EFFECT OF ORTHODONTIC-STRAIGHT JAW COMBINED THERAPY OF SKELETAL ANGLE CLASS III MALOCCLUSION ON TEMPOROMANDIBULAR JOINT MORPHOLOGY AND MANDIBULAR MOVEMENT FUNCTION

Xin Li^#, Jieyun Zhang^#, Shishu Fang, Zuolin Jin^*

State Key Laboratory of Military Stomatology and National Clinical Research Center for Oral Diseases and Shaanxi Clinical Research

Center for Oral Diseases, Department of Orthodontics, School of Stomatology, the Fourth Military Medical University, Xi'an, 710032,

Shanxi Province, China

Objective: To study the effect of orthodontic-straight jaw combined therapy of skeletal Angle class III malocclusion on temporomandibular joint (TMJ) morphology and mandibular movement function. 

Methods: 38 patients with skeletal Angle class III malocclusion admitted to our hospital from January 2019 to December 2020 were selected as the research object and given the orthodontic treatment combined with bilateral sagittal split ramus osteotomy (BSSRO) for straight jaw to compare their indexes of TMJ morphology and mandibular movement function before and after treatment. 

Results: One month after surgery, various joint space indexes were significantly different compared with those before surgery; except for the left S1, there were statistical differences among the remaining indexes after correction when comparing with those at postsurgical one month, but no obvious difference was obtained if comparing with those before surgery; at 1 month after surgery, patients’ right P01 and P02 were significantly different from those before surgery, but were recovered to the presurgical status after correction; the left P02 at postsurgical 1 month was significantly higher than that before surgery and after correction; 5 of 11 patients with clicking of joint and 5 of 6 patients with abnormal mouth opening were healed, with statistically significant differences before and after treatment; in addition, no obvious change was seen in Angle I, Angle II and Height. 

Conclusion: Applying the orthodontic-straight jaw combined therapy in the treatment of skeletal Angle class III malocclusion does not cause change in the glenoid fossa morphology or TMJ disorder related diseases, also, as some patients with abnormal mouth opening and clicking of joint were healed after treatment, it has certain efficacy to treat TMJ disorders.