The relationships between two indices of mandibular bone quality and bone mineral density measured by dual energy X-ray absorptiometry.

OBJECTIVES: To establish whether a relationship exists between the bone quality index (BQI), the mandibular cortical index (MCI) and bone mineral density (BMD) of the body of the mandible as measured by dual energy X-ray absorptiometry (DXA).
METHODS: Mandibular DXA and panoramic radiography were performed on 40 edentulous female patients. Mandibular body BMD was calculated by manual analysis of DXA scans. Panoramic radiographic appearances of the mandibles were assessed according to the BQI and MCI. All assessments were performed by two observers.
RESULTS: There were significant correlations between BQI and BMD (P < 0.01 for both observers) and between MCI and BMD (P < 0.005), but MCI was the more dominant of the two variables. Inter-observer agreement between BQI assessments was superior to that between MCI assessments. There were marked differences between intra-observer agreement for the two observers for both indices.
CONCLUSIONS: Both BQI and MCI are significantly related to BMD. However, particularly in the case of MCI, there were problems in repeatability of assessments which might limit their use in clinical practice.