Pixel gray measurement for the diagnosis of dental ankylosis in cone beam computed tomography images

Abstract

The aim of this study was to investigate dental ankylosis in unerupted or partially erupted teeth by using cone beam computed tomography (CBCT) to quantify pixel intensity. In total, 157 CBCT images from individuals with a total of 206 unerupted or partially erupted teeth with suspected ankylosis were evaluated. CBCT images were analyzed for the presence of ankylosis by 2 oral radiologists by quantifying mean pixel intensities (analysis 1) and variations in pixel intensities (analysis 2) in normal and ankylosed regions. The association between ankylosis and demographic and tooth-related factors was also examined. Ankylosis was diagnosed in 57 teeth (27.7%). The diagnosis was established with all 3 multiplanar reconstruction views in 22 of these teeth (38.6%). In analysis 1, a higher pixel intensity was observed in areas with ankylosis compared with normal periodontal ligament (PDL) density as a result of bone deposition in this region, which is characteristic of ankylosis (P < .001). In analysis 2, reductions in pixel intensity were greater in the PDL areas than in the ankylosed areas. Ankylosis was significantly associated with the anterior teeth, the maxillary arch, single-rooted teeth, and impacted teeth (P ≤ .026). Our results suggest that CBCT measurement of pixel intensity may be useful for the diagnosis of ankylosis.