Reinhardt 1993.

Methods	Title: a clinical study of nightguard vital bleaching Trial design: double‐blinded, randomised controlled clinical trial Location: University of Iowa, USA Language: English Number of centres: 1 Recruitment period: not reported Funding source: Dentmart and Omnii International
Participants	Participants: not reported Total number: 56 Inclusion criteria: not reported Exclusion criteria: patients with significant periodontal disease; internal tooth staining Number randomised: 56 Method of randomisation: not reported Method of allocation concealment: mentioned, but method not reported Method of blinding: not reported Number evaluated: 56
Interventions	Total number of intervention groups: 4 (3 different tray‐based brands versus placebo). Intervention with 2 different application regimens for each Proxigei Overnight n = 9 3 hours n = 8 White & Brite Overnight n = 6 3 hours n = 9 Rembrandt Lighten Overnight n = 8 3 hours n = 8 Control Overnight n = 4 3 hours n = 4 Duration of treatment: 3 weeks
Outcomes	Improvement in shade: Vita shade guide: lightest to darkest using Munsell Value Gingival Index: 0 = no inflammation; I = inflammation, but no bleeding; 2 = bleeding on probing; and 3 = spontaneous bleeding Plaque Index: 0 = no plaque; 1= plaque detectable; 2 = plaque from interproximal surface to interproximal surface; 3 = plaque on more than half of tooth
Notes	Sample size calculation: not reported Adverse effects: sensitivity Health‐related quality of life: not reported Key conclusions of the study authors: "The overnight (1 application) method produced tooth‐lightening resulted at least equivalent to those of the multiple application (3‐application, 3‐hour) method. When Proxigei or Rembrandt was used, overnight and 3‐hour replenishment produced similar results. The use of White & Brite overnight also produced results similar to those of Rembrandt and Proxigei. The least effective treatment was White & Brite used with 3‐hour replenishment" Correspondence required: yes: the percentage of the active ingredient used in the trial is not clear. Authors contacted Contact: John W Reinhardt, Department of Operative Dentistry, University of Iowa College of Dentistry, Iowa City 52242, USA