无症状颞下颌关节盘前移位个体的动态磁共振及髁突运动轨迹特点

目的 颞下颌关节盘早期的前移位临床上可无弹响症状,了解无症状颞下颌关节盘的早期移位个体的髁突运动中心轨迹特点,将有助于早期发现隐匿性颞下颌关节结构内紊乱疾病。 方法 动态磁共振(Cine-MRI) 和ARCUSdigma系统检查30例无症状个体开闭口过程中髁状突-关节盘运动特点和下颌运动范围。 结果 Cine-MRI显示30例无症状人群中,20例健康颞下颌关节、10例单侧可复性关节盘前移位,闭口位关节盘本体部仍呈双凹形、盘后区均有轻度增厚和前移位,盘-突关系在小开口（<2 cm）期恢复正常;无症状可复性关节盘的运动中心轨迹出现弹跳切迹和偏摆,光滑性、重复性及双侧运动中心轨迹的对称性不及健康人,但是切点运动轨迹平滑,与健康人的切点运动轨迹基本一致;运动轴在髁突轨迹弹跳时出现偏斜,然后保持平行,呈现开闭口初、末时密度比开闭口中时大;髁突运动中心运动距离（13.6±3.7）mm,下颌切点运动距离（40.5±3.4）mm。 结论 髁突运动轨迹能间接反映髁突-关节盘复合体在开闭口运动中的位置变化,为下一步临床使用下颌运动轨迹仪作为早期关节盘移位的诊断提供一定的理论参考。     

上颌扩弓对颞下颌关节应力影响的有限元分析

目的 通过三维有限元法对比扩弓前和放置扩弓器时颞下颌关节(temporomandibular joint, TMJ)内部各组织应力分布情况。方法 根据1名上颌牙弓狭窄患者CBCT影像资料,构建扩弓前和包含扩弓器的TMJ三维有限元模型,对模型加载相同的肌力和边界约束,观察TMJ髁突、关节盘、关节窝的等效应力、最大主应力和最小主应力。结果 扩弓前TMJ等效应力主要分布在下颌支前缘、髁突前斜面、关节盘中间带和后带以及关节窝顶部。放置扩弓器时,TMJ应力分布特征与扩弓前基本一致,应力虽然明显增加,但应力分布区域更加均匀;髁突和关节盘应力向前、向外侧移动,髁突后斜面表现出更加均匀的最大主应力分布范围。结论 上颌扩弓器产生的矫形力能够使TMJ应力增加,诱导髁突发生组织改建,协调髁突和关节盘的关系。临床上对于牙弓狭窄的患者应该采用合适的手段进行扩弓矫治。     

正畸减数患者后牙前移对颞下颌关节应力影响的三维有限元分析

背景：颞下颌关节紊乱病与颞下颌关节内有高应力密切相关。减数拔牙后伴随着磨牙位置的改变,建立新的咬合关系往往会导致颞下颌关节内应力环境发生改变。目的：在牙尖交错位时,利用三维有限元模型分析正畸减数拔牙后不同程度磨牙前移下颞下颌关节的应力分布。方法：选择在山东青岛市市立医院口腔正畸科就诊的正常牙合患者1例,收集其锥形束CT和MRI数据,分别建立减数前、减数后上下磨牙前移1/3拔牙间隙(拔除4颗第二前磨牙)及减数后上下磨牙前移2/3拔牙间隙(拔除4颗第二前磨牙)的有限元模型,通过建模软件分析牙尖交错位时颞下颌关节各部位的应力分布。结果与结论：(1)减数前后模型中髁突、关节盘、骨关节窝的受力分布基本一致,髁突的应力主要分布于髁突的前部及顶部,关节盘的应力主要分布于关节盘的中带及外侧,颞骨关节窝的应力主要集中分布在关节窝的前部及顶部。与减数前相比,减数后模型中髁突、关节盘及关节窝的等效应力值减小;正畸减数拔牙后,上下磨牙前移1/3拔牙间隙模型中髁突及关节盘的等效应力值小于上下磨牙前移2/3拔牙间隙模型。(2)从生物力学角度上讲,正畸减数拔牙可以降低颞下颌关节的应力,进而提供良好的生物力学环境。     

