat to facilitate the procedure (3). The ProTaper Universal Retreatment System (PTR) (Dentsply Maillefer, Ballaigues, Switzerland) consists of three instruments for use in each third of the root canal: D1 - 30/.09, 16 mm; D2 - 25/.08, 18 mm; and D3 - 20/.07, 22 mm. The D1 file presents an active tip to facilitate its penetration into the filling material (4) These files present convex triangular cross-sections similar to those of the ProTaper shaping and finishing files (4)

Objectives

Methods

Results

Conclusion