Background Degenerative joint disease (DJD) can be associated with disc displacement (DD) in temporomandibular disorder (TMD) patients. However, the relationship between different types of DDs and DJD remains unclear. Objectives To investigate the odds ratios of different types of sagittal and coronal DDs confirmed by magnetic resonance imaging (MRI) and DJD confirmed by cone‐beam computed tomography (CBCT) in TMD patients. Methods Radiographic data from 69 males and 232 females were collected for analysis. CBCT was used to diagnose DJD, with criteria including erosion, osteophytes, generalised sclerosis and cysts in the joint. Eight types of DDs were evaluated by sagittal and coronal MRIs: NA, no abnormality; SW, sideways; ADDR, anterior with reduction; ADDR+SW; ADDNR, anterior without reduction; ADDNR + SW; single SW; PDD, posterior; PDD + SW. The odds ratios of DJD in joints with different types of DDs were determined after joint correlation, age and gender adjustment. Results Compared with NA, the odds ratio of DJD in ADDR was 2.397 (95% CI [confidence interval]: 1.070–5.368), ADDR + SW was 4.808 (95% CI: 1.709–3.528), ADDNR was 29.982 (95% CI: 15.512–57.950) and ADDNR + SW was 25.974 (95% CI: 12.743–52.945). Erosion was significantly increased in ADDR, ADDR + SW, ADDNR and ADDNR + SW; osteophytes were significantly increased in ADDR + SW, ADDNR and ADDNR + SW; and generalised sclerosis and cysts were significantly increased in ADDNR and ADDNR + SW. There were no significant associations between single SW, PDD, PDD + SW and the DJD. Conclusions ADDR, ADDR+SW, ADDNR and ADDNR+SW were associated with DJD. ADDNR had a significantly higher prevalence of DJD than ADDR. There were no significant relationships between single SW, PDD, PDD + SW and the DJD.

Disc displacement (DD) appears in the majority of temporomandibular disorder (TMD) patients. The correlation between craniofacial morphology and different disc positions has been underlined, while the craniofacial morphological differences based on sex and sagittal skeletal pattern stratification have been insufficiently studied. In this study, 304 patients with TMD complaints were included and classified into normal position, disc displacement with reduction (DDwR) and disc displacement without reduction (DDwoR) groups according to magnetic resonance imaging. A total of 24 cephalometric measurements, covering the cranial base, vertical relationship, sagittal relationship, mandible position and morphology, and dental relationship, were assessed using lateral cephalograms. A stratified analysis was performed based on the sex and sagittal skeletal pattern. Overall, DD patients had distinctive craniofacial morphological features. The posterior cranial base length and mandibular arc angle were statistically different only in females, while the Y-axis angle, occlusal plane angle and sella nasion point A angle (SNA) might be unique features in males. Skeletal class II had the most statistically different measurements compared to the others. Differences in the Frankfort mandibular incisor angle (FMIA) and saddle angle were especially displayed in skeletal class III patients. The sex and skeletal sagittal pattern could affect the morphological differences in TMD patients with different disc positions.

Purpose. To evaluate head and cervical posture in individuals with or without temporomandibular disorders (TMDs) and to assess the correlations between pain, severity of symptoms, and posture. Methods. A total of 384 patients (129 males and 255 females) was included. The Fonseca Anamnestic Index (FAI) was used to assess the severity and prevalence of TMD and the presence of temporomandibular joint (TMJ) pain. Patients were divided into three groups: the TMD-free group, TMD without TMJ pain group, and TMD with TMJ pain group. Subsequently, the patients with TMJ pain were further divided into mild TMD and moderate/severe TMD groups. Nine parameters were traced on cephalograms to characterize the head and cervical posture. Results. TMD patients with TMJ pain showed increased forward head posture (FHP) than patients without TMJ pain and TMD-free subjects. No significant difference was observed between the TMD patients without TMJ pain and TMD-free subjects. In the TMD patients with the TMJ pain group, the moderate/severe TMD patients demonstrated increased FHP compared to mild TMD patients. TMD patients with joint pain had greater CVT/RL (B = 3.099), OPT/RL (B = 2.117), and NSL/C2’ (B = 4.646) than the patients without joint pain after adjusting for confounding variables ( P < 0.05 ). Conclusion. TMD patients with TMJ pain showed increased FHP compared to other groups, and FHP became more significant as TMD severity increased in male patients, indicating the FHP might play an important role in the development of TMJ pain. In the clinical assessment of TMD, the patients’ abnormal head and cervical posture might be considered.

ObjectiveThis study aims to develop a new category scheme for the profile morphology of temporomandibular disorders (TMDs) based on lateral cephalometric morphology.MethodsFive hundred and one adult patients (91 males and 410 females) with TMD were enrolled in this study. Cluster tendency analysis, principal component analysis and cluster analysis were performed using 36 lateral cephalometric measurements. Classification and regression tree (CART) algorithm was used to construct a binary decision tree based on the clustering results.ResultsTwelve principal components were discovered in the TMD patients and were responsible for 91.2% of the variability. Cluster tendency of cephalometric data from TMD patients were confirmed and three subgroups were revealed by cluster analysis: (a) cluster 1: skeletal class I malocclusion; (b) cluster 2: skeletal class I malocclusion with increased facial height; (c) cluster 3: skeletal class II malocclusion with clockwise rotation of the mandible. Besides, CART model was built and the eight key morphological indicators from the decision tree model were convenient for clinical application, with the prediction accuracy up to 85.4%.ConclusionOur study proposed a novel category system for the profile morphology of TMDs with three subgroups according to the cephalometric morphology, which may supplement the morphological understanding of TMD and benefit the management of the categorical treatment of TMD.