Lateral cephalometric characteristics of malocclusion patients with temporomandibular joint disorder symptoms

Introduction: There is much controversy about the relationship between temporomandibular joint (TMJ) disorders and the skeletal structures of the lower face. It is not clear whether the disharmony of the facial skeletal structure is caused by the TMJ disorder or vice versa. The aim of this study was to determine the relationship between craniofacial skeletal structures and TMJ disorders by using lateral cephalogram measurements to examine the characteristics of the facial profile of patients with TMJ disorders. Methods: Of 111 patients over 18 years of age from the Department of Orthodontics, Dental Hospital, Yonsei University, those showing symptoms of TMJ disorders were chosen as the experimental group (56 patients), and patients without TMJ disorders were chosen as the control group (55 patients). A lateral cephalogram of each subject was taken and traced to confirm the significance of the craniofacial measurements between the experimental group and the control group of Class I (mean ANB angle, 2.89°), Class II (mean ANB angle, 6.32°), Class III (mean ANB angle, -2.02°) patients, who were grouped according to ANB-angle difference. Results: Each experimental subject with a TMJ disorder had a hyperdivergent facial profile, more lingual tilting of the maxillary incisors, and a steeper inclined occlusal plane. Conclusions: There was a significant correlation between the structure of the lower face and the temporomandibular disorder.