骨缝牵张成骨的比较组织学研究

目的:比较HE染色和三联染色中不截骨的缝牵张成骨组织学变化情况.方法:不截骨直接三维牵张羊颧骨缝,固定期1、3、5、8周取材,进行三联染色和HE染色,与对侧空白对照标本比较,观察缝区组织变化、新骨质形成情况.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,大量胶原纤维形成、排列有序,3周时以胶原纤维为主,形成较成熟的骨小梁,5周时编织骨形成,8周时未见网状纤维和弹力纤维,结构成熟完整.结论:三联染色显示固定早期大量胶原纤维形成,HE染色显示新骨形成速度快.     

颧骨缝牵张成骨过程中组织超微结构变化的研究

目的:观察天然骨缝牵张成骨过程中组织和细胞超微结构的变化。方法:对牵张成骨的缝区组织经过系列处理,进行超薄切片、透射电镜观察。结果:间充质细胞在牵引早期大量增生,并不断分化为成纤维细胞和成骨细胞,后2种细胞的超微结构显示出具有活跃的合成和分泌功能。1周标本成纤维细胞沿牵引力的长轴方向排列,胞核增大,在其周围包绕着发达并扩张的内质网系统;3周标本大量增生活跃的成骨细胞和成纤维细胞,成骨细胞核仁增大、粗面内质网扩张、核糖体丰富、线粒体增多、富含紧密排列的嵴;5、8周标本中骨细胞形成并发育成熟,骨基质逐渐矿化,清晰可见新形成的胶原纤维、哈氏管,以及骨基质矿化的过程。结论:三维牵张过程中,成纤维细胞、成骨细胞活跃,缝区形成新骨。     

β-catenin在大鼠前腭缝牵张成骨中的表达

目的:β-catenin作为一种胞质内的糖蛋白,参与调节成骨细胞形成和骨骼发育.本实验观察β-catenin在大鼠前腭缝牵张成骨过程中的表达并探讨其作用.方法:将32只35天龄雌性SD大鼠随机分为实验组(n=20)和对照组(n=12).实验组大鼠在上颌切牙上安放扩大簧,牵张前腭缝,对照组动物不加力,2组动物均在牵张骨缝1、3、5、7d的相同时间取前腭缝标本.采用甲苯胺蓝染色观察前腭缝成骨细胞的形态和分布,免疫组织化学染色检测β-catenin 和骨桥蛋白(osteopontin,OPN)的表达.结果:在未牵张的前腭缝,成骨细胞沿着骨缝两侧稀疏排列,β-catenin主要在成骨细胞的细胞膜上表达.牵张1d后,前腭缝扩大,成骨细胞在骨缝两侧聚集分布,大部分细胞呈β-catenin和OPN阳性,β-catenin在成骨细胞的细胞膜和细胞质中均有表达,其表达量高于对照组;牵张3d后,骨缝边缘有明显类骨质沉积,大量细胞质呈β-catenin强阳性的成骨细胞积聚成树突状指向骨缝中央,而OPN在这些成骨细胞中表达较弱;牵张5d后,新骨呈树突状大量形成,β-catenin表达减弱,OPN则在新骨基质及埋在期间的成骨细胞内大量表达;7d后大片新骨形成,骨缝变窄.结论:上颌骨缝牵张成骨过程中,β-catenin在成骨细胞中表达,其表达量与表达部位和成骨细胞的成熟相关,提示β-catenin参与了成骨细胞分化的调节.     

颧骨缝牵张成骨的定量研究

目的:研究缝牵张成骨过程中ALP、BGP 、Ca含量变化与新骨形成的关系。方法:牵张成骨后的标本经过匀浆、离心,进行对硝基苯磷酸盐法测量新形成骨中碱性磷酸酶活性水平,利用骨钙素放射免疫试剂盒测定骨钙素含量,用原子吸收分光光度计测定钙含量。结果:骨中碱性磷酸酶在牵张成骨后1周明显升高,3周达到峰值(3.42±0.35) U/g,5周有所下降,8周时接近对照组水平;骨钙素的水平在牵张成骨后有所增加,3周明显上升,牵张成骨后5周达到峰值(74.86±2.71) ng/g,8周下降接近对照组水平;实验组钙含量明显低于对照组,随牵张成骨进行,钙含量逐渐升高,与对照组比较具有明显统计学意义,牵张成骨后5周,实验组钙含量明显增高,8周时钙含量(46.56±2.20) mg/g接近对照组水平。结论:牵张成骨时大量骨碱性磷酸酶、骨钙素先后形成,牵张区钙化迅速,促进新骨质形成。     

