Objective To analyze the cosmetic effect of orthodontic treatment before repair in patients with dentition defect and malocclusion. Methods A total of 86 patients with dentition defect and malocclusion admitted from February 2019 to October 2021 were randomly divided into control group and observation group, with 43 patients in each group. The control group was treated with conventional repair, and the observation group was treated with orthodontic treatment before repair. The clinical efficacy, periodontal index, tooth recovery and function, aesthetics and comfort scores were compared between the two groups. Results The total effective rate of treatment in the observation group was 95.35%, which was higher than 74.42% in the control group (P<0.05). After treatment, the probing depth, bleeding index and plaque index in the observation group were lower than those in the control group (P<0.05). The rate of good occlusion of teeth, the rate of neat arrangement of teeth and the rate of good coverage of anterior teeth in the observation group were higher than those in the control group (P<0.05). The scores of language function, chewing function, fixation function, aesthetics and comfort satisfaction in the observation group were higher than those in the control group (P<0.05). Conclusion Orthodontic treatment before repair is effective for patients with dentition defect and malocclusion, which can effectively improve tooth function, help restore tooth occlusion, and meet the needs of patients for tooth aesthetics. It is worthy of clinical application.