Identification of Specific Panoramic High-Risk Signs in Impacted Third Molar Cases in Which Cone Beam Computed Tomography Changes the Treatment Decision

Abstract

The aim of this study was to investigate the treatment decisions of oral-maxillofacial surgeons in the management of impacted lower third molars (M3s) according to panoramic radiography (PR) and cone beam computed tomography (CBCT) risk analysis. Ten surgeons analyzed 40 deliberately selected M3 cases showing 1 or more panoramic high-risk signs: 1) darkening of the root, 2) interruption of the white line, 3) diversion of the inferior alveolar canal (IAC), 4) narrowing of the IAC, and 5) 2 or more signs occurring simultaneously (including darkening and/or interruption of the IAC). After evaluating the PR images, the observers analyzed the patients' CBCT images. The treatment decision (extraction vs coronectomy) and surgical technique (number of planned tooth sections) were recorded. On the CBCT coronal slices, direct contact between the M3 and IAC, together with narrowing and/or fenestration of the IAC, was observed most frequently when 2 or more panoramic signs were seen simultaneously on the PR images (odds ratio [OR], 7.2; P=.021). CBCT findings led to a significant decrease in the number of coronectomy decisions (23% vs 14.5%, P=.002), which was most prominent in the groups showing panoramic signs of darkening (approximately 50%, P=.007) and narrowing (approximately 66%, P=.044). A significant number of extraction decisions were modified to coronectomy when 2 or more panoramic signs occurred together (OR, 7.9; P<.001). However, there were no significant differences regarding the number of planned hypothetical tooth sections. The results showed that the surgeons' confidence in the treatment decision increased after CBCT imaging, resulting in fewer coronectomy decisions. CBCT information that changed a previous coronectomy decision to extraction was most frequently observed in cases showing darkening and narrowing PR signs. The chance of changing an extraction decision to a coronectomy decision after evaluating the patient's CBCT images was the highest when 2 or more PR signs were observed simultaneously.