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The purpose of the present study was to determine mandible bone mineral density and results compare based on using two kinds of phantoms. Two kind composites contain hydroxyapatite powders in micro or nano scale . Periapical radiographs were obtained with a constant current of 8 mA, 70 kVp, and 3 s exposure times, always from the same distance. Images were recorded by use of standard radiographic film. The calibration curve was drown, by plotting against the measured mean grey level values of each step on the step wedge phantom and those values of the measured mean grey level of digitized films. Its segment densities were measured with DXA and corrected with chemical content estimations. The mean grey levels were measured on each of the steps using dedicated software with a probe of 5x5 pixels. Measured GL values of each step on the step wedge phantom were plotted against the measured densities on the DXA to obtain a calibration curve. On the mandibular image, the mean GLs were measured on the step wedge phantom and the regions of interest.The plain x-ray films were scanned using a standard film digitizer. After the film digitized, the developed Matlab software was used to image processing. In 207 postmenopausal women central BMD was measured through DXA method. In each women periapical radiography performed in two regions of mandible. Prevalence of osteoporosis and osteopenia in one of regions in central DXA were 17.4% and 48.2% respectively. In osteoporotic patients bone loss in mandible BMD was more than central DXA (p=0.02). There was strong correlation between mandible and total femur BMD (p=0.001, r=0.78) when using of composite mixed from nano hydroxyapatite powder, inter assay and intra Coefficient of variance significantly lower than other (p=002) and its sensitivity more than another phantom especially when the T-score of central BMD was lower than -1.5. These result indicated that composite containing nano scale of hydroxyapatite by homogenous demonstration may be improve sensitivity of mandibular BMD. The main advantage of the proposed mandible BMD is to help clinicians make more accurate evaluation of Bone loss. Based on developed the suggested system a routine dental X-ray may be used to screen for bone loss.
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