截骨牵张联合骨缝牵张对腭裂修复后咬合关系影响的实验研究

目的:观察截骨牵张联合骨缝牵张对腭裂修复近期咬合关系的影响。方法:健康杂种幼犬6只,建立Ⅱ°腭裂模型,3~4周后沿腭外侧缝内侧1 mm纵行切开腭骨水平板,腭横缝区不截骨,立即以250~280 g力持续向内侧和后方牵张至硬腭裂隙关闭,裂隙关闭1周后进入保持期。分别于牵张结束即刻、1、2、4、8、12周处死动物,对牵张过程中咬合关系的变化进行观察,对牵张前后上颌牙列模型进行测量分析。结果:所有实验犬牵张5~7 d后人工裂隙逐渐关闭,牵张过程中上、下颌咬合关系稳定,上颌牙弓左、右对称,上颌牙弓长度、宽度较术前增加,有显著性差异(P<0.05)。结论:截骨牵张联合缝牵张不会导致咬合关系的改变,但对颌骨形态存在影响。     

骨髓间充质干细胞移植对山羊颅骨骨缝牵张成骨的影响

目的研究自体骨髓间充质干细胞（MSCs）移植对生长期山羊颅骨冠状缝牵张后组织改建的影响。方法选用处于发育期山羊10只,随机分为实验组与对照组,各5只。在颅骨冠状缝两侧安放自行研制的牵张器,以每天0．4mm的速率进行骨缝牵张,连续加力8d。实验组动物骨缝牵张区给予注射自体骨髓间充质干细胞,对照组同期注射生理盐水。在牵张结束后第4周处死动物,取骨缝标本进行组织学和扫描电镜观察。结果所有实验动物的冠状缝均被成功牵开,骨缝边缘均可见新骨组织生成与改建。同对照组相比,实验组骨缝成骨与矿化较快,骨小梁分布密度及成熟程度也较高,骨缝形状已开始恢复正常。结论自体骨髓间充质干细胞移植对山羊颅骨缝牵张成骨可能有明显的促进作用。     

放疗对兔下颌骨牵张成骨骨再生的影响

目的：探讨兔下颌骨放疗后牵张成骨（DO）的可行性及其骨再生的特点。方法：将12只成年新西兰大白兔随机分为放疗组和未放疗组，每组6只：放疗组用^60Co机照射大白兔下颌骨，5．4Gy／次，隔天1次，共5次，总剂量为27Gy。3个月后，在2组动物下颌骨的双侧截骨处安装牵张器，经5天延迟期开始牵张，速率为1mm／d，0．5mm／次，每天2次．连续7d，共延长下颌骨7mm．固定期的第4、6周拍摄下颌骨侧位X线片，取双侧新生骨痂行组织学和扫描电镜检查，观察其成骨特征。结果：X线片显示，2组动物同一固定时间牵张间隙内透射密度无明显差异；组织学观察显示，牵张区以膜内成骨为主，但放疗组有更多的软骨形成，放疗组较未放疗组新骨骨小梁细小、稀疏；扫描电镜示同定第6周时，放疗组新骨不如未放疗组致密、成熟。结论：在兔下颌骨放射损伤区行DO是可行的，但成骨质量较差，成骨方式以膜内成骨为主，放射线照射可促进软骨成骨。     

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。     

牵张成骨修复犬腭裂愈合过程的观察

目的:探索截骨牵张联合缝牵张修复犬腭裂中两侧骨岛在中线区愈合的机理。方法: 健康杂种幼犬6只,建立人工Ⅱ°腭裂模型3～4周后沿腭外侧缝内侧1mm纵行切开腭骨水平板,腭横缝区不截骨,立即以250～280g力持续向内侧和后方牵张至硬腭裂隙关闭,裂隙关闭1周后进入保持期。分别于牵张结束即刻、1、2、4、8、12周处死,采用直接观察、X线片和组织学方法评价中线区愈合情况。结果: 牵张5～7d后人工裂隙逐渐关闭,两侧骨岛后移,硬腭平均延长4.78mm。两侧骨岛后份在5～8mm长腭中线上呈叠瓦状重叠,表面粘膜受压凹陷,逐渐融合,4周时出现新生骨桥连结;其前方15～18mm的裂缘粘膜变薄,于正中相互接触,但并未发生组织融合。结论:截骨牵张联合缝牵张可使两侧腭裂裂缘在中线区后分发生骨性融合。     

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.     

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.     

