牵张成骨延长山羊下颌骨后下齿槽神经的组织学变化

目的 :研究下颌骨牵张成骨术后不同时间内下齿槽神经的组织学改变。方法 :对 8只成年山羊行双侧下颌体骨皮质切开术 ,经口外安置自行研制的下颌牵张器 ,以每天 1mm的速率向前牵引延长其中 6只山羊的下颌骨10mm。于牵张结束后第 2、4、8周各处死 2只动物 ,取双侧下齿槽神经作组织学检查 ,另 2只未牵张的山羊作对照。结果 :下齿槽神经受牵张力作用发生了一定程度的沃勒变性 ,主要表现为髓鞘肿胀、碎裂及轴索数目减少。但随着固定时间的延长 ,受损神经纤维逐渐得以再生。结论 :下颌骨牵张成骨术后下齿槽神经发生了轻度的退行性变 ,但这种退行性变在适宜的速率牵张下是可逆的     

不同速率牵张山羊下颌后下齿槽血管变化与血管生成的实验研究

目的:研究不同速率牵张延长山羊下颌骨后下齿槽动静脉的变化和新骨组织内血管生成情况。方法:8只成年山羊随机分为3组,A组(3只)以110 mm/d牵张,B组(3只)以210 mm/d牵张,C组(2只)为对照。A、B两组均牵张延长下颌10 mm,于牵张结束固定后第2周时处死动物,取牵张区下齿槽动静脉及新骨组织行组织学和定量组织学研究,观察下齿槽血管的管壁厚度和管径大小变化,以及新骨中微血管数量变化。结果:两种速率牵张后均未见下齿槽血管壁有病理性改变,但210 mm/d组的血管管径变小,管壁变薄,与对照组相比有显著差异(P<0105)。110 mm/d牵张后微血管密度较210 mm/d牵张后微血管密度高,且新生骨小梁更为成熟,其差异具有统计学意义(P< 0105)。结论:下颌骨牵张后下齿槽血管无明显变化,但快速牵张可能对牵张间隙内血管生成有不良影响。     

不同速率牵张下颌后下齿槽神经的组织学和超微结构改变

目的 研究不同速率牵张延长下颌骨后下齿槽神经的组织学和超微结构改变,为临床上确立合理而安全的牵张速率提供实验依据。方法 ８只山羊随机分为Ａ、Ｂ、Ｃ三组,Ａ、Ｂ组各３只,Ａ组１ｍｍ／ｄ,Ｂ组以２ｍｍ／ｄ牵张,Ｃ组２只动物为对照。牵张延长下颌骨１０ｍｍ,固定２ｗ处死。取下齿槽神经行组织学,透射电镜观察。结果 牵张动物的下齿槽神经均发生了Ｗａｌｌｅｒ变性,以２ ｍｍ／ｄ牵张组神经退行性病变严重而广泛。超微结构病变主要发生于粗大的有髓神经纤维,而细小的有髓神经及无髓神经纤维未见异常。结论 ２ｍｍ／ｄ牵张会对下齿槽神经造成严重损伤,而１ｍｍ／ｄ牵张速率为较适宜而安全的下颌牵张速率。     

Response of Schwann cells in the inferior alveolar nerve to distraction osteogenesis: an ultrastructural and immunohistochemical study

The biological mechanisms of nerve adaptation to distraction osteogenesis have not yet been elucidated. This study observed response of Schwann cells in the inferior alveolar nerve (IAN) following mandibular lengthening by electron microscopy and immunohistochemistry of S-100 protein, a specific marker of Schwann cells. Unilateral mandibular distraction (10mm elongation) was performed in nine young adult goats. Three animals were sacrificed at 7, 14 and 28 days after completion of distraction, respectively. The distracted IAN specimens and control nerves (from the contralateral sides) were harvested and processed for histological, ultrastructural and immunohistochemical examinations. Wallerian degeneration was observed in the distracted IAN, and Signs of axonal regeneration, as well as many activated Schwann cells were seen in the lengthened nerves. The expression of S-100 protein increased significantly at early stage of distraction osteogenesis, but almost returned to the normal level at 28 days after distraction. This study suggests that Wallerian degeneration caused by mechanical stretching may stimulate Schwann cells to enter a proliferated and activated state. Schwann cells and S-100 protein appear to play crucial roles in axonal regeneration that contributes to nerve adaptation to gradual distraction. Therefore, the IAN injury caused by mandibular gradual distraction was not serious; it seems to recover totally through a complicated repair mechanism.     