颞下颌关节盘前移位对髁状突软骨中纤溶酶原激活剂系统表达的影响

目的研究颞下颌关节盘前移位对关节软骨组织中尿激酶型纤溶酶原激活剂（uPA）系统的影响.方法24只日本大耳白兔在不打开关节囊的情况下建立右侧颞下颌关节盘前移位动物模型,分别于术后4、1、2、4、8d和12周各处死4只动物.常规HE染色观察髁突软骨的形态学变化,并以原位杂交法检测髁突软骨细胞中uPA和纤溶酶原激活剂抑制剂-1（PAI-1）的基因表达变化.结果术后髁突受力区出现一过性的软骨变薄、各层排列紊乱等病理变化.uPA和PAI-1基因转录水平在术后即开始上调,至2周时达到最高水平,至12周时基本恢复至正常水平,与髁突软骨的适应性改建相一致.结论颞下颌关节盘前移位后,关节软骨内uPA系统的变化与关节软骨的适应性改建密切相关.     

不同功能位颞下颌关节盘影像解剖学研究进展

颞下颌关节 (temporomandibularjointTMJ)是人体颌面部稳定而灵活的左右联动关节。CT、MRI等影像技术的广泛应用 ,促进了颞下颌关节动态解剖的发展。本文就不同功能位颞下颌关节盘的解剖及影像解剖文献作一综述。1　关节盘的解剖1.1　关节盘的形态闭口齿正中咬合位关节盘多为椭圆形 ,有上、下两面 ,其形态分别与关节窝和髁突相适合。上面与关节窝接触 ,从后向前分为三段 ,后端形突、中段形凹、前端较平。下面与髁突邻接 ,分两段 ,后段与髁突的关节面接触 ,呈凹型 ,前段向下凸。关节盘周缘与关节囊相连 ,同时 ,盘内侧、外侧分别与髁突的…     

计算机辅助三维重建下的颞下颌关节形态发生

目的:观察颞下颌关节的形态发生,初探形态变化与组织分化的联系.方法:光镜下观察并描记胎儿期颞下颌关节窝、关节盘、髁状突及Meckel软骨组织学图像,PC机行三维重建.结果:颞骨关节面从中线向侧方逐渐沉积,覆盖原始髁突始基;软骨始基的下后缘改建迅速,稍后软骨中血管长入,并常与其上方颞骨软骨内成骨同时出现;骨化区初现于Meckel软骨下缘开始扭曲处.结论:胎儿期颞下颌关节各部分外形不断改变,与组织分化关系密切.     

用于分析面形态与颞下颌关节生物力学关系的三维有限元模型的建立

目的为研究(牙合)面形态变化对颞下颌关节应力影响的规律,建立包括下颌牙列(牙合)面形态及双侧髁突的三维有限元模型.方法尸头1具,平行于眶耳平面作CT扫描,获取下颌骨几何参数;取石膏模型,以三维扫描仪对牙列(牙合)面扫描(精度0.5mm);将石膏模型参数与CT参数换算到同一坐标系下,在髁突上方设均厚类关节盘,关节盘顶及下颌角作约束设计,经划分网格生成有限元模型.结果建立了包括双侧髁突、类关节盘及下颌牙列在内的用于分析咬合与颞下颌关节关系的三维有限元模型.结论采用本方法可建立研究(牙合)面形态与颞下颌关节应力关系的三维有限元模型.     

