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.
Keywords: Reciproc Blue; XP-endo Shaper; micro-CT; retreatment; scanning electron microscope.
© 2019 Wiley Periodicals, Inc.