Heymann 1998.

Methods	Title: clinical evaluation of 2 carbamide peroxide tooth‐whitening agents Trial design: blinded‐study Location: not available Language: English Number of centres: not available Recruitment period: not available Funding source: not available
Participants	Participants: not available Total number: 51 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 10% carbamide peroxide: 2 different brands Duration of treatment: 1 week
Outcomes	Improvement in tooth shade
Notes	Sample size calculation: not available Adverse effects: tooth sensitivity and gingival irritation Health‐related quality of life: not available Key conclusions of the study authors: "Not significant difference in the bleaching was noted between 2 groups. Mild gingival irritation and hypersensitivity was noticed between both the groups" Not able to retrieve full text