(PR26) Evaluation of the extent of Calcification of Root Canals by Cone Beam Computed Tomography vs. P.A. Radiography

Objective: The aim of the study was to assess, in a comparative manner, the relative accuracy of P.A. radiography and CBCT when evaluating calcified root canal segments.

Methods: 25 single canal teeth which appeared calcified - at least up to the interproximal CEJ on a parallel cone and parallax (with both a mesial and distal angulation) p.a. exposures - were placed respective to their corresponding human mandible and maxilla empty sockets. High resolution (75 micron voxel-) limited field CBCT (PlanMeca Promax 3D) was also performed in the specimens inside the jaws. 10 micron voxel-resolution microcomputed tomography images of the specimens outside the skull were used as the gold standard. The chamber and/or canal seemingly calcified segment length for each tooth was assessed by two evaluators using all three methods (a 40 millimeter diameter on a cross view was set as a minimum for patency in microCT images).

Results: The first quartile, median and third quartile values in the distribution of obliterated segment length overestimation by P.A. radiography vs CBCT compared to microCT were 0, 0.5 and 4.6 mm vs. 0.38, 1.1 and 4.0 mm, respectively. Approximately 42% of the average canal segment length falsely assessed as obliterated by P.A. radiography or microCT presented a 0.03 mm-0.06 mm diameter on a cross view in microCT images.

Conclusions: Despite being a very important tool in locating the patent part of a calcified root canal, CBCT is in general not superior to P.A. radiography method in evaluating the extent of root canal obliteration.