[Prevalence of temporomandibular joint disc displacement in patients malocclusion].

Purpose: To investigate the prevalence characteristics of temporomandibular joint disc displacement in patients with malocclusion and influencing factors of disc displacement, and to provide reference for orthodontic treatment.

Methods: A total of 1 157 consecutive orthodontic cases admitted to the Department of Orthodontics at Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from January 2012 to December 2021 were selected retrospectively. Based on temporomandibular joint MRI, the prevalence of disc displacement in orthodontic cases was investigated. The influencical factors of gender, age and skeletal classification on disc displacement was analyzed. SPSS 25.0 software package was used for data analysis.

Results: Among 1 157 orthodontic cases, there were 672 cases(58.08%) of disc displacement, and 334 cases(28.87%) had anterior disc displacement. The prevalence of disc displacement in female was significantly higher than that in male. The prevalence of disc displacement in skeletal Class Ⅱ malocclusion was significantly higher than that in skeletal Class Ⅲ malocclusion. In orthodontic cases aged between 10 and 18, the prevalence of disc displacement increased with age.

Conclusions: There is a high proportion of abnormal articular disc position in patients with malocclusion. Age, gender(female) and skeletal Class Ⅱ malocclusion have higher correlation with temporomandibular joint disc displacement.