Panoramic-based mandibular indices in relation to mandibular bone mineral density and skeletal status assessed by dual energy X-ray absorptiometry and quantitative ultrasound.

OBJECTIVES

The panoramic-based indices (Mandibular Cortical Index-MCI, the height of mandibular inferior cortex-IC (mm), Panoramic Mandibular Index-PMI, Mandibular Ratio-MR) were used to evaluate their diagnostic efficacy and to determine whether they correlate with bone mineral density (BMD (g/cm(2))) of the mandible and hip, and with ultrasound parameters of the calcaneus and hand phalanges in postmenopausal, edentulous women.

METHODS

Basing on MCI women were divided into three subgroups differed in the appearance of the mandibular cortex (C1 n=6, C2 n=16, C3 n=8). BMD of the hip (neck-BMD, Ward's-BMD, trochanteric BMD) and mandible (m-BMD) were measured by dual-energy X-ray absorptiometry (DXA). Calcaneus using Achilles (Speed of Sound-SOS (m/s), Broadband Ultrasound Attenuation-BUA [dB/MHz], Stiffness Index-SI [%]) and hand phalanges (amplitude dependent speed of sound-Ad-SoS (m/s)) using DBM Sonic 1200 were assessed by Quantitative Ultrasound (QUS).

RESULTS

There were no significant differences between subgroups in parameters measured except for significant differences in m-BMD (P<0.01). Only m-BMD correlated significantly with DXA (r=0.43-0.45, P<0.05) and QUS (r=0.36-0.55, P<0.05) measurements excluding correlations with calcaneal SOS and trochanteric BMD. The ability of the mandibular variables to discriminate between normal and osteopenic/osteoporotic cases was assessed by calculating: specificity (ranging from 31 to 81%), sensitivity (ranging from 21 to 93%), negative and positive predictive values (ranging from 47 to 83% and 40 to 79%, respectively).

CONCLUSION

MCI is a simple three-graded classification of changes in the cortex but is not able to distinguish normal and osteopenic/osteoporotic postmenopausal edentulous women. The efficacy of the panoramic-based mandibular indices in diagnosing osteopenia/osteoporosis is low to moderate.