骨膜牵张成骨的实验研究

目的　建立骨膜牵张成骨模型 ,探讨骨膜牵张成骨新技术 ,为牙槽骨缺损及其他骨缺损寻找新的修复方法。方法　将自制骨膜牵张成骨装置及钛网植入 12只成年兔的一侧下颌升支外侧面 ,从术后第 7天开始牵张 ,第 1次牵拉 2mm ,后每 3d牵拉 1mm ,共牵拉 15d ,最终将钛网牵拉离开骨面 7mm。术后第 2 8、35、4 2、5 6天分别处死 3只动物 ,进行组织计量学、X线片及组织学观察。结果　所有标本在计量学及X线片上均显示有新骨形成 ,术后第 2 8、35、4 2和 5 6天形成的新骨厚度平均分别为 (1 90± 0 13)mm、(2 2 2± 0 30 )mm、(3 17± 0 14 )mm和 (4 5 6± 0 4 6 )mm。组织学观察显示了新形成骨在成骨细胞数量上的增长 ,以及胶原纤维排列方向上的变化。结论　骨膜牵张法可以形成新骨 ,用于增加骨量。     

利用种植作牵张增高牙槽嵴的实验研究

目的研究种植体牵张装置应用的可能性.方法杂交家犬6只,随机分为3组,拔除下颌前磨牙3月后进行手术,在术后4、9、14周依次处死两只动物,所有标本都经大体观察、X线连续检查、组织学检查、计算机定量组织学研究.结果①X线片测得采用种植体牵张成骨增高牙槽嵴为(2.83±0.42)mm;②组织学切片显示术后14周时牵张区形成成熟的骨小梁及骨皮质,与周围骨质无明显区别,与种植体结合紧密.结论种植体能够作为口内牵张器和固定装置,完成牵张过程;在牵张成骨后可作为义齿修复的基牙.     

两、三焦点牵张成骨在下颌骨缺损修复中的应用

目的：通过两焦点、三焦点对山羊下颌骨缺损进行牵张,比较两种牵张成骨方式的新骨成骨量。方法：将8只成年山羊随机分成两组,每组4只,分别采用两焦点和三焦点牵张成骨术进行骨缺损修复。牵张结束后固定8周,处死动物取牵张区新生骨组织标本进行X线检查、组织学检查、骨密度分析。结果：两实验组牵张区新骨生长的质无明显区别,在量的比较上,三焦点组X线检查、组织学检查、骨密度测定的结果均好于两焦点组,骨密度测定分析结果有统计学意义（P〈0.05）。结论：三焦点牵张成骨在大面积颌骨缺损的修复中新骨的成骨量好于两焦点牵张成骨组。     

骨膜原位成骨促进兔下颌骨缺损修复的研究

目的动态观察并验证骨膜在骨缺损修复过程中的作用。方法12只6个月龄新西兰大白兔随机分为去除骨膜组和保留骨膜组,每组6只,均制备下颌骨体10mm×8mm全层骨缺损,术后2周、4周、8周每组处死2只动物,标本行肉眼、X线、扫描电镜及组织学观察,计算缺损区新骨面积,两组间行独立样本t检验。结果X线、扫描电镜及组织学结果显示,第4、8周时保留骨膜组的成骨速度、新骨量及骨密度均优于去除骨膜组,第2周时两组间差异不明显。保留骨膜组后期出现少量中央成骨,去除骨膜组整个观察期间主要为边缘成骨。第2周时两组间新骨生成面积无明显差异,第4、8周时差异有统计学意义。结论保留骨膜能促进成骨,手术1个月后骨膜成骨的效果更明显。     

两焦点与三焦点牵张成骨方式在下颌骨缺损修复中的应用

目的对山羊下颌骨缺损进行两焦点与三焦点牵张,比较两种方式的新骨成骨量。方法将8只成年山羊随机分成两组,每组4只,分别采用两焦点和三焦点牵张成骨术来进行骨缺损修复。牵张结束后固定8周后处死两组动物取牵张区新生骨组织标本进行X线、组织学、骨密度分析。结果两组牵张区均有新骨形成,质无明显区别,在量的比较上,三焦点组X线、组织学、骨密度测定的结果均优于两焦点组,骨密度测定分析结果有统计学意义(P<0.05)。结论三焦点牵张成骨在大面积颌骨缺损的修复中新骨的成骨量优于两焦点牵张成骨。     

腭裂缘骨膜牵张成骨不同阶段的组织学变化分析

目的 对腭裂裂隙缘的骨膜进行牵张,研究新骨形成的过程及规律,初步探讨骨膜牵张成骨方法修复腭裂的机制.方法 选用健康杂种幼犬8只制作腭裂动物模型,采用安置骨膜牵张器的方法对裂隙缘的一侧骨膜进行牵张,牵张力为(2.45±0.20)N.在牵张器放置后20、30、40、60 d各处死动物2只,未放置一侧为对照侧.结果 裂隙缘骨膜受牵张后,新生成骨细胞数量随时间变化而增多,大量沿牵张方向排列的胶原纤维组织在增生的成骨细胞作用下,钙化沉积成新骨,并逐渐改建成熟.结论 新骨形成是沿牵张方向的膜内成骨方式完成的,在骨膜牵张器放置20d后牵张区已有新骨形成,随着牵张时间的延长,成骨量逐渐增加,40d时的成骨活动最活跃,至60d时新骨钙化程度较成熟,以骨改建和塑形为主.     

