Intraoral distraction osteogenesis for the repair of mandibular defect——An biomechanical study / 实用口腔医学杂志

ABSTRACT

Objective:To explore the roentgenographic and biomechanical characters of distraction osteogenesis(DO) in the treatment of mandibular defect.Methods:4 beagle dogs were used to establish 2.0 cm mandibular defect model,after 6 months, a 1.5 cm transport disc was surgically created adjacent to the defect area in an intraoral way, and intraoral device was placed on the transport disc and the base bone segments.A reconstructive plate was applied to stabilize the bone segments. After a 10 day latency period, the transport disc was advanced at a rate of 0.5 mm ? 2/day until the bone fragments were docked at the planned position.35 weeks after completion of distraction the animals were sacrificed,specimen retrieval,roentgenography and the stress testing were performed.Results:The regenerated segments were comparable with the corresponding segments of native mandible,and exact location of junction between the regerated and preexisting bone could not be determined easily. Roentgenographic revealed that the defects were reconstructed with outer cortical layer and trabecular medullary cavity of the bone.The regenerated segments remained less radiodense than the native mandible.Stress test demonstrated that the average ultimate strength of regenerated segmens was (69.4?19.2) MPa,that of the corresponding normal mandible was (86.9?31.9) MPa,and that of junction between transport disc and base bone was(46.9?8.4) MPa. Conclusion:Intraoral distraction osteogenesis may be feasible in the treatment of mandibular defect.