Tsubura 2005.

Methods	Title: clinical evaluation of a new bleaching product Polanight in a Japanese population Trial design: split‐mouth, randomised controlled trial Location: private dental clinic Language: English Number of centres: 1 Recruitment period: not reported Funding source: SDI Ltd
Participants	Participants: 18 to 47 years old. Mean age 30 years Total number: 58 Inclusion criteria: not reported Exclusion criteria: not reported Number randomised: 58 Method of randomisation: not reported Method of allocation concealment: not reported Method of blinding: not reported Number evaluated: 58
Interventions	Total number of intervention groups: 2 Polanight: 10% carbamide peroxide Opalescence: 10% carbamide peroxide Duration of treatment: 2 weeks
Outcomes	Improvement in tooth colour ΔL, a*, b* values: increase in ΔL and decrease in b* indicates lightening of teeth
Notes	Sample size calculation: not reported Adverse effects: sensitivity Health‐related quality of life: not reported Key conclusions of the study authors: "Treatment with either agent demonstrated significant bleaching effects produced by the treatment. Bleaching with PN was considered more effective than that with OP in the young patient group and in the women" Correspondence required: no Contact: R Yamaguchi, hshimo@ngt.ndu.ac.jp
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...were randomly selected from the patients visiting." However, method of randomisation is not described
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not mentioned
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not mentioned
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts
Selective reporting (reporting bias)	Low risk	All outcomes described were reported. Conclusions are in accordance with the results
Other bias	Low risk	None