The relation between bone mineral density in the heel and pixel intensity in the mandibular jaw bone among elderly...

The purpose of this study was to investigate the correlation between pixel intensity (PI) in digital radiographs of the lower jaw and bone mineral density (BMD) in the heels of post-menopausal women (as measured with DXL, a combination of dual energy X-ray absorptiometry and lasers).

Two intraoral periapical digital radiographs were taken in the right and left mandible premolar region, and the digital images were analysed by a computer program (Dimaxis) regarding PI. As the radiographs were taken, the BMD of the patient's left heel was measured via a portable Calscan device. The patient answered a questionnaire concerning risk factors. The correlation between variables was analysed using statistical tests.

A significant correlation was found between the PI in the left (P = 0.001) and right (P = 0.004) mandible and the BMD of the left heel for the whole group. A pronounced correlation was found to exist for women > 70 years old. Based on a cut-off value of the PI, to differentiate between healthy individuals and those who required further analysis for osteoporosis, the following values were obtained: sensitivity 0.74, specificity 0.50, positive predictive value 0.77 and negative predictive value 0.46.

A positive correlation was found between PI in digital radiographs of the mandible and the BMD of the heel. The low predictive value does not allow any definite conclusions to be drawn from the present study. A reasonable recommendation could be for future studies to employ a larger study population to explore the effect on this value.