A Three-Dimensional (3D) Evaluation Unveiling if the Anterior Mandible Is Truly a Safe Zone for Implant Placement

Background Dental implants are increasingly being used in the rehabilitation of the edentulous areas in the maxilla and mandible. The anterior mandible is considered a safe zone for implant placement, but clinicians often find it challenging to control bleeding in this area. This is due to the presence of the sublingual artery, which can be of varying dimensions and can cause severe bleeding. This can be of higher significance in patients with high or uncontrolled blood pressure and in patients on blood thinners like Aspirin or Coumadin where establishing a clot can be difficult. With newer guidelines recommending that medication be discontinued only a few hours before surgery and that bleeding be managed locally, this issue has become even more challenging. With three-dimensional (3D) imaging using cone beam computed tomography (CBCT) becoming more common for implant planning, the presence of the sublingual artery can be evaluated and incorporated into the treatment plan. The objective of this study is to evaluate the 3D location of the sublingual artery in the edentulous anterior mandible of CBCT scans of patients referred for dental implant therapy. Methodology A total of 50 de-identified CBCT scans with an edentulous anterior mandible referred for dental implant therapy were evaluated for this study. Cross-sectional images were generated using a CBCT reconstruction program INVIVO-5 (Anatomage, San Jose, CA, USA). After the sublingual artery was localized, measurement was conducted from a standardized point on the alveolar crest to the artery's entry point on the lingual aspect. Measurements were also obtained from the terminal point of the artery's course to the buccal cortical plate. Alveolar crest can either resorb or be subjected to alveoloplasty during implant placement, similar measurements were also done from a standardized point on the inferior cortical border of the mandible to the artery's entry points on the lingual aspect. Two oral and maxillofacial radiologists conducted all measurements. Results It was found that the median value of the sublingual artery from the alveolar crest to the level of entry (V1) was 6.78, the vertical measurement of the artery coursing into the alveolar bone was ~4.03 mm (V2), the vertical measurement of the artery's position within the alveolar bone at the terminal point form the crest was ~11.71 (V3), and the inferior vertical measurement from the course of the artery to the inferior border of the mandible was 9.60 mm. The artery extended about ~8.3 mm within the alveolar bone from the lingual cortex (H1), and the artery was located about 4.97 mm away from the buccal cortex (H2). Cronbach's Alpha test showed high interoperator reliability.  Conclusions In this retrospective study, the sublingual artery was noted to be at a critical location in the potential implant site. A site-specific evaluation using CBCT can help in localizing and avoiding perforation of the sublingual artery.