Quantitative study on the degree of anterior disc displacement and its association with temporomandibular joint pain

    ZHAO Erª²Jun, JIAO Guoª²Liang, WANG Yongª²Hai, ZHU Yuª²Fen, DU Yuª²Ping

    1Department of Stomatology, 2Central Laboratory, Bethune International Peace Hospital, Shijiazhuang 050082, China

    ¡¾Abstract¡¿ AIM: To quantitatively evaluate the degree of anterior disc displacement and its association with temporomandibular joint pain. METHODS: Oblique sagittal T1 weighted MR imaging at closed mouth was obtained from 88 joints of 44 patients who complained of unilateral TMJ pain. On MRI view, a straight line AE was drawn through the lowest point of articular eminence (A) and the highest point of external auditory meatus (E), and then the perpendicular lines were dropped from condylar head (C) and the most poterior band of the disc (D) to AE on which the cross points were marked as C¡ä and D¡ä. The distance AD¡ä and C¡äD¡ä reflect the anteriorª²posterior position of the disc in the glenoid fossa. The painful joints were divided into mild, moderate and severe pain groups according to the VAS score. The painª²free joints served as control. RESULTS£º The distance AD¡ä and C¡äD¡ä in mild, moderate, severe and painª²free groups were respectively (8.7¡À2.8) mm and (1.2¡À3.2) mm, (6.4¡À2.5) mm and (4.1¡À2.9) mm, (7.5¡À2.8) mm and (2.2¡À3.4) mm, and (10.9¡À1.7) mm and (-0.9¡À1.7) mm. Significant difference between all painful groups and painª²free group was found. But no significant difference was found between painful groups, except for mild and moderate pain groups. CONCLUSION£º Temporomandibular joint pain is associated with anterior disc displacement. But the degree of anterior displacement of the disc has no influence on pain levels, which indicates that the pain level could not reflect the condition of disc displacement. ......