牙种植体骨感知现象外周神经机制的电生理实验研究

目的:研究种植体周围骨组织内是否存在功能性神经感受器,并探讨种植体外周神经反馈通路重建的程度及其影响因素.方法:比格犬3只,拔除双侧下颌3颗前磨牙及1颗磨牙,即刻或延期植入共27颗种植体,完成修复后负重3～6个月.采用肌电图仪行电生理实验,分别给予各实验组种植体以电刺激,在下牙槽神经附近记录感觉神经动作电位(sensorynerve action porential,SNAP)的潜伏期和波幅,以同侧下颌尖牙为对照.结果:种植体及天然牙受到电刺激时,均可记录到SNAP.天然牙SNAP波幅为44.04±6.23μV,明显高于各实验组种植体SNAP波幅18.37±4.62μV(P＜0.01);天然牙与各实验组种植体之间SNAP潜伏期的差异没有统计学意义(P＞0.05).结论:种植体周围骨组织内存在功能性神经感受器,其数量少于天然牙;种植手术方式及负重时间对种植体周围骨组织内神经反馈通路的重建无明显影响.     

放疗后颌骨骨内种植的Beagle犬动物模型的建立

目的 评估放疗对颌骨骨内种植的影响,以及不同治疗方法对放疗后颌骨骨内种植体周围组织成骨性能、成骨特点、种植体骨结合情况的影响,建立一种符合放疗后颌骨骨内种植特点的动物模型.方法 以Beagle犬为实验动物,拔除其双侧下颌前磨牙和第一磨牙,1个月后,每只犬右侧下颌骨给予50 Gy剂量放射治疗.左侧为对照.放疗后9个月两侧植入埋入式螺纹种植体各4枚,于种植体植入后8周和12周处死动物,取材制作种植体-骨磨片.结果 4只实验犬均无死亡,饮食、活动正常,种植体无松动.组织病理学观察见:8周时,放疗组种植体周围有少量骨组织形成,部分有纤维组织长入,对照组骨组织形成量较放疗组多,与种植体形成了部分骨结合;12周时,两组种植体周围骨组织较8周时明显增加,都与种植体发生了骨结合,对照组的骨组织量及种植体-骨结合程度都优于放疗组.结论 本研究采用的建模方法,较符合放疗后颌骨骨内种植临床实际情况,为今后放疗后骨内种植体周围骨组织再生的研究奠定了动物实验基础.     

跨下颌神经管种植在萎缩下颌后牙区的应用

目的：探讨在下颌后牙缺失骨高度严重不足时,采用超声上颌窦内提升骨刀制备种植窝,进行偏颊侧跨下牙槽神经种植的可行性。方法：11例下颌后牙缺失患者,牙槽嵴顶至下颌神经管上缘距离3.2-5.5mm,按照手术导板偏颊侧倾斜角度,常规制备种植窝至下颌神经管上端1mm处,再用超声内提升骨刀头从已备种植床中央向下方跨过下牙槽神经继续备洞至植入长度,共植入种植体25颗;术中及术后当天密切观察种植床出血及下唇感觉,负载后1、3、6、9、12个月定期复查。结果：术中均未损伤下牙槽神经;观察期间种植体稳固无一脱落,种植体周围牙龈组织健康,种植体周围未见骨低密度影,负载后12月种植体边缘骨高度与刚负载时边缘骨高度差异无统计学上意义;咀嚼功能恢复满意。结论：应用超声上颌窦内提升骨刀,进行跨下颌神经管种植是一种安全、简单、可靠的修复下颌后牙缺失骨高度严重不足的方法,可避免使用传统的外置法植骨、牵张成骨术、下牙槽神经移位术。     

