Chen Yunn-Jy, Gallo Luigi M, Palla Sandro
Clinic for Masticatory Disorders & Complete Dentures, Center for Dental and Oral Medicine, Maxillofacial Surgery, University of Zurich, Plattenstrasse 11, CH-8028 Zurich, Switzerland.
J Orofac Pain. 2002 Winter;16(1):29-38.
Temporomandibular joint (TMJ) discs displaced simultaneously, dorsoventrally, and mediolaterally are assumed to be rotated. However, a pilot study performed with individualized oblique-axial scans on supposedly rotated discs did not show disc rotation consistently. The aim of this study was the quantitative evaluation of disc rotation on a larger sample size, assessing the mediolateral disc geometry and position by the use of a reference system determined by the condylar long axis.
Eighty-five TMJs from 50 subjects were analyzed. One series of sagittal and 1 of 14 individualized oblique-axial magnetic resonance (MR) scans were taken for each joint. The dorsoventral disc position was diagnosed by means of the sagittal scans. The mediolateral disc width and position were then measured on every oblique-axial scan. The width and midline was computed for each disc and its deviation from the perpendicular to the condylar long axis was calculated. Finally, a statistical analysis was performed to study whether the disc width and the direction of the disc midline varied between discs normally positioned and anteriorly displaced.
The disc width varied significantly more within the anteriorly displaced discs than within the normal ones. The midline of the anteriorly displaced discs deviated more from the perpendicular to the condylar long axis than that of normally positioned discs and was mostly in a lateral direction. The disc midline also deviated more in the ventral than in the dorsal part of the disc.
Most anteriorly displaced discs were laterally displaced and showed a larger width variation than normally positioned discs. This fact seems to indicate disc deformation.
颞下颌关节（TMJ）盘同时发生背腹向和内外侧移位时被认为发生了旋转。然而，一项针对疑似旋转盘进行个体化斜轴扫描的初步研究并未始终显示出盘的旋转。本研究的目的是在更大样本量上对盘旋转进行定量评估，通过使用由髁突长轴确定的参考系统来评估盘的内外侧几何形状和位置。
分析了来自50名受试者的85个颞下颌关节。每个关节进行了一系列矢状位扫描和14个个体化斜轴磁共振（MR）扫描中的1个。通过矢状位扫描诊断盘的背腹向位置。然后在每个斜轴扫描上测量盘的内外侧宽度和位置。计算每个盘的宽度和中线，并计算其与垂直于髁突长轴的偏差。最后，进行统计分析以研究正常位置盘和前移盘之间盘宽度和盘中线方向是否存在差异。
前移盘中盘宽度的变化明显大于正常盘中的变化。前移盘的中线比正常位置盘的中线更偏离垂直于髁突长轴的方向，且大多偏向外侧。盘中线在盘的腹侧部分比背侧部分偏离得更多。
大多数前移盘向外侧移位，并且与正常位置盘相比显示出更大的宽度变化。这一事实似乎表明盘发生了变形。