自发成骨修复小型猪下颌骨缺损的组织病理学研究

目的研究保留和去除骨膜情况下自发成骨修复小型猪下颌骨节段性缺损的组织学表现。方法选择18月龄雌性中国小型猪8只,拔除其右侧下颌前磨牙及第一磨牙,2个月后动物随机分为保留骨膜组（A组）与去除骨膜组（B组）。A组骨块切除长度分别为5cm与6cm,B组骨块切除长度分别为1cm与2cm,每个长度对应2只动物,骨块切除后均行坚固内固定。术后12周处死动物,标本行大体、x线及HE染色后组织学观察。结果保留骨膜5cm与去除骨膜1cm组完成骨连接,保留骨膜6cm与去除骨膜2cm组未完成骨连接。保留骨膜组可见膜内成骨,去除骨膜组可见软骨内成骨。两组未完成骨连接处可见纤维组织或纤维软骨组织。结论保留骨膜的成骨作用优于去除骨膜;保留骨膜时可以自行修复较大长度的骨缺损。     

用三焦点牵张成骨技术修复重建颏部骨缺损的实验研究

目的:探讨应用三焦点牵张成骨技术修复重建颏部骨缺损的可行性及其方法。方法:选取4只成年恒河猴,通过下颌前份骨截除术形成颏部正中联合骨缺损。在两侧下颌体部各制备一个输送盘,并用自行研制的可调式多平面牵张装置使双侧输送盘向前内方向缓慢移动,并在颏部正中对接以修复重建颏部骨缺损。通过X线片与螺旋CT三维重建技术检查双侧输送盘移动与新骨形成情况。在牵张结束的第8和16周分别处死2只动物,取下颌骨牵张区标本作组织学检查。结果:牵张结束后,4只恒河猴的颏部形态接近正常猴,X线片与螺旋三维CT片显示两侧输送盘远心端在正中成功对接。牵张结束的第8周,螺旋三维CT与实验组织学观察发现牵张间隙内均有新骨形成;两侧输送盘在下颌正中呈纤维连接,并可见活跃的成骨和改建活动。牵张结束的第16周,牵张间隙内新骨成熟,两侧输送盘下颌正中逐渐呈纤维骨性连接。结论:用可调式多平面牵张装置进行三焦点牵张成骨可以作为修复重建颏部骨缺损的一种选择手段。     

局部应用胰岛素样生长因子对下颌牵张成骨的作用

目的 研究局部应用外源性胰岛素样生长因子-I（IGF-I）对兔下颌牵张成骨的影响。方法 成年大耳白兔6只,随机分为A、B两组,每组3只。在兔双侧下颌骨前部行骨切开术,以IGF-I与I型胶原膜的复合物和单纯I型胶原膜分别应用于A、B两组动物的骨切开区域,用自行研制的牵张器延长双侧下颌骨6mm,在牵张结束后第4周处死动物,取双侧下颌骨标本进行X线和组织学检查。结果 两组动物下颌牵张后新骨生成速度和数量未见显著性差异。结论 外源性导入胰岛素样生长因子-I未见有明显促进兔下颌牵张成骨的作用。     

应用钛镍记忆合金牵张成骨增高下颌牙槽嵴的初步研究

目的 探讨应用钛镍记忆合金牵张成骨增高下颌牙槽嵴的可行性。方法 选用成年杂种犬10只，拔除两侧下颌全部前磨牙和第1磨牙，实验组1个月后用完全埋置的钛镍记忆合金牵张器完成牵张手术。在牵张手术前及术后1、5、13周测量术区颌骨高度，拍X线片，分别在牵张完成后1、3个月处死动物，进行组织学研究。结果 牵张器就位后骨块即开始牵张升起，术后1周达7．5～11．5mm，其后无明显变化。X线片可见牵张完成后1个月牵张区骨密度增高，有新骨生成；3个月骨密度与周围牙槽骨接近。组织学观察牵张区早期有胶原束形成，随后钙化成骨。结论 用钛镍记忆合金牵张器可成功牵张增高犬下颌后牙区牙槽嵴，新骨以膜内成骨方式生成。     

Induced osteogenesis by periosteal distraction.

