The Challenge of C-shaped Canal Systems: A Comparative Study of the Self-Adjusting File and ProTaper

Abstract Introduction C-shaped canals are anatomic features that present the clinician with both diagnostic and operational challenges. The aim of this study was to compare the efficacy of the Self-Adjusting File (SAF; ReDent, Ra’anana, Israel) in shaping C-shaped canals with that of the rotary ProTaper file system (Dentsply-Maillefer, Ballaigues, Switzerland). Methods Sixteen mandibular second molars and 4 maxillary second molars with C-shaped canals were obtained, originating from native Chinese population. They were divided into 2 equal groups of 10 teeth each, based on similar canal morphology as presented in preliminary micro–computed tomography–derived images. One group was shaped using the SAF, whereas the other was shaped using the ProTaper file system. Reconstructed micro–computed tomographic images before and after treatment were superimposed over each other, and the percentage of the canal wall unaffected by the procedure was calculated. Comparison of the 2 groups for this parameter was performed using the Student t test. Results When treated with the SAF, 41% ± 14% of the canal walls remained unaffected by the procedure, whereas 66% ± 6% of the wall area was unaffected when using ProTaper, which was significantly higher than that of the SAF-treated group ( P < .001). Conclusions The SAF was more effective than the ProTaper file system in shaping the walls of C-shaped root canals.