Objective To explore the application effect of invisible orthodontic treatment without brackets in patients with mild to moderate dental crowding. Methods Fifty patients with mild to moderate dental crowding admitted to our outpatient department from January to December 2022 were selected as the research subjects. They were randomly divided into an observation group and control group using a random number table method, with 25 patients in each group. The control group was treated with traditional fixed orthodontic methods, while the observation group was treated with invisible orthodontic treatment without brackets. The clinical treatment effect, canine width change and treatment satisfaction were compared between the two groups. Results The total effective rate of treatment in the observation group was 92.00 %, which was higher than 68.00 % in the control group (P <0.05); After treatment, the change of maxillary canine width in the observation group was better than that in the control group (P <0.05); but there was no significant difference in the change of mandibular canine width between the two groups (P >0.05); After treatment, the satisfaction scores of language function, masticatory efficiency, convenience, fixation function and aesthetic comfort in the observation group were higher than those in the control group (P <0.05). Conclusion Compared with the traditional fixed orthodontic method, the use of invisible orthodontic treatment without brackets has a better therapeutic effect, which can improve the width of the maxillary canine area, improve the patient's treatment satisfaction, and has high application value.