Comparison of non-transport disc and conventional distraction osteogenesis for mandibular segmental defect reconstruction

BACKGROUND: An animal model of non-transport disc distraction osteogenesis (NTDDO) was developed for repairing segmental mandibular defects in dogs. This study aimed to determine whether any difference exists in osteogenesis within the distraction zone between non-transport disc distraction osteogenesis (NTDDO) and conventional distraction osteogenesis (CDO), in order to provide a reference for its clinical application in the repair of segmental mandibular defects. METHODS: Twenty-four dogs were divided into two groups, and animal models of NTDDO and CDO were established respectively.Samples were taken at 0, 2, 4,and 8 weeks of consolidation. The new bone in the distraction zone was observed or detected by gross condition, X-ray film, Micro CT, biomechanical test. The histological manifestation of new bone was observed by HE staining. The expression of the osteoblast marker Runx2, and the endothelial cell marker CD31 were detected by immunohistochemistry and microvessel density was calculated. RESULTS: The results from gross specimens, radiographs, and HE staining indicated no significant differences in new bone formation within the distraction gap between the NTDDO and CDO groups at any time point. Micro-CT analysis revealed no statistically significant differences in BMD, BV/TV, Tb.Th, Tb.N, or Tb.Sp (P > 0.05). Similarly, biomechanical testing showed no significant difference in maximum load (P > 0.05). Immunohistochemical staining demonstrated comparable expression levels of CD31 and Runx2, with no significant difference in neovascular density (P > 0.05). CONCLUSIONS: Non-transport disc distraction osteogenesis achieves osteogenic quality equivalent to conventional distraction osteogenesis, with inferior alveolar neurovascular resection posing no adverse effects on bone regeneration. The underlying mechanisms, particularly the potential interplay between nerve regeneration and periosteal contributions, warrant further exploration.