Endodontic filling removal procedure: an ex vivo comparative study between two rotary techniques

Abstract

In this study, we compared the ex vivo removal capacity of two endodontic rotary techniques and determined whether there was a significant quantitative difference in residual material when comparing root thirds. Forty extracted molars were used. The palatal roots were selected, and the canals were prepared using a step-back technique and filled using a lateral condensation technique with gutta-percha points and Endofill sealer. After two weeks of storage in a 0.9% saline solution at 37°C in an oven, the specimens were divided into 2 groups of 20, with group 1 samples subjected to Gates-Glidden drills and group 2 samples subjected to the ProTaper retreatment System. Hedstroem files and eucalyptol solvent were used in both groups to complete the removal procedure. Then, the roots thirds were radiographed and the images were submitted to the NIH ImageJ program to measure the residual filling material in mm. Each root third was related to the total area of the root canals. The data were analyzed using Student's t test. There was a statistically significant difference between the two techniques as more filling material was removed by technique 2 (ProTaper) than technique 1 (Gates-Glidden drills, p < 0.05). The apical third had a greater amount of residual filling material than the cervical and middle thirds, and the difference was statistically significant (p < 0.05). None of the selected techniques removed all filling material, and the material was most difficult to remove from the apical third. The ProTaper files removed more material than the Gates-Glidden drills.

Analysis of the presence of filling material in oval root canals using computed microtomography after endodontic retreatment performed by different techniques

“…Other studies have also presented similar results 8,9,19 , as the apical third is a critical area and requires enlargement for proper cleaning and shaping of canals 17 . The canal enlargement in this region may lead to apical deviations, which can play an important role in the retention of filling material during canal retreatment 18,19 .…”

“…The removal procedure was interrupted when filling material was no longer detected in the instruments 5,7,8,10 . Canal irrigation and drying was performed as described before.…”

“…Several studies have demonstrated that the complete removal of the root filling from the canal walls is not always possible [1][2][3][4][5][7][8][9][10][11][12] . The remaining filling material after retreatment has been described by its presence 8,9 , area 3,5,7,10,12 and volume 11,13 , through different analytical techniques using microscopy 9 , radiographies 3,8,10 , photographies 5,12 , and computed tomography 4,6,11,13 . However, the studies do not report in which canal walls filling material remained in larger amounts…”

Removal of obturation material in endodontic retreatment: a literature review

“…The ProTaper retreatment system has been demonstrated to be efficient in the removal of the filling material compared with other mechanized systems, exhibiting significant superiority associated with disintegration using the ProTaper R system in combination with Hedströem and solvent files compared with the Gates Glidden drill technique [43]. Similar results were observed when the ProTaper retreatment system was compared with other rotational (ProTaper conventional, Mtwo, ProTaper Next, D-Race, and Easy ProDesign Logic RT) and reciprocating (WaveOne) systems, and although no statistically significant difference was found among them, the ProTaper R system showed the best overall intracanal cleaning results [4,29,30,32,33,46].…”

“…Ultrasound-activated irrigators have also been used in endodontic retreatment with the aim of reducing the volume of intracanal remnants through continuous movement of the irrigation solution [43].…”