en Endodontics Endodontics Original article Original article <div> <table align="center" hspace="0" vspace="0"> <tbody> <tr> <td style="padding: 0cm 12px; text-align: justify;" valign="top"><span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Background and Aim</span></span></span></b><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">:</span></span></span></b><b> </b><span style="font-size:9.0pt"><span style="font-family:" verdana="">The present study compared the retreatment efficacy of D-RaCe, SP1, and R-Endo rotary files in gutta-percha removal from the mesiobuccal canal of mandibular molars by micro-computed tomography (micro-CT). &nbsp;&nbsp;</span></span></span></span><br> <span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Materials and Methods: </span></span></span></b><span style="font-size:9.0pt"><span style="font-family:" verdana="">In this experimental in vitro study, 30 mandibular molars were prepared with Denco-D-Super files and filled using gutta-percha and AH Plus sealer by the lateral compaction technique. Root canals then underwent micro-CT, and the amount of root filling material was measured on images using LOTUS InVivo-REC software. The teeth were randomly assigned to three groups (n=10) for retreatment with D-RaCe, SP1, and R-Endo systems. They underwent micro-CT again after retreatment, and the volume of residual root filling material in the root canals was calculated. The percentage of cleaning efficiency of each system in removal of gutta-percha from the mesiobuccal canal was calculated and compared among the three groups by two-way ANOVA and Tukey&rsquo;s test (alpha=0.05).</span></span></span></span><br> <span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Results</span></span></span></b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">:</span></span></span><span style="font-size:9.0pt"><span style="font-family:" verdana=""> File type (P=0.05) and root canal region (apical, middle, or coronal third) (P<0.001) had significant effects on the percentage of cleaning efficiency. SP1 was significantly superior to R-Endo regarding cleaning efficiency (P=0.04). D-RaCe had the highest cleaning efficiency in the apical third (85.12%) while SP1 had the highest cleaning efficiency in the middle (91.57%) and coronal (68.22%) thirds. R-Endo had the lowest cleaning efficiency in the entire root canal system.</span></span></span></span><br> <span style="font-size:13pt"><span new="" roman="" style="font-family:" times=""><b><span style="font-size:9.0pt"><span style="font-family:" verdana=""><span style="color:#2e74b5">Conclusion:</span></span></span></b> <span style="font-size:9.0pt"><span style="font-family:" verdana="">Although none of the systems had 100% cleaning efficiency, the cleaning efficiency of D-RaCe and SP1 was superior to R-Endo for retreatment of mesiobuccal canal of mandibular molars. &nbsp;</span></span></span></span></td> </tr> </tbody> </table> </div> Mandible, Molar, Retreatment, Root Canal Therapy, X-Ray Microtomography 28 37 http://jrdms.dentaliau.ac.ir/browse.php?a_code=A-10-352-5&slc_lang=en&sid=1 Parinaz Beikian Ghavidel s_savadkouhi@yahoo.com 100319475328460011375 100319475328460011375 Yes Endodontic Department, Dental School, Islamic Azad University of Medical sciences, Tehran, Iran Amir Abbas Moshari 100319475328460011376 100319475328460011376 No Endodontic Department, Dental School, Islamic Azad University of Medical sciences, Tehran, Iran Sohrab Toursavadkouhi 100319475328460011377 0000000315054696 No Dental Material Research Center, Endodontic Department, Dental School, Islamic Azad University of Medical sciences, Tehran, Iran