IMPACT OF FIELD OF VIEW AND SCATTER INDUCED NOISE IN DETECTION OF MB2 CANALS

Abstract

<h3>Background</h3> Cone beam computed tomography (CBCT) units provide different fields of view (FOVs) for different clinical applications. Small FOV scans are often used in endodontic treatment planning. However, endodontic pathology is also detected as an incidental finding in large FOV scans. Some machines have introduced a new feature known as <i>zoom reconstruction.</i> This essentially allows for a specific area of interest to be carved out of the original data set and made into an independent scan that will allow for evaluation of the area in better detail. <h3>Objective(s)</h3> The objective of this study was to evaluate the number of missed canals on small FOV scans and zoom reconstruction gleaned from large field of scans. <h3>Study Design</h3> A total of 30 extracted maxillary first molars were used in this study. The teeth were scanned with small FOV to locate MB2 canals. The results were used as the gold standard. The teeth were endodontically treated and restored. The MB2 canal was not instrumented when it was present or detected clinically. The prepared teeth were mounted on a dry human skull and secured with sticky wax. The skull was scanned with large and small FOV scans. The areas of interest were zoom reconstructed from large FOV scans. Interobserver variations were calculated using kappa statistics. Nonparametric tests were used to compare the reading of the observers with gold standard. <h3>Results</h3> Kappa statistics from 0.605 to 0.650 for small FOV, from 0.350 to 0.650 for large FOV, and from –0.305 to 0.590 for zoom reconstruction. In general, the smaller FOV scans had better agreement with gold standard. <h3>Discussion/Conclusions</h3> Small FOV scans were found to have better detection accuracy compared with small scans gleaned out of a larger FOV scan through zoom reconstruction in its ability to detect missing root canals and pathology.