一种新型人工颞下颌关节的生物力学分析

目的　建立下颌骨髁突缺损有限元模型,研究新型人工颞下颌关节的应力分布及位移改变。 方法　运用Mimics、Geomagic、Solidworks、ANSYS软件建立含完整牙列的下颌骨右侧髁突缺损有限元模型并分析新型人工颞下颌关节在模拟咬合力加载的情况下假体及下颌骨硬组织的应力分布和位移情况。 结果　下颌骨整体等效应力值均低于20 MPa,最大形变值不超过0.05 mm。 结论　新型人工颞下颌关节能避免过大应力导致的假体断裂和骨质吸收,具有良好的生物力学特性。     

成人颞下颌关节的矢状张口运动分析

作者采用X线电影摄影技术和运动生物力学研究方法,对14例正常人颞下颌关节的矢状张、闭口运动进行了分析。本文进一步肯定了下颌运动的瞬时运动中心理论,确定了瞬心曲线的形态、位置和趋势,并提出了下颌张口运动的两阶段模式,提供了各标志点的运动轨迹和范围。这些结论对颞下颌关节的理论分析和病理分析,均有参考价值。由于张口运动一开始髁突就向前下滑动,滑动在该阶段约占整个运动的70～86%,而转动仅占14～30%,因此在咀嚼运动中,髁突前斜面与关节结节后斜面通过关节盘,始终保持接触并承受主要的咀嚼压力,故可解释关节窝顶骨板菲薄及髁嵴形成的原因。     

颞下颌关节三维动态磁共振成像研究及生物力学分析

目的通过在多层面二维动态MR成像上获取颞下颌关节组织的运动数据,构建颞下颌关节的三维动态模型,并进行初步生物力学分析。方法 MRI检查采用GE Signa 1.5T TwinSpeed超导型磁共振扫描仪。选取2例无症状男性志愿者行颞下颌关节MRI检查,将图像数据导入Mimics软件,构建颞下颌关节的三维模型,动态分析张口幅度和关节盘横径的量化关系。结果建立的颞下颌关节三维动态模型清晰显示三维动态盘髁关系及关节盘在动态过程中的形态变化;志愿者1张口/关节盘横径拟合直线为:y=-0.03x+14.44,相关系数R2=0.591,志愿者2相关拟合直线为:y=-0.061x+13.48,相关系数R2=0.306,志愿者张口位置与关节盘横径变化具有直线趋势,关节盘横径随着张口幅度的加大而呈现减小的趋势,颞下颌关节盘对于髁突的包绕程度与张口幅度呈反比。颞下颌关节盘纵径厚度在张口活动中后带外份及中带内份的变化幅度最大。结论通过颞下颌关节二维动态MR成像数据可构建三维动态模型立体动态地观察颞下颌关节运动,可直观、准确显示颞下颌关节盘髁关系,可作为颞下颌关节二维静态MR成像的有益补充,弥补常规MRI检查的局限。     

偏侧咀嚼对颞颌关节影响的超微结构研究

目的　观察单侧后牙缺失偏侧咀嚼不同时期对双侧颞颌关节 (temporomandibularjoint,TMJ)的致病作用及其病理特征。方法　采取拨除Wistar雄性大鼠右侧上、下颌磨牙 ,人为造成偏侧咀嚼的动物模型 ,分别用于光镜、扫描电镜和透射电镜观察。结果　实验组TMJ出现明显的退行性改变。颞颌关节盘的胶原纤维及髁突骨小梁均出现裂隙 ,超微结构亦有明显变化。结论　长期偏侧咀嚼可引起TMJ发生病理性改变     

Morphological Changes in the Mandible of Male Mice Associated With Aging and Biomechanical Stimulus