下磨牙区种植体尖端与下颌管间安全距离的探讨

目的:探讨下颌磨牙区植入的种植体尖端与下牙槽神经管上缘之间的安全距离。方法:用游标卡尺测量23例患者全景片中的30颗下颌磨牙区种植体长度,除以对应的种植体实际长度,计算全景片中下颌磨牙区垂直放大率(vertical magnification factor,MF);选择种植体尖端至下牙槽神经管上缘间距离小于2mm的8例患者的全景片,测量片中12颗种植体尖端至下牙槽神经管上缘间的距离,除以对应种植体的垂直放大率,计算其实际距离;记录该8例患者有无下唇和(或)颏部感觉异常。结果:①全景片中下颌磨牙区垂直放大率为1.27±0.02;②12颗种植体尖端距下牙槽神经管上缘之间的距离为(1.19±0.33)mm(0.69～1.89mm);③8例接受种植体植入的患者,无一例出现下唇或颏部感觉异常。结论:下颌磨牙区植入种植体的尖端与下颌管上缘之间保存完整的骨壁,是防止损伤下牙槽神经的最关键因素之一。     

下颌磨牙区种植体同下颌神经管间距的临床分析

目的探讨下颌磨牙区种植体同下颌神经管之间的安全间距的范围。方法选择临床上种植体末端同下颌神经管距离小于2 mm的12例患者15颗种植体(包括软组织水平和骨水平种植体)测算出其种植体末端同下颌神经管之间的实际距离。记录种植体植入期间下牙槽神经有无阳性体征。结果 15例种植体末端距离下颌神经管上缘平均距离为(0.94±0.50)mm(0.24~1.52 mm)。12例患者中有1例患者出现短期下颌神经感觉麻木。结论在回顾分析了下牙槽神经损伤、下颌骨感染、种植体周围炎、逆行性种植体周围炎等可能出现的问题后,结合本研究实际情况,我们考虑种植体末端同下颌神经管之间的安全距离可小于2 mm。     

早期不同时间种植体骨界面改建的骨组织定量测定

目的建立种植体植入Beagle犬下颌骨的动物模型,应用Micro-CT对早期的种植体周围骨组织情况进行分析研究。方法选用4只健康纯系雄性Beagle犬,随机分A、B两组,拔除下颌双侧第4前磨牙、第1磨牙,3个月后在相应缺牙区植入8枚植体,分别在植入后2周、4周处死两只Beagle犬,并对其作相应临床检查及Micro-CT检测。结果各组实验犬拔牙创愈合良好,种植体成功植入相应拔牙位点,各项临床指标无明显差异,Micro-CT检测显示种植体植入后2周的骨体积分数大于植体植入后4周的骨体积分数,且两组具有显著统计学差异(P≤0.01),其余骨微结构计量无统计学差异。结论成功建立口腔种植Beagle犬动物实验模型,早期植体周围骨愈合是一个骨吸收骨生成的骨组织改建或骨组织修复过程,植体植入后4周其周围骨吸收大于骨生成,Micro-CT能很好地应用于口腔种植骨微结构分析研究。     

富血小板血浆在种植体周围骨缺损修复中的实验研究

目的:探讨富血小板血浆(platelet-richplasma,PRP)、PRP复合骨诱导活性材料(osteoinduction active material,OAM)对种植体周围骨缺损修复的作用。方法:Beagle犬4只,拔除每只犬一侧下颌第一、二前磨牙及其双侧下颌第四前磨牙作为实验牙位。3个月后拔牙处植入种植体,每只犬共植入3颗种植体,第一、二前磨牙牙位植入1颗种植体为对照组,对侧第四前磨牙牙位植入1颗种植体为实验A组,同侧第四前磨牙牙位植入1颗种植体为实验B组。种植术中同期制备种植体周围骨缺损并植入相应骨移植材料:A组植入PRP/OAM;B组植入PRP/磷酸三钙;对照组植入磷酸三钙。种植术后8、16周处死动物,进行组织学观察,测量种植体周围骨密度,采用SPSS13.0软件对数据进行单因素方差分析。结果:8周时,实验A组新骨与种植体形成区段性骨结合;实验B组种植体边缘可见新骨形成,但量较少;对照组种植体边缘为纤维性界面。8周时骨密度测量,各组间骨密度差异无统计学意义。16周时,实验A组可见哈佛系统,实验A、B组新骨与种植体形成骨整合;对照组仅为纤维性结合。16周时骨密度测量,两实验组骨密度均显著高于对照组。结论:PRP及PRP/OAM可促进种植体周围骨缺损修复。     

