兔下颌骨牵张成骨中神经生长因子对骨痂钙化的作用

目的:观察局部注射神经生长因子(NGF)对下颌骨牵张成骨中新生骨痂钙化的作用。方法:对20只新西兰白兔实施牵张速率为1mm/d的双侧下颌骨牵张成骨。从牵张结束时开始,每只兔的一侧下颌骨新生骨区接受人NGFβ溶液注射(40μg/次,2次),另一侧注射生理盐水作为对照。在固定期第14和28d,新生骨痂经X线侧位片和外径测量后,进行骨沉积速度和钙化面积比定量分析。应用SPSS10.0软件包进行配对t检验,分析NGF处理侧与对照侧之间上述2个钙化指标的差异。结果:与对照侧比较,NGF处理侧的钙化面积比和固定期第1～11d内的骨沉积速度均显著提高(P<0.05),骨痂钙化得到了促进。结论:局部注射人NGFβ溶液能促进兔下颌骨牵张成骨中新生骨痂的钙化,为临床上解决固定期过长的问题提供了一种新的思路。     

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。     

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     

Application of nerve growth factor by gel increases formation of bone in mandibular distraction osteogenesis in rabbits

The long period of bony consolidation is a concern in mandibular distraction osteogenesis (DO). We have previously shown that repeated local injections of human nerve growth factor beta (NGFβ) can appreciably improve bony consolidation in a rabbit model of DO. The present study was designed to test the effect of a single injection of human NGFβ delivered by collagen/nano-hydroxyapatite/kappa-carrageenan gels to sites of new bony formation in DO. Rabbits underwent mandibular DO at a rate of 0.75 mm/12 h for 6 days. At the end of the distraction period, the following injections were given percutaneously into the callus (n = 6 in each of the four groups): human NGFβ in the gel; human NGFβ in saline; the gels alone; and saline alone. Fourteen days after the end of distraction, mechanical testing, histological and histomorphometric variables of the new bone were evaluated. Histologically, the NGFβ group had more advanced consolidation than the other three groups. Both maximal load and bone volume/total volume in this group were significantly higher than in the other three (P < 0.05). In conclusion, the delivery of human NGFβ in the gels results in better acceleration of new bone formation than when it is given in saline, and may be a possible way to shorten the duration of craniofacial DO.     

下颌骨牵引成骨术对兔下牙槽神经的影响

目的观察牵引成骨术的不同牵引速度和距离对下牙槽神经的影响。方法新西兰白兔16只,以不同的牵引速度和牵引距离组合,随机分成5组。通过肉眼观察、X线片及电生理检查、组织学观察等了解下颌骨成骨及下牙槽神经再生情况。结果以2.0mm/d速度牵引下颌骨会产生骨不连接,以1.5mm/d速度牵引颌骨15mm,虽可获得良好的成骨,但可造成下牙槽神经不可逆性的损伤。结论下颌骨牵引成骨术的速度宜控制在0.5～1.5mm/d范围内;当牵引距离较小时,可适当加大牵引速度以提高牵引效率,当牵引距离较大时,应调小牵引速度,以减小对下牙槽神经的损伤。     

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。     

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。     

下牙槽神经挤压伤后再生的实验研究

目的 探讨外源性神经生长因子（NGF）对成年大白兔下牙槽神经挤压伤后再生的影响。方法 30只成年新西兰大白兔，下牙槽神经挤压伤后，随机分成2组，即对照组和用药组，对二组的再生有髓神经纤维传导速度、数目、直径和髓鞘厚度作比较。结果 NGF能使理生有髓神经纤维数目、直径、髓鞘厚度增加；术后相同时间NGF组神经传导速度大于对照组。。结论 外源性神经生长因子能够促进下牙槽神经损伤后再生及功能的恢复。     

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。     

Intermittent loading improves results in mandibular alveolar distraction osteogenesis

AIM: To evaluate clinical and morphological effects on distractive callus after application of an original protocol of bone stimulation. MATERIAL AND METHODS: Traditional or mechanically stimulated alveolar-distraction osteogenesis was studied on 16 highly selected subjects subdivided into two groups. Clinical, radiological, densitometric and histological (on biopsies) analyses were performed 6, 8 and 12 weeks after distraction was completed. RESULTS: In subjects undergoing stimulated alveolar-distraction osteogenesis, bone density was higher and at histology, bone with ordered structure was observed after 6 weeks. Moreover, bone trabeculae with oriented architecture and greater amounts of lamellar bone were observed after 8 and 12 weeks in the same subjects. DISCUSSION AND CONCLUSIONS: In conclusion, although osteogenic processes were similar in both groups, they were induced earlier and were better structured in subjects undergoing stimulated alveolar-distraction osteogenesis. These encouraging results can only be achieved and preserved by strict monitoring of distractive vectors.     

