Distraction osteogenesis to achieve mandibular vertical bone regeneration: a case report

In this case report a surgical technique for vertical ridge augmentation is presented. The procedure, performed in a 30-year-old woman with an atrophied alveolar ridge in the anterior portion of the mandible, is based on the biologic concept of osteogenesis distraction previously introduced in orthopedic and maxillofacial surgery. After elevation of a full-thickness flap a horizontal osteotomy was performed 7 to 8 mm from the top of the ridge. Two vertical osteotomies were prepared with drills of increasing diameter (2, 2.8, and 3.25 mm), tapping was performed for the first 5 to 6 mm, and two distractor base plugs were placed at the base of the osteotomies with a repositioning tool. An intraosseous distraction implant was then inserted and 2 inward vertical cuts were made in the bone to allow proper distraction to take place. Correct functioning of the device was checked by distracting the bone fragment 1 mm using the axial distraction screw. A latency distraction healing screw was inserted in each of the distraction implants and the area was left to heal for 5 days. Once primary healing had occurred, the distraction of the newly formed bone callus was activated each day for 10 days (1 mm per day). At the end of the distraction period a final distraction screw was left in place and a final healing screw was inserted. During this time there were no complications and the patient on no occasion complained of discomfort. The distractor device was removed 30 days later, leaving the base plugs in place. One month later a vertical augmentation of 7 mm had been achieved; the base plugs were removed, 3 intraosseous implants were inserted, and a biopsy of the newly formed tissue was obtained. Histologic evaluation of the biopsy specimen showed woven bone formation approximately 75 days after the initial procedure.