Berga‐Caballero 2006.

Methods	Title: at‐home vital bleaching: a comparison of hydrogen peroxide and carbamide peroxide treatments Trial design: randomised controlled trial Location: not reported Language: English Number of centres: 1 Recruitment period: not reported Funding source: not reported
Participants	Participants: age not reported Total number: 6 Inclusion criteria: not reported Exclusion criteria: not reported Number randomised: 6 Method of randomisation: not reported Method of allocation concealment: not reported Method of blinding: not reported Number evaluated: 6
Interventions	Total number of intervention groups: 2 10% carbamide peroxide: 20 to 28 days 3.5% hydrogen peroxide: 28 days Duration of treatment: 20 to 28 days
Outcomes	Improvement in tooth shade
Notes	Sample size calculation: not reported Adverse effects: sensitivity Health‐related quality of life: not reported Key conclusions of the study authors: "In carbamide peroxide group, the daily length of application was 2 hours. In the first case the treatment lasted for 24 days, there was no pre‐ or post‐operative sensitivity and the tooth shade changed from A4 (canines) – A3.5 (incisors) to A2 (canines) – A1 (incisors). In hydrogen peroxide the duration of treatment was similar (28 days), no sensitivity was shown during treatment and the shade changed from A3.5 (canines) – A3 (incisors) to A1. Case 3 presented a change in shade from A4 (canines) – A3 (incisors) to A2 (canines) – A1 (incisors) after only 20 days; in this case the patient did mention slight sensitivity in the anterior mandibular teeth throughout the treatment" Correspondence required: no Contact: Professor Dr Forner Navarro; forner@uv.es
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "They were randomly assigned to the two treatment groups." However, the method is not mentioned
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	All subjects completed the trial
Selective reporting (reporting bias)	Low risk	All outcomes described were reported. Conclusions are in accordance with the results
Other bias	Low risk	None