Safe Zone Mapping in the Anterior Mandible for Implant Osteotomy: Insights from a Cone Beam Computed Tomography Study

Abstract

Surgical procedures involving dental implant placement in the anterior mandible may place adjacent neurovascular structures, particularly the inferior alveolar nerve and its anterior loop, at risk of injury. This study aimed to evaluate the anatomical relationships between the genial tubercle (GT), mental foramen (MF), and anterior loop (AL) using cone-beam computed tomography (CBCT). The dimensions of the crestal surgical safe zone and variations according to sex and side were also investigated. A retrospective CBCT-based study was conducted using 712 scans. After applying predefined exclusion criteria, 200 scans with a clearly identifiable anterior loop were randomly selected, including 100 males and 100 females (mean age: 44.5 years). Bilateral measurements included the distances from the GT to the MF, from the GT to the AL, and the corresponding crestal safe zone. Statistical analyses were performed to assess sex-related differences, side-specific variations, and the distribution of safe-zone categories. All morphometric parameters were significantly greater in males than in females. Mean GT-MF distances were 28.11 ± 2.60 mm and 27.38 ± 2.40 mm on the right and left sides in males, compared with 26.63 ± 1.55 mm and 26.22 ± 2.12 mm in females. The mean crestal safe zone measured 24.62 mm (right) and 23.78 mm (left) in males, and 21.66 mm (right) and 20.55 mm (left) in females. Right-sided GT-AL and safe-zone measurements were significantly greater than left-sided values in both sexes. Most males (66%) were classified within the 20-25 mm safe-zone category, whereas 58% of females were grouped within the 15-20 mm category. The anterior mandibular interforaminal region exhibits significant sexual dimorphism and bilateral asymmetry. Patient-specific CBCT assessment is essential for safe implant planning and minimizing neurovascular complications.