VALIDATION OF SPIRAL COMPUTED-TOMOGRAPHY FOR DENTAL IMPLANTS

Objectives: To investigate the accuracy of 2DCT orthoradial reformatte d images from spiral computed tomography (CT) for pre-surgical plannin g of dental implants in proximity to the mental foramen. Methods: Eigh t cadaver heads were imaged by spiral CT (S/Xpress, Toshiba - America, Tustin, CA) with I mm thick axial slices by I mm/sec of table feed. T he image data set was transferred to a networked computer workstation. Using computer graphics the data was analysed with 2D orthoradial ref ormatting using the ToothPix(TM) (Cemax, Fremont, CA, USA) protocol. L inear measurements were made by two oral radiologists independently fr om the superior border of the mental foramen to the crest of the alveo lar process and from the inferior border of the mental foramen to the mandibular inferior border. The soft tissues were removed and physical measurements made using a 3 Space(TM) (Polhemus, Colchester, VT) elec tromagnetic digitizer with a personal computer running Windows(R) 95. Results: The differences between the measurements on orthoradial 2DCT images and the physical measurements were not statistically significan t (P > 0.05). Conclusions: Two-dimensional spiral CT imaging allows hi ghly accurate measurements for dental implant placement in proximity t o the mental foramen. Computer graphics software, using reformatted re construction, is suitable for implant planning.