Prevalence of Anterior Loop and other Patterns of Mental Nerve in a Sample Population of an Indian City: A Retrospective Study

INTRODUCTION: The final portion of the inferior alveolar nerve (IAN), the mental nerve (MN), is a general somatic afferent nerve that provides sensation to the lip, chin, and gingival tissue. Three patterns of MN have been observed – straight, perpendicular or vertical, and anterior loop (AL) of MN. The interforaminal region of the mandible possesses a MN with a path that creates an AL before entering the mental foramina. The aim of the study is to evaluate the presence of AL of MN using cone-beam computed tomography (CBCT) and to measure the length of the AL of MN, if present, also to evaluate the prevalence of other anatomical patterns of MN – straight and vertical patterns. MATERIALS AND METHODS: Mandible CBCT of 400 patients with the age of 20 years onward was included in the study. The images obtained were assessed for the different patterns of MN – straight, vertical, and ALs. The statistical analysis was done using the Chi-square test, paired t-test, and sample t-test. RESULTS: Out of 400 CBCT scans comprising 800 hemimandibles, straight pattern was observed in 67.1%, vertical pattern in 26%, and Anterior Loop in 6.9%. The prevalence of AL pattern was 6.9%. AL length was found to be in a range of 2.4–6.6 mm. DISCUSSION: Surgical trauma or injury to the AL of MN is possible during implant surgery in the interforaminal area of the mandible if AL is not assessed preoperatively.