富含血小板血浆诱导口腔种植体周围骨再生的实验研究

目的:通过犬下颌骨种植周围缺损模型,探讨与评估富含血小板血浆与磷酸三钙联合应用后,对种植体骨结合的效应。方法:采用自身对照,在6只成年杂种犬双侧下颌骨下缘各植入2颗纯钛种植体(共24颗)并在种植体周围造成缺损。右下颌2颗为对照组,在缺损处填入磷酸三钙和生理盐水的混合物,左下颌2颗为实验组,在缺损处填入磷酸三钙和富血小板血浆的混合物;术后4、8、12周分别处死2只犬,先后行大体观察、电镜观测和组织学观察。结果:大体观察实验组比对照组缺损处愈合更平整且种植体更稳定;4、8、12周电镜观测时均示实验组和对照组有显著性差异,实验组种植体骨结合率高;组织学观察在实验组可见大量成骨细胞、骨细胞及新生骨小梁,新生骨组织较成熟,而对照组成骨细胞少、骨小梁细而少、纤维组织多见。结论:富含血小板血浆可能具有促进新骨形成及种植体骨结合的效应。     

BMSCs复合PRP修复牙种植体周围骨缺损的实验研究

目的:探讨骨髓基质细胞(bone marrow stromal cells,BMSCs)复合富血小板血浆(platelet-rich plasma,PRP)修复牙种植体周围骨缺损的可行性。方法:拔除6只Beagle犬双侧下颌8颗前磨牙,术后1个月抽取犬骨髓,采用全骨髓贴壁法培养BMSCs,并向成骨细胞诱导,将BMSCs与PRP、β-磷酸三钙(β-tricalcium phosphate,β-TCP)分别复合形成组织工程化复合物。术后2个月,在实验犬每侧下颌缺牙区分别植入BLB4mm×11mm种植体4颗,同时在每个种植体的近中制造4mm×4mm×5mm大小的骨缺损,分别植入BMSCs-PRP复合凝胶、自体骨、BMSCs-β-TCP复合物以及空白对照,分别于种植术后4、8、12周各处死2只犬,行大体、环境扫描电镜及组织学检查,观察各个时期各组骨缺损区的成骨情况以及新生骨与种植体间骨结合情况。结果:3个实验组在术后4、8、12周均有不同程度的骨组织再生,而空白对照组只有少量骨组织再生。各个时期内扫描电镜观察显示BMSCs-PRP组新生骨与种植体间的骨结合较其他三组多。结论:BMSCs-PRP复合凝胶是一种良好的骨修复材料,具有促进新骨形成及种植体骨结合的效应。     

种植体与新生骨结合界面电镜观察研究

目的：通过动物实验观察同期种植体与多孔支架植入后种植体与骨组织的结合状况来为临床应用提供依据。方法：将预制成形的PLA/PGA材料,通过上颌窦提升术植入新西兰兔的上颌窦中,同期植入钛种植体,术后12周全部处死通过大体、组织学及电镜观察成骨及种植效果。结果：12周后肉眼可见所有种植体顶端周围多孔支架均形成骨组织且与新骨结合紧密牢固：扫描电镜和透射电镜均证实新生骨组织与种植体结合紧密。结论：种植时在骨质不足的条件下,可以通过同期植入种植体和多孔支架来同时完成新骨形成及其二者的结合,种植体与新生骨结合牢固,方法有效效果可靠。     

Development of the pioneer sympathetic innervation into the dental pulp of the mouse mandibular first molar

