The aim of the present study was to assess the presence and course of the anterior loop in the mental foramen region according to age and gender, using cone beam computed tomography (CBCT). Both the right and left sides were retrospectively studied in 141 patients (n = 282). Axial, sagittal, cross-sectional and panoramic images were evaluated and three-dimensional images were reconstructed and evaluated as necessary. The morphology, course and length of the anterior loop were measured. The reliability and reproducibility were assessed based on the intraclass correlation coefficient (ICC) and the coefficient of variation. An anterior loop was found in about 86% of the scans. The mean anterior loop proximal edge was 3.15 mm and the mean distance between the buccal border of the anterior loop and buccal alveolar wall was 2.24 mm. The mean volume of the mandibular canal was 1140 mm(3) and the mean volume of the anterior loop was 90 mm3. Statistically significant difference was found in male patients in terms of the canal and anterior loop volume (p < 0.05). A high prevalence of anterior loop was detected by CBCT imaging, with predominance in female patients. Clinicians should be careful during implant or bone surgery procedures to avoid possible complications, with special emphasis on patient age, using this imaging modality that involves use of less radiation.