Long-term Evaluation after Splint Therapy of Anterior Disk Displacement without Reduction of the TMJ

Objectives: In this prospective investigation the long term effect of splint therapy on patients suffering from ADD without reduction was evaluated. Methods: 65 patients suffering from unilateral or bilat-eral ADD without reduction, as proven by MR imaging, were randomly treated with either a centric or a distraction splint, that was worn at least 18hrs/day. Follow-up evaluation was to be conducted after 1, 3, 6, 9, 12 months and then once a year, for consecutive 5 years after splint insertion. Primary outcome variables were the maximum mouth opening, the patients' subjective rating (0-10) of pain and functional limitation using the Visual Analogue Scale (VAS). Furthermore risk factors were identified by use of binary logistic regression. Results: The Mann-Whitney-Test showed no difference between the treatment with a distraction and a centric splint. Compared to the initial values (median 35 mm), the mouth opening increased significantly (Wilcoxon signed rank test) within the first year (median 43 mm). The values after 2, 3, 4 and 5 reached at least the values of the one year follow up examination (median at least 44 mm). The assessment of pain on chewing showed a significant decrease from median 5.5 to below 1 within the first year, without exceeding a median of 1 in the follow up examinations. Logistic regression identified high initial VAS-ratings, long standing complaint, extra cranial pain, erosions and osteophytes in MRI and bilateral ADD without reduction as predictors for negative outcome. Conclusions: Splint therapy is effective on patients with ADD (without reduction) in consistently reducing pain and functional limitation on long term observation.