舌神经在下颌第三磨牙区的毗邻关系及其临床意义

本文在53侧成人头部标本上对舌神经在下颌第三磨牙区的毗邻关系进行了研究。舌神经在第三磨牙后区多为扁圆形,在第三磨牙舌侧多为扁平形,平均横径为1.7mm,舌神经距第三磨牙槽嵴的垂直距离为11.2mm、距第三磨牙远中距离为9.0mm、距牙槽骨舌侧骨板的水平距离为3.0mm、距下颌舌骨肌附着缘的距离为6.2mm。对拔除第三磨牙时,损伤舌神经的解剖学原因进行了探讨并提出防止其损伤的建议。     

舌神经的解剖观测及其临床意义

在33侧成人头颈部标本和61块下颌骨标本上对舌神经在下颌第三磨牙舌侧区的位置及其与周围结构的毗邻关系进行了观测。舌神经在第三磨牙舌侧正中垂线上至牙龈的距离为11.7mm,至舌侧骨板的水平距离为3.1mm。第三磨牙根尖至内侧牙槽嵴的距离为11.3mm。依据观测结果,结合下颌第三磨牙拨除术等讨论了有关应用解剖学要点.     

牙周膜厚度对舌侧矫治中下颌第1磨牙近中移动的影响

目的 研究舌侧矫治中下颌第1磨牙近中移动过程,牙周膜厚度因素对牙齿及牙周组织应力和位移的影响。方法 基于逆向工程技术的方法,分别建立牙周膜厚度为0.15、0.2、0.25、0.3、0.35 mm的等牙槽骨高度的牙齿—牙周膜—牙槽骨三维模型,在舌侧矫治中倾斜、旋转及整体移动载荷作用下,分析牙周膜、牙根及牙槽骨表面的应力和位移状况。结果 由牙周膜厚度差异引起的牙周膜、牙根以及牙槽骨表面最大应力极大值与极小值之比分别为1.46、2.06、6.72,牙根、牙槽骨表面的最大位移极大值与极小值之比分别为1.65、1.50;对应不同的牙周膜厚度值,牙根及牙周组织最大应力部位在牙根、根分叉以及牙颈间变动。结论 临床治疗中,应注意观察牙颈、根分叉以及牙根部位的变化,针对牙周膜厚度较小的患者,整体移动更有利于牙齿及牙周组织的健康。     

下颌第一磨牙不同冠根比种植修复体的三维有限元分析

背景：为了尽量避免种植义齿修复时出现种植体周围骨组织应力集中。以往有研究应用增大种植体与骨界面的结合面积、增加直径、增加长度等方法以期使种植体骨界面应力分布更趋均匀,以提供更大的支持力,但观察时间较短,且临床报告并不一致。 目的：设计不同冠根比种植修复体,采用三维有限元法,对轴向加载和颊舌向加载下的不同冠根比种植修复体周围骨组织应力分布进行分析,以求找到适合临床种植修复的冠根比范围。 方法：应用CT断层扫描技术得到下颌骨和下颌牙列的大致轮廓,通过交互式的医学影像控制系统对图形特征进行整体图像拟合,再以计算机软件生成云图,根据云图的数据进行三维重建,从而得到包括下颌骨和下颌牙列的三维有限元模型;运用几何模型方法建立不同冠根比种植修复下颌第一磨牙的三维模型。运用Hyperwork 8.0及Ansys 11.0大型有限元分析软件,建立下颌不同冠根比的种植修复体模型,并完成牙冠的修复。在模拟牙合向载荷的基础上,比较不同冠根比种植修复体周围骨组织应力分布状况。 结果与结论：获得了下颌骨及下颌牙列的三维有限元模型,以及下颌不同冠根比种植修复体的有限元模型。通过对不同冠根比种植体施加轴向100 N及颊舌向50 N的力,种植体周围骨组织产生的应力分布状况比较发现,颊舌向受力下种植体颈部及周围骨皮质为应力集中区;轴向施力时种植体颈部、根尖部周围的骨组织为应力集中区。     

应用Micro CT测量下颌第二磨牙牙根尖到颊侧骨板的距离

目的运用Micro CT技术测量牙根尖到颊侧骨板的解剖距离。方法应用Micro CT(Skyscan 1072,Antwerpen,Belgium)及cutome计算机软件分析三维骨结构。结果下颌第二磨牙,近中根和远中根到颊侧骨板的距离平均为5.18mm和4.09mm。上颌骨的颊根中,上颌第二磨牙近中颊根和远中颊根到颊侧骨板的距离最大,分别是4.63mm和3.61mm。结论Micro CT是一种快速、准确、不损伤样本内部结构有效的评价方法。     

