Anterior Loop of the Inferior Alveolar Nerve to Estimate the Safe Zone in Implant Planning

Objectives: The objective of this study is to measure the prevalence of anterior loop presence, the average length of the loop on the right and left sides, and to evaluate age-, sex-, and ethnicity-related variations in prevalence and the length of the anterior loop in the study population. Methods: Using the DICOM database from the Oral Health Centre at the International Medical University, the inferior alveolar nerve was manually traced along with the anterior loop and part of the incisive nerve using the software. The vertical length of the nerve was estimated from the canal to the opening of the mental foramen from the cross-sectional view and translated to the OPG view. A measurement was made from this point to the most anterior point of the anterior loop following the trajectory of the nerve. Measurements were repeated for the opposite side. Results: A total 100 CBCT DICOM files were selected for study. The anterior loop was present in 94% of the subjects. The length of the anterior loop ranged between 0.73mm to 7.99mm, with the mean length being 3.90±1.41mm on the left side and 4.06±1.53mm on the right. Among all the subjects, there were no statistically significant differences between the left and right sides of the mandible (P=0.689), and no statistically significant differences was found between gender (P=0.108). When comparing the left anterior loop length between males and females, there were significant differences seen (P=0.041). Between 3 ethnic groups, there were no statistically significance differences seen. Conclusion: The mean anterior loop length was found to be 3.90±1.41mm on the left side and 4.06±1.53mm on the right, with a range of 0.73mm to 7.99mm. Due to its inconsistency and high variability, a CT scan is recommended for visualisation of the anterior loop before placing implants close to the mental foramen region. Schlagwörter: anterior loop, CBCT, dental implants, inferior alveolar nerve