Degenerative changes in the temporomandibular joint (TMJ) associated with aging can affect mandibular shape and reduce growth potential when stimulated by functional appliance therapy. This study was designed to evaluate the morphological changes in the mandibles of male mice associated with aging and biomechanical stimulus. Every 3 days over the course of 1 month, the lower incisors were trimmed by 1 mm to induce mandibular advancement (MA) when the animal was feeding. The left mandibles of the 23 experimental and 27 control animals were subsequently dissected, and digital images were obtained to analyze nine linear/angular measurements. Because mandibular morphology depends on the maintenance of condylar cartilage, the surfaces of the condylar cartilage and the ascending ramus of the mandible were also analyzed by scanning electron microscopy (SEM). The linear measurements of the mandible showed changes according to age in the control group and a growth response in the mandibular condyle in 7‐ and 15‐month‐old mice after MA. Moreover, SEM analysis revealed depressions in the anterior region of the condylar cartilage and inclined vascular grooves in the ascending ramus in the 7‐ and 15‐month‐old experimental mice. Although the growth potential is reduced in mice after 6 months of age, the results showed that continuous growth of the mandible occurs after maturation, except in the condyle, and that biomechanical stimulus of the TMJ of male mice leads to condylar growth. These results suggest that mature and old individuals can favorably respond to maxillary functional orthopedic therapy. Anat Rec, 292:431–438, 2009. © 2009 Wiley‐Liss, Inc.     

伴偏斜对下颌前突患者颞下颌关节应力分布的影响

目的探究伴偏斜对下颌前突患者颞下颌关节(temporomandibular joint,TMJ)应力分布的影响。方法在Mimics中建立4名下颌前突伴偏斜患者和4名下颌前突不伴偏斜患者的三维颌面部模型,在ABAQUS中赋予模型偏侧咬合(单侧磨牙咀嚼)的肌肉力与边界条件,分析偏侧咬合工况下患者TMJ的最大和最小主应力。结果偏侧咬合工况下,伴偏斜患者髁突的平均最大应力显著大于不伴偏斜患者(P<0.05),伴偏斜会使髁突处应力增加2~3倍,关节窝应力增加5~7倍,且伴偏斜患者中颞下颌关节紊乱综合征(temporomandibular disorder,TMD)患者同侧TMJ处的应力高于无TMD患者。结论伴偏斜会增大患者髁突和关节窝的应力,TMD会引起伴偏斜患者同侧TMJ的高应力。建议根据偏斜与否考虑下颌前突的治疗。     

Functional state of the mandible and rolling–gliding characteristics in the TMJ

For the physiological intact stomatognathic system, the three main functional states (occlusal articular functions, free mandibular movements, and ideal bolus function) were biomechanically discussed concerning the structure of movement, rolling–gliding characteristics, and force transfer in the temporomandibular joint (TMJ). In all three cases, rolling is not possible in the TMJ since the instantaneous rotational axis is positioned outside of the joint – rolling is not necessary because the TMJ is not loaded by appreciable forces. In the aged stomatognathic system with a lost discus and considerable loads in the TMJ, however, the attrition of the joint is eased by rolling movement at the articulating surfaces. The destruction of the discus can be seen as a physiological adaptation which brings back the joint to an original odontogen condition.     

Success Rate in Puncture of the Temporomandibular Joint

Puncture of the temporomandibular joint (TMJ) is a minimally invasive treatment for various jaw disorders. This study used a cadaveric model to evaluate the procedure from two entrance points with respect to hit ratio and possible complications, such as extraarticular extrusion of injection fluid. Ten heads, embalmed with Thiel's method, were investigated. A straight line drawn with a colored pen connected the center of the tragus and the lateral canthus. The first portal “A” was located at a distance of 1 cm anterior and 2 mm caudal from the center of the tragus. Portal “B” was located 2 cm anterior and 1 cm caudal starting from the same reference point. Punctures “A” and “B” were performed alternately on the right and left sides. Specimens were dissected and the local distribution of the injected latex was recorded. With Approach A, four punctures (40%; 4/10) reached the TMJ, whereas with Approach B, six injections (60%; 6/10) entered the TMJ. There were no statistically significant differences between the tested puncture methods (P = 0.0317) and body sides (P = 1). With each method, for example, 35% (7/20) each, the injected latex was either periarticular or retromandibular. In a further 20% (4/20), it was located subperiosteally alongside the ramus of mandible. The latex was injected into the infratemporal fossa and the external acoustic meatus in one case each (each 5%). There was no statistically significant difference between the techniques. The adjacent anatomy has to be kept in mind during TMJ puncture as the complication rate was remarkably high, suggesting that ultrasound guided intraarticular injection could improve the hit rate. Clin. Anat., 33:683–688, 2020. © 2019 Wiley Periodicals, Inc.     

