口腔颌面部神经疾病

三氧化二砷颏孔注射后对兔颏神经影响的研究；去细胞异体面神经移植早期的组织学研究；上颌骨前牵引对犬眶下神经的影响。     

镍钛记忆合金牵引装置前牵上颌骨成骨的可行性研究

目的通过对经腭横缝前牵上颌骨后颌面骨形态的观察,研究该牵引成骨方式前牵上颌骨引导成骨的可行性。方法同窝12周龄杂种犬4只,随机分为空白对照组1只,实验组3只。实验组于腭横缝前后打孔,安置特制内置式镍钛记忆合金牵引装置,利用其产生的弹力前推上颌骨。向前持续弹性前推1个月,初始牵引力约为760g×2,牵引前后进行大体观察。于16周龄时将两组犬均处死,进行组织学观察。结果上颌逐渐前突,咬合关系呈现Ⅱ类错骀。上颌骨前移明显。实验组各犬的腭横缝有大量骨生成。结论本牵引装置可有效地平行前移上颌,上颌骨前移后留下的空隙被新生骨占据。     

AZ31镁合金在垂直牵张犬下颌骨成骨的初步研究

目的初次探讨自行研制的可降解AZ31镁合金牵引器在牵张成骨中下颌骨的成骨情况和材料的降解性、生物安全性。方法采用12只杂种犬为实验动物。截骨术前3个月拔出12只犬单侧3颗磨牙。然后,12只犬均行一侧下颌骨截骨术,安置自行设计的镁合金和不锈钢牵引器。经5 d间歇期后,两组以0.3 mm/8 h的速度牵张7 d进入固定期。固定期4周处死12只动物,标本进行牙槽骨垂直向高度测量、扫描电镜观察、组织学观察以及肝、肾病理切片观察。结果牙槽骨垂直向高度:实验组平均增加(6.300±0.018)mm,对照组平均增加(6.307±0.027)mm,无显著性差异(P>0.05)。两组牵张间隙中均可见活跃的成骨细胞和骨小梁结构,以及少量成熟的骨组织。镁合金表面有较明显的腐蚀产物。实验组肝、肾病理观察结果均未见异常。结论自制ZA31镁合金牵引器在牵引完成后4周可提高下颌骨的高度,且骨质生成良好。镁合金在下颌骨内有一定的降解速度。镁合金对肝脏和肾脏无毒性作用。     

口内入路个体化三焦点圆弧牵引器修复下颌骨大型缺损

目的:根据下颌骨缺损类型,设计个体化内置式圆弧牵引器,通过三焦点牵引成骨技术修复下颌骨缺损畸形。方法:对患成釉细胞瘤行下颌骨部分切除的患者,确定手术切除范围及修复后下颌骨形态,在快速原型模型上设计个体化内置式圆弧形牵引器,应用三焦点转移盘牵引方式,在肿瘤切除同期行牵引成骨手术,牵引前间歇期7d,牵引参数为0.4 mm/次,2次/d,固定期6个月。拆除牵引器后,二期行牙列修复。结果:牵引器植入后牵引过程顺利,固定6个月后X线片显示新骨形成均良好,但2个转移盘间见纤维愈合,拆除牵引器时需行钛板内固定。牙列修复前,发现下颌骨形态略小、矢状向后缩,再次行双侧下颌支矢状劈开前移下颌骨,到达设计位置并稳定后,行覆盖义齿修复。结论:个体化内置式圆弧牵引器可以有效修复下颌骨大型缺损,避免传统骨移植手术造成的供区创伤,但在前期设计时,需要适当矫枉过正。     

上颌后缩畸形Le Fort Ⅰ型截骨牵引的三维有限元模型研究

目的 研究上颌骨牵引延长时上颌骨的应力分布状况,探讨上颌骨牵引器的安放位置与方向的最佳选择。方法 在发育性上颌后缩畸形和腭裂继发上颌后缩畸形的上颌模型上分别加载不同方向及大小的牵引力。分别计算上颌骨最大主应力、最小主应力及颌骨内部的位移情况,并比较两种加载方式对上颌骨内部应力分布的影响。结果 在非腭裂上颌骨,当牵引力方向与正中矢状面平行时,双侧上颌骨前壁应力主要为压应力,但应力较小,当牵引方向与正中矢状而成30°角时,对上颌骨前壁的压应力显著增大;在腭裂继发上颌后缩畸形牵引时,裂隙双侧上颌前壁的压应力显著增大,健侧颌骨的位移显著大于患侧。和牵引方向与矢状面平行时相比较,当腭裂上颌骨斜向牵引时,上颌骨前壁及硬腭的位移均较平行牵引时显著增大;腭裂上颌骨在两种牵引力牵引时均出现上颌前部压应力集中,颌骨内部位移增大,牙槽突裂隙两侧位移增大明显。结论 上颌骨牵引时,应尽量使牵引方向与矢状面平行;在上颌骨牵引时应注意防止上颌牙弓缩窄,牵引阻力增大时应戴(牙合)板至稳定期。     

