Intramandibular course of the mandibular nerve; clinical significance for distraction and implantology.

OBJECTIVE: Loss of teeth is accompanied with loss of function and therefore reduction of alveolar bone height. Insufficient bone height can jeopardize the anchorage of implants or surgical procedures such as distraction osteogenesis, because of possible mandibular nerve damage. The goal of this investigation was to determine the exact course of the intramandibular nerve in edentulous mandibles. MATERIAL AND
METHOD: The study samples included 37 dry human edentulous mandibles. A dental CT scan analysis was performed and four cross sectional views were investigated for each mandible. The Cawood classification was used to assess the grade of atrophy. Implantation simulation was performed in every case.
RESULTS: There was no bilateral symmetry in edentulous mandibles, whatever the cross-section studied. A rate of 38.7% were classified Cawood class IV, the most common group in edentulous patients. Our study results led us to place the distraction osteogenesis device in the posterior edentulous mandible. Implant placement was not possible in every case. DISCUSSION: Our findings allow better understanding from the pathway of the mandibular canal close to the first and second molar in edentulous mandibles. This anatomical data and surgical techniques such as implant insertion and distraction osteogenesis allow finding solutions for "mandibular edentulism". Distraction is essential for a successful implantology.