Cephalometric Characteristics of TMD Patients based on RDC/TMD Axis I Diagnosis

Abstract

The aims of this study were to investigate whether the facial skeletal patterns previously reported to be related to temporomandibular disorder (TMD) in other studies could be consistently observed in the TMD patients diagnosed according to Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) Axis Ⅰ and evaluate its usability in the orthodontic clinics to examine the patients with TMD related symptoms. The clinical records and radiographs of female patients who visited the TMD and Orofacial Pain Clinic of Seoul National University Dental Hospital and were diagnosed as TMD were consecutively filed for this study. Patients were clinically examined and diagnosed according to the revised diagnostic algorithms of RDC/TMD Axis Ⅰ and the lateral cephalogram, panoramic orthopantomogram, temporomandibular joint (TMJ) orthopantomogram, and transcranial radiograph of each patient were taken and digitalized. The data of patients who were under 18 years of age or had any systemic disease, trauma history involving the TMJ, or skeletal deformity at the time of the first examination were excluded. The remaining data of 96 female patients were finally analyzed. The obtained results were as follows: 1. There are no significant differences of cephalometric measurements between RDC Ⅰ (muscle disorders) diagnostic groups. 2. Only the articular angle of the RDC group Ⅱc (disk displacement without reduction without limited opening) patients was larger than patients of the no diagnosis of RDC Ⅱ group (disk displacement). 3. Larger articular angle and smaller facial height ratio were observed in RDC Ⅲc group (osteoarthrosis) compared to Ⅲa group (arthralgia). Larger articular angle, larger Bjork sum, smaller posterior facial height, and smaller facial height ratio were observed in RDC group Ⅲc compared to no diagnosis of RDC Ⅲ group (arthralgia, arthritis, and arthrosis). 4. According to the results of cephalometric analysis in simplified RDC groups, smaller overjet was observed in muscle disorders (MD) group. Facial height ratio and IMPA were smaller and articular angle was larger in disk displacements (DD) group than in no diagnosis of DD group. In arthrosis (AR) group, posterior facial height, and facial height ratio were smaller, and articular angle, gonial angle, facial convexity, FMA, Bjork sum, and ANB were larger than in no diagnosis of AR group. In joint pain (JP) group, only posterior facial height was smaller than no diagnosis of JP group. In conclusion, Facial morphologic patterns showing posterior-rotated mandible and lower posterior facial height is related to RDC group Ⅱ and Ⅲ diagnosis of the TMJ in female TMD patients. RDC/TMD Axis Ⅰ diagnosis can provide a good clinical diagnostic tool for the standardized examination of the TMJ in orthodontic clinics.