In vivo prediction of temporomandibular joint disc thickness and position changes for different jaw positions

Temporomandibular joint disorders (TMD) are common dysfunctions of the masticatory region and are often linked to dislocation or changes of the temporomandibular joint (TMJ) disc. Magnetic resonance imaging (MRI) is the gold standard for TMJ imaging but standard clinical sequences do not deliver a sufficient resolution and contrast for the creation of detailed meshes of the TMJ disc. Additionally, bony structures cannot be captured appropriately using standard MRI sequences due to their low signal intensity. The objective of this study was to enable researchers to create high resolution representations of all structures of the TMJ and consequently investigate morphological as well as positional changes of the masticatory system. To create meshes of the bony structures, a single computed tomography (CT) scan was acquired. In addition, a high‐resolution MRI sequence was produced, which is used to collect the thickness and position change of the disc for various static postures using bite blocks. Changes in thickness of the TMJ disc as well as disc translation were measured. The newly developed workflow successfully allows researchers to create high resolution models of all structures of the TMJ for various static positions, enabling the investigation of TMJ disc translation and deformation. Discs were thinnest in the lateral part and moved mainly anteriorly and slightly medially. The procedure offers the most comprehensive picture of disc positioning and thickness changes reported to date. The presented data can be used for the development of a biomechanical computer model of TMJ anatomy and to investigate dynamic and static loads on the components of the system, which could be useful for the prediction of TMD onset.     

Distraction osteogenesis for correction of post ankylosis mandibular deformities

Temporomandibular joint ankylosis, a debilitating disease mainly affecting children, is characterized by progressive restriction of mouth opening and maxilla-mandibular developmental deformities. Craniofacial distraction osteogenesis has been developed as a standard surgical strategy for rectification of craniofacial deformities. The purpose of this study was to assess mono-planar distraction devices for the correction of various mandibular asymmetries in patients with unilateral temporomandibular joint ankylosis who developed restricted mouth opening and mandibular retrognathia. All patients were treated using one-stage distraction osteogenesis followed by temporalis fascia interpositional arthroplasty under general anesthesia. A significant increase in mandibular ramus and base length was observed. Although an increase in anterior lower facial height was observed, it was not significant statistically. A decrease in posterior lower facial height and corpus was observed. Oblique distraction with angular osteotomy allowed lengthening of both the ramus and corpus, yielding satisfactory results and hence eliminating the need of secondary surgery. In conclusion, univector internal distractors are effective for correction of multi-planar mandibular deficiencies by optimizing its placement through meticulous planning.     

广东地区人群颞下颌关节解剖参数的三维分析

目的 对广东地区不同人群的下颌骨及髁突解剖参数进行三维分析。 方法 选取就诊于南方医科大学口腔医院的患者265名,利用CBCT分别测量男性和女性的髁突长度、髁突高度、下颌升支高度、下颌体高度以及下颌神经进入下颌升支的位置。 结果 所有患者髁突的平均长度（内极-外极）二维测量为19.2 mm、三维测量为20.3 mm,男性比女性长3.6 mm,两者之间无统计学差异。下颌骨高度、髁突高度和下颌升支高度分别为59.6 mm,22.8 mm和38.3 mm,其中下颌骨高度男性比女性长6.4 mm,两性之间有统计学差异。下颌升支的宽度、下颌小舌到升支前缘的距离和下颌小舌到升支后缘的距离分别为：29.4 mm,14.8 mm及14.6 mm,男女之间均无统计学差异。 结论 CBCT测量颞下颌关节有着更显著的准确性,本实验结果丰富了中国人群下颌骨解剖数据,有助于开发适合广东地区的人工颞下颌关节。 【关键词】 下颌骨; 髁突; CBCT; 人工颞下颌关节