Gerlach 2004b.

Methods	Title: vital bleaching with a thin peroxide gel: the safety and efficacy of a professional‐strength hydrogen peroxide whitening strip Trial design: double‐blinded, randomised controlled trial Location: not available Language: English Number of centres: not available Recruitment period: not available Funding source: not available
Participants	Participants: adults Total number: 38 Inclusion criteria: not available Exclusion criteria: not available Number randomised: not available Method of randomisation: not available Method of allocation concealment: not available Method of blinding: not available Number evaluated: not available
Interventions	Total number of intervention groups: 2 6% hydrogen peroxide 14% hydrogen peroxide Duration of treatment: 2 weeks
Outcomes	Improvement in tooth shade
Notes	Sample size calculation: not available Adverse effects: oral irritation Health‐related quality of life: not available Key conclusions of the study authors: "Use of the thin 14% hydrogen peroxide gel strip resulted in greater whitening, including 42% to 49% greater improvement in tooth colour and faster whitening onset than that seen with a 6% hydrogen peroxide whitening strip, without clinical evidence of increased oral‐tissue irritation" Not able to retrieve full text Contact: Dr Robert W Gerlach, Hill Top Research, West Palm Beach, Florida, USA, gerlach.rw@pg.com