Objective To explore the effect of modified oral hygiene nursing on tooth surface roughness and smile confidence in patients after ffxed orthodontic treatment. Methods A total of 102 patients who underwent ffxed orthodontic treatment at the College of Stomatology, Anhui Medical University from July 2023 to June 2025 were selected, and they were divided into the control group and the experimental group by the random number table method, with 51 patients in each group. The control group received conventional oral hygiene nursing, and the experimental group received modiffed oral hygiene nursing. The tooth surface roughness, smile conffdence, oral plaque index and adverse event rate were compared between the two groups. Results The tooth surface roughness of the experimental group at 4 and 8 weeks after intervention was better than that of the control group (P<0.05). The smile conffdence score of the experimental group at 8 weeks after intervention was better than that of the control group (P<0.05). The oral plaque index of the experimental group at 8 weeks after intervention was better than that of the control group (P<0.05). The incidence of adverse events in the experimental group (7.84%) was lower than that in the control group (23.53%) (P<0.05). Conclusion The application of modiffed oral hygiene nursing in patients after ffxed orthodontic treatment can effectively reduce tooth surface roughness, improve smile conffdence, decrease oral plaque index, and reduce the incidence of related adverse events.