Introduction: Cone beam computed tomography (CBCT) has been used for preoperative treatment planning for dental implants, one of the major advantages is its accurate linear measurements. But when it comes to automatic detection of voxel intensity values as in automatic nerve detection, little evidence in the literature was found. Thus; in order to examine the accuracy of this automatic process, this study was performed in vitro.
Methods: A dry edentulous mandible was imaged using i-CAT next generation (Imaging sciences international, Hatfield, PA, USA) using gutta percha markers at certain areas of interest, the reconstructed panoramic image was evaluated and nerve tracing was done for both sides, then linear measurements was performed from the edge of the inferior alveolar nerve canal (IANC) to the inferior border of mandible, buccal, lingual and crest of the ridge. These measurements were compared to actual physical measurements performed by using a digital caliber after sectioning of the mandible at the gutta percha sites.
Results: Intra-observer agreement was good to very good regarding all measurements for both observers, while inter observer agreement was weak to very good regarding all measurements for both observers. There was no statistically significant difference between the CBCT scans (0.2 mm, 0.3 mm, and 0.4 mm voxel size) regarding all measurements except one measurement at the 0.4 mm voxel size CBCT scan showed a statistically significant high mean error.
Conclusion: The choice of FOV and voxel size should be made by clinicians based on the clinical task at hand, keeping in mind that their choices not only affect the diagnostic quality of images but also the amount of radiation exposure that their patients receive.