Purpose: Investigate the accuracy of CBCT based computer aided surgical guide CASG for implant placement in posterior
atrophied mandible with tilted position (buccal or lingual) to inferior alveolar nerve IAN avoiding its injury.
Materials and Methods: 15 partially edentulous patients with atrophied mandible were included based on certain eligibility
criteria, the work flow in this study run as following, CBCT imaging, virtual implant planning and CASG designing, 3D
stereolithographic printing of surgical guide, surgical procedures of implant placement using the CASG, post-operative CBCT
imaging, registration of pre- and post-operative CBCT images, assessment of angular deviation between actual and planned
implants and linear deviation between them cervically and apically, comparison between virtual and actual implants distance
to IAN.
Results: Wilcoxon signed-rank test Comparing between virtual and actual implants' distance to IAN showed a statistically
significant difference with a mean distance of 0.72 ± 0.25 mm for actual implants and 1.7 ± 0.56 mm for virtual
implants. (4.13 ± 1.86°) was the mean angular deviation, while 1.15 ± 0.49 mm and 1.32 ± 0.63 were the mean cervical and
apical linear deviation respectively.
Conclusion: although a significant difference was found between virtual and actual implants distance to IAN, the values
of linear and angular deviation between them were well accepted and within the range reported by most of similar clinical
studies with less crucial situations, which enhance using fully guided stereolithographic CASG for implant placement with
tilted position in posterior atrophied mandible but with considering at least 2 mm distance between virtual implant and IAN in
planning procedures.