Three-dimensional dental imaging by spiral CT: A progress report

Objective. To demonstrate the feasibility of using spiral computed tomographic data for three-dimensional image acquisition, display, and segmentation of dental structures and lesions and to demonstrate the feasibility of metal artifact suppression. Study design. Isolated extracted teeth, a dry mandible, cadaver mandible, and cadaver head were scanned and reconstructed using spiral computed tomography data. Algorithms for metal artifact reduction including extended attenuation range and interpolation of missing projections were applied. Volumetric rendering was performed to synthesize images comparable to conventional intraoral dental radiographs. Serial examinations were obtained by spiral computed tomographic tomography, registered by surface matching, and interval change determined by three-dimensional subtraction. Results. Metal artifact reduction was successful in markedly reducing the streaks and star patterns that usually accompany metallic restorations and intraoral appliances. Voxel sum images were comparable to dental radiographs. Image segmentation could successfully isolate dental structures, and simulated lesions could be detected through three-dimensional subtraction. Conclusion. The results demonstrate the feasibility of spiral volumetric computed tomography for quantitative study of oral hard tissues in the presence of metal restorations.