下齿槽神经缺失大鼠下颌骨牵张成骨牵张期蛋白质组学分析

目的：探讨用蛋白质组学iTRAQ技术分析下齿槽神经缺失大鼠下颌骨牵张成骨牵张期新生组织蛋白表达的改变.方法：6只大鼠随机分为2组,实验组为下齿槽神经缺失大鼠下颌骨牵张成骨,对照组为正常大鼠下颌骨牵张成骨,均进行单侧下颌骨牵张,速率：0.2mm/12h,牵张期为10d,下颌骨牵张成骨牵张期第10d取材.将取材的新生骨组织标本进行理化性分析、蛋白质提取及蛋白质定量检测.应用iTRAQ技术对蛋白质样本进行检测,寻找及鉴定差异蛋白.结果：应用iTRAQ技术质谱鉴定出置信度95％的蛋白315种,共鉴定出差异蛋白146个,其中上调≥1.5倍的39个,下降≤0.8倍的58个.结论：感觉神经系统在牵张成骨的成骨过程中起到一定调控作用.筛选出多种下齿槽神经缺失下颌骨牵张成骨牵张期新骨形成相关的差异蛋白,为进一步验证感觉神经缺失对下颌骨牵张成骨新骨形成相关蛋白质奠定了基础.     

兔下颌骨牵张成骨过程中内源性硫化氢信号系统的表达

目的 探讨兔下颌骨牵张过程中内源性硫化氢(H2S)信号系统的表达.方法 34只雄性新西兰兔下颌骨牵张术后5天,被随机分为A组:牵张速率为1mm (2次/d,共5d);B组:牵张速率为0.5mm(2次/d,共10d).选取5个时间点抽取静脉血监测血浆H2S含量.牵张结束后4周及8周,利用CT及双能骨密度测量仪检测牵张间隙成骨效果,收集牵张间隙组织检测局部胱硫醚-γ-裂解酶(cystathionine-γ-lyase,CSE)水平.结果 H2S信号系统在整个牵张过程中有表达,而快速牵张速率条件下,全身及局部H2S信号明显减弱,同时牵张间隙成骨不良明显.牵张结束后4周及8周B组牵张间隙组织CSE相对含量和表达强度均强于A组.结论 内源性H2S信号系统在牵张过程中有一定的作用,补充外源性的H2S可能促进牵张.     

Perineural infiltration of the inferior alveolar nerve in mandibular ameloblastomas

Our aim was to evaluate the histological association of mandibular solid and multicystic ameloblastoma with the inferior alveolar nerve, both in situ and in segments of the nerve that had been removed separately, to assess the feasibility of preserving the nerve during resection of mandibular ameloblastomas. In this prospective histological examination of 13 resected hemimandibulectomy specimens, we studied the proximity of tumour cells to the inferior alveolar nerve. In group 1 (n = 8) this association was examined with the nerve still within the mandibular segment after resection, while in group 2 (n = 5) the nerve was removed from the resected tumour and examined separately. Perineural and intraneural involvement of the ameloblastoma with the nerve was confirmed in 5 cases in group 1 and 2 cases in group 2. Tumour cells abutted the nerve directly in group 1. In group 2 tumour was removed with, and found within, the nerve. On this evidence we cannot recommend preservation of the inferior alveolar nerve during operation for large, advanced, mandibular ameloblastomas.     

兔双侧下颌骨牵张成骨实验动物模型的建立

目的:建立兔双侧下颌骨牵张成骨实验动物模型。方法:选用16只成年雄性新西兰大白兔,随机分为4组,每组4只。在双侧下颌骨第一前磨牙前方无牙区行骨切开术,用自制牵张器固定。经过7d潜伏期,以每次0.5mm的速度牵张,每天2次,连续7d。分别在潜伏期末、牵张结束、固定期第14天、第28天处死动物,切取标本行X线和组织学观察。结果:全部动物的下颌骨被成功延长,牵张间隙逐渐被新生骨组织充填。结论:该方法建立的动物模型具有可行性和可重复性。     

TGF和BMP在兔上颌缝牵张成骨中的表达

目的:观察兔上颌缝牵张成骨时TGF-β和BMP在前颌缝中的表达,探讨上颌骨改建的机制及意义。方法:年轻家兔12只,随机分为7d组6只,14d组6只,戴自制前牵引装置,均持续前牵上颌骨,分别在牵引后7、14d处死动物,切取一侧前颌缝组织块,制作标本,免疫组织化学方法对TGF-β、BMP进行染色,光镜观察、灰度值分析,并进行统计分析。结果:14d较7d2因子高表达(TGF-β、BMP均P<0.05);骨缝外侧带较中央带高表达;成骨活跃者成纤维细胞增多,血管分布增多;骨缝缘无典型的活跃成骨细胞排列。结论:牵张成骨过程中TGF-β和BMP表达升高。     

双向牵张器增高牙槽骨的实验研究

目的：自行研制一种双向牙槽骨牵张器，通过建立萎缩牙槽嵴实验动物模型，评价其应用效果。方法：实验犬8只，随机分为2组，每组4只。自行设计双向牙槽骨牵张器装置。实验动物拔除一侧下颌前磨牙1个月后，骨切开放置牵张器．间歇7d后，以1mm／d速度牵张，共牵张6d。第1组于牵张过程中逐步颊向改变移动骨段位置，第2组于牵张完成后第2天，一步颊向改变移动骨段位置至术前预定位置，2个月后对牵张区行X线及组织学检查。结果：移动骨段均达到术前预定的高度及颊向位置。牙槽骨的高度平均增加5．5mm±0．23mm，移动骨段颊侧移位平均为2．6mm±0．17mm。X线及组织学检查显示，牵张区新骨形成良好。结论：双向牵张器能在垂直向及颊舌向上精确控制牵张方向．并能在垂直牵张过程中或牵张完成后，改变移动骨段位置。避免牙槽骨牵张成骨常见的并发症：轴向移位。     