不同牵张速率对下颌骨延长后新骨生成的影响

目的 :研究不同牵张速率延长下颌骨时对新骨生成的影响。方法 :将 12只山羊随机分为三组 ,行双侧下颌体骨皮质切开术后以三种不同牵张速率 (0 .5mm/d ,1mm/d ,2mm/d)向前延长下颌 10mm。牵张完成后第 2、4周各处死 2只山羊 ,取双侧牵张间隙内新骨组织作X光片、组织学、扫描电镜和能谱仪分析。结果 :以 0 .5mm/d和1mm/d牵张下颌骨后形成的新骨质量要好于 2mm/d。结论 :在牵张延长下颌骨时 ,1mm/d可能是最适宜的速率     

山羊下颌牵张成骨的超微结构观察及新骨钙磷元素测定

目的为进一步探索DO的成骨方式和新骨改建过程提供实验依据。方法标本取自6只山羊双侧下颌骨牵张成骨形成的新生骨组织及其邻近原骨组织,用扫描电镜观察骨组织断面的超微结构,同时用X线能谱仪测定新骨Ca/P原子个数比及其动态变化。结果牵张间隙超微结构观察显示大量新骨组织生成,其骨质密度和钙、磷元素含量随牵张后固定时间的延长而趋于正常骨组织。结论山羊下颌牵张成骨形成的新生骨段可逐渐改建为具有正常结构的骨组织。     

Changes in the temporomandibular joint after mandibular lengthening with different rates of distraction

This study assessed the changes in the condyle after mandibular lengthening with 2 different rates of distraction (1 mm/day and 2 mm/day). Unilateral mandibular distraction was performed in 8 young adult goats. The animals were sacrificed 8 weeks after the completion of distraction, and the temporomandibular joint (TMJ) specimens were harvested and processed for histologic examination and histomorphometric analysis. Adaptive changes in the condyle were observed in the goats distracted at a rate of 1 mm/day, whereas degenerative alterations were found in those distracted at a rate of 2 mm/day. This study suggests that the TMJ is able to withstand the impact of distraction at a rate of 1 mm/day, but more rapid distraction may induce degeneration in the condylar cartilage.     

变速牵引成骨对兔下牙槽神经的影响

目的　研究变速牵引兔下颌骨15mm对下牙槽神经的影响。方法　5只新西兰白兔单侧下颌骨截开。延迟5d ,以每天1 5mm ,每天2次牵引9mm ,然后继续以每天1mm ,每天2次牵引6mm ,完成牵引后固定15周,分别行肉眼及组织学观察和电生理学检查。结果　下颌骨延长15mm ,新骨生成良好。下牙槽神经牵长2 1. 99% ,牵引结束时神经变性明显,感觉神经动作电位波幅下降为术前的9. 70 % ,潜伏期较术前有所延长,随后出现恢复趋势,到固定15周时,波幅恢复到术前的33. 85 % ,潜伏期基本恢复正常。结论　下颌骨变速牵引15mm后,下牙槽神经受到明显的影响,到15周时,下牙槽神经的功能有恢复的趋势,但恢复尚不完全。     

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。     

基质金属蛋白酶-3和金属蛋白酶组织抑制因子-1在兔下颌牵张成骨改建期的表达及意义

目的　研究基质金属蛋白酶-3(MMP-3)和金属蛋白酶组织抑制因子-1(TIMP-1)在下颌骨牵张后形成的新骨组织中的定位表达。方法　对8只成熟大耳白兔按每天1 mm的牵张速率延长双侧下颌骨6 mm,在牵张结束后第4周处死动物,取牵张区新骨标本作组织学和免疫组化检测。结果　MMP-3与TIMP-1在牵张骨痂中均呈高水平表达,MMP-3阳性信号主要定位于新生骨小梁边缘的成骨细胞和埋入新骨基质中的骨细胞,TIMP-1则定位于成骨细胞。结论　MMP-3及TIMP-1可协同调节胞外基质的降解来影响牵张成骨的改建过程。     

下颌骨牵引延长后下齿槽神经功能的评价

目的 采用三叉神经体感诱发电位（trigeminal somatosensory evoked potential,TSEP)检查恒河猴下颌骨牵引延长术对下齿槽神经功能的影响。方法 健康青年恒河猴7只，行下颌角部完全骨截开术，右侧或双侧安放牵引器。截骨间隙平均牵引距离为13．5mm。于术前、牵引完成时、牵引完成后4周分别进行下齿槽神经SEP检查。结果 术前下齿槽神经SEP各波的潜伏期测量值，两侧对比检验差异无显著性。牵引术完成时SEP各波的潜伏期较术前均有不同程度延长（P＜0．01，P＜0．001），波幅显著下降（P＜0．001）。术后4周各波潜伏期及波幅均有恢复，但多数差别仍有显著性。结论 TSEP检查提示下颌骨牵引延长术对下齿槽神经功能有一定影响，术后4周其功能有部分恢复。     