颧骨牵张成骨修复上颌骨部分缺损的实验研究

目的:探讨用颧骨牵张成骨修复部分上颌骨缺损的可行性、科学性和规律性。方法:以犬建立实验动物模型,制造上颌骨颧突、颧骨节段性缺损,以内置式牵张成骨器牵张颧骨修复部分上颌骨,每次 1. 0mm, 1次 /d,连续 10d,共牵引 10mm,固定期X线观察。结果: 3只犬实验内容按计划完成,X线影像示,固定期 2周时,牵张间隙内早期骨结构形成,随后,骨密度进行性加强; 8周时,新生骨密度接近正常,与双侧正常骨质连续,骨缺损修复基本完成。结论:颧骨牵张成骨修复部分上颌骨具有临床应用可能性;颧骨牵张成骨实验动物模型切实可行,且受咬合力影响小,在某些领域可望获得更广泛的应用。     

三焦点牵引成骨下颌骨缺损重建的实验研究

目的探讨采用内置式三焦点牵引器在犬下颌骨骨段缺损功能重建中牵引成骨的特点、规律。方法使用内置式三焦点牵引器对4只成年犬下颌骨骨段缺损进行牵引成骨重建。制作3cm下颌骨缺损区,同期植入内置式三焦点牵引器。牵引间歇期8天,牵引速度0.5mm×2次/天,稳定期3个月。结果下颌骨牵引成骨约30mm,牵引成骨过程中无感染、成骨不良等并发症。牵引完成后第3个月X线片、组织学观察及扫描电镜观察均可见新生骨的形成,新生骨的形态、组织结构接近正常下颌骨。结论三焦点牵引成骨技术重建的颌骨形态、组织结构和功能接近正常颌骨,牵引成骨区和压力成骨区局部应用rh-BMP2可以促进新骨的形成及钙化。     

传送盘回复式牵引成骨修复山羊上颌骨缺损的实验研究

目的：结合上颌骨的解剖生理特点,探讨采用传送盘回复式牵引成骨修复上颌骨缺损的可行性。方法：11只成年山羊．随机分为实验组和对照组。其中实验组9只,按固定期不同分为1、2、3个月组,每组3只;对照组2只。实验组山羊通过手术制作上颌骨前部节段性缺损,缺损长度12～14mm,平均大小12．7mm。同期制作缺损前方传送盘并使之后退．关闭缺损区,安置牵引器,通过牵引将传送盘回复原位。术后7天开始牵引,每天2次,持续15～18d,每次0．4mm．采用大体、影像学及组织学观察缺损区愈合情况。结果：传送盘牵引复位后,缺损区被新生骨修复,X线、三维CT及组织学检查显示,新骨形成良好,新骨形成方式符合传统牵引成骨的成骨方式。结论：传送盘回复式牵引成骨符合上颌骨的解剖特点．具有一定的临床可行性。     

生长期犬上颌骨缝牵张的实验研究

目的：了解上颌骨缝牵张成骨的骨质生成方式及不同牵引力对腭横缝组织影响。方法：以3～4月龄杂种犬21只为实验动物，实验组18只，空白对照组3只。实验组在两侧腭横缝及额上颌缝安置内置式镍钛合金牵引器。设计牵引器合力分别为：900g（A组）、1200g（B组）、1500g（C组）。牵引后5、10、15、20、30、40d切取腭横缝组织，行组织学观察。分光光度仪定量分析骨组织中碱性磷酸酶含量。结果：实验组上颌骨被成功前徙，组织学观察可见腭横缝改建活跃。牵引期内Ⅰ型胶原增多明显，Ⅱ、Ⅲ型胶原逐渐减弱。各组碱性磷酸酶增高明显，差异有显著性。结论：缝牵引是早期修复上颌发育不足的一种较佳方法；缝牵张成骨方式是膜内成骨；3种作用力差异有显著性，最佳作用力是1200g。     

种植型骨牵张器的初步实验研究

目的：了解种植型骨牵张器的牵张成骨效果及骨结合情况。方法：杂种犬6只,拨除双侧下颌前磨牙,12周后随机选取一侧犬下颌牙槽嵴,矩形截骨,植入种植型骨牵张器,延迟1周后垂直牵引加高牙槽嵴,1次／d,1.05mm/次,共加力牵引4d,固定6周,并进行X线和组织学观察。结果：除一枚牙种植型牵引器因伤口感染发生松动而取出外,其余牵引器与周围组织均愈合良好,牙槽嵴平均加高4．00mm,X线显示牵引6间隙消失,牵引器的周围骨组织密合,组织学观察牵张间隙被成熟新生骨修复,牵张器－肌界面形成良好的骨性结合。结论：种植型骨牵张器可用于垂直牵张加牙槽嵴,并可发生骨结合。     

