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Effectiveness of self-ligating versus conventional brackets for treatment of bimaxillary protrusion: a single-centre
Trudee Hoyte1, Anil Ali1, Akini James1
1Orthodontic Department, School of Dentistry, Faculty of Medical Sciences, University of the West Indies, St. Augustine, Trinidad.
Objective:
To compare treatment duration between self-ligating and conventional brackets, determine factors influencing treatment duration and compare the quality of orthodontic care with both bracket systems in a bimaxillary protrusion population.
Subjects And Methods:
Participants were randomly allocated into the Smart Clip™ self-ligation bracket group or the Victory Series™ conventional ligation bracket group, both with MBT prescription (3M-Unitek, Monrovia, California, USA). Both extraction and nonextraction cases were included. Primary outcome measures included (i) overall treatment duration, (ii) levelling and aligning duration, (iii) Space closure and finishing duration, and (iv) number of appointments and other treatment related factors. The secondary outcomes assessed the quality of care. These occlusal outcomes included incisor inclination, ABO CR-EVAL, patient perception using the Index of Treatment Need and three validated questionnaires before, during and after treatment, measuring patient satisfaction with treatment and patient experience. Independent sample t-test and chi-square tests were conducted to assess differences in groups. Descriptive statistics and parametric tests were conducted. Also, nonparametric tests were carried out where appropriate. This clinical trial was ongoing during the COVID-19 pandemic, therefore, the effect of the pandemic on the trial was also assessed.
Results:
A total of 109 participants were enrolled. They were randomized in a 1:1 ratio; 13 were excluded (poor attendance prior to and poor attendance due to the COVID-19 pandemic). Forty-nine participants were analysed in the conventional bracket group and 47 in the self-ligating group. The overall mean age was 13 years. The groups were similar pre-treatment, and no statistical significance was found between the groups for treatment duration, duration of key stages and number of appointments (P > 0.05). The mean duration of treatment was 24.34 months for the conventional bracket group and 25.83 months for the self-ligating bracket group. ABO CR-EVAL showed a better quality of finish in the self-ligating bracket group. This, however, was not significant statistically. In both the conventional and self-ligating groups, the post-treatment U1-PP and L1-MP angles were consistent with the reported norms for this population. In extraction and nonextraction cases the self-ligating bracket retroclined the upper (9.2°in extraction and 2.2°in nonextraction cases) and lower incisors (7.3° in extraction and 3.9° in nonextraction cases) more than conventional bracket. In nonextraction cases these differences were not statistically significant (P > 0.05). Pre to post-treatment, there was a highly statistically significant improvement in the IOTN aesthetic component in both groups (P < 0.01).There was a significant difference between groups for pre-IOTN aesthetic assessment. The COVID-19 pandemic had no statistically significant impact on the overall treatment duration. However, it did have an effect on the collection and analysis of some data, with no overall effect on the majority of outcomes assessed in the trial. It was not possible to blind the operator or participants to the allocation.
Conclusions:
Use of Smart Clip™ self-ligating bracket does not reduce overall treatment time in bimaxillary protrusive patients. There were fewer total visits in the self-ligating bracket group when compared with the conventionally ligated bracket group. There is no evidence to suggest a difference in the quality of care or patient experience between self-ligating and conventional bracket systems in a bimaxillary protrusive population. The COVID-19 pandemic did not affect treatment duration.
Registration:
The trial was registered with ClinicalTrials.gov on 26th June 2019. Registration number NCT04001816.
Protocol:
The protocol was not published before trial commencement.
Funding:
The trial was funded by grants from The University ofThe West Indies ( CRP.3.MAR14.3, CRP.3.MAR14.3(1), CRP.3.MAR 14.3(4))andproduct donations from 3M Unitek.
