Objective To evaluate the clinical effect of orthodontic treatment before repair in the treatment of dentition defect with malocclusion. Methods A total of 76 patients with dentition defect and malocclusion who were treated in our hospital from July 1, 2020 to June 30, 2023 were selected and divided into control group and study group by random number table method, with 38 patients in each group. The control group was not given orthodontic treatment before repair, and was directly repaired. The study group was given orthodontic treatment before repair, and then repaired. The clinical indicators, treatment effect, periodontal indicators, pain, masticatory function and adverse reactions were compared between the two groups. Results The clinical indexes of the observation group were better than those of the control group (P <0.05). The total effective rate of treatment in the observation group (92.11%) was higher than that in the control group (65.79%) (P <0.05). The indexes of CAL, PPD, tooth loosening and BOP in the observation group were better than those in the control group (P <0.05). The VAS score of the observation group was lower than that of the control group, and the masticatory function score was higher than that of the control group (P <0.05). The incidence of adverse reactions in the observation group (5.26%) was lower than that in the control group (21.05%) (P <0.05). Conclusion In the treatment of dentition defect with malocclusion, it is effective to provide patients with pre-repair orthodontic treatment, which can reduce the incidence of adverse reactions and improve the condition of teeth.