Gambarini 2004.

Methods	Title: efficacy and safety assessment of a new liquid tooth whitening gel containing 5.9% hydrogen peroxide Trial design: double‐blinded randomised controlled trial Location: University of Rome, Italy Language: English Number of centres: 1 Recruitment period: not reported Funding source: not reported
Participants	Participants: 21 to 52 years Total number: 30 Inclusion criteria: Vita shade score of A2 or darker; adults; staining in teeth Exclusion criteria: not reported Number randomised: 30 Method of randomisation: not mentioned Method of allocation concealment: not mentioned Method of blinding: not reported Performance/detection bias: not reported Number evaluated: 30
Interventions	Total number of intervention groups: 2 Hydrogen peroxide gel 5.9% Placebo Duration of treatment: 2 weeks
Outcomes	Tooth colour change Sensitivity Bleeding on probing Gingival recession
Notes	Adverse effects: sensitivity Health‐related quality of life: not reported Key conclusions of the study authors: "5.9% hydrogen peroxide was significantly effective in lightening tooth shade. After only 2 weeks, patients enrolled in the study exhibited an overall mean 4.48‐shade improvement from baseline, which was significantly greater than placebo group and far exceeded the ADA minimum requirements to claim "clinical efficacy". In the new Colgate Simply White Clear Whitening Gel group, periodontal health (PI and BOP) improved with time overall. Moreover, dentin hypersensitivity did not significantly increase, and all treatments were generally well tolerated" Correspondence required: yes: missing data, standard deviation cannot be calculated as P values have not been reported in the study. Author has been contacted Contact: Dr Gianluca Gambarini, ggambarini@tin.it