Finite Elemental Analysis of the displaced disc in TMJ.

颞下颌关节内紊乱是指关节盘相对于髁突和关节隆起的错位。随着关节造影术的发展，以及随后的TMJ关节断层摄影术的发展，已经确定关节盘前移位与关节咔嗒声和锁定有关。此后，人们利用关节造影技术进行了大量研究，以建立真实的椎间盘位置和形态图像，并将下颌闭合位椎间盘变形描述为反向双凹、双平面或双凸。然而，在最大颌开位置的椎间盘形态尚未报道。目前，磁共振成像（MRI）可以很容易地显示颞下颌关节内紊乱患者的关节盘位置。但MRI不能显示椎间盘形态。本研究的目的是制作颞下颌关节盘永久性移位的三维图像，以研究在下颌打开位置的盘的配置。马特里亚 ...更多信息 LS和方法：对100例颞下颌关节盘永久性移位患者进行了116次最大张口位关节断层扫描。一个铅标记的参考点被放在电影盒，其中涉及五个电影。在数字化之前，在透明纸上描绘每个胶片的以下结构的参考点和轮廓：外髁管、关节窝、关节隆起、上室中染料的下缘、下室中染料的上级缘和髁。随后，使用平板光标对关节结构的参考点和轮廓进行数字化。三维重建由软件包COSMOZONE-2S（Nikon Co.）进行。上室中染料的下缘（蓝色）和下室中染料的上缘（橙子）分别表示椎间盘的上缘和下缘。所有评估均由同一名观察员进行。结果：所有关节在最大张口位时，关节盘形态均发生变形。可识别出四种类型的椎间盘畸形：1）折叠型椎间盘构型，2）扭曲型椎间盘构型，3）压缩型椎间盘构型，4）组合型椎间盘构型讨论：该结果可能提示我们为什么一些减少型椎间盘移位会转变为永久性椎间盘移位。关节盘三维图像的应用可以提高传统关节断层摄影的诊断价值，而不会给患者带来额外的风险，并可能为颞下颌关节内紊乱患者的复杂关节盘畸形提供新的见解。少

Internal derangement of the temporomandibular joint(TMJ) means a malposition of the articular disc relative to the condyle and articular eminence. With the development of arthrography and,subsequently ,arthrotomography of the TMJ, it has been established that anterior disc displacement is related to joint clicking and locking. Since then, a lot of researches have been done using arthrographic technique to establish an actual image of disc position and configuration.Disc deformation at the jaw closing position has been described as reversed biconcave, biplanar, or biconvex. Nevertheless, Disc configuration at the maximal jaw opening position has not yet been reported. Now, magnetic resonance imaging(MRI) has easily revealed disc position in the patients with internal derangement of TMJ. But MRI can not reveal disc configuration. The aim of this study was to produce 3-dimensional images of permanent displaced disc of TMJ for study of disc configuration at the jaw opening position. Matria … More ls and methods: 116 simultaneous multisectional arthrotomograms at the maximal jaw opening position were taken from 100 patients with permanent disc displacement of TMJ. A leaden marker for a reference point was put on the film cassette which involved five films. Prior to digitizing, the reference point and the contours of the following structures of each film were traced on transparent paper: external auditorycanal, glenoid fossa, articular eminence, the inferior border of the dye in the upper compartment, the superior border of the dye in the lower compartment, and condyle. Subsequently, the reference point and contours of the joint structures were digitized with the tablet cursor. Three-dimensional reconstruction was performed by the software package COSMOZONE -2S(Nikon Co.). The inferior border of the dye in the upper compartment(blue) and the superiorborder of the dye in the lower compartment(orange) means the upper and lowerborder of disc, respectively. All assessments were performed by the sameobserver. Result:On all of the joints, disc configuration was deformed at the maximal jaw opening position. Four types of disc deformity were discerned:1) folding disc configuration,2) twisted disc configuration , 3) compressed disc configuration, 4) combination disc configuration Discussion: This results may give us a hint about why some reducing disc displacement change in to permanent disc displacement. The use of three-dimensional disc images may improve the diagnostic value of conventional arthrotomogram at no additional risk to the patients and may provide new insights into the complex deformities of disc in the patients with internal derangement of TMJ. Less