Objective: The aim of this study was to evaluate the topographic relationship between the inferior dental canals (IDCs) and the roots of impacted mandibular third molars. Methods:Preoperative orthopantomograms (OPGs) were examined and the proximity of the IDC to the roots of impacted mandibular third molars was categorized into the following: groups: superimposition, adjacent, perforation, grooving, notching, or none. The categories notching, grooving, and perforation were regrouped together and called the true relationship between the IDC and the root apices. The type of impaction, age, and sex of the patient were also noted. Results:The positional category of 96.1% of the radiographs with bilateral impactions was identical on both sides of the mandible. Out of 2526 impacted mandibular third molars examined, 1146 (45.3%) belonged to the superimposition category, 663 (26.2%) were adjacent, 312 (12.3%) showed grooving, 78 (3.08%) showed notching, and 9 (0.35%) were actually perforating the IDC. The results showed 15.7% of the total cases were in true relationship with the IDC. There was a significant association (p = 0.000) between patient's age and true relationship. Conclusions:Identical positional relationship of the bilateral impacted third molars to the IDC was noted in 96.1% of the radiographs. The position of the IDC in relation to the roots of impacted third molars varied according to the patient's age.