Abstract: Objective To analyze the risk factors of temporomandibular disorder (TMD) in middle school students in some urban areas of Zhengzhou. Methods Totally 1 800 middle school students with TMD who were admitted to the hospital between August 2016 and August 2019 were selected as the observation group. Meanwhile, 1 800 healthy middle school students who completed routine physical examination during the same period were selected as the control group. The relationship between the possible risk factors and TMD in middle school students was analyzed. Results There were no statistically significant differences in the following items between the control group and observation group: the proportions of students often staying up late (44.44% vs.47.22%), with study pressure(58.06% vs.61.22%), chewing hard objects (51.94% vs.54.56%), and with history of maxillofacial injury(19.78% vs.21.94%)(P>0.05). The proportions of students with bruxism or tooth clinching, unilateral chewing and history of orthodontic treatment in the control group (36.22%, 51.78%, 20.00%) were significantly lower than those in the observation group (41.44%, 57.11%, 25.11%) (P<0.05). The self rating anxiety scale(SAS) scores and self rating depression scale(SDS) scores of the observation group were higher than those of the control group(P<0.05). Conclusion There are many risk factors for TMD, and junior high school students with unilateral chewing habits, history of orthodontic treatment, bruxism or tooth clinching, anxiety and depression symptoms are more prone to having TMD.

Key words: Temporomandibular disorder, Middle school students, Risk factors