Removal Efficiency of Different Root Canal Preparation Methods for Smear Layer on Patients' Tooth Crown

Objective To investigate the removal effect of smear layer on paients' tooth crown withlayer back root canal preparation method, layer-depth root canal preparation method and Pro Tapercrown down root canal preparation method. Methods 273 patients with tooth crown smear layerwere selected in our hospital from October 2011 to October 2013. These patients were randomlydivided into three groups. In the first group, 91 patients were treated with layer back root canalpreparation method. In the second group, 91 patients were treated with layer-depth root canalpreparation method. In the third group, 91 patients were treated with Pro Taper crown down root canalpreparation method. Then root canal wall smear layer scores, colony numbers of root canal smear layerand the occurence rates of adverse events before and after treatment were compared within three groups. Results After treatment, root canal wall smear layer scores, colony numbers of root canal smear layerand the occurence rates of adverse events significantly decreased in three groups. Root canal wall smearlayer score, colony number of root canal smear layer and the occurence rate of adverse events in thesecond group were significantly lower than those in the first group(P0.05). Root canal wall smear layerscore, colony number of root canal smear layer, and the occurence rate of adverse events in the thirdgroup were significantly lower than those in the first group and the second group(P0.05). ConclusionThese three methods are effective in removing smear layer on the tooth crown of patients, while theremoval effect of Pro Taper crown down root canal preparation method is the best of all.