The challenge of C-shaped canal systems: a comparative study of the self-adjusting file and ProTaper.

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.