中位牵引前移犬面中份骨骼的实验研究

目的 为弥补传统治疗面中份发育不全方法不足,本研究采用以上颌骨承力,中位牵引上颌向前,观察其可行性。方法 16周龄杂种犬14只,随机分为对照组8只,实验组6只。所有犬在上颌各骨缝的前后种植钛钉,作为骨标志。实验组犬安置特制牵引支架和牵引钩,橡皮圈连接,向前持续牵引,牵引力值约为600g,牵引前后进行临床和X检查及头影测量。1个月后处死,做组织学观察。结果 实验犬上颌逐渐前突,咬合关系呈现Ⅱ类错(牙合)。骨缝前后骨标志点间距离测量结果提示,前颌骨前移最明显,上颌骨次之,颧骨前移不多。对照组与实验组颅底角度变化差异不显著,未见上颌逆向旋转。实验犬各骨缝大量新骨生成,大量的成骨细胞,成纤维细胞沿张力方向排列,前颌缝尤为明显。结论 本牵引装置可有效地前移上颌,作用力更直接,避免了上颌的逆向旋转。     

Expression of nerve growth factor and vascular endothelial growth factor in the inferior alveolar nerve after distraction osteogenesis

The objective of this study was to evaluate changes occurring in the inferior alveolar nerve (IAN) subsequent to mandibular distraction osteogenesis, with regard to the expression of nerve growth factor (NGF) and vascular endothelial growth factor (VEGF). Unilateral mandibular distractions (0.5mm each, twice per day for 10 days) were conducted on 8 mongrel dogs. Two animals were killed at 7, 14, 28 and 56 days after completion of distraction. The distracted IAN and contralateral control nerve were then harvested and analysed histologically and immunohistochemically. Signs of acute nerve injury, including demyelination, were observed in the distracted IAN on the 7th and 14th day after distraction. At 56 days, the histological features of the distracted IAN were similar to those of the control nerve. The levels of NGF and VEGF expression were significantly elevated on the 7th and 14th day after distraction. NGF was expressed in most of the distracted nerve tissues, but VEGF was primarily detected in Schwann cells and the neurovasorum. VEGF expression had returned to normal but NGF expression was still profoundly elevated 28 days after distraction. NGF expression returned to normal levels at 56 days after distraction. NGF and VEGF appeared to have been elicited from the Schwann cells and damaged nervous tissues, and they may play important roles in the initial healing of damaged nerves. VEGF expression returned to normal more quickly than did NGF expression. This may indicate that hypoxic conditions within the distracted nerve had recovered to normal during the early stages of consolidation. Micro-vessels in the distracted nerve may have recovered more rapidly than did the nerve tissue itself.     

Dual segmental distraction osteogenesis of the midface in a patient with Apert syndrome.

OBJECTIVE: To present orthodontic treatment combined with dual segmental distraction osteogenesis in a patient with Apert syndrome. PATIENT: A 15-year-old boy exhibited severe midfacial hypoplasia with retruded and hypoplastic maxilla and anterior open bite. The patient was treated with a rigid external distraction II system for distraction osteogenesis, a preadjusted edgewise appliance, and a modified maxillary protraction headgear. The concave profile with midfacial hypoplasia was improved. A tight occlusal relationship between maxillary and mandibular teeth was achieved. Postoperative treatment results have been stable for 1 year.     

The bone regenerative effect of growth hormone on consolidation in mandibular distraction osteogenesis of a dog model

The purpose of this project was to study the effect of growth hormone on early bony consolidation in distraction osteogenesis of a dog model.Sixteen dogs were used for this study. 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 divided into a control group and growth hormone group. Dogs in the growth hormone group received a daily subcutaneous injection of 100 microg (1 IU) of recombinant human growth hormone per kilogram of body weight. The daily administration of growth hormone was performed from the day of the osteotomy through the whole distraction period to the sacrifice. Normal saline was injected in the control group. Eight dogs were allocated to each group. Two dogs in each group, a total of four dogs, were killed at 2 weeks after completion of distraction, four dogs were killed at 4 weeks, and the other eight dogs were killed at 6 weeks.The level of serum IGF-I in the growth hormone group was elevated and peaked between 8 days and 12 days after systemic administration of growth hormone. Bone mineral density was higher in the growth hormone group and lower in the control group for the whole period. Bone mechanical strength was 300% higher in the growth hormone group than in the control group. However, results were more suggestive than conclusive. On histological examination, the formation of a substantial amount of active woven bone was observed throughout the distracted zone at six weeks in the growth hormone group. In the control group, new bone was generated from the edge to the center of the distracted zone. In addition, most of the central area of the distracted zone was filled with fibrous tissue at six weeks.In conclusion, these findings suggest that growth hormone appears to be effective in early bony consolidation in distraction osteogenesis.     

