Sebastian 2012.

Study characteristics
Methods	Setting: Noorul Islam College of Dental Sciences, Trivandrum, Kerala, India Design: parallel (2 arms) No. of centres: 1 Study duration: 12 weeks
Participants	Inclusion criteria: "female patients in postmenarche period between 13 and 15 years of age with crowding in the lower anterior segment and having a mandibular irregularity index greater than 6, Class I skeletal pattern, extraction treatment in mandibular arch, all mandibular teeth erupted with no spacing between them, no relevant medical history, no recent history of intake of drugs such as nonsteroidal anti‐inflammatory drugs (NSAIDs). No previous active orthodontic treatment. Receiving full arch mechanics, preadjusted edgewise appliance therapy and no therapeutic intervention planned involving intermaxillary or other intraoral or extraoral appliances during the study period". Exclusion criteria: "recruitment of patients who may have experienced periodontal disease and hence loss of attachment, was avoided; participants who had taken any drugs because of unavoidable circumstances" Participant sampling: N = 24 selected Group 1 (n = 12): 12 female, no male (mean age of 13.8 ± 0.7 years) Group 2 (n = 12): 12 female, no male (mean age of 13.6 ± 0.6 years) Sex: 100% female Dropouts: none
Interventions	Orthodontic intervention: fixed appliances and auxiliaries Coaxial nickel‐titanium versus nickel‐titanium archwires
Outcomes	Crowding
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Adequate method of randomisation “Randomization was done using computer software–generated numbers”
Allocation concealment (selection bias)	Low risk	Adequate method of allocation concealment “Opaque envelopes were used to allocate the archwires to two groups, each consisting of 12 participants. Allocation thus was concealed from the investigator and from participants during the study.”
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	Low risk	Adequate blinding of assessor “All readings were measured by an expert single operator, who was not aware of the archwire specimen used for the arches being measured.”
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Unclear risk	All participants female; sample size based on pilot study