A computerized method for evaluating root canal morphology.

Access was performed on nine extracted single-rooted permanent human premolars. Complete debridement of the root canal system was accomplished by running high volumes of NaOCl through them for 90 min. Volumes of the root canal system and access preparation were calculated for each specimen by weighing the teeth, filling them with contrast medium at a known density, and reweighing them. Radiographs were taken of each tooth at known angles with the contrast medium in place. Then each tooth was cross-sectioned at known distances from the anatomical apex. Microscopic measurements were made of canal diameter on each cross-section. The radiographs of each tooth were evaluated by a computerized digital image processing program. Computerized calculations of canal volume and diameter were made and compared with the actual measurements taken from each tooth. The data were analyzed by paired t tests. Results indicate this computerized method for evaluating diameter of root canals to be accurate within 0.1 mm of actual measurements. The volumetric data differed significantly. The difference was probably due to voids in the contrast medium. Overall, this technique appears to be very accurate in determining the anatomy of root canal systems.