磨牙与下颌管、上颌窦的位置关系及临床意义

目的:为牙种植术等临床口腔外科提供解剖学基础.方法:选取新鲜及成人全牙上、下颌骨标本和全牙志愿者,观察下牙槽神经、血管的关系和上颌窦下壁的凸起结构,测量磨牙牙根至下颌管、上颌窦的距离和牙槽窝的深度.结果:下颌管内的下牙槽血管位于下牙槽神经上方,下颌第1磨牙、第2磨牙、第3磨牙牙根至下颌管上壁的距离分别为(3.22±1.40)mm、(2.96±1.54)mm、(3.64±1.72)mm.上颌窦下壁有凸起的骨隔和黏膜隔,上颌第1磨牙、第2磨牙、第3磨牙牙根至上颌窦下壁的距离分别为(2.02±0.91)mm、(2.06±1.04)mm、(3.74±1.73)mm.下颌磨牙的牙槽窝深度均大于上颌磨牙相应的牙槽窝.结论:磨牙牙根至下颌管、上颌窦的距离和牙槽窝的深度对选择适宜长度的牙种植体,避免牙种植体损伤下牙槽神经和误入上颌窦等具有重要意义.     

下颌第一磨牙远中缺损牙体修复后的力学性能分析

本研究结合了三维激光扫描、逆向工程、三维有限元分析等技术，建立了下颌第一磨牙远中牙体缺损修复后的三维有限元模型，研究了其在不同加载方案、修复材料及修复洞型下的全场应力分析，并通过Mohr强度理论对修复体进行了校核。结果表明，临床上制备壁厚1mm的预备牙体进行充填修复在力学上是可行的；而对大面积缺损牙体的修复，桩核全冠修复并未显示出明显优势。     

从下颌第二磨牙的解剖学形态分析其临床治疗特点

我科从1995年初至今对172颗下颌第二磨牙依据其解剖形态进行液剂充填法的根管治疗,收到了较为满意的临床效果,提示液剂充填法对下颌第二磨牙的根管治疗是一种较为理想的方法。     

不同受力方式下上颌第一磨牙牙槽骨应力分布的有限元分析

目的　利用有限元的方法研究上颌第一磨牙在牙齿矫治过程中不同受力方式牙槽骨应力分布的特点。方法　应用三维激光扫描的方法建立上颌第一磨牙、牙周膜、牙槽骨及颊面管的有限元模型,进行不同方式的加载并观察牙槽骨及其各个截面的应力分布。结果　牙齿在单一水平力和垂直力作用下,上颌第一磨牙牙槽骨在牙颈部和根部分叉处出现应力集中;牙齿趋于整体移动时,上颌第一磨牙牙槽骨处于均匀的低应力分布,各应力都小于倾斜移动或旋转移动时的应力,牙槽骨的应力在根分叉平面稍大。结论　不同受力方式下,上颌第一磨牙牙槽骨在牙颈部平面或根分叉平面应力最大,临床上应注意观察这些部位的变化;整体移动更有利于牙齿及牙周组织的健康。     

中国近代与青铜铁器时代人群下颌磨牙磨耗的分析与比较

目的 探讨青铜铁器时代、近代人群下颌骨第1磨牙齿冠面4个区域的磨耗特点。方法 将青铜铁器时代（大同、陇县共35例）、近代（云南、华北共195例）人群下颌骨第1磨牙齿冠面分为4个区域,根据磨耗程度进行分级,然后比较各个区域的磨耗级别,并对比近代人群与青铜铁器时代人群。结果 青铜铁器时代磨牙4个区域的磨耗都大于近代人群,近代人群与青铜铁器时代人群下颌磨牙4个区域的磨耗都表现为区1最大,区2最小,左右侧结果一致。结论 下颌磨牙4个区域的磨耗大小关系为：区1＞区3＞区4＞区2,这种大小关系可能至少从青铜铁器时代就开始形成了。     

Nerve fiber analysis for the lingual nerve of the human adult subjects

The neuro-motor control of the human tongue musculature had not been investigated in detail. This study identified first that the lingual nerve should play the neuro-motor control of some lingual muscles. Six en bloc samples (12 sides), including the tissues from the skull base to the hyoid bone, and three whole tongues were obtained from adult human cadavers. The former samples were used for the study of nerve fiber analysis of the lingual nerve with the aid of binocular stereomicroscope, and the latter samples were used for histological study by serial section method. On nerve fiber analysis of the lingual nerve from the trigeminal ganglion to the tongue musculature, we found that the motor- root of the trigeminal nerve gave off its supply to the lingual nerve and traveled into the lingual nerve, and branched to the superior and the inferior longitudinal muscles. On histological study, it was revealed that in the anterior part of the tongue the superior and the inferior longitudinal muscles surrounded the other lingual musculature and combined with the sub-mucosal connective tissues closely like the cutaneous muscle, for example, the facial muscles. The lingual nerve entered the inner side of the space between the genioglossus and the inferior longitudinal muscles with the lingual artery. These findings suggested that the superior and the inferior longitudinal muscles should be innervated by the motor fibers traveled into the lingual nerve from the motor root of the trigeminal nerve, and do not originate from the myotome originating in occipital somites but branchial muscles.     

