A quantitative analysis of splint therapy of displaced temporomandibular joint disc

The effects of the Michigan splint on the change in disc displacement (DD) as well as the position of the condyles were determined by metrical analysis using magnetic resonance imaging (MRI).

Twenty-five patients with clinical DD symptoms were treated by means of the Michigan splint, and an assessment of the effects of the splint was conducted or verified by MRI before and during the period of therapy, 5 months follow-up. The positions of the condyles and the disc were calculated from the MRI in the parasagittal plane.

There were no changes in the positions of the disc and condyles in the physiological joints of the patients (n=23) prior to and during the time the splint was in place (p>0.05). The splint achieved a DD decrease (p<0.05), and pain was eliminated in 69.2% of the DD joints with reduction (n=13). As far as the DD joints without reduction (n=13) are concerned, pain was eliminated in 74.9% of the joints, that is, without any change in the positions of the disc and condyles (p>0.05).

The evaluation of the Michigan splint therapy showed that it has no influence in the repositioning of the DD joints without reduction, but the DD joints with reduction have a limited positive effect. In both forms of these displacements, conditions for the elimination of the clinical symptoms are created.