Localization of Mandibular Canal in Dry Mandibles using Digital Orthopantomography and Cone Beam Computed Tomography: A Pilot Study

Context and Aim: Dental implants are widely used for rehabilitation of edentulous arches. Yet, placement of oral implants in mandible is associated with numerous complications including hemorrhage and neurosensory disturbances. Enumerating precise information concerning the vital structures of the mandible, thus, becomes all the more important before the placement of implants. The aim of the present study was to determine the efficiency and accuracy of digital orthopantomography (OPG) and cone beam CT (CBCT) in determining the location of mandibular canal in pre-operative assessment of mandibles for implant placement. Materials and Methods: Ten dry edentulous mandibles of adult humans were selected for this study. The study comprised of two phases, namely, a radiographic phase and a clinical phase. The radiographic phase was based on obtaining digital orthopantomographs and cone-beam computed tomograms. During the clinical phase, all the mandibles were sectioned at an angle of 90 degrees to the inferior border of the mandible and direct clinical measurements were obtained. Statistical Analysis Used: Statistical analysis was done using IBM SPSS statistics 20 (Chicago, USA). Paired and Unpaired t-tests were used to do a comparative analysis of the two modalities used. p<0.05 was considered to be statistically significant. Results: The results of the present study revealed that the measurements of both the vertical (D1 and D2) and the buccolingual distances of the mandible (D3 and D4) obtained by CBCT were in accordance with the ones obtained with the help of direct clinical measurements and there was no statistically significant difference in the said variables (D1, D2, D3, D4) between the two measurements. On the contrary, there was a significant statistical difference between the values obtained with the help of digital orthopantomography (OPG) (D1, D2) as against the same values obtained with the help of direct clinical measurements. Conclusion: The findings of the present study implied that CBCT is the most efficient and accurate diagnostic tool available to locate the course of mandibular canal in the selection of potential implant sites. The accuracy of the i-CAT Cone Beam Computed Tomography (CBCT) unit was found to be superior to the digital panoramic images in the present study because of multiplanar 3D reconstructions.