Bilateral mandibular distraction in adult dogs with an epiperiosteal distractor

We tested the function and efficiency of a new intraoral, bone-borne distraction device for mandibular lengthening, and the effect of bilateral transsection of the inferior alveolar arteries on osteogenesis in adult dogs. Nine adult Beagles had bilateral complete mandibular osteotomies and epiperiosteal placement of the distractor. After 7 days, the mandibles were distracted at 1 x 1mm/day, 1 x 0.5 mm/day or 2 x 0.25 mm/day for 15 or 30 days, respectively. Hemimandibles were harvested after 1, 14, or 42 days consolidation and evaluated clinically, radiographically and histologically. The mean distraction achieved was 11 mm (range 4-16 mm). New bone formation and clinical stability increased with increasing consolidation time and was independent of the distraction protocol used. Osteogenesis at the distal and proximal mandibular fragments did not differ. In 10/18 distraction sites, wound dehiscences compromised osteogenesis. The new epiperiosteal distractor permitted successful distraction osteogenesis despite complete bilateral osteotomy with section of the medullary vessels in adult dogs.     

下颌骨牵引成骨术对下牙槽神经功能影响的实验研究

目的　研究下颌骨牵引成骨术对下牙槽神经功能的影响。方法　对青年恒河猴 16只 ,全麻下行下颌角部骨截开术及牵引器置入术 ,术后第 5天开始以 0 5mm× 2次 /d的速度牵引 ,共15d。采用八导肌电图仪 ,表面电极在颏孔处刺激 ,针电极在卵圆孔附近记录 ,分别在术前、牵引完成后 0、2、4、6、9、12周时行感觉神经动作电位测试。结果　牵引完成时潜伏期较术前增加 2 2 18% ,其后逐渐降低 ,至牵引完成后 12周时仍较术前高 10 70 %。牵引完成时波幅降至术前的 2 8 5 4% ,牵引后 12周时恢复至术前的 99 84%。结论　下颌骨牵引成骨术对下牙槽神经的功能会产生暂时性影响 ,随着神经髓鞘和轴突的再生 ,神经功能可逐渐恢复正常。     

Temporospatial expression of vascular endothelial growth factor and basic fibroblast growth factor during mandibular distraction osteogenesis.

OBJECTIVE: Distraction osteogenesis is a vascular-dependent process. This study investigated expression patterns of two major angiogenic factors, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), in the distracted calluses following mandibular lengthening in a goat model. MATERIAL AND METHODS: Bilateral mandibular osteotomies were performed in 15 young adult goats. After a latency of 7 days, the mandibles were elongated using custom-made distractors with a rate of 1 mm/day for 10 days. Three animals each were sacrificed at the end of the delay phase, at 0, 7, 14, and 28 days after completion of distraction, respectively. The lengthened mandibles were harvested and processed for histological and immunohistochemical examinations. RESULTS: Elevated cellular expression of VEGF and bFGF, with neovascularization in the distraction gap, was observed following mandibular lengthening. VEGF staining was noted in the endothelial cells and osteoblasts. bFGF staining was seen in the fibroblast-like cells, osteoblasts and immature osteocytes. Their strongest expression was found 0-7 days after the end of distraction, and declined with maturation of the newly formed bone. CONCLUSION: A temporal and spatial expression pattern of VEGF and bFGF was found during distraction osteogenesis in goat mandibles. It suggests that distraction forces can stimulate the production of VEGF and bFGF, which contribute to neovascularization and new bone formation during gradual distraction of the mandible. Application of angiogenic factors may be considered as a potential method to enhance angiogenesis and osteogenesis in osteodistraction, especially in sites without enough vascularization.     

重组人骨形成蛋白-2促进兔下颌牵张成骨的研究

目的　研究局部应用基因重组人骨形成蛋白-2(rhBMP-2)对兔下颌牵张成骨的影响。方法　在12只成年大耳白兔的双侧下颌骨前部行骨切开术,将rhBMP-2与胶原复合植入一侧下颌骨切开处,另一侧单纯植入胶原作对照。用自行研制牵张器延长双侧下颌骨6 mm,在牵张结束后第4周处死动物,取双侧牵张区新生骨痂行组织学、扫描电镜及Ca/P元素测定。结果　下颌延长后两侧牵张间隙均有新骨形成,应用rhBMP-2的一侧牵张骨痂中的新骨组织比对照侧多而成熟,钙化程度较高。结论　基因重组人骨形成蛋白-2可能有促进兔下颌牵张成骨的作用。     

