Miles 2016.

Study characteristics
Methods	Setting: Caloundra, Queensland, Australia, private practice Design: parallel (2 arms) No. of centres: 1 Study duration: 10 weeks
Participants	Inclusion criteria: "(1) children up to age 16, (2) a fully erupted dentition from first molar forward, (3) erupted or erupting second molars, (4) no missing or previously extracted permanent teeth, (5) undergoing comprehensive orthodontic treatment with full fixed appliances, and (6) a Class II malocclusion requiring extraction of 2 maxillary premolars but no mandibular extractions". Exclusion criteria: not reported Participant sampling: N = 40 selected Group 1 (n = 20): 12 female, 8 male (mean age of 13.0 ± 1.5 years) Group 2 (n = 20): 14 female, 6 male (mean age of 12.7 ± 1.2 years) Sex: 26 female, 14 male Dropouts: none
Interventions	Orthodontic intervention: fixed appliances and auxiliaries Vibrational appliance versus no vibrational appliance (control)
Outcomes	Crowding, time to alignment, harms (discomfort)
Notes	Funding source: "a special research grant was obtained from the Australian Society of Orthodontists Foundation for Research and Education to purchase the AcceleDent Aura appliances and to fund the statistical analysis"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Adequate method of randomisation “Randomization was performed using permuted blocks of 10 randomly generated numbers with the random generation function in Excel (Microsoft, Redmond, Wash)"
Allocation concealment (selection bias)	Low risk	Adequate method of allocation concealment Quote: “The numbers were sealed in opaque envelopes and shuffled by a staff member."
Blinding of participants and personnel (performance bias) All outcomes	High risk	Clinician blinded, however not possible to blind participants due to the different interventions used “A clinical assistant opened an envelope for the group assignment after a patient's brackets were bonded and gave routine instructions in a closed consultation room to ensure that the operator (P.M.) was blinded.”
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Adequate blinding of assessor “And the model assessor (E.F.) was blinded to the treatment group and the model time point”
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts "All subjects, once assigned, completed the trial with no lost data."
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Low risk	None identified