Pandis 2009.

Methods	Study design: double‐blind RCT, 2 parallel groups Location: Corfu, Greece Setting: private orthodontic office of Nikolaos Pandis Number of centres: 1 Study period: December 2006‐March 2008 Funding source: not stated
Participants	Inclusion criteria: non‐extraction treatment on the mandible; eruption of all mandibular teeth; no spaces in the mandibular arch; no crowding in the posterior segments; mandibular irregularity index > 2 mm; no therapeutic intervention planned involving intermaxillary or other intraoral or extraoral appliances including intra‐arch or interarch elastics, lip bumpers, maxillary expansion appliances, or headgears Exclusion criteria: not stated Number randomised: 60 participants (male/female 14/46; mean age 13.1 ± 1.8 years, age 10‐18 years) Number evaluated: 60 participants (60 arches, upper/lower 0/60) (group A: male/female 5/25, mean age 12.8 ± 1.7 years; group B: male/female 9/21, mean age 13.4 ± 1.8 years)
Interventions	Comparison: conventional NiTi vs copper thermoactive NiTi Group A (n = 30, upper/lower 0/30): 0.016‐inch NiTi (Modern Arch) Group B (n = 30, upper/lower 0/30): 0.016‐inch copper thermoactive NiTi 35ºC (Ormco) All participants were bonded with In‐Ovation‐R self ligating brackets with 0.022 in slot (GAC). All first and second molars (when present) were bonded with bondable tubes (Speed System Orthodontics). Bracket bonding, arch wire placement and treatment were performed by the same clinician. Operators: 1 clinician
Outcomes	Time to alignment of the mandibular anterior dentition (for participants not aligned after 6‐month treatment, the remaining crowding was recorded)
Notes	Sample size calculation: "The planned sample of 60 subjects was based on a time‐to‐event analysis, with a power of 80% to detect a 45% difference in effect (hazard ratio) and for type I error of 0.05." Baseline comparability: "No variable was identified to discriminate the 2 samples, thus verifying the random allocation of the intervention to the 2 wire groups." Other information: further information was requested from the study authors but there was no reply.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was done using random permuted blocks of size 6."
Allocation concealment (selection bias)	Low risk	Quote: "Opaque envelopes were used to allocate treatment." "Allocation was concealed from the operator and participants during the observation period"
Blinding of participants and personnel (performance bias) Patient reported outcomes	Low risk	Quote: "Double blind investigation"
Blinding of outcome assessment (detection bias) Clinician assessed outcomes	Low risk	Quote: "Double blind investigation"
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: no withdrawals
Selective reporting (reporting bias)	Low risk	Comment: planned outcomes reported
Other bias	Low risk	Comment: no other sources of bias identified