A comparison of the mandibular index on panoramic and cross-sectional images from CBCT exams from osteoporosis risk group

Osteoporosis is a degenerative disease that primarily affects postmenopausal women. Based on panoramic radiographs, several assessment methods have been proposed for the diagnosis and evaluation of bone changes and as a predictor of osteoporosis for example the mandibular index. The purpose of this study is to compare the assessment of mandibular indices on panoramic and cross-sectional images. Forty-four cone beam computed tomography (CBCT) images from postmenopausal female subjects aged more than 45 years without systemic changes were selected for this study. From those images, cross-sectional and panoramic reconstruction images were assembled into a template for evaluation. The evaluation was conducted by observing the panoramic images and parasagittal sections. The appearance of the inferior cortex of the mandible was classified according to the mandibular index: C1, the endosteal margin of the cortex was even and sharp; C2, the endosteal margin presented semilunar defects or appeared to form endosteal cortical residues; or C3, the cortical layer formed heavy endosteal cortical residues and was clearly porous. Based on Wilcoxon statistical test (p > 0.01), the data showed no statistically significant difference between the exams. The mandibular index assigned in tomographic images is comparable to that obtained in panoramic images, indicating a valid use of the index in CBCT images, which can lead to the identification of patients with bone mass loss and a premature referral to further exams and treatment.