Prediction of the outcome of treatment of temporomandibular joint disorders using a mandibular repositioning splint according to MRI data with functional tests

Abstract

Internal temporomandibular joint disorders account for approximately 80% of symptomatic temporomandibular disorders. EULAR guidelines for the treatment of temporomandibular joint disorders recommend magnetic resonance imaging for both diagnosis and subsequent monitoring of treatment outcomes. However, there is no sufficient data on advisability of magnetic resonance imaging during treatment stages, including when using a mandibular repositioning splint. The aim of the study is to substantiate the value of MRI data in patients with temporomandibular joint disorders for predicting the outcome of treatment using a mandibular repositioning splint.
Materials and methods.
Three groups comparative study. The study included 120 patients with internal disorders of the temporomandibular joint. The median age of the patients was 37 [25—54] years. Treatment was carried out using a repositioning splint developed by us in three groups of patients formed in accordance with the severity of internal disorders according to the classification of C.H. Wilkes (stage 2, 3, 4). Magnetic resonance imaging was performed before and after treatment. The following visualization parameters were considered: synovial proliferation, osteitis, synovitis, bone erosions, destruction of articular surfaces, changes in disc position, signs of arthrosis.
Results.
In patients with internal TMJ disorders, the most frequently diagnosed conditions were Costen’s syndrome (73%), clicking jaw (78%), and arthrosis (53%). Bruxism (36%) and recurrent dislocation or subluxation (12%) were less common. Disc displacement was detected in 70% of cases. Articular surface changes were diagnosed in 60% of patients. Articular disc shape changes were observed in 41% of cases with the mouth open and in 27% with the mouth closed. In the subgroup with disc deformation, disc displacement with the mouth closed was observed more often than in the subgroup with an unchanged disc — 86% versus 67% (p≤0.01). A statistically significant lack of regression after treatment was established in the presence of disc displacement without reposition (p=0.003), changes in the ligaments of the bilaminar zone (p=0.001) and signs of arthrosis (p=0.001).
Conclusions.
The most informative assessments include the disc, its morphological features, and position in the closed and open mouth, as well as degenerative changes in the joint structures. The treatment algorithm using our repositioning splint caused in clinical recovery or significant improvement in 84% of patients with internal TMJ disorders, as confirmed by MRI. Despite possible regression of clinical manifestations of TMJ disorders, morphological changes may persist in repeat MRI studies in patients with Wilkes stage 3—4.