Radiographic Detection of Implant Related Inferior Alveolar Canal Injuries

Objectives: The aim of this in vitro study is to evaluate the diagnostic accuracies of Panoramic radiography (PR) and Cone Beam Computed Tomography (CBCT) for simulated implant related nerve injuries in sheep mandible.
Methods: 50 fresh sheep hemimandibles were used in this study. Standard “trap door windows” were created in order to reveal the inferior alveolar canal. In one group, the pilot drill was inserted until there was 1 mm distance left to the superior border of the canal and other drills with gradually increasing diameters were used to prepare the implant bed. The other group received no implants but the pilot drill penetrated to the mandibular canal. The pilot drill entered 1 mm below the superior border of the mandibular canal in the group which had also implants. Implant only depressed the bony canal of the inferior nerve in one group. Control group had no treatment. All of the samples with attached bone windows were mounted on a custom designed radiographic phantom. They all were exposed to PR and CBCT, respectively. Images were analyzed by three observers. Inter- and intra-observer agreements were calculated with weighted Kappa statistics. Areas under the curve (AUC) values were used to compare diagnostic accuracy of the radiographs in each model.

Results: AUCs for the simulated groups in which drill insertion without penetrating into the canal, drill penetration without implant placement and compression to the mandibular canal were significantly higher in CBCT (p<0.05 for each) when compared to PR.

Conclusions: Within the limits of this study, it can be suggested that CBCT is more accurate than PR in the detection of implant related inferior alveolar canal injuries.