Mandibular canal cortical assessment for screening low bone mineral density in panoramic radiographs: the cortical index of mandibular canal.

OBJECTIVES

To qualitatively assess the continuity of the mandibular canal cortices at different segments (ramus, angle, and body) on panoramic radiographs and to correlate these findings with bone mineral density (BMD) status determined by dual-energy X-ray absorptiometry (DXA), using a novel visual index: the Cortical Index of the Mandibular Canal (CIMC) for osteoporosis screening.

METHODS

Panoramic radiographs and DXA results were retrospectively selected. Women were grouped according to consistent DXA classifications in all evaluated sites. The mandibular canal was segmented into three anatomical regions, and the continuity of its cortices was visually assessed using the CIMC. The Mandibular Cortical Index (MCI) was also applied for comparative evaluation.

RESULTS

Ninety postmenopausal women aged 40 years or older were included. The mandibular body showed the strongest correlation between CIMC classification and BMD status. CIMC in the mandibular body also demonstrated higher accuracy (AUC = 0.731) compared to the MCI (AUC = 0.650). Accuracy of both indices improved when combined with body mass index (BMI).

CONCLUSIONS

The CIMC applied to the mandibular body is a simple visual index for screening individuals with low BMD. Loss of cortical continuity in this region may indicate systemic bone loss.