Songra 2014.

Study characteristics
Methods	Setting: Musgrove Park Hospital, Taunton, UK Design: parallel (3 arms) No. of centres: 1 Allocation ratio: 2:2:1 Study duration: recruitment span 2006‐2010; last debond 2011
Participants	Inclusion criteria: "Less than 18 years of age, ready to commence maxillary and mandibular fixed appliance treatment, intact labial segments, and premolar extractions required in all 4 quadrants." Exclusion criteria:  "...could not understand English, had learning difficulties, and had incomplete labial segments."  Participant sampling: N = 100 randomised; 98 analysed Group 1 Damon 3MX passive self‐ligating brackets (n = 41): 25 female, 17 male (mean age of 14.2 ± 1.09 years) Group 2 In‐Ovation R active self‐ligating brackets (n = 37): 20 female, 10 male (mean age of 13.9 ± 1.49 years) Group 3 Omni conventional brackets (n = 20): 12 female, 8 male (mean age of 13.5 ± 1.0 years) Sex: 47 female, 63 male Dropouts: 2 (2%)
Interventions	Orthodontic intervention: fixed appliances and auxiliaries Self‐ligating brackets versus conventional brackets
Outcomes	Crowding, time to alignment
Notes	We combined the data from the Damon 3MX and In‐Ovation R bracket groups as they are both self‐ligating brackets
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"The randomization was carried out by the local research and development office, which was contacted by telephone before the bond‐up of each participant."
Allocation concealment (selection bias)	Low risk	"The randomization was carried out by the local research and development office, which was contacted by telephone before the bond‐up of each participant. This process allowed allocation concealment from the researchers and prevented the possibility of prediction of the next randomization in each block."
Blinding of participants and personnel (performance bias) All outcomes	High risk	The brackets had different physical appearance so participants and personnel could not be blinded to the interventions. "The patients and the operators carrying out the treatment (N.E.A., G.S., and others) could not be blinded."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	"This was done to facilitate easy removal of the impression and to ensure that the bracket type would remain concealed on the study models during subsequent measurements. Therefore, only the model assessor (G.S.) was blinded during the study."
Incomplete outcome data (attrition bias) All outcomes	Low risk	"In total, 100 patients were recruited into the trial, and 98 were followed to completion of treatment, with 2 dropouts."
Selective reporting (reporting bias)	Low risk	All expected outcomes reported
Other bias	Low risk	A priori power calculation undertaken; reliability testing undertaken; measurements undertaken in standardised conditions; single centre but multiple operators; standardised archwire sequence