Efficacy of reciprocating systems for removing root filling material plus complementary cleaning methods in flattened canals: Microtomography and scanning electron microscopy study

Abstract

The aim of this study was to evaluate three reciprocating systems and complementary cleaning methods on filling material removal during retreatment of flattened canals. Thirty-six mandibular incisors were prepared using rotary instruments up to size 25.08 and filled using the single-cone technique. Subsequently, the teeth were divided into three groups (n = 12) according to retreatment procedures: Reciproc Blue (RB): 25/0.08 and 40/0.06; ProDesign R (PDR): 25/0.06 and 35/0.05; and WaveOne Gold (WOG): 25/0.07 and 35/0.06. The remaining filling volume materials were assessed by means of micro-CT imaging before and after retreatment. After this, the specimens were subdivided into three groups according to complementary cleaning methods: XP-Endo Shaper (30/0.01); passive ultrasonic irrigation (PUI); 60 oscillatory instrumentation with #30 H-file, and micro-CT scan was taken. Then, the roots were cut in half and the samples were analyzed by scanning electron microscope (SEM). The data were analyzed statistically using Kruskal-Wallis and Dunn's Multiple Comparison test with significance level of 5%. None of the reciprocating files promoted complete removal of filling material and there was no statistical difference between the groups, regardless instrument size (p > 0.05). Complementary cleaning methods increased remnant filling removal (p < 0.05). XP-endo Shaper significantly reduced the amount of filling material in the apical and middle thirds, compared with H-files (p < 0.05), with no difference with PUI. In the SEM, there was no statistical difference among the instruments (p > 0.05). The reciprocating systems showed similar effectiveness in removing root filling material. Complementary cleaning method with the XP-Shaper enhanced filling material removal.

Effect of Sonic Agitation of a Binary Mixture of Solvents on Filling Remnants Removal as an Alternative to Apical Enlargement—A Micro-CT Study

“…An increased enlargement of apical re-preparation has been associated with a lower volume of residual filling materials [ 7 , 10 , 12 ]. This difference has been reported between additional instrumentation with larger tip sizes (size 35–40) compared to size 25.…”

“…Strategies for cleaning and disinfection will essentially depend on either supplementary approaches or enlargement to even larger sizes [ 1 , 2 , 3 , 4 ]. Adjunctive procedures show controversial outcomes and still do not enable the thorough cleaning of root canals [ 5 , 6 , 7 , 8 , 9 , 10 ]. Using a larger preparation size would be expected to result in fewer unprepared areas and, consequently, a higher volume of old filling material removal, optimizing disinfection [ 7 , 10 , 11 , 12 , 13 ].…”

“…Adjunctive procedures show controversial outcomes and still do not enable the thorough cleaning of root canals [ 5 , 6 , 7 , 8 , 9 , 10 ]. Using a larger preparation size would be expected to result in fewer unprepared areas and, consequently, a higher volume of old filling material removal, optimizing disinfection [ 7 , 10 , 11 , 12 , 13 ]. Nevertheless, a correlation between disinfection and optimal canal size was failed to be proved [ 14 , 15 ].…”

Analysis of the quality of root canal preparation and retreatment using different instruments associated or not with different irrigant agitation protocols

“…Several studies have been conducted to evaluate different removal procedure techniques of the root canal and all are unanimous that no method is able to completely filling material remove (5,8,11). These results corroborate with the data obtained in the present study in which, regardless of the kinematics and characteristics of the instruments used, all presented residual filling material (Table 1).…”

“…Reciproc (VDW GmbH, Munich, Germany) was one of the first reciprocating systems to be used in root canal shaping, however, several studies have also demonstrated its efficiency in endodontic retreatment (5,10). In order to further improve the mechanical properties, the Reciproc suffered a process of heating/cooling giving rise instruments Reciproc Blue (VDW GmbH, Munich, Germany) which have a NiTi alloy with blue technology (5,11). These instruments have been the subject of studies that point to a greater resistance to cyclic fatigue than their predecessor (12)(13) and also show to be efficient in endodontic retreatment (5,11…”