The changes in temporomandibular joint disc position and configuration in early orthognathic treatment: a magnetic resonance imaging evaluation

This study aimed to examine the effects of chin cup therapy on the temporomandibular joint (TMJ) disc position and configuration with magnetic resonance imaging (MRI). Twenty-five individuals ranging in age from 5 to 11 years were evaluated. The treatment group consisted of 15 subjects (10 females and five males) with prognathic facial structures, while the control group comprised 10 subjects (six females and four males) with an orthognathic facial structure. The magnitude of the chin cup force applied to the mandible was 600 g. Unilateral MRIs of the TMJ were taken in all subjects at the beginning and end of the study. No statistically significant changes in the TMJ disc position and configuration during the treatment and control periods could be seen. The values of the alpha angle measurements were found to be different in the treatment and control groups at the beginning (166.23 +/- 2.15 and 172 +/- 1.97, respectively), and end of the treatment and control periods (160.00 +/- 2.16 and 172.00 +/- 2.68). These findings show that if the chin cup appliance is used at an early age and with appropriate forces, there will be no adverse effect on the TMJ disc position and configuration.