de Leeuw R, Boering G, Stegenga B, de Bont L G
Department of Oral and Maxillofacial Surgery, University Hospital, Groningen, The Netherlands.
J Oral Maxillofac Surg. 1995 Mar;53(3):234-41; discussion 241-2. doi: 10.1016/0278-2391(95)90215-5.
This study evaluates disc position and configuration on magnetic resonance imaging (MRI) in temporomandibular joints (TMJs) with a long history of internal derangement.
Sagittal T1-weighted MRIs of 55 TMJs that were diagnosed with internal derangement approximately 30 years ago were made with the mouth closed and open, and the position and configuration of the articular disc were determined. For comparison, a control group consisting of 15 asymptomatic TMJs without clinical signs of internal derangement or of other TMJ disorders were studied in the same way.
Anterior disc position was found in 90% of the TMJs with a history of internal derangement. Reducing disc displacement was found in one third of these TMJs, whereas permanent displacement was found in two thirds. In four joints, no disc was discernible. In one of the joints of the control group, a permanent disc displacement was found; normal disc position was found in all other joints of the control group. A biconcave disc configuration, which was considered normal, was found only in TMJs with normal disc position or with reducing discs.
It was concluded that, after 30 years of displacement, the TMJ disc can be clearly identified on MRI in most cases. If the disc becomes permanently displaced, its configuration deviates from the normal biconcave configuration, and its anteroposterior length decreases. Convex and folded appearances of the disc are common in this situation. However, the disc usually maintains its biconcave configuration as long as it resumes its position on top of the condyle during mouth opening, even if this condition lasts for several decades.
本研究评估有长期颞下颌关节内紊乱病史的颞下颌关节（TMJ）在磁共振成像（MRI）上的盘位置和形态。
对约30年前被诊断为颞下颌关节内紊乱的55个颞下颌关节在闭口和开口时进行矢状面T1加权MRI检查，并确定关节盘的位置和形态。作为对照，对15个无颞下颌关节内紊乱或其他颞下颌关节疾病临床体征的无症状颞下颌关节组成的对照组采用相同方法进行研究。
有颞下颌关节内紊乱病史的颞下颌关节中，90%发现关节盘前移位。其中三分之一的颞下颌关节发现可复性盘移位，而三分之二发现不可复性盘移位。在四个关节中未发现关节盘。对照组的一个关节发现有不可复性盘移位；对照组的所有其他关节均发现关节盘位置正常。仅在关节盘位置正常或可复性关节盘的颞下颌关节中发现被认为正常的双凹形关节盘形态。
得出的结论是，移位30年后，大多数情况下在MRI上可清晰识别颞下颌关节盘。如果关节盘发生不可复性移位，其形态会偏离正常的双凹形，前后长度减小。在这种情况下，关节盘出现凸形和折叠状外观很常见。然而，只要在开口时关节盘能恢复到髁突上方的位置，即使这种情况持续数十年，关节盘通常仍保持其双凹形形态。
