Influence of an Occlusal Splint on TMJ Position

Objectives:The purpose of this study was to evaluate the movement of condyle and articular disc position with or without an occlusal splint in volunteers and patients with temporomandibular disorder. Methods: Seventy joints of 18 volunteers and 17 patients with temporomandibular disorder were enrolled in this study. The movements of condyle and articular disc were evaluated using magnetic resonance imaging with or without an occlusal splint. Statistical analyses were performed using the t-test, analysis of variance and Bonferroni's multiple comparison tests when a significant difference was observed. Results: Statistical analyses demonstrated that both the volunteer and patient groups showed a significant anteroinferior and rotated movement of the condyle by using splint. The articular disc of the volunteers showed significant forward displacement, while the patients did not. When patients and volunteers were divided into three groups such as bilateral normal articular disc position group, unilateral anterior disc displacement group, and bilateral anterior disc displacement group, anteroposterior movement of the condyle and articular disc with the splint was significantly less in the unilateral anterior disc displacement group. The condyle and articular disc movements showed a stronger correlation in normal articular disc position group than another two groups. Conclusion: The condyle could be moved anteroinferiorly and rotated in the opening direction by splint, but unilateral anterior disc displacement group showed different movements from the volunteers. This suggests that patients with unilateral anterior disc displacement may be less likely to benefit from splint therapy.