1. Details of analyses performed in multiarm trials.

Trial	Interventions reported in the trials	Interventions considered in analyses	Reason
Aka 2017	Placebo 10% carbamide peroxide (Opalescence PF) gel in tray 6% hydrogen peroxide (Opalescence Go) gel in tray	Bleaching agent vs placebo 10% carbamide peroxide gel in tray vs placebo Bleaching agent vs bleaching agent 10% carbamide peroxide gel in tray vs 6% hydrogen peroxide gel in tray	Most commonly used concentrations
Alonso 2014	10% carbamide peroxide in tray 15% carbamide peroxide in tray 7.5% hydrogen peroxide in tray 9.5% hydrogen peroxide in tray	Bleaching agent vs bleaching agent 10% carbamide peroxide in tray vs 7.5% hydrogen peroxide in tray	Most commonly used concentrations
Bizhang 2007	6% hydrogen peroxide whitening strips 19% sodium percarbonate brush‐applied gel that dries to a film Placebo brush‐applied gel without peroxide	Bleaching agent vs placebo 6% hydrogen peroxide whitening strips vs placebo Bleaching agent vs bleaching agent 19% sodium percarbonate brush‐applied gel that dries to a film vs 6% hydrogen peroxide whitening strips	Most commonly used concentrations
Browning 2008	10% carbamide peroxide in tray 10% carbamide peroxide, 3% potassium nitrate in tray 10% carbamide peroxide, 0.5% potassium nitrate in tray 10% carbamide peroxide, 0.5% potassium nitrate, 0.25% sodium fluoride in tray Placebo	Bleaching agent vs placebo 10% carbamide peroxide, 0.5% potassium nitrate, 0.25% sodium fluoride in tray vs placebo Bleaching agent vs bleaching agent 10% carbamide peroxide in tray vs 10% carbamide peroxide, 0.5% potassium nitrate, 0.25% sodium fluoride in tray	Most commonly used concentrations
Gerlach 2000	5.3% hydrogen peroxide strips 10% carbamide peroxide gel in tray 15% carbamide peroxide gel in tray 20% carbamide peroxide gel in tray	Bleaching agent vs bleaching agent 5.3% hydrogen peroxide strips vs 10% carbamide peroxide gel in tray	Most commonly used concentrations
Hyland 2015	5% carbamide peroxide gel 10% carbamide peroxide gel Placebo	Bleaching agent vs placebo 5% carbamide peroxide gel vs placebo Bleaching agent vs bleaching agent 5% carbamide peroxide gel vs 10% carbamide peroxide gel	Most commonly used concentrations
Krause 2008	10% carbamide peroxide gel in tray 17% carbamide peroxide gel in tray 0% carbamide peroxide gel in tray (control)	Bleaching agent vs bleaching agent 10% carbamide