Abstract: PURPOSE: To analyze the safety of closed traction appliance in the treatment of impacted anterior teeth and its effect on pulp blood flow and masticatory function. METHODS: A total of 80 patients with impacted anterior teeth who received treatment from January 2017 to December 2022 were selected, and randomly divided into experimental group and control group with 40 cases in each group. The two groups of patients were treated with occlusion adjustment and orthodontic traction. Closed traction was used in the experimental group, while open traction was used in the control group. The clinical efficacy, treatment duration, chewing ability, root length, periroot bone density, dental aesthetic score, pulp blood flow at different time points and the occurrence of adverse events were compared between the two groups. Statistical analysis was performed with SPSS 22.0 software package. RESULTS: The total effective rate was 95.00% in the experimental group and 90.00% in the control group, with no significant difference(P>0.05). There was significant difference in traction eruption time and orthodontic time between the two groups(P<0.05). There were significant differences in masticatory efficiency, bite force and masticatory pain score between the two groups before and after treatment(P<0.05). There was no significant difference in root length and periroot bone density between the two groups before and after treatment(P> 0.05). There was no significant difference in white aesthetic score between the two groups before and after treatment(P> 0.05), but there was significant difference in red aesthetic score between the two groups before and after treatment(P< 0.05). There was no significant difference in pulp blood flow between the two groups at each time point(P>0.05). At T1, the pulp blood flow reached its peak higher than T0; at T2, it rapidly decreased below T1 but higher than T0; at T3, it gradually decreased below T1 and T2 but higher than T0(P<0.05). The incidence of adverse events in the experimental group was 10.00% compared with 27.50% in the control group, and the difference was statistically significant(P<0.05). CONCLUSIONS: Both closed traction and open traction correction can effectively treat the impacted anterior teeth, and the two methods have no significant effects on root length, surrounding bone density and pulp blood flow. Although the treatment time of closed traction is slightly longer, it is more beneficial to improve patients' masticatory ability, and has high aesthetics and safety, which is worthy of clinical promotion.

Key words: Closed traction, Anterior teeth, Ambush impacted, Security, Pulp blood flow, Masticatory function