Efficacy of a thermally treated single file compared with rotary systems in endodontic retreatment of curved canals: a micro-CT study

ObjectivesThis study aimed to compare WaveOne Gold with ProTaper and RaCe systems regarding remaining filling material, apical transportation (AT), and working time (WT) after (i) filling removal and (ii) shaping of curved canals.MethodsThirty mesiobuccal canals of maxillary molars were prepared and filled. After 30days, they were randomly assigned into three groups (n=10), according to the instruments used for filling removal and shaping, respectively: WOGWaveOne Gold Primary and Medium; PTGProTaper Retreatment and ProTaper Next; RCGD-RaCe and RaCe. Micro-CT analysis assessed the residual filling material and AT. WT was recorded. Data were statistically analyzed (=.05).ResultsThere was no significant difference between groups in the amount of filling material at any evaluated moment (P>.05). All groups presented low AT values. The WT was similar in all groups in filling removal (P>.05), and in shaping step WOG was faster than PTG and RCG (P<.05).ConclusionsNeither system could completely remove the filling material. The instruments evaluated were safe and the reciprocating system was faster than the rotary systems in shaping the canals.Clinical relevanceThis study provided consistent information on filling material removal capacity of WaveOne Gold. Considering that all tested systems were safe, WaveOne Gold may be an alternative with cost-effectiveness and shorter learning curve for endodontic retreatment.