钛下颌骨重建假体修复下颌骨缺损的初步实验研究

Reconstruction of mandibular defect by using titanium mandibular prosthesis:A preliminary experimental study

目的:研究钛下颌骨重建假体在下颌骨节段性缺损重建中的应用价值。方法:采用2只健康成年山羊,术前收集羊下颌骨的螺旋CT数据,采用快速原形技术重建出羊的下颌骨实体模型,并设计出一侧下颌骨体部5cm的缺损,以及对侧下颌角部缺损。应用CAD／CAM技术,形成与缺损部位完全吻合的医用纯钛假体。通过手术建立山羊下颌骨与假体形态大小完全吻合的缺损,然后将假体植入并固定,角部假体内植入自体松质骨。术后每月进行X线检查,3个月后处死动物,切取标本制备硬组织切片和正常组织切片,光镜观察。采用生物力学方法,分析骨与假体结合处的结合强度。结果:术后2周,1只羊下颌体的假体前部暴露于口腔,内固定尚稳同,但是在术后一月,该假体与前部的下颌骨残端分离,完全暴露在口腔内。另1只羊下颌体假体,术后2个月前部部分外露,但同位良好。光镜观察未暴露的假体与骨组织之间结合良好,特别是下颌角的假体达到骨结合。植骨区肌附丽通过肌-骨-假体三者有机结合,形成假体-肌的真正附丽。结论:作为下颌骨缺损修复的一种方法,CAD／CAM制造的仿真钛假体在龈骨膜下的部分容易暴露于口腔内,暴露处易于引起假体周围炎,破坏假体与骨间的结合。肌假体之间的再附丽,需通过假体中植骨的存活及肌-骨-假体结合模式实现。

PURPOSE: The aim of this experiment was to investigate the possibility of application of mandibular reconstruction with titanium mandibular prosthesis. METHODS: Two healthy adult goats were used in this study. Spiral CT of the mandibular region was performed. The data collected was related to the computer. Then a 5cm mandibular body defect and a mandibular angle defect were designed accordingly. Titanium mandibular prostheses were manufactured according to the size of the above defect. Surgical operation was performed and the prosthesis were implanted into the aimed defects and internal fixation was used. Autogenic bone graft was introduced into the holes of the angle prosthesis. Radiographic examination was used to evaluate the healing of prostheses every month after operation. Three months later, the animal was sacrificed and the mandible specimens were sectioned for histological and biomechanical evaluation. RESULTS: One of the body prosthesis was found to be exposed two weeks after operation. Four weeks later, fixation failed and the anterior part of the prosthesis separated from the mandible attached. The other body prosthesis also suffered from exposure,but the connection between the prosthesis and the mandible was still stable. Histological examination revealed that there was presence of osseointegration in the angle prosthesis as well as area that was not exposed in the body prosthesis model. Reattachment of the muscles to the bone graft area was found. CONCLUSIONS: CAD/CAM generated Titanium mandibular prosthesis is applicable in human model. The vitality of this experiment revealed that atight closure plays an important role in the healing by osseointegration.If there was any exposure,the osseointegration will be failed.Reattachment of the muscle to the prosthesis can be achieved by 'muscle-bone-prosthesis'model.