A methodology for quantitative evaluation of root canal instrumentation using microcomputed tomography.

Aim: The aim of this paper was to present an objective methodology for quantitative evaluation of root canal instrumentation using microcomputer tomography, together with developed software based on a constructed mathematical model.

Methodology: A desktop X-ray micro-CT scanner (SkyScan 1072) was used to provide data sets of an extracted mandibular molar before and after instrumentation (ProFile 0.04 Taper instruments, Dentsply Maillefer, Ballaigues, Switzerland) that were stored for later use by software. A volume visualization package (T3D) was applied to obtain 3D renderings of the molar to illustrate the qualitative visualization capacity. Next, medical image volume fusion software was used to allow alignment of pre and post image volumes. Finally, software was developed to make quantitative measurements and to provide additional qualitative information on the registered image volumes. This procedure implemented a true 3D mathematical model for quantification of instrumentation effects. Using a local co-ordinate frame, perpendicular reslices were made at five different levels within the mesio-buccal canal to evaluate transportation and centring ability.

Results: At first accurate and detailed 3D renderings were obtained. The general and local canal shape before and after preparation could visually be examined in 360 degrees rotation. Numerical values were obtained for volume, volume changes and transportation. Centring ability was calculated by centring ratio and centre movement.

Conclusions: This methodology is a new and objective way for quantitative evaluation of root canal instrumentation using microcomputer tomography and dedicated software.