Abstract: Objective To evaluate the application value of passive self-ligating brackets in fixed orthodontic treatment by comparing the differences between passive self-ligating brackets and traditional brackets in non-extraction fixed orthodontic treatment. Methods Forty patients were selected from the existing cases, including 20 cases in Damon Q self-ligating bracket group and 20 cases in traditional bracket group. The changes of periodontal related index, the effect of arch expansion before and after treatment, the average course of treatment, the average number of visits, and the average time spent on chair-side operation of the doctor were compared between two groups. Results At 6 months (T6) and 12 months (T12) after adhesion, PLI and GI of patients in Damon Q self-ligating bracket group were significantly lower than those in the traditional bracket group, and the difference was statistically significant (P＜0.05). Compared with traditional bracket group, Damon Q self-ligating bracket group had obvious arch expansion effect, while the expansion effect of the Damon Q self-ligating bracket group on the maxillary first molar was prone to bodily movement. The average treatment course, the number of visits, and the average time spent on chair-side operation for each return visit in the Damon Q self-ligating bracket group were significantly less than those in the traditional bracket group. Conclusion Passive self-ligating brackets have obvious advantages over traditional brackets in terms of periodontal health and arch expansion effect, reducing average course of treatment, number of visits and chair-side operation time.

Key words: self-ligating brackets, periodontal health, arch expansion, treatment time