OBJECTIVE: Our goal was to study the development of pioneer sympathetic innervation of dental pulp of mouse mandibular first molar. DESIGN: We used double fluorescent immunohistochemistry with tyrosine hydroxylase (TH) and anti-medium-chain neurofilament (2H3) antibodies to detect sympathetic and sensory nerve fibres. Serial sections of whole teeth from postnatal days (PN) 0-14, trigeminal and sympathetic superior cervical ganglia of PN 15 mice were examined with confocal microscope. RESULTS: There were two main findings. The unexpected finding was that 2H3 antibody was specific only for sensory nerve fibres and neurons and failed to stain either sympathetic nerve fibres or neurons. The main finding was that although both sympathetic and sensory nerve fibres were already seen near the tooth germ at the newborn stage, the pioneer sympathetic nerve fibres were first observed in the dental pulp only after the onset of root formation on day 9, in contrast to sensory nerve fibres which entered the tooth already on day 4. CONCLUSION: Pioneer sympathetic innervation of dental pulp starts on postnatal day 9 and follows sensory innervation. This indicates differential developmental regulation of the initial sensory and sympathetic innervation of teeth and provides essential background data for further studies on the molecular regulation of pulp innervation.     

Recurrent idiopathic trigeminal sensory neuropathy

Idiopathic trigeminal neuropathy is a rare disorder characterized by transient sensory disturbances in the territory of one or more branches of the trigeminal nerve. Acute and chronic forms of the disease have been recognized, but to our knowledge no recurrent cases have been reported. Two cases of recurrent idiopathic trigeminal sensory neuropathy are reported. The patients presented sensory alterations limited to the territory of the trigeminal nerve in the absence of other clinical features. In both cases sensory disturbances began in the tongue and lips and later spread throughout the face. The whole trigeminal nerve territory was involved in the first patient, but in the second patient only the second and third trigeminal branches were affected. There was no muscle weakness or pain, and the corneal reflex was present in both patients. The first patient recovered completely after 3 months, but the symptoms recurred in a similar fashion 3 years later. In the second patient the symptoms occurred each winter for more than 10 years. The conditions in these two patients could be considered as recurrent idiopathic forms of trigeminal sensory neuropathy.     

Neurosensory disturbance of the inferior alveolar nerve after bilateral sagittal split osteotomy: a systematic review.

PURPOSE: The evaluation of neurosensory disturbance of the inferior alveolar nerve (IAN) can be performed by purely subjective, relatively objective, or purely objective methods. The aim of this study was to provide a systematic review of the incidence of inferior alveolar nerve sensory disturbance after bilateral sagittal split osteotomy, as well as the frequency of recovery of sensory function using objective methods of evaluation only. MATERIALS AND METHODS: Searches were conducted employing MEDLINE, Scirus, and the Cochrane Central Register of Controlled Trials (CENTRAL). Seven studies were included in this review. RESULTS: This systematic review has shown that the frequency of nerve impairment evaluated by subjective methods was higher than that indicated by studies adopting objective methods at each time of follow-up considered. In particular at the seventh postoperative day the frequency obtained using the objective methods was 63.3% while that obtained with subjective methods was 83%. At 1 year follow-up a frequency of sensory impairment of 12.8% was obtained using objective methods and a frequency of 18.4% when subjective methods were used. The data were analysed using the index of inter-rater reliability (Cohen's Kappa) with the degree of nerve damage evaluated by objective methods considered the "gold standard." The value of Cohen's Kappa at 1 week follow-up is 0.53; at 1 year follow-up it increased to 0.90. CONCLUSIONS: On the basis of these results, objective methods provide the most sensitive diagnostic tests at early controls-within 3 months of the operation. At later control points the sensitivity increases and the inter-rater reliability is satisfactory.     

Idiopathic trigeminal sensory neuropathy.