上颌骨牵引成骨术矫治上颌牙弓狭窄

目的 观察上颌骨牵引成骨术矫治上颌牙弓狭窄的疗效。方法 对１０例成年患者行上颌Ｌｅ Ｆｏｒｔ Ｉ型截骨术（不移动骨块）,并手术截开腭中缝骨联结。以上颌快速扩弓装置（６４１４６带环）,每日打开螺旋４次,共１．０ｍｍ。其中２例行单侧扩大牙弓,矫正上颌单侧牙弓宽度不足。利用计算机图形数据分析系统对扩弓前后的后前位头颅定位片进行测量（上颌骨、上颌牙弓基骨、上颌后牙间的宽度）并通过上颌前部咬合片观察腭中缝的     

下颌骨缺损牵张成骨动物模型的建立

目的建立兔下颌骨缺损牵张成骨动物模型,为进一步研究牵张成骨奠定实验基础。方法25只健康成年兔随机分成6组,实验组5组,每组4只,对照组1组共5只。25只兔均行一侧下颌骨切开截骨术,实验组安置自行设计的下颌骨牵张器,经6 d间歇期后,以每天2次,每次0.4 mm的速度牵张8 d进入固定期,于牵张中期(牵张第4天)、牵张末期(牵张第8天),固定期第2、4、6周分别处死4只动物;对照组术后仅保持缺隙而不牵张,与实验组对应的每个时间点处死1只动物,取下颌骨观察骨愈合情况。结果牵张器牵张效率好,固位稳定,实验组动物的下颌骨被成功牵张,牵张区可见新骨形成。实验对照组表现为不同程度的骨不连及骨缺损。结论本研究建立的兔下颌骨缺损牵张成骨模型是较理想的动物模型。     

The role of hyaluronic acid,chitosan, and calcium sulfate and their combined effect on early bony consolidation in distraction osteogenesis of a canine model

The purpose of this project was to study the effect of hyaluronic acid, calcium sulfate, and chitosan on early bony consolidation in distraction osteogenesis of a canine model. Sixteen dogs were used for this study. The lateral surface of the mandibular body was exposed in the subperiosteal plane, and the vertical osteotomy on the mandibular body was extended downward. An external distraction device was applied to the mandibular body, and the mandibular distraction was started 5 days after the operation at a rate of 1 mm/d up to a 10-mm distraction. The experimental group was then divided into a control group, chitosan group, hyaluronic acid group, calcium sulfate combined with hyaluronic acid group, and calcium sulfate combined with chitosan group, depending on the type of implantation material in the distracted area. After completing the distraction, implantation material was injected into the distracted area, although no material was implanted into the distracted area of the control group. After implanting the materials, the distraction device was left in place for 6 weeks to allow for bony consolidation. Four dogs were allocated to each group. Two dogs in each group (total of 8 dogs) were killed 3 weeks after implantation of the material, and the other 8 dogs were killed after 6 weeks. New bone was generated in the distracted zone of all groups. In the calcium sulfate combined with chitosan group and calcium sulfate combined with hyaluronic acid group, the formation of active woven bone was observed throughout the distracted zone. Moreover, the new bone seemed to be nearly normal cortical bone at 6 weeks after implantation. In the chitosan group and hyaluronic acid group, the development of new bone was observed in the distracted zone at 6 weeks. The amount was less than that in the calcium sulfate combined with hyaluronic acid group and calcium sulfate combined with chitosan group. These findings suggest that calcium sulfate and its combined materials seem to be quite effective in early bony consolidation in distraction osteogenesis.     

Einfluss von bFGF auf die Regeneration von distrahierten Unterkiefern nach Radiatio

The potential of distraction osteogenesis in mandibular reconstruction has been limited by its questionable efficacy in previously irradiated bone. The possible osteogenetic effect of recombinant human basic fibroblast growth factor (bFGF) on lengthening of irradiated mandibles was investigated in beagle dogs. We studied nine adult dogs which underwent a full course of external beam radiation therapy (60 Gy/30 fractions). Six months after completion of radiotherapy, the molars were extracted bilaterally followed by bone lengthening of the mandible using an intraoral device. On postoperative day 3 and 7 we injected 10 μg bFGF into the osteotomy site of each right hemimandible. The left sides were used as controls. The time course in ossification of the distracted area was evaluated at 2, 4, and 6 weeks after completion of bone lengthening. The radiographs of the newly formed bone tissue were measured by digital image analysis. Corresponding to the radiographic findings, the histological examination of the removed jaws showed an earlier and more intensive bone formation in the treated side after 2, 4, and 6 weeks compared to the control side. We conclude that bFGF promotes the ossification of distracted mandibles after radiation therapy in dogs.     

