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Am J Orthod Dentofacial Orthop. 2014 May;145(5):569-78. doi: 10.1016/j.ajodo.2013.12.024.

Comparative assessment of alignment efficiency and space closure of active and passive self-ligating vs conventional appliances in adolescents: a single-center randomized controlled trial.

Author information

1
Senior specialist registrar, School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
2
Private practice, Salisbury, United Kingdom.
3
Consultant orthodontist, School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
4
Visiting professor, Medical School, University of Exeter, Exeter, United Kingdom.
5
Visiting professor, School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
6
Professor, School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom.
7
Professor, School of Oral and Dental Sciences, University of Bristol, Bristol, United Kingdom. Electronic address: tony.ireland@bristol.ac.uk.

Abstract

INTRODUCTION:

The aim of this study was to compare the time to initial alignment and extraction space closure using conventional brackets and active and passive self-ligating brackets.

METHODS:

One hundred adolescent patients 11 to 18 years of age undergoing maxillary and mandibular fixed appliance therapy after the extraction of 4 premolars were randomized with stratification of 2 age ranges (11-14 and 15-18 years) and 3 maxillomandibular plane angles (high, medium, and low) with an allocation ratio of 1:2:2. Restrictions were applied using a block size of 10. Allocation was to 1 of 3 treatment groups: conventional brackets, active self-ligating, or passive self-ligating brackets. All subjects were treated with the same archwire sequence and space-closing mechanics in a district general hospital setting. The trial was a 3-arm parallel design. Labial-segment alignment and space closure were measured on study models taken every 12 weeks throughout treatment. All measurements were made by 1 operator who was blinded to bracket type. The patients and other operators were not blinded to bracket type during treatment.

RESULTS:

Ninety-eight patients were followed to completion of treatment (conventional, n = 20; active self-ligating brackets, n = 37; passive self-ligating brackets, n = 41). The data were analyzed using linear mixed models and demonstrated a significant effect of bracket type on the time to initial alignment (P = 0.001), which was shorter with the conventional brackets than either of the self-ligating brackets. Sidak's adjustment showed no significant difference in effect size (the difference in average response in millimeters) between the active and passive self-ligating brackets (the results are presented as effect size, 95% confidence intervals, probabilities, and intraclass correlation coefficients) (-0.42 [-1.32, 0.48], 0.600, 0.15), but the conventional bracket was significantly different from both of these (-1.98 [-3.19, -0.76], 0.001, 0.15; and -1.56 [-2.79, -0.32], 0.001, 0.15). There was no statistically significant difference between any of the 3 bracket types with respect to space closure. Space-closure times were shorter in the mandible, except for the Damon 3MX bracket (Ormco, Orange, Calif), where active and total space-closure times were shorter in the maxilla. No adverse events were recorded in the trial.

CONCLUSIONS:

Time to initial alignment was significantly shorter for the conventional bracket than for either the active or passive self-ligating brackets. There was no statistically significant difference in passive, active, or total space-closure times among the 3 brackets under investigation.

Comment in

PMID:
24785921
DOI:
10.1016/j.ajodo.2013.12.024
[Indexed for MEDLINE]

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