Validation of spiral computed tomography for dental implants

Objectives: To investigate the accuracy of 2DCT orthoradial reformatted images from spiral computed tomography (CT) for pre-surgical planning of dental implants in proximity to the mental foramen. Methods: Eight 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. The image data set was transferred to a networked computer workstation. Using computer graphics the data was analysed with 2D orthoradial reformatting using the ToothPix(TM) (Cemax, Fremont, CA, USA) protocol. Linear measurements were made by two oral radiologists independently from the superior border of the mental foramen to the crest of the alveolar 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) electromagnetic 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 significant (P > 0.05). Conclusions: Two-dimensional spiral CT imaging allows highly accurate measurements for dental implant placement in proximity to the mental foramen. Computer graphics software, using reformatted reconstruction, is suitable for implant planning.