Evaluation of distraction osteogenesis of membranous onlay bone graft: An experimental animal study

Purpose: This study aimed to assess the changes of membranous bone onlay grafting in the mandible of dogs after application of distraction osteogenesis. Materials and Methods: Twenty adult Mongrel dogs were divided into four groups; each with five dogs.  A 3–4 cm zygomatic arch membrane onlay graft were secured on the lateral side of the mandible. Vertical osteotomy was performed after 1, 2, 3, and 4 weeks for Groups I, II, III, and IV, respectively. One week after osteotomy, distraction osteogenesis was initiated at a rate of 1 mm/day for ten days using an external apparatus. The apparatus remained for six weeks to stabilize the bone. Radiographs were taken at 2, 4, and 6 weeks post-distraction, and the dogs were euthanized six weeks after distraction for analysis. Results: The results showed new bone formation between the distracted mandibular segments in all dogs. Groups II, III, and IV showed new bone formation beneath the onlay graft, but this was not observed in Group I. In Group IV, the onlay graft partially reabsorbed, but the newly formed bone had a near-normal cortical structure.&nbsp