Relationship between CBCT and panoramic images of the morphology and angulation of the posterior mandibular jaw bone

Abstract

We determined actual bucco-lingual angulation values and morphological variations of residual bone in the mandibular posterior edentulous region using cone-beam computed tomography (CBCT) and panoramic radiography. A second aim was to investigate whether it was possible to predict bone morphology from panoramic radiographs. Data were collected from 77 consecutive patients referred for both CBCT and panoramic radiography in our department. Two-dimensional and three-dimensional images of the probable implant placement region were investigated. The bucco-lingual angulation values and crest type were determined directly from the cross-sectional images of the posterior edentulous region. The edentulous region was divided into three groups: second premolar, first molar, or second molar region. The observations were evaluated by the computer software, SPSS 22.0 (SPSS Inc. Chicago, USA). The crest type was classified into three groups: type U, type C, or type P. Kappa statistics, Kolmogorov-Smirnov tests, ANOVA, and Kruskal-Wallis tests were used in statistical analyses. The significance level was set at p<0.05. TypeC was more frequent in the second premolar region and the crest type had changed to typeU in the second molar region. The predictability of the typeU was highest in the second molar region. Moderate agreement was found in the predictability of typeU in the molars (κ=0.602). The mean value of bucco-lingual angulation was highest in the second molar region, followed by the first molar region. There were statistically significant differences between the bucco-lingual angulation of the crest types in the second premolar and first molar regions (p<0.05). Bucco-lingual angulation values and morphology change through the posterior mandible. TypeU was predicted at a higher rate in the second molar region from panoramic radiographs. These results demonstrate predicting high-risk areas in the posterior mandible for implant therapy from panoramic radiography.