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.     

Neurolytic effects of ampicillin on the rat infraorbital nerve

J Oral Pathol Med (2012) 41 : 268–271 Purpose: The aim of this study was to investigate the histomorphological changes of the infraorbital nerve of rats treated with ampicillin. Materials and Methods: The infraorbital nerve was approached through the infraorbital foramen, and 0.01 ml of ampicillin dissolved in distilled water was injected taking care not to damage the nerve. Saline solution was used in control animals. Nerves were dissected and after routine histology processing analysed by light microscopy. Results: Cross‐section of the nerve treated with ampicillin showed damaged axons with disintegration of heavily myelinated fibres, while thinly myelinated fibres remain unaffected. In the saline group, no damage was observed. The signs of regeneration of the damaged infraorbital nerves were detected on the fourth post‐operative week. Conclusion: Ampicillin can cause peripheral nerve damage when injected perineurally.     

Effects of streptomycin on the rat infraorbital nerve.

INTRODUCTION: It has been reported that streptomycin can have anti-neuralgic effects. However, the mode of action is unknown. This article was intended to investigate eventual neurolytic effects of streptomycin on peripheral nerves when applied topically. MATERIAL AND METHOD: The rat infraorbital nerve, used as the experimental model, was treated with 0.01 ml of streptomycin sulphate dissolved either in distilled water or in lidocaine via an infraorbital perineural injection. Saline was used in control animals. RESULTS: Cross-sections of the nerve, a week following treatment with streptomycin, revealed damaged axons with disintegration of both heavily and thinly myelinated fibres. Signs of regeneration were detected from the fourth postoperative week on. In control rats no damage was observed. CONCLUSION: Streptomycin can cause peripheral nerve damage when injected perineurally. These morphological changes may be responsible for anti-neuralgic effects of streptomycin.     

Character of distracted bone in irradiated canine mandibles and electrophysiological changes in the inferior alveolar nerve

Our aim was to explore the character of distracted bone in irradiated canine mandibles and the electrophysiological changes in the irradiated inferior alveolar nerve (IAN). Twelve Chinese dogs were studied, 10 of which were given unilateral irradiation of ⁶⁰Co in the mandible with a total dose of 22.8 Gy in four 5.7 Gy fractions (biologically equivalent to 50 Gy/25 fractions) (experimental group). The other two dogs were not irradiated and served as controls. All had a bilateral corticotomy 3 months after irradiation. After a 1-week latency period distraction of the mandible was activated at a rate of 0.5 mm twice daily for 10 days, followed by a consolidation phase of 8 weeks. New bone was assessed by radiographic, histological, and single-photon electron computed tomographic (SPECT) analysis. The IAN was analysed electrophysiologically. One dog in the experimental group was excluded from the study with anaesthetic problems. After 8 weeks of consolidation there was no difference between the percentage area of new bone in the two groups. New bone was more mature and organised in the control group than in the experimental group. SPECT analysis showed that there was active osteogenic activity in dogs in the experimental group. The action potential of the IAN showed corresponding changes during the irradiation and distraction processes.     

Co-expression of nerve growth factor and p75NGFR in the inferior alveolar nerve after mandibular distraction osteogenesis

During mandibular distraction osteogenesis (DO), the inferior alveolar nerve (IAN) is damaged during distractor activation, but spontaneously recovers during consolidation. Although many neurotrophic factors are known to play critical roles, there have been few studies on the mechanism of peripheral nerve recovery after DO. The aim of this study was to observe the expression pattern of p75NGFR (low-affinity receptor of NGF) and to detect autocrine growth activity in IANs following mandibular DO. Unilateral mandibular distractions (0.5mm each, twice per day for 10 days) were conducted on eight mongrel dogs. Two each were killed at 7, 14, 28 and 56 days after completing distraction. The distracted IAN and contralateral control nerve were harvested. Immunohistochemical staining was performed to determine p75NGFR expression, and double immunofluorescent staining to detect NGF and p75NGFR co-expression. Levels of p75NGFR expression were found to be significantly elevated at 7 and 14 days in Schwann cells located in the outer layer of axon, but were almost undetectable at 28 and 56 days. In double immunofluorescent images, the co-expression of NGF and p75NGFR was also detected at 7 and 14 days. p75NGFR plays an important role in remyelination due to its abundant expression in Schwann cells of damaged nerves, and NGF is an autocrine growth factor present in distracted IANs during the early consolidation period after mandibular DO.     

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