Research on clinical effect and bond failure of self-ligating and MBT brackets

OBJECTIVE To compare the clinical effect of self-ligating brackets and conventional brackets on arch expansion,the rate of bond failure and periodontal condition.METHODS 30 patients were divided into 2 groups(observation group:15 patients with self-ligating brackets and control group:15 patients with MBT brackets).The clinical effect on arch expansion,rate of bond failure and periodontal indices(PLI,GI and SBI)were recorded in both group before and after 6 months of treatment.RESULTS ① There were no obvious differences in the anterior dental arch widths and length between two groups.But compared with control group,the effect on the increase of the mid-length of maxillary after treatment was different in observation group(P﹤0.05).② After 6 months treatment,gum inflammation,dental plaque were in patients in both groups,but PLI,GI,SBI were not different between two groups(P﹥0.05).③ Failure rate of brackets was 12/300(4.0%)in observation group,14/300(4.7%)in control group.No difference in failure incidence was noted for self-ligating brackets and conventional brackets(P﹥0.05).CONCLUSION Self-ligating brackets has the same clinical effect and bond failure compared to MBT brackets,and do not have an advantage over the periodontal status.