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。     

胶原海绵在下颌骨牵张成骨早期成骨中的作用

目的建立山羊双侧下颌骨牵张成骨动物模型,研究胶原海绵在山羊下颌骨牵张成骨早期成骨中的作用。方法将6只山羊的下颌骨截断,安置牵张器,延迟4d后以每次0.5mm、每天2次的速率连续牵张10d,随后进入固定期。于固定期2、4、6、8周处死动物,行大体标本、X线观察,骨密度、骨矿物质质量测定,苏木精-伊红染色后的组织形态学观察。结果牵张过程被所有山羊耐受,下颌骨牵张长度达到预期效果。加入胶原海绵的实验侧牵张区新骨早期成骨效果明显好于同期的对照侧。结论山羊是一种良好的牵张成骨动物模型。胶原海绵可加速牵张区新骨早期成骨,缩短牵张成骨的固定期。     

山羊双侧下颌骨牵引成骨动物模型的建立

目的:建立一个可行性良好的山羊下颌骨牵引成骨模型。方法:将6只山羊的下颌骨截断,安置牵引器,延迟期4 d后以0.5 mm/次,2次/d的速度牵引10 d;随后进入固定期。分别于固定期的2、4、6、8周处死动物,进行大体标本和放射学观察。结果:牵引过程被所有山羊耐受,牵引长度达到预期效果。结论:山羊是一种良好的牵引成骨动物模型;该模型有助于DO临床的应用及研究。     

Histomorphometric evaluation of short-term changes in masseter muscle after lengthening the rabbit mandible by distraction osteogenesis.

PURPOSE: Structural changes in muscles may affect the process during and after distraction osteogenesis (DO) of the mandible. However, the response of the masticatory muscles is still not well defined after gradual lengthening of the mandible. In this experimental study, short-term structural changes in masseter muscles of the rabbits are evaluated after mandibular DO. MATERIALS AND METHODS: Left mandibles of 10 New Zealand rabbits were lengthened by DO for 7 days in the rate of 1 mm/day. Mandibles of all animals were removed at the end of the consolidation period. Muscle biopsy samples of distracted and contralateral sides were histopathologically investigated, and histomorphometric results were statistically analyzed. RESULTS: Atrophy, hypertrophy, regeneration, and concomitant mild interstitial edema and fibrosis were found more evident in experimental side biopsy samples 30 days after distraction. Histomorphometric analysis revealed a statistically significant decrease in the mean regions of masseter muscle fibers of the distracted sides compared with the control sides (P <.05). CONCLUSION: This experimental study showed that the structure of masseter muscle is influenced during and shortly after mandibular distraction osteogenesis. Atrophic changes of the ipsilateral masseter muscles may be regarded as regenerative response that occurs during and shortly after distraction period.     

下颌骨牵张成骨对下牙槽神经影响的实验研究

目的　观察狗双侧下颌骨牵张成骨术中不同时间点的下牙槽神经的电生理功能及组织学结构的变化。方法　实验组 :12只狗行保留下牙槽神经的双侧下颌骨截断术 ,装上自制的口内牵张器 ,于术后第 8天开始牵张 ,1mm/d ,共 10d ,牵张长度约 10mm。分别在牵张中第 6天、牵张完毕后固定 2周及 8周时各处死 4只动物。分别在术前及术后的不同时期用电生理方法检测双侧下牙槽神经的传导功能 ,并于处死前取出双侧下牙槽神经进行组织病理学及超微结构组织学检查。对照组 :4只狗 ,其中 2只狗作为对照组 ,未行手术 ;另 2只狗为手术对照组 ,进行与实验组相同的骨切开截断术 ,上牵张器 ,但未行牵张和固定 ,于操作完毕时取出双侧下牙槽神经作为术后的组织学结构标本。结果　实验组动物的下牙槽神经在光镜下显示部分神经纤维稍肿胀变粗 ;电镜下显示部分神经纤维髓鞘的板层松解及脱髓鞘现象 ;电生理结果显示 ,神经传导的速度于截断术后的不同时期均低于术前 ,但仅术后第 8天 (即牵张前 )的传导速度与术前的传导速度差异有显著性 (P <0 .0 1)。结论　对狗的双侧下颌骨进行牵张成骨时 ,可一过性引起下牙槽神经损伤。其损伤的主要原因是手术过程所致。在适当的牵张速率、牵张长度和牢固的固定条件下 ,下颌骨的牵张成骨术对下牙槽 还原。