Barnes 1998.

Methods	Title: clinical evaluation of a new 10% carbamide peroxide tooth‐whitening agent Trial design: double‐blinded clinical trial Location: University of Maryland Dental School, USA Language: English Number of centres: 1 Recruitment period: not reported Funding source: Dentsply
Participants	Participants: 18 to 65 years Total number: 61 Inclusion criteria: A3 or darker shade Exclusion criteria: not reported Number randomised: not reported Method of randomisation: not reported Method of allocation concealment: not reported Method of blinding: not reported Number evaluated: 50
Interventions	Total number of intervention groups: 2 groups 10% carbamide peroxide gel in tray Placebo Duration of treatment: 4 hours to overnight for 2 weeks
Outcomes	Improvement in tooth shade: 2 weeks, 3 months and 6 months Tooth sensitivity Gingival irritation
Notes	Sample size calculation: not reported Adverse effects: sensitivity Health‐related quality of life: not reported Key conclusions of the study authors: "The average shade change for the placebo users was less than 1 shade. The average shade change for the NUPRO Gold users was 6.96 shades. Tooth hypersensitivity varied from none to severe. Tissue irritation was minimal. The results of these evaluations indicate that NUPRO Gold is effective as a tooth whitening system, when administered properly under the supervision of a dentist, with commonly reported side effects of transient tooth sensitivity and minimal gingival sensitivity. Little or no change in tissue health was noted" Correspondence required: yes: unclear if it is a randomised controlled trial. Authors have been mailed requesting for the data Contact: Dr Douglas Barnes, University of Maryland, Maryland, USA