Ong 2011.

Study characteristics
Methods	Setting: private orthodontic practice, Caloundra, Queensland, Australia Design: parallel (3 arms) No. of centres: 1 Study duration: 1 year
Participants	Inclusion criteria: "all patients who required both upper and lower orthodontic appliances were included. There were no restrictions regarding age, previous orthodontic experience, or extraction/non‐extraction treatment. No patients had craniofacial abnormalities" Exclusion criteria: "children were excluded if they had asymmetrically missing or extracted premolars, missing or unerupted lower incisors or canines, or teeth blocked out that did not allow for placement of all brackets at the initial bonding appointment" Participant sampling: N = 132 selected Group 1 (n = 44): 30 female, 14 male (mean age of 14.4 ± 4.4 years) Group 2 (n = 44): 25 female, 19 male (mean age of 15.5 ± 6.4 years) Group 3 (n = 44): 25 female, 19 male (mean age of 16.1 ± 8.3 years) Sex: 80 female, 52 male Dropouts: 1 dropout from group 3; however, missing data due to missing or broken models and discomfort questionnaires not being returned
Interventions	Orthodontic intervention: fixed appliances and auxiliaries Copper nickel‐titanium versus nickel‐titanium archwires
Outcomes	Crowding, time to alignment, harms (discomfort)
Notes	Funding source: “This study was supported by a grant from the Australian Society of Orthodontists’ Foundation for Research and Education”
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants randomly allocated to 3 groups "A restricted randomization process was employed, where patients were randomized in blocks of 12 to ensure equal allocation of patients to the treatment groups. Randomization was performed using computer generated numbers."
Allocation concealment (selection bias)	Low risk	Adequate method of allocation concealment "A list of numbers was kept by the laboratory staff, who on the day of bracket placement would then assign them to the appropriate group, so the treating clinician was not involved"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Participants blinded, however not possible to blind personnel due to the different interventions used "The patients were blinded to their group allocation throughout treatment; however, the treating clinician could not be masked."
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Adequate blinding of assessor "The clinician’s staff assigned an identification number to each model prior to measurement in order to mask the principal researcher (EO) to the patient name, treatment allocation, time‐point and archwire group during study model analysis. The models were rematched to the patient and archwire group after data collection was complete."
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	1 dropout, however missing data due to missing or broken models and discomfort questionnaires not being returned. "One patient transferred and was lost to follow up; therefore, 131 patients completed the trial. Some of the irregularity data were lost because nine study models were missing and two were broken. Some discomfort data were also lost because 63 questionnaires were not returned. The data were checked for non‐response bias and there were no significant differences in the number of returned forms between the archwire groups, therefore, this is unlikely to have affected the results."
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Low risk	None identified