Is 2 mm a safe distance from the inferior alveolar canal to avoid neurosensory complications in implant surgery?

Aim: The aim of the present study was to compare the neurosensory complications related to implants inserted closer than 2 mm to the inferior alveolar canal (IAC) with those inserted further than 2 mm. Materials and Methods: A total of 474 implants in 314 patients placed posterior to mental foramen area were evaluated retrospectively on panoramic radiographs. Patients were divided into two groups regarding implant proximity to the IAC (Group 1, distance <= 2 mm, Group 2, distance >2 mm). Postoperative neurosensory complications (pain and paresthesia) were recorded. Chi-square test was used for statistical comparison and P <= 0.05 was considered significant. Results: One hundred and fifty-three implants (32.2%) were inserted closer than 2 mm to the IAC whereas 321 implants (67.8%) were inserted further than 2 mm. Three implants which had a distance of 0 mm to the IAC (0.63%) caused paresthesia after surgery. Implant distance to IAC did not show a significant difference regarding pain and paresthesia (P = 0.06 and P = 0.08, respectively). Conclusion: When 2 mm is considered as a safety distance, the distance of the implants to the IAC did not yield any statistical difference regarding postoperative neurosensory complications.