Loaded hydroxylapatite-coated implants and uncoated titanium-threaded implants in distracted dog alveolar ridges

AIMS: The aim of this study was to determine the response of alveolar bone after it was augmented vertically with distraction osteogenesis, implanted with hydroxylapatite (HA)-coated implants and noncoated titanium-threaded implants, and subsequently loaded for 1 year. METHODS: Eight dogs each had 4 implants placed horizontally into an edentulous mandibular quadrant. After integration, a distraction osteogenesis device was fabricated in the laboratory. An osteotomy was made to allow the crest of the alveolar ridge to be distracted vertically. After 10 mm of vertical distraction, the distraction devices were stabilized with light cured resin. After bone fill of the distraction gap was radiographically confirmed in all dogs at 10 weeks, 2 implants were placed into the ridges. Four dogs had threaded titanium implants placed, and 4 dogs had threaded HA-coated implants placed, with 1 implant in the distracted bone and 1 implant in adjacent nondistracted bone, for both groups. After 4 months for implant integration, bridges were fabricated and secured to the implants with screws. Crestal bone levels were evaluated by radiographs through 1 year of function. Animals were killed after 1 year of loading for histologic evaluation. RESULTS: The vertical ridge augmentation averaged 8.8 +/- 1.0 mm after 10 weeks of healing after distraction. Analysis of variance indicated a significantly greater change from baseline for HA-coated implants and for distracted bone sites. Histologic examination showed that bone had formed between the distracted segments creating an augmented ridge. The average thickness of the labial cortex in the distraction gap was significantly thinner than the lingual cortex in distracted bone or the lingual and labial nondistracted cortical bone. The presence of a dental implant did not significantly affect cortical bone thickness. Serial sections showed that implants remained integrated and functional without soft tissue inflammation. CONCLUSION: Dental implants placed into alveolar ridges augmented with the technique of distraction osteogenesis were functional for the length of this study.     

兔下颌骨放疗后牵张成骨动物模型的建立

目的探讨建立兔下颌骨放疗后牵张成骨动物模型的可行性。方法24只成年新西兰大白兔随机分为放疗组和未放疗组,每组12只。放疗组采用60Co放疗机照射兔下颌骨,5.4Gy/次,隔日1次,共5次。3个月后在2组兔下颌骨的双侧截骨处安装牵张器,经5d延迟期后开始牵张,速率为1mm/d,0.5mm/次,每日2次,连续7d,共延长下颌骨7mm。固定期的第0、4、6周摄下颌骨侧位X线片。固定期的第4、6周分别取出下颌骨行组织学观察。结果兔对放疗和牵张成骨术耐受良好,未见放疗引起的不良反应。X线片有新骨形成,未见死骨;组织学观察见放疗组较未放疗组有更多软骨形成。结论兔是一种用于建立放射损伤区牵张成骨模型的良好动物。     

Experimental alveolar ridge augmentation by distraction osteogenesis using a simple device that permits secondary implant placement

The purpose of this study was to develop an improved technique of alveolar ridge augmentation by distraction osteogenesis using distraction screws, and to investigate tissue reactions to titanium implants at the distraction site. The left mandibular premolars were extracted from 6 adult dogs. After 12 weeks, a box-shaped osteotomy of the alveolar bone was carried out, and distraction devices were placed on the transport and base segments. After a 7-day latency period, the alveolar bone was augmented by 7 mm vertically at a rate of 1.0 mm/day. Just after distraction, these devices were replaced with dental implants for fixation of the transport segment and bone formation of the distraction site. Histologic and radiographic evaluations were made at 8 and 12 weeks after distraction. Vertical augmentation averaged 6.1 mm after 12 weeks of consolidation. It was possible to lengthen the alveolar bone without great difficulty, and good bone formation was recognized in the distraction site. Greater integration between the implant and the distracted bone was observed at 12 weeks after distraction than at 8 weeks. Distraction osteogenesis was successfully applied to alveolar ridge augmentation by this improved technique, and the implants osseointegrated in the augmented ridge.     

Effect of calcium sulphate on the rate of osteogenesis in distracted bone.

The effect of applying resorbable calcium sulphate material to newly distracted bone to hasten osteogenesis and consolidation was investigated using 24 New Zealand rabbits. The animals were divided into four groups each containing six rabbits. Groups 1 and 2 were test groups and Groups 3 and 4 were controls. A custom-made submerged distractor was used to distract the rabbit mandibles. The distractor was first used on the third postoperative day at a rate of 1 mm/day for a total of 10 mm. After the completion of distraction, a medical grade resorbable calcium sulphate mixture was applied on the distracted bones in the test groups, whereas the distracted bones in the control groups were exposed postdistraction and closed without intervention. Groups 1 and 3 were sacrificed 11 days postdistraction and Groups 2 and 4 were sacrificed 21 days postdistraction. Undecalcified sections of the distracted bone were examined. Half of the distracted mandibles in each group were stained with Goldner's trichome stain to identify the amount and maturity of the new bone in the distraction zone. The other half of each group was stained with von Kossa stain to identify the amount of calcification and calcium deposition in the distracted bone. Osteogenesis was seen as early as 11 days postdistraction in test animals. Rich lamellar bone deposition was noted in Group 2 (21 days postdistraction +CaSO4). Calcification of the newly formed bone was predominant in the distraction zone in the test groups, especially Group 2, compared to the control groups, which showed incomplete bone deposition and calcification. In conclusion, the application of calcium sulphate to newly distracted bone increased the rate of osteogenesis and calcification.