Cross-sectional imaging of the jaws for dental implant treatment: accuracy of linear tomography using a panoramic machine in comparison with reformatted computed tomography.

PURPOSE Although various panoramic X-ray machines with linear tomographic functions are now frequently applied to diagnosis related to dental implant treatment, the angles of the tomographic objective planes are automatically determined and cannot be adjusted for individual patients. To resolve this problem, a direct laser positioning (DLP) system was developed. In this investigation, the measurement accuracy of images obtained by the DLP system in comparison with those from reformatted computed tomography (CT) was assessed. MATERIALS AND METHODS A rectangular parallel piped phantom was scanned with the system and the height and width were measured on linear tomograms. Ten sites in 3 dried mandibles and 21 mandibular molar sites in 15 patients were examined both with the DLP system and the reformatted CT to compare the measured values on both images. RESULTS The phantom experiment showed that the difference between the actual and measured heights and widths of the phantom were within 1 mm. DISCUSSION The difference between the values obtained by the DLP system and CT was slightly larger in the patients than those in the dried mandibles. CONCLUSION The DLP measurement accuracy was deemed sufficient for clinical use.