Comparative Morphometric Evaluation of the Relationship Between the Mental Foramen and the Mandibular Bone Using Ultrasonography and Panoramic Radiography

Background: The mental foramen (MF) is a critical anatomical landmark in many invasive dental and maxillofacial procedures. Accurate localization is essential to prevent iatrogenic nerve injury. Panoramic radiography (OPG), although commonly used for this purpose, has limitations due to its two-dimensional nature and susceptibility to artifacts. Ultrasonography (USG), which offers real-time imaging without ionizing radiation, has emerged as a promising alternative. This study aimed to compare the effectiveness of OPG and USG in identifying the MF and measuring its distance to the mandibular bone. Methods: A total of 120 patients (60 males, 60 females) aged 18 years and older were included in the study. A total of 240 mental foramina were evaluated. Vertical measurements were obtained from the superior border of the MF to the alveolar crest and from the inferior border to the inferior cortical border of the mandible. Ultrasonographic imaging was performed using an extraorally placed probe in a longitudinal position; during evaluation, the operator positioned themselves on the patient’s right side when examining the right MF and on the left side when examining the left MF to ensure consistency throughout the measurement process. Panoramic radiographs were acquired using standard protocols, and calibration was achieved by attaching orthodontic wires to the second premolars. All measurements were performed on calibrated digital images using dedicated measurement software. Statistical analysis included paired samples t-test, one-way ANOVA, independent samples t-test, and Pearson correlation. Results: Statistically significant differences were found between the two methods in all regions (p < 0.05), with OPG consistently yielding higher distance values than USG. MF–mandibular bone distances were significantly greater in males than in females (p < 0.01). In participants aged 40 years and older, OPG showed significantly greater inferior distances, while USG revealed no significant age-related differences. A strong positive correlation (r = 0.801–0.911) and high intra-observer reliability (r = 0.982–0.996) were observed between the methods. Conclusions: Ultrasonography offers a reliable and non-invasive alternative to panoramic radiography for identifying the mental foramen. Despite the technical limitations of OPG, the strong correlation between the two methods supports USG’s complementary role. In clinical situations where radiation exposure should be minimized, USG may serve as both a supportive and, when appropriate, standalone diagnostic tool. Trial registration: Not applicable. This study did not involve a health care intervention and was not a clinical trial.