Idiopathic trigeminal sensory neuropathy is a rare disorder characterized by transient sensory disturbances in the territory of one or more branches of the trigeminal nerve. Acute and chronic forms of the disease have been recognized, but the boundaries between these groups are not clearly defined. Six cases of idiopathic trigeminal sensory neuropathy are reported. All patients presented with sensory abnormalities limited to the territory of one trigeminal nerve, in the absence of other clinical features. The symptoms were on the left side of the face in five cases and on the right side in one. No bilateral involvement was seen. There were no cases of muscle weakness, and the corneal reflex was always present. In two cases, sensory disturbances began in the tongue or lips and later spread through the entire territory of the three trigeminal branches. Both patients recovered completely after 3 months. The other four patients had involvement of the second and third branches (two cases), or the third branch alone (two cases), and the symptoms persisted unmodified for 2 to 4 years. There were no clinical variables at onset to enable one to predict an acute or chronic evolution of the disease.     

Efficacy of steroid treatment for sensory impairment after orthognathic surgery.

PURPOSE: Steroid hormones are therapeutic for motor and/or sensory dysfunctions caused by nerve injury. However, the timing for giving such medicine is unclear. This study aimed to estimate the efficacy of steroid treatment and determine an appropriate start time after sensory impairment. PATIENTS AND METHODS: Twenty-seven patients with sensory impairment who received orthognathic surgery were classified into groups called 1W (n = 6), 3W (n = 6), or 6W (n = 8) group on the basis of start time for steroid treatment, being 1 week, 3 weeks, or 6 weeks after surgery, respectively, and a no steroid treatment (NST) group (a control group) (n = 6) that did not receive treatment for 10 to 12 weeks after surgery. Sensory impairment was diagnosed if postoperative first week mechanical-touch threshold was over 4.0 as measured by Semmes aesthesiometer. Prednisolone treatment was administered orally to patients at 30 mg for 7 days, 15 mg for 4 days, and 5 mg for 3 days. Mechanical-touch threshold and thermal perceptions were compared before and after treatment. RESULTS: At 1 week postoperatively, there were no significant differences in mechanical-touch threshold among the 4 groups (analysis of variance, P >.05). Changes in mechanical-touch threshold in the 1W group showed no significant improvement (analysis of variance, P >.05), but in the 3W and 6W groups, there were significant differences compared with the NST group (Dunns methods, P <.05). CONCLUSIONS: Steroid treatment for sensory impairment after orthognathic surgery has the potential to accelerate recovery and it appears desirable to start treatment later than 1 week postoperatively.     

Primary and secondary microneuroanastomotic repair of the mental nerve in the rat

The rate of sensory recovery and axonal regeneration after primary and secondary graft and direct microneuroanastomotic repair of the mental nerve was examined in the rat. The mental nerve was subject to experimental transection and immediately approximated with epineurial sutures, with or without a 3 mm autogenous nerve graft, left unapproximated, or left intact. 8 weeks later, the unapproximated stumps were rejoined with suture, with or without a nerve graft. Repair was evaluated using horseradish peroxidase as a tracer and electrically-evoked head withdrawal as a measure of gross sensation. The association in rates of recovery for the anastomosis groups were statistically significant. There was no significant association between negative and positive controls or anastomosis groups. Gross sensory return was established within 28 days of repair and axonal continuity was confirmed by the uptake of HRP in trigeminal ganglion cells. The present study strongly suggests that direct approximation and small autogenous interpositional nerve grafts have the same rate of recovery of gross sensation following primary and secondary repair of mental nerve transections in the rat.     

Effect of ageing on responses of nerve fibres to pulpal inflammation in rat molars analysed by quantitative immunocytochemistry.

