Kugel 2002.
| Methods | Title: daily use of whitening strips on tetracycline‐stained teeth: comparative results after 2 months Trial design: randomised controlled trial Location: Tufts University, USA Language: English Number of centres: 1 Recruitment period: not reported Funding source: Procter & Gamble |
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| Participants | Participants: 22 to 70 years old Total number: 40 Inclusion criteria: adult patients with tetracycline stains Exclusion criteria: not reported Number randomised: 40 Method of randomisation: not reported Method of allocation concealment: not reported Method of blinding: identical packages Number evaluated: 33 |
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| Interventions | Total number of intervention groups: 2 6.5% hydrogen peroxide strips 10% carbamide peroxide tray Duration of treatment: 2 months |
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| Outcomes | Improvement with tooth shade. Vita shade guide arranged from darkest to lightest (B4 to C1) Plus 2 additional shades of B4+ and C1+ |
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| Notes | Sample size calculation: not reported Adverse effects: tooth sensitivity and oral irritation Health‐related quality of life: not reported Key conclusions of the study authors: "6.5% carbamide peroxide strips provided similar benefit to 10% carbamide peroxide used over 2 months period" Correspondence required: no |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "randomised clinical trial." However, method of randomisation is not reported |
| Allocation concealment (selection bias) | Unclear risk | Not mentioned |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Quote: "Products were packed in 1 month kits, and all labelling was identical except for unique.." |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | Not mentioned |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Quote: "7 subjects withdrew from the treatment in the first month" Comment: missing outcome data balanced in numbers across intervention groups |
| Selective reporting (reporting bias) | Low risk | All outcomes described were reported. Conclusions are in accordance with the results |
| Other bias | Low risk | None |