Effect of Endodontic Instrumentation on Root Canal Circumference and Area

Objectives:  To evaluate the resultant canal circumference and area from endodontic root canal preparation using a rotary nickel-titanium file and a standard endodontic hand file.

Methods:  Pre-operative radiographs were taken of twenty extracted molars and the working length determined.  Apical patency was established and maintained.  The specimens were mounted in a resin block using the Endodontic Cube.  The palatal root of each specimen was sectioned into thirds.  The apical and coronal section was photographed under magnification using a 35-mm Nikon camera. The circumference and area of each canal section was measured and recorded with the Image Pro Plus Software.  The specimens were reassembled in the Endodontic Cube allowing access to the occlusal portion.  Endodontic preparation was completed randomly using a Profile .04 taper Series 29 rotary-file or a standard .02 taper stainless steel K file.  One operator instrumented all canals, and one set of instruments was used to shape a single canal.  The cube was disassembled and each section re-photographed and measured.  Means and standard deviations were calculated to determine the difference between measurements before and after instrumentation.  The student t-test was used to determine statistical significance. 

Results:

Conclusions:  Treatment with the Profile resulted in more tooth structure loss in both the coronal and apical section compared to treatment with the K files, although not statistically significant.  The apical section of the group treated with the Profile resulted in a statistically significant larger mean area difference compared to the group treated with K files.  Funded by:  NIDCR DE: 007057