Prevalence of the Inferior Alveolar Nerve’s Anterior Loop and Mandibular Incisive Canal by Use of Cone Beam Computed Tomography (CBCT) in an Iranian Population.

Background and aim: Mental nerve injury is one of the challenges of implant surgeries in the anterior mandibular region, which leads to complications such as paresthesia of the lip and chin. The present study aimed to evaluate the prevalence of the Inferior Alveolar Nerve's (IAN) anterior loop and mandibular incisive canal by use of  CBCT. Materials and Methods: In this descriptive study, 200 high resolution CBCT images of the patients referring to a private oral and maxillofacial radiology center were evaluated. The images were obtained by NewTom Giano unit and were measured in NNT viewer software. Reconstructed panoramic-like images were prepared, and upon the detection of the anterior loop, cross sectional slices were made and dimensions of the anterior loop were calculated by counting the cross sections. In addition, the maximum diameter of the incisive canal was measured, and the location of this diameter was determined on the cross sections relative to dental roots. Data were analyzed by Chi-Square test. Results: In the 200 evaluated subjects, the prevalence of the anterior loop, with the minimum length of 3mm, was estimated to be 19% and the prevalence of the incisive canal was valued to be 87.5%. No significant correlation was detected between the presence of the anterior loop and age, gender, dental status and side of the jaw. Also, no significant association was detected between the presence of the incisive canal and age, gender and dental status (p=0/597,p=0/492,p=0/643) respectively. The maximum diameter of the incisive canal was 5.3 mm which was located between the first and second premolars. Conclusion: Considering the results, it seems that evaluation and measurement of the length of the IAN's anterior loop and the diameter of the incisive nerve by CBCT are necessary steps to prevent nerve injuries during surgical procedures in the anterior mandibular region.