The response of sensory nerve fibres to inflammation in young adult rat molars has recently been shown to include increases in nerve sprouting and neuropeptide content. The objective was to evaluate neural responses to class V dental preparations in molars of old (1-2 yr) as compared with young adult rats (3-4 months). Tissues were investigated immunocytochemically 4 days post-injury for the sensory neuropeptides calcitonin gene-related peptide (CGRP) and substance P. Quantitative image analysis of the material demonstrated that more immunoreactivity was present for CGRP than for substance P in intact control teeth for each age group. Four days after injury, both immunoreactivities were increased in pulp adjacent to the injury in both young and old teeth. The increase depended on at least three factors: (1) enhanced immunoreactivity of the nerve fibres; (2) increased terminal nerve sprouts near the injury and (3) elevated peptide content of the pulp tissue. Although the incidence of CGRP- and substance P-immunoreactive nerve fibres had decreased in older teeth, the proportional increases in both neuropeptides near the injury were greater in old than in young teeth, owing to a reduction in pulpal volume during ageing. Pulpal tissue was also immunostained for the low-affinity nerve growth factor receptor (p75-NGFR) as an index of pulpal ageing; and an extensive decrease was found in the old adult as compared to young adult rats. These results indicate that old rats maintain the capacity for nerve sprouting despite the decreases in p75-NGFR labelling of pulp cells, pulp volume and nerve fibre numbers that occur as part of dental ageing.     

Trapezius muscle innervation from the spinal accessory nerve and branches of the cervical plexus

The aim of this study was to demonstrate the extent of motor innervation of the trapezius muscle from the accessory nerve and branches of the cervical plexus using intraoperative electroneurography and histochemical staining. In 34 patients during radical neck dissection the accessory nerve and C2-C4 branches running to the trapezius were identified and stimulated. Potentials were registered under three conditions: intact accessory nerve, section of superior part of communication between the nerve and the cervical branches, and complete section of the nerve. Projections that did not elicit responses were analyzed for acetylcholinesterase activity. Before cutting the accessory nerve, its stimulation led to a recordable contraction in all parts of the trapezius muscle in all patients. C2 contributions were seen in 15, C3 in 21 and C4 in 20 patients. After sectioning of the upper half of the nerve, the results were similar. After the nerve was completely cut, C2 contributions were seen in only 2 patients, but C3 were seen in 20 patients and C4 in 19 patients. Histochemical staining revealed that the branches with no responses contained both motor and sensory axons. The accessory nerve provides the main motor input to the trapezius muscle, but preservation of the C2-C4 branches to the muscle during modified neck dissection should improve outcomes.     

Lateralization of the inferior alveolar nerve with simultaneous implant placement: a modified technique

PURPOSE: Several nerve repositioning techniques have ben presented in the literature, each with limitations. This article presents a new technique involving the use of 2 osteotomies, with minimizes particularly the potential duration of sensory disruption and the risk of nerve paresthesia and inadvertent nerve transection or compression. MATERIALS AND METHODS: Ten patients ranging in age from 47 to 67 years were selected for nerve lateralization utilizing the modified technique. A total of 23 cylindrical implants were placed. An average follow-up period was 29.8 months. RESULTS: Of the 10 patients, 4 experienced total return of sensation within 3 to 4 weeks. One patient experienced complete recovery at 6 weeks. DISCUSSION: Creating 2 osteotomies as described minimizes the chances for postoperative neuropraxia and nerve paresthesia or anesthesia. CONCLUSION: When there is moderate-to-severe bone resorption of the mandible posterior to the mental foramen, repositioning the inferior alveolar nerve using both an anterior and posterior osteotomy allows for more bone to accommodate ideal placement and greater length of implant.     

皮瓣及肌皮瓣移植感觉功能恢复过程的临床研究

非神经化皮瓣及肌皮瓣２９例，神经化皮瓣４例。非神经化瓣的感觉功能从术后３月起逐渐恢复，依次是痛觉、触压觉、温度觉和二点分辨觉。恢复从边缘向中央逐渐进行，术后２－３年，约６５．５％的组织瓣感觉功能取得较好恢复，此时痛觉、触压觉、温度觉和二点分辨觉的恢复率分别为６４．７％、６４．７％、５３．０％和２３．５％，其中，皮瓣感觉恢复较肌皮瓣为好。神经化皮瓣感觉再生恢复明显优于非神经化皮瓣。组织瓣的感染来源于