Sandhu 2013.
| Methods |
Study design: double‐blind RCT, 2 parallel groups Location: India Setting: not stated Number of centres: 1 Study period: December 2010‐June 2012 Funding source: not stated |
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| Participants |
Inclusion criteria: 11‐17‐year‐old boys and girls who required fixed orthodontic treatment; moderate‐severe crowding (4‐9 mm) in the mandibular anterior segment that was not severe enough to prevent bracket engagement, patients with severe crowding related to 1 or 2 teeth (such as blocked out lateral incisors) were not included; eruption of all mandibular anterior teeth; no history of medical problems/medication that could influence pain perception; informed and witnessed consent from the minor participant and their parent/guardian Exclusion criteria: presence of a severe deep bite that could affect bracket placement on the mandibular anterior teeth; malocclusion correction required treatment procedures other than continuous arch wire mechanics; participants taking pain medications for chronic pain; participants with a positive history of dental pain or pain in the orofacial region; a medical condition that precluded the use of a fixed orthodontic appliance Number randomised: 96 participants (96 arches, upper/lower 0/96) (age 11‐17 years) Number evaluated: 85 participants (85 arches, upper/lower 0/85) (male/female 42/43; mean age 14.1 ± 2.0 years) (group A: male/female 21/22, mean age 13.9 ± 2.0 years; group B: male/female 21/21, mean age 14.2 ± 1.9 years) |
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| Interventions |
Comparison: multistranded stainless steel vs superelastic NiTi Group A (n = 43, upper/lower 0/43): 0.0175‐inch multistranded stainless steel (Six‐stranded, 3M) Group B (n = 42, upper/lower 0/42): 0.016‐inch superelastic nickel‐titanium (austenitic active, Unitek) Preadjusted Edgewise Appliances with 0.022 x 0.028‐inch slot twin brackets (Roth prescription, Unitek) were bonded directly to the mandibular dentition using light‐cure composite resin (Transbond XT, Unitek). Operators: 2 qualified orthodontists |
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| Outcomes | Pain: intensity of pain measured on a 100 mm VAS at 1, 2, 4, 6 and 12 hours for first 12 hours, then 3 times (morning, afternoon and bedtime) daily on days 1‐7, day 10 and day 14 | |
| Notes |
Sample size calculation: "Sample size was based on power analysis (Stata/SE 10.0 software, College Station, TX, USA) for a repeated measure design with 1 baseline and 32 follow‐up repeated measurements (r=0.15) to detect a 3‐mm (SD 10 for each group, Cohen’s effect size 0.3) mean difference on a 100‐mm VAS. The sample size determining assumptions, such as effect size and correlation coefficient (r) between follow‐up repeated measurement, were based on pilot study results. We determined that 42 participants per group (84 in total) were required to achieve 90% power with a significance level of 0.05. Considering possible drop out of 10–15% during follow up, it was decided to enrol at least 95 participants." Baseline comparability: baseline demographic and clinical characteristics data shown in a table about age, sex, initial crowding and extractions |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "The randomization schedule was prepared by using ralloc procedure (Stata/SE 10.0 software) to enrol 96 participants into superelastic NiTi and multistranded stainless steel groups using stratified block (size 4) randomization." |
| Allocation concealment (selection bias) | Low risk | Quote: "A statistician generated the random allocation sequence, and the dental assistant helped enrol and conceal participant allocation using the opaque sealed envelope method." |
| Blinding of participants and personnel (performance bias) Patient reported outcomes | Low risk | Quote: "double‐blind" |
| Blinding of outcome assessment (detection bias) Clinician assessed outcomes | Low risk | Quote: "The VAS score was measured by trained dental assistants (blinded to the study) using a manual 0.1mm calibrated Vernier caliper (manual type)." |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Comment: 11 participants (11.5%) excluded from analysis |
| Selective reporting (reporting bias) | Low risk | Comment: planned outcomes reported |
| Other bias | Low risk | Comment: no other sources of bias identified |