Objective To analyze the effect of preventive treatment of complications on orthodontic patients treated with nonremovable orthodontic appliances and its effect on enamel demineralization. Methods A total of 83 patients who underwent orthodontic treatment with non-removable orthodontic appliances in Xuyi County People's Hospital from October 2021 to June 2024 were selected and divided into conventional group (n =41) and observation group (n =42) according to the random number table method. The conventional group received routine treatment, and the observation group received preventive treatment of complications on the basis of the conventional group. The enamel demineralization, enamel debris index, oral function and treatment satisfaction were compared between the two groups. Results After treatment, the enamel demineralization and enamel debris index in the observation group were lower than those in the conventional group, and the difference was statistically significant (P <0.05). The levels of ME, MF and SO in the observation group were higher than those in the conventional group, and the differences were statistically significant (P <0.05). The treatment satisfaction of the observation group (100.00%) was higher than that of the conventional group (90.24%) , and the difference was statistically significant (P <0.05). Conclusion Preventive treatment of complications in orthodontic patients treated with non-removable appliances can effectively improve enamel demineralization, and improve the oral function of patients, with better therapeutic effect.