Risk factors of temporomandibular joint anterior disc displacement associated with dental malocclusion: a cross-sectional study

Abstract Objective This study aimed to investigate the risk factors associated with temporomandibular joint (TMJ) anterior disc displacement (ADD) in relation to dental malocclusion. Methods In this cross-sectional study, a clinical examination was conducted on patients aged 11–35 years who visited the TMJ and Orthodontic Clinic at a hospital. Magnetic resonance imaging (MRI) of the TMJ was performed to diagnose both ADD and condylar resorption (CR). Occlusal measurements were obtained and analyzed using 3D scanning models. Results A total of 552 patients underwent TMJ MRI examination and dental occlusion scanning. The presence of mandibular midline shift > 2 mm and posterior crossbite were found to be associated with unilateral ADD (OR > 1, p < 0.05). Additionally, apart from these malocclusions, anterior open bite > 3 mm showed a strong correlation with unilateral ADD accompanied by CR (OR > 1, p < 0.05). Furthermore, overbite > 4 mm and posterior crossbite were associated with bilateral ADD (OR > 1, p < 0.05). In addition to these malocclusions, Angle Class II malocclusion, overjet > 5 mm, and anterior open bite > 3 mm were strongly correlated with bilateral ADD accompanied by CR (OR > 1, p < 0.05). Conclusions In conclusion, our study highlights the significance of occlusal characteristics in relation to TMJ health. Specific malocclusions, such as mandibular midline shift > 2 mm, posterior crossbite, and overbite > 4 mm appear to be associated with the presence of TMJ ADD. Angle Class II malocclusion, anterior open bite and overjet > 5 mm seem to be associated with progression of ADD. These findings emphasize the crucial importance of early detection and management of malocclusions to prevent or minimize the development of TMJ ADD and associated complications.