| Background:Distractiuon Osteogenesis (DO)is a new technology which developed on the basis of limb long bone distraction osteogenesis in the 1990s,and it is the product of multidisciplinary. DO has been widely used in craniofacial deformities and mandibular defects. And it was also the important issues concerned by the fields of Maxillofacial and plastic surgery in recent years. At present, although a variety of commercial linear stretch devices used in clinical,it can not apply to the defects of mandibular symphysis and mandibular regional patterns which possess the anatomy and physiology curve. Therefore, the curve distractor even three-dimensional distractor is a bottleneck that DO used on complex forms mandibular defect,and it also is current research focus.AimIn this study, we developed a new semi-buried curve distractor on the principle of transmission with the ball squeezing,which based on the spherical multi-directional and extrusion force transmission principle, fundamentally change the traditional way of distraction. We studied the feasibility of reconstruction chin of mandibular by ball- transmissioned device, discussed the possibility and regularity of distraction application in clinical through in vitro experiments and animal experiments.Methos(1)New ball- transmissioned distractor was designed and made according to squeeze the ball-type multi-directional and force transmission principle. Adding welding of titanium was used to strengthen rail section,and to obtained by three-point bending experiments rail bending strength compared with titanium alloy compared TA1.(2)six mixtus dogs as experimental animal,which were manufactured by anesthesia to establish mandibular symphysis defect animal models.(3)Ball transmission-type curved distractor was used on the improved dog mandibular defect model to distract osteogenesisResults(1)We think this distractor can meet the requirements of arc stretch and built-in functions. And can be adjusted according to the length and curvature of rail to meet the needs of different defect. It was equivalency with the most extensive medical titanium alloy TC4 in three-point bending test. Is a reasonable, simple, practical and innovative design .(2)The mental region mouth mucosa after chin osteotomy in dogs can not be effectively re-establish blood supply,occur natural necrosis in gum edge,which lead to oral wound dehiscence or re-implantation of the distractor plate and bone surface exposure, distraction could not continue. In such circumstances, our preliminary view, it is not feasible to use the dog to made mandibular symphysis defect model.(3) The modified model of the experimental animals completed the process of traction and stationary, and bone showed slight arc. Discuss Distractor presented in this study design, rail shape curvature can form specific manufacturing defect,fixed-wing completely mobile within the rail,and its movement precise trajectory control. Distractor was used in all good biocompatibility of titanium alloy production. In smaller sizes can ensure sufficient strength. Therefore, this design were met with practical application .In direct osteotomy,the mental regionmouth mucosa after chin osteotomy in dogs can not be eff ectively re-establish blood supply,occur natural necrosis in gum edge,which lead to oral wound dehiscence or re-implantation of the distractor plate and bone surface exposure, distraction could not continue. So we think it is not feasible to use made mandibular symphysis defect model.In the modified mandibular symphysis defect model, it was no significant difference with general distraction,and this distraction simple and well into the bone. So this distraction device is designed to promote the clinical application... |
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