Efficacy Of ProTaper Universal Rotary Retreatment System For Gutta-Percha Removal From Oval Canals: A Micro-Computed Tomography Study

IntroductionThe aim of this study was by using micro-computed tomography (μ-CT) to evaluatethe percentage of volume of remaining filling material in oval canals filled with twoobturation techniques after retreatment with ProTaper Universal Retreatment (ProTaper UR)with or without a solvent.MethodsForty mandibular incisor teeth with oval canals were prepared and filled with gutta-percha and iRoot SP sealer using continuous wave of condensation or cold lateralcondensation techniques. Gutta-percha removal was done with ProTaper UR system with orwithout solvent, then further canal re-preparation accomplished with ProTaper Universal F4.The operating time was measured. Pre-and postoperative μ-CT imaging was used to assessthe percentage of volumes of residual filling material.ResultsRemaining filling material was observed in all specimens. The mean volumes ofremaining material in continuous wave of condensation groups were higher than those incold lateral condensation groups (P <.05). In the apical portions of root canals, specimensin cold lateral condensation groups had a lower percentage of remaining material than thosein continuous wave of condensation groups (P <.05). Solvent groups were significantlyfaster than the non-solvent group to reach the working length (P <.05). However, non-solvent groups required less time to achieve satisfactory gutta-percha removal and rootcanal refinement than the solvent groups (P <.05).ConclusionsNone of the retreatment techniques was able to completely remove traces of gutta-percha/sealer from the oval canal. The root canals filled with continuous wave ofcondensation left remnants in a higher proportion than with cold lateral condensation. Non-solvent groups required less time to achieve satisfactory gutta-percha removal and rootcanal refinement than the solvent groups.