Maxillofacial Anatomy: The Mandibular Symphysis
Placement of dental implants in the anterior mandible is considered by many clinicians to be a relatively low-risk procedure. However, hemorrhagic episodes following implant placement in the mandibular symphysis are regularly reported and can have serious consequences. The use of high-resolution focused cone beam scanners has given us the ability to visualize the intricate neurovascular network of the intraforaminal region without distortion and in greater detail. Knowledge of the arterial supply and navigated implant placement in the mandibular symphysis can help to avoid these potentially life-threatening emergencies.
Figure 1. Cross-sectionals, anterior to the mental foramen, demonstrating the course of the incisive canal. Figure 2. Panorex view of incisive canal, demonstrating contralateral anastomosis. Figure 3. Buccolingual position of incisive canal approaching the midline. Figure 4. Harvesting of symphysis block grafts, exposing the incisive canal.
Figure 5. Lingual artery anastomosis with the incisive canal at midsymphysis. Figure 6. Consequence of severe bleeding subsequent to implant placement in the mandibular symphysis. Figure 7. Submental artery at midsymphysis, anastomosing with the incisive canal. Figure 8. Anteroposterior course of mylohyoid artery.
Figure 9. Anastomosis of mylohyoid artery with the incisive canal. Figure 10. Multiple perforating vessels on the lingual surface of the anterior mandible. (A) Lingual artery. (B) Sublingual artery. (C) Submental artery. (D) Mylohyoid artery. (E) Secondary mylohyoid artery. Figure 11. Crosssectional of superior genial foramen at the cuspid position. Figure 12. Reconstructed 3-dimensional image showing positions and relative sizes of the superior genial and mental foramina.
Figure 13. Distal bifurcated branch of the mental nerve. Figure 14. Axial tomography tracing the path of a bifurcated mental nerve. Figure 15. Cross-sectional tomograph demonstrating severe facial resorption. Figure 16. Virtual implant placement that bypasses critical structures (EasyGuide, Keystone Dental, Inc, Burlington, Mass).
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