引导组织再生膜促进兔下颌骨牵张成骨的实验研究

目的 探讨引导组织再生膜（GTRM）对兔下颌骨牵张成骨新骨形成的促进作用。方法 将20只新西兰大白兔随机分为2组,每组10只,建立兔下颌骨牵张成骨模型,A组单纯单侧下颌骨牵张成骨;B组将GTRM固定于牵张器内侧行单侧下颌骨牵张成骨。分别于固定期第2、6周时随机处死半数动物获取标本,通过X线、骨组织形态计量学比较2组牵张间隙内成骨效果。采用SPSS11.0软件包对数据进行两样本均数t检验。结果 通过X线及骨组织形态计量学检查并经过统计学分析发现,在固定期第2周和6周时,B组牵张区域内成骨质量显著好于A组（P<0.05）。结论 引导组织再生膜能有效促进兔下颌骨牵张成骨区域新骨的形成。     

Effects of locally applied nerve growth factor to the inferior alveolar nerve histology in a rabbit model of mandibular distraction osteogenesis

Distraction osteogenesis (DO) is widely used in deformities and defects of the craniofacial bone. Accelerating inferior alveolar nerve (IAN) recovery would aid the process. Nerve growth factor (NGF) plays a vital role in peripheral nerve regeneration. In this study, the ability of locally applied human NGF beta (hNGFβ) to enhance the morphological recovery of the IAN in a rabbit model of mandibular DO was studied. Rabbits underwent bilateral DO with a rate of 0.5 mm per 12 h. Two doses of 40 μg hNGFβ in buffer were injected into callus at the beginning the of consolidation time. The contralateral side received injections of placebo. Rabbits were killed at 14 and 28 days. IAN specimens were subjected to histological and histomorphometric analysis. In both 14 and 28 days consolidation experiments, nerve histological analysis showed less degeneration and more regeneration in nerve fibers on the hNGFβ treated side than the control side. Histomorphometric analysis showed that the myelinated fiber density on the hNGFβ treated side was significantly higher than on the control side (p < 0.01). The data indicate that locally applied hNGFβ can accelerate the morphological recovery of the IAN and may play a role in reducing nerve injury in mandibular DO clinically.     

Anesthetic technique for inferior alveolar nerve block: a new approach

Background

Effective pain control in Dentistry may be achieved by local anesthetic techniques. The success of the anesthetic technique in mandibular structures depends on the proximity of the needle tip to the mandibular foramen at the moment of anesthetic injection into the pterygomandibular region. Two techniques are available to reach the inferior alveolar nerve where it enters the mandibular canal, namely indirect and direct; these techniques differ in the number of movements required. Data demonstrate that the indirect technique is considered ineffective in 15% of cases and the direct technique in 1329% of cases.

Objective

Objective: The aim of this study was to describe an alternative technique for inferior alveolar nerve block using several anatomical points for reference, simplifying the procedure and enabling greater success and a more rapid learning curve.

Materials and Methods

A total of 193 mandibles (146 with permanent dentition and 47 with primary dentition) from dry skulls were used to establish a relationship between the teeth and the mandibular foramen. By using two wires, the first passing through the mesiobuccal groove and middle point of the mesial slope of the distolingual cusp of the primary second molar or permanent first molar (right side), and the second following the oclusal plane (left side), a line can be achieved whose projection coincides with the left mandibular foramen.

Results

The obtained data showed correlation in 82.88% of cases using the permanent first molar, and in 93.62% of cases using the primary second molar.

Conclusion

This method is potentially effective for inferior alveolar nerve block, especially in Pediatric Dentistry.     

变速牵引与常速牵引成骨对下牙槽神经影响的比较研究

目的:通过比较变换速度和常规速度牵引成骨对下牙槽神经的影响,探讨较大距离牵引时提高牵引成骨效率的可能途径。方法:新西兰白兔9只,随机分成2组,单侧下颌骨截开。延迟5 d。变速组5只,以0.75mm×2/d,牵引9 mm,继续以0.5 mm×2/d,牵引6 mm,最长固定30周。常速组4只,以0.5 mm×2/d,牵引15mm,最长固定15周。分别行大体观察、电生理检查和组织学观察。结果:下颌骨延长15 mm,两组新骨都生长良好。牵引后两组下牙槽神经出现严重变性,感觉神经动作电位波幅明显下降,潜伏期延长,固定15周时,两组波幅都出现恢复趋势,潜伏期基本恢复,固定30周时,变速组神经结构和功能基本恢复正常。结论:变速牵引成骨可以在不增加下牙槽神经损伤的情况下,提高牵引成骨的效率。