Assessment of the Metal Artifact Reduction Tool for the Detection of Root Isthmus in Mandibular Molars with Intraradicular Posts in Cone-beam Computed Tomographic Scans

Introduction: This study evaluated the performance of the metal artifact reduction (MAR) tool in cone-beam computed tomographic scans using different fields of view (FOVs) in the detection of a root isthmus in mandibular molars with intraradicular posts. Methods: Twenty-eight teeth were scanned by micro-computed tomographic imaging (gold standard images). Thereafter, specimens were allocated into the following groups: gutta-percha (teeth without posts, n = 10), a prefabricated metal post (n = 9), and a fiberglass post (n = 9). Cone-beam computed tomographic scans were taken using 8 acquisition protocols, varying the size of the FOV (10 ! 5.5 cm and 5 ! 5.5 cm) and the MAR tool (disabled, low, normal, and high modes). A root isthmus was evaluated considering a 5-point scale. Data were analyzed considering a 5% significance level. Results: Intra-and interexaminer agreement varied from moderate to substantial. The frequency of correct diagnosis varied significantly in all groups regardless of the image acquisition protocol selected (P < .05). In the gutta-percha group, there was no difference in the accuracy, sensitivity, and specificity values between the tested protocols. In the metal and fiberglass post groups, the accuracy values were higher with the disabled and low modes of the MAR tool regardless of the FOV size. This was also observed for the sensitivity values in the metal post group (P < .05). Conclusions: The size of the FOV did not affect the performance of the MAR tool in the diagnosis of a root isthmus in molars with intraradicular posts. Our findings suggest that the use of the tool in the normal and high modes is contraindicated for this purpose. (J Endod 2021;47:1583-1591.)

Automated summary

This study evaluated the performance of a metal artifact reduction (MAR) tool in cone-beam computed tomographic scans for detecting root isthmus in mandibular molars with different intraradicular posts. The results showed that the size of the field of view (FOV) did not affect the tool's performance, with disabled and low modes of MAR tool showing higher accuracy values for metal and fiberglass post groups. The study suggests that normal and high modes of the MAR tool are not recommended for this purpose.