Topographic anatomy of the lingual nerve and variations in communication pattern of the mandibular nerve branches

We made a thorough observation of the morphology and course of the lingual nerve (LN) and inferior alveolar nerve (IAN) to clarify their topographical relationships in the infratemporal fossa and in the paralingual area. Thirty-two Korean hemi-sectioned heads were dissected macroscopically and microscopically from a clinical viewpoint. On the 32 tracings on the radiograph, the average distance between the retromolar portion and the LN was 7.8 mm, and no case was found where the LN ran above the alveolar crest as passing along the mandibular lingual plate. The bifurcation of the LN and IAN was located around the mandibular notch, inferior to the otic ganglion in 66% of the cases, and a plexiform branching pattern of the mandibular nerve was observed in only two cases. The bifurcation spot of the LN and IAN was located 14.3 mm inferior to the foramen ovale and 16.5 mm superior to the tip of hamulus. Collateral nerve twigs from the LN to the retromolar area were observed in 26 cases (81.2%), with an average of one nerve twig. We observed four types of variations in terms of communication pattern. In four specimens, the mylohyoid nerve passed through the mylohyoid muscle and connected with the LN. In other four specimens, the IAN communicated with the auriculotemporal nerve. We also observed another type of variational communication between the IAN and the nerve to the lateral pterygoid (LPt); this was observed in only one specimen, and it could be predicted that motor innervation from the nerve to the LPt was transmitted via the mental nerve to the depressor anguli oris. Another type was observed where the IAN divided into two branches with the posterior branch being partially entrapped by the LPt muscle fibers.     

TRPA1 expression in human lingual nerve neuromas in patients with and without symptoms of dysaesthesia

The TRPA1 receptor is a member of the ankyrin family and is found in both spinal and trigeminal neurones. There is evidence to suggest that this receptor may be a sensor of noxious thermal stimuli in normal animals. After nerve injury, TRPA1 shows increased expression in uninjured axons, and has been implicated in the development and maintenance of hyperalgesia. We examined expression of TRPA1 in lingual nerve neuromas and investigated any potential correlation with the presence or absence of symptoms of dysaesthesia. Thirteen neuroma-in-continuity specimens were obtained from patients undergoing repair of a lingual nerve that had previously been damaged during lower third molar removal. Visual analogue scales (VAS) were used to record the degree of pain, tingling and discomfort. Tissue was processed for indirect immunofluorescence and the percentage area of PGP 9.5-immunoreactive neuronal tissue also labelled for TRPA1 was quantified. No significant difference between levels of TRPA1 in neuromas from patients with or without symptoms of dysaesthesia and no relationship between TRPA1 expression and VAS scores for pain, tingling or discomfort were observed. TRPA1 expression and the time after initial injury that the specimen was obtained also showed no correlation. These data show that TRPA1 is expressed in lingual nerve neuromas, but, it appears that, at this site, TRPA1 does not play a principal role in the development of neuropathic pain.     

不同槽沟方向舌侧托槽转矩控制性能三维有限元分析

目的分析不同槽沟方向的舌侧托槽转矩控制性能以及不同弓丝尺寸、材质对其转矩的影响规律。方法建立上颌前牙垂直槽沟及水平槽沟舌侧托槽、3种材质(不锈钢弓丝、β钛丝、镍钛丝)、2种尺寸(0.43 mm×0.56 mm、0.41 mm×0.56 mm)弓丝的有限元模型,对左上颌中切牙施以±20°的转矩加载,分析对比其力学性能。结果随着弓丝弹性模量的增大,不同槽沟方向的舌侧托槽转矩力矩逐渐增大;槽沟方向对舌侧托槽的转矩性能有影响,但小于弓丝尺寸及材质变化带来的影响。相同转矩角度下,垂直槽沟舌侧托槽产生约为水平槽沟舌侧托槽1~2倍的转矩力。弓丝尺寸对两种托槽转矩控制的影响小于弓丝材质,两者协同变化影响最大。结论槽沟方向、弓丝尺寸、材质改变均能影响舌侧托槽转矩控制性能。临床应用中,可以根据所需转矩力大小,对舌侧托槽槽沟方向及弓丝尺寸、材质组合进行选择。     

Distribution pattern of the human lingual nerve

The tongue is an intricate organ with many functions. Despite the knowledge of the presence of muscular and neural connections in the tongue, a detailed neuroanatomical depiction of the nerves' topography in the tongue has not been demonstrated. The topography, branching patterns and neuronal interconnections of the lingual nerve were studied in five postmortem human tongues. They were stained with Sihler's stain, a technique that renders most of the tongue tissue translucent while counterstaining nerves. The lingual nerve reaches the tongue posterolaterally. There are two main branches off of the main trunk: the medial branch sends 2-4 small branches to the medial part of the ventrolateral tongue and the lateral branch runs along the lateral tongue border and sends 3-4 large branches to the anterior tip of tongue. Each subdivision gives off 2-5 distal branches. Both medial and lateral branches have interconnections with the proximal part of the hypoglossal nerve. One of the unexpected discoveries in this study was the high density of nervous fibers in the lateral aspect of the tongue as compared to the midline region. The average diameter of the main trunk of the lingual nerve is 3.5 mm. The medial and lateral branches average 1 mm in diameter, the more distal subdivisions measure 0.5-0.75 mm, and the lingual-hypoglossal interconnections measure 0.125-0.250 mm. In summary, this study provides the first detailed depiction of the topography of the human lingual nerve and its branches in situ, confirmation of lingual-hypoglossal nerve connection, and the first depiction of the high density of lingual nerve innervation in the lateral tongue.     

Anatomy of the lingual nerve: Application to oral surgery

The purpose of this research is to obtain morphological information about the traveling route, branching pattern, and distribution within the tongue of the lingual nerve, all of which are important for oral surgical procedures. Using 20 sides from 10 Japanese cadaveric heads, we followed the lingual nerve from its merging point with the chorda tympani to its peripheral terminal in the tongue. We focused on the collateral branches in the area before reaching the tongue and the communication between the lingual and hypoglossal nerves reaching the tongue. The collateral branches of the lingual nerve were distributed in the oral mucosa between the palatoglossal arch and the mandibular molar region. Two to eight collateral branches arose from the main trunk of the nerve, and the configuration of branching was classified into three types. More distally, the lingual nerve started to communicate with the hypoglossal nerve before passing the anterior border of the hyoglossus muscle. Nerve communications were also found in the main body and near the apex of the tongue. A thorough understanding of the collateral branches near the tongue, and the communication with the hypoglossal nerve inside the tongue, will help to prevent functional disorders from local anesthesia and oral surgical procedures associated with the lingual nerve. Clin. Anat. 32:635–641, 2019. © 2019 Wiley Periodicals, Inc.     

Parameters of the static burst discharge of lingual cold receptors in the cat

Thermal stimuli were applied to the upper surface of the tongue of the cat. The stimuli ranged from 40°C to 10°C and were changed in cold steps of 5°C, each temperature lasting 2 min. Afferent impulses of single specific cold fibers from the lingual nerve were analysed by a computer program. About 90% of the fibers showed bursts under static conditions. The bursts began as doublets at the temperature of maximal average frequency. This temperature varied from 40°C to 15°C in different fibers, the average being 30°C. The parameters burst period, burst duration, pause duration, intraburst interval and spikes per burst increased monotonically from 30°C to 15°C. The possible physiological significance of the burst pattern is discussed.     

The effect of a monoclonal antibody to calcitonin-gene related peptide (CGRP) on injury-induced ectopic discharge following lingual nerve injury

The development of ectopic neural discharge at a site of peripheral nerve injury is thought to contribute to the initiation of sensory disturbances and pain. We have previously shown that this discharge can be initiated or increased by the neuropeptide calcitonin gene-related peptide (CGRP). We have now studied a potential therapeutic approach to reducing the discharge by evaluating the effect of a systemically administered monoclonal antibody to CGRP on injury-induced activity in the lingual nerve. In 16 anaesthetised adult ferrets the left lingual nerve was sectioned. One day after the injury, the animals received a subcutaneous injection of either a monoclonal antibody to CGRP or a vehicle control. Three days after the injury, under a second anaesthetic, single-unit electrophysiological recordings were made from central to the injury site (469 and 391 units were analysed in antibody and vehicle groups, respectively), and the proportion of units that were spontaneously active was determined. In the vehicle-treated animals 6.4 ± 2.7 [SEM]% of the units were spontaneously active, with conduction velocities of 8.8-40.8 m/s and discharge frequencies of 0.03-2.7 Hz. In the monoclonal antibody-treated animals 5.7 ± 2.0% of the units were spontaneously active, with conduction velocities of 13.9-38.8 m/s and discharge frequencies of 0.07-1.8 Hz. There was no significant difference between these two groups (for spontaneous activity and conduction velocity: p > 0.05, Student's t-test; for discharge frequency: p > 0.05, Mann-Whitney test), suggesting that the spontaneous activity initiated by a nerve injury cannot be modulated by administration of a monoclonal antibody to CGRP.