Factors Influencing the Duration of Occlusal Appliance Treatment for Patients with Temporomandibular Joint Internal Derangement

Purpose: The purpose of this study is to determine factors influencing the duration of occlusal appliance (OA) treatment for patients with temporomandibular joint (TMJ) internal derangement. Methods: Ninety patients were included for this study, who satisfied the following including criteria: (i) those who were diagnosed as disc displacement of TMJ by taking magnetic resonance imaging (MRI) and (ii) those who were finished OA treatment. The subjects were classified into three groups according to the period of OA treatment: (i) early response group (<6 months), (ii) moderate response group (6 months-1 year), and (iii) delayed response group (>1 year). Demographic data, data from chief complaints and past history of temporomandibular disorder, data from clinical examination and diagnostic imaging including panoramic view and TMJ MRI were compared among groups. One-way ANOVA and chi-square analysis were used to test statistical significance. Results: There were no significant differences in demographic data, data from chief complaints and TMJ imaging. However, only the prevalence of oral parafunctional habits including bruxism, clenching, and unilateral chewing showed significant differences among groups. Conclusions: Oral parafunctional habits could be factors to influence the duration of OA treatment in the patients with TMJ internal derangement.