Jacobs Journal of Anatomy and Physiology

The Incidence of Temporomandibular Joint Structural Abnormalities in Orthodontic Pretreatment Patients

* Bing Fang
Department Of Oral And Cranio Maxillofacial, Shanghai Jiao Tong University School Of Medicine, Shanghai, China

*Corresponding Author:
Bing Fang
Department Of Oral And Cranio Maxillofacial, Shanghai Jiao Tong University School Of Medicine, Shanghai, China

Published on: 2017-03-21


Objectives Structural variations of the temporomandibular joint (TMJ) will affect orthodontic treatment. So we analyzed common issues of TMJ structure among patients with different types of malocclusions. Methods 312 orthodontic pretreatment patients were randomly selected as subjects. Conventional anteroposterior and lateral cephalometric radiographs, panoramic radiographs, TMJ magnetic resonance images were obtained and the subjects’ TMJ structures were assessed. Results Among all the 312 pretreatment patients, 206 patients (66.03%) presented with TMJ structural variations, and for male patient Class I patients, 72.97% of skeletal Class II patients, 64.04% of skeletal Class III patients. Horizontal analysis indicated that a varied TMJ structure was present in 78.18% of patients with mandibular deviation to the left, 60.87% of patients without mandibular deviation, 85.19% of patients with mandibular deviation to the right. Vertical analysis revealed that a varied TMJ structure was present in 77.12% of high-angle patients, 56.88% of average-angle patients, 70.59% of low-angle patients. Conclusions TMJ structural variations were present in a high proportion of orthodontic pretreatment patients. Although most of these patients did not present clinical symptoms, orthodontists should pay more attention to such potential risk.


Orthodontic, Temporomandibular Joint, Malocclusion, Structural Variations


Temporomandibular joint (TMJ) disorders constitute a common disease of the oral cavity that is encountered in clinical contexts. Moreover, the normality of the TMJ structure is closely related to both occlusal function and orthodontic treatment. This topic has attracted increasing attention from dentists, including orthodontists. The normality of the TMJ structure not only affects the development of orthodontic treatment plans but also plays an important role in determining the stability of orthodontic effects and can even influence decisions regarding whether to begin orthodontic treatment. However, few domestic or international studies have examined the epidemiology of this disease, especially among the population of orthodontic pretreatment patients. Therefore, in this study, an epidemiological analysis of TMJ structural variations in orthodontic pretreatment patients was performed from multiple perspectives, thereby facilitating an exploration of the overall prevalence of these structural variations in the orthodontic patient population and in different gender groups. In addition, we also evaluated the correlations between TMJ structural variations and malocclusions from the sagittal, horizontal, and vertical directions, with the goal of providing reference data for developing orthodontic treatment programs for clinically treating patients with varied TMJ structures.