Assessment of the Capability of Bone Density Contrast Dissociation in Cone Beam Computed Tomography Compared to Digital Periapical Radiography by Using a Phantom

STATEMENT OF THE PROBLEM: Assessment of bone density changes plays an important role in diagnosis, treatment, and follow-up procedures. The feasibility of cone-beam computed tomography (CBCT) for assessment of bone density changes is still controversial. PURPOSE: The aim of this study was to investigate the capability of bone density contrast dissociation of CBCT compared to digital periapical radiography. MATERIALS AND METHOD: In this in vitro, experimental study, we designed radiographic phantom for bone density simulation. The phantom was a polytetrafluoroethylene rectangular cube with five-chambers. Five micro-tubes (2 mL) containing different concentrations of dipotassium phosphate (K(2)HPO(4)) were placed within these chambers. Different concentrations of K(2)HPO(4) were scanned by CBCT; the mean voxel value of each micro-tube was measured and compared with the concentration of K(2)HPO(4) that represented bone density. RESULTS: CBCT results showed that there were no significant correlations between 300 mg/mL and lower concentrations of K(2)HPO(4) and CBCT voxel values (P≤0.52) but there was a significant correlation between concentrations of K(2)HPO(4) higher than 300 mg/mL and CBCT voxel values (p< 0.001). CONCLUSION: CBCT is a reliable method for the assessment of bone density changes in the high range of bone density but it is not reliable for such assessment in the lower range of bone density. Digital periapical imaging method may not be applied for the assessment of bone density, whereas in higher densities, the employment of CBCT seems to be feasible.