Gravina 2013.

Study characteristics
Methods	Setting: Brazil, Rio de Janeiro Design: parallel (3 arms) No. of centres: 1 Study duration: 8 weeks
Participants	Inclusion criteria: "presence of all erupted permanent teeth except for second and third molars; no previous orthodontic treatment; no indications for tooth extraction; overbite and overjet that allowed brackets to be placed on the lower teeth without occlusal interferences; level of crowding and teeth position that allowed a maximum deflection of 2 mm in the archwire when inserted in the bracket slots, and good conditions of oral hygiene and health". Exclusion criteria: not reported Participant sampling:  N = 36 selected Group 1 (n = 11): sex and mean age of group not reported Group 2 (n = 12): sex and mean age of group not reported Group 3 (n = 13): sex and mean age of group not reported Overall age reported across groups: mean age of 14 ± 2 years Overall sex reported across both groups: 18 male, 18 female Dropouts: not reported
Interventions	Orthodontic intervention: fixed appliances and auxiliaries Stainless steel versus multi stranded stainless steel versus nickel‐titanium
Outcomes	Crowding
Notes	Funding source not cited
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Unclear method of randomisation
Allocation concealment (selection bias)	Unclear risk	Unclear if allocation sequence concealed from those assigning patients to participant groups
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not possible to blind participants and personnel due to the different interventions used
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear if assessor was blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Dropouts not reported
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Unclear risk	Possible measurement bias