PURPOSE: The purpose of this project was to evaluate a novel technique for inducing osteogenesis through periosteal distraction in a rabbit model. MATERIALS AND METHODS: A periosteal distraction device was rigidly fixed to the lateral surface of the mandible in 10 adult rabbits. Periosteal distraction was started 7 days after placement of the periosteal distraction device. The periosteum was distracted 7 mm over 15 days. The unoperated, contralateral side of the mandible served as the control. The animals were killed at postoperative days 28, 35, 42, and 56. The specimens were then fixed, decalcified, and stained with hematoxylin and eosin. Histologic examination and histomorphometric analysis were performed on all specimens. RESULTS: Nine of 10 periosteal distraction devices remained rigidly fixed to the lateral surface of the mandible. On postoperative day 28, the histologic specimen from the experimental side showed periosteal proliferation and an increase in the number of osteoblasts. On postoperative days 35, 42, and 56, the experimental side showed an increase in the number of osteocytes per unit area, collagen fibers parallel to the vector of distraction, islands of osteoblasts surrounded by newly formed bone, and maturation of bone. An average of 2.86 +/- 0.56 mm of new bone height was formed. CONCLUSION: We report on a novel technique for generating bone by periosteal distraction. Our histologic analysis showed proliferation of the periosteum, an increase in the number of osteoblasts and osteogenesis.     

不同牵张速率对山羊下颌骨牵张成骨中新骨形成的影响

目的:探讨山羊下颌骨牵张成骨中不同牵张速率对术后新骨形成的影响。方法:12只山羊随机分为3组,每组各4只,在对动物右下颌骨行骨皮质切开术后进行牵张,第1组动物以0.8mm/d的牵张速率进行牵张,第2组动物以1.6mm/d的牵张速率进行牵张,第3组动物以2.0mm/d的牵张速率进行牵张,随机选取实验组4只动物未手术侧正常下颌骨作为对照组。将各组新骨组织和对照组下颌骨组织分别进行骨密度检测和三点弯曲测试,对采用不同速率进行骨牵张后动物下颌骨新骨的生物力学强度和骨密度进行了对比观察。结果:0.8mm/d牵张组新骨骨密度值显著高于其余各牵张组,0.8mm/d牵张组新生骨三点弯曲实验指标均大于另2牵张组。结论:采用0.8mm/d的牵张速率进行牵张能最快促进新骨形成,提高成骨质量。     

Effect of recombinant human bone morphogenetic protein-2 on mandibular distraction osteogenesis

The purpose of this investigation was to study the effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) on bone formation of mandibular distraction osteogenesis. Six skeletally mature sheep underwent 10 mm of bilateral mandibular distraction osteogenesis via a custom-made distractor. Three micrograms of rhBMP-2 with a collagen carrier was implanted in the osteotomy site of one side of the mandible during the osteotomy phase. The contralateral side was used as the control group, and no material was implanted into the distracted area. At 10 days after the end of distraction, all animals were killed, and the distracted calluses were harvested for radiologic and histologic analysis. New bone was generated in the distracted zone in all groups. Histologic and radiologic examination showed that the new bone formation was greater in the rhBMP-2 group than in the control group. Quantitative computed tomography evaluation, however, did not demonstrate a significantly different mean bone density of the regenerates between the 2 groups. The results indicate that application of a rhBMP-2/collagen implant during the osteotomy phase of distraction osteogenesis increased bone formation but did not have a significant effect on bone density of the regenerates.     

羊颧骨缝三维牵张成骨的组织学观察

目的探索不截骨的骨缝牵张成骨组织学变化。方法采用10～13个月龄普通山羊为实验对象，每只动物左颧骨行三维牵张成骨，固定1、3、5、8周后取材，和对侧空白对照标本比较，观察缝区组织变化、新骨形成情况。结果骨缝被牵开后1周，成纤维细胞、成骨细胞、毛细血管增生，大量纤维软组织排列有序并连接骨缝两侧，骨缝两侧组织面不整齐，牵张侧成骨活跃，大量类骨质形成；3周时形成较成熟的骨小梁；5周时编织骨形成；8周时结构成熟完整。结论不截骨的骨缝三维牵张成骨，骨缝牵张侧新骨快速形成；     

The effects of irradiation and hyperbaric oxygen on bone formation during rabbit mandibular distraction

[18F-]fluoride positron-emission tomography (PET) was used to assess bone formation during mandibular distraction osteogenesis. There were three study groups: irradiation, irradiation+hyperbaric oxygen and control. The two experimental groups received a tumoricidal dose of irradiation to the mandible, and one group was also given hyperbaric oxygen (2.5 ATA (atmospheres absolute) for 90 min) 18 times preoperatively. Control animals received neither irradiation nor oxygen. A unilateral osteotomy was made and, after a period of latency, bone distraction was started, continued for 2 weeks, and the distraction generated was then allowed to consolidate for 4 weeks. The first PET study was performed at the end of distraction and the second at the end of consolidation. At the end of distraction, the metabolic activity of bone in the distracted area was significantly higher in the controls than in either experimental group; differences between the experimental groups were not statistically significant. By the end of consolidation, activity in the control group had diminished to the same as in the two experimental groups, in which no significant change had occurred. Radioactivity was still significantly higher at second imaging on the distracted than non-distracted side in the control and irradiation+hyperbaric oxygen groups, but not in the group that was only irradiated. The results indicate that previous irradiation disturbs bone formation during mandibular distraction osteogenesis. Hyperbaric oxygen was not able to prevent the suppression of osteogenesis caused by radiotherapy but it might improve bone formation by prolonging high osteogenic activity.     

Does the sheep mandible relapse following lengthening by distraction osteogenesis?

AIM: Distraction osteogenesis is a technique used to lengthen the shortened mandible. However, the long term stability of the distracted mandibular bone is not known. The aim of this study was to assess if the sheep mandible relapses following lengthening, and to assess the quality of distracted bone up to 1 year post lengthening. METHODS: Twenty-four sheep had bilateral external mandibular distractors applied, with three sheep as controls. Titanium marker screws were positioned both proximal and distal to the distraction zone in all sheep. Following a 5 day latency period, the interdental gap was distracted 1 mm/day for 20 days, with a subsequent 20 day consolidation period. Ante-mortem serial X-rays were used to assess for relapse by measuring the distance between the screws. The animals were sacrificed at either 3, 6, 9 or 12 months post-distraction. At post mortem, the distance between the screws was re-measured. The distracted bone was assessed mechanically and histologically. RESULTS: The mean mandibular lengthening obtained was 13.2 mm. There was no relapse of the mandible over 12 months. The distracted bone had attained the strength and stiffness of undistracted bone by 6 months post-distraction (p < 0.05). Histological evaluation revealed significant amounts of lamellar bone by 6 months post-distraction. CONCLUSIONS: No relapse occurred for 12 months post distraction lengthening. The bone formed following distraction was stable and of good quality. These findings lend support to the use of distraction osteogenesis in clinical practice.     

Expression of vascular endothelial growth factor and its receptors after mandibular distraction osteogenesis

During distraction osteogenesis, angiogenic activity is essential for new bone formation. This study examined the expression of vascular endothelial growth factor (VEGF) and two of its receptors, Flt-1 (VEGFR-1) and Flk-1 (VEGFR-2), in cellular components after mandibular distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in six mongrel dogs. Two animals each were killed on days 7, 14 and 28 after completion of distraction. The distracted mandibular segments and contralateral undistracted control segments were harvested and processed for immunohistochemical examination. Seven days after distraction, there was a significant increase in the expression levels of VEGF and its receptors in the osteoblasts, osteocytes and immature fibroblast-like cells compared to control specimens. These levels were maintained for 14 days after distraction in the osteoblasts and fibroblast-like cells. Twenty-eight days after distraction, VEGF and VEGFR-1 were expressed only moderately/weakly in the osteoblasts, and no VEGFR-2 expression was detected in the cellular component of the distracted bone. Throughout the observation period, VEGFR-1 expression was stronger than that of VEGFR-2. The expression patterns of VEGF and its receptors suggest that it plays an important role in osteogenesis, and that osteoblasts and immature fibroblast-like cells of the distracted bone may have an autocrine growth effect during distraction osteogenesis.     

失感觉神经支配大鼠下颌骨牵张成骨动物模型的建立

目的：建立一个新的可行性和重复性俱佳的失感觉神经支配大鼠下颌骨牵张成骨模型。方法：24只大鼠随机分为2组,实验组大鼠先自下颌孔至颏孔切除下齿槽神经后,从升支前缘至下颌骨下缘行全层骨切开,用螺钉固定特制的钛牵张器,对照组为保留下齿槽神经的大鼠下颌骨牵张成骨,5d延迟期后,均进行单侧下颌骨牵张,速率：0．2mm／12h,牵张期为lOd,随后进入固定期。分别于固定期第14d、28d处死大鼠,进行大体标本观察和组织学检测。结果：实验过程被所有24只大鼠很好的耐受,切口感染率低,无牵张器脱落。大体标本观察表明,在牵张间隙形成了很好的骨痂组织,牵张间隙达到了预期的长度。感觉神经缺失对牵张成骨具有负面调节作用。结论：成功建立了一个新的可行性和重复性俱佳的失感觉神经支配大鼠下颌骨牵张成骨模型,该模型有助于感觉神经对牵张成骨影响的分子机制的进一步深入研究。