Quantitative Analysis of Cone-Beam Computed Tomography Artifacts Induced by Nonmetallic Root Canal Filling Materials Using Different Fields of View: In Vitro Study

Abstract

Cone-beam computed tomography (CBCT) imaging artifacts can hinder accurate diagnosis of several conditions. The aim of this study was to quantify CBCT artifacts created by nonmetallic root canal filling materials using two fields of view (FOV). Root canals of twenty extracted maxillary central incisors ( $n=20$ ) were instrumented and randomly divided into four equal groups: canals in Group 1 were filled with gutta-percha, canals in Group 2 with mineral trioxide aggregate (MTA) and gutta-percha, canals in Group 3 with gutta-percha and glass-fiber posts, and canals in Group 4 with MTA and glass-fiber posts. Each tooth was mounted on a silicon block and scanned three times using a CBCT machine, first with a prefilling scan (control) and then with postfilling scans, using two different FOV ( $40\ast 50\text{mm}$ and $80\ast 50\text{mm}$ ). Imaging software was used to measure grayscale pixel values of canal cross sections. Data were analyzed using $t$ -test and paired $t$ -test statistical tests, with statistical significance set at $p\le 0.05$ . Dentin at the apical and middle third of the teeth showed a significant decrease in minimum grayscale values in association with gutta-percha ( $p=0.027$ , $p=0.034$ ). However, a wide $80\ast 50$ FOV showed a significant increase in maximum grayscale values of coronal ( $p=0.048$ ) and apical dentin ( $p=0.049$ ). Glass-fiber posts in middle third cross sections also corresponded to an increase in maximum grayscale values ( $p=0.018$ ). Gutta-percha produced dark band artifacts in the root’s middle and apical thirds, whereas white streak artifacts were produced by gutta-percha in the coronal third and glass-fiber posts in the coronal and middle thirds when imaged with a wider FOV. A smaller FOV is therefore recommended for CBCT imaging, as it produces fewer artifacts.