Transportation assessment in simulated curved canals after retreatment with rotary and reciprocating systems

Abstract

Objective: this study evaluated the ability of rotary (ProTaper-Retreatment and Mtwo-Retreatment) and reciprocating (Reciproc and WaveOne) systems in maintaining the original shape of the canal after root canal retreatment. Material and Methods: forty curved resin blocks with simulated root canals were prepared and filled. After that, each block was randomly assigned to 4 groups (n = 10) according to the retreatment system used. Stereomicroscopic images from each block were taken before and after retreatment procedures. Evaluation of canal transportation was obtained for all canal length and for 2 independent canal regions: straight and curved parts. ANOVA followed by Tukey's test was used (P<0.05). Results: for all canal length ProTaper-Retreatment system showed lowest transportation values followed by Reciproc, MTwo-Retreatment and WaveOne systems (P <0.01). At the straight part, ProTaper-Retreatment system produced the lowest canal transportation followed by Reciproc and MTwo-Retreatment systems (P < 0.05); at the curved part, ProTaper-Retreatment and Reciproc systems produced the lowest canal transportation followed by MTwo-Retreatment system (P < 0.05). The WaveOne system resulted in the highest transportation values at both canal parts (P < 0.05). Conclusion: overall, ProTaper-Retreatment system produced less canal transportation in both portions of the simulated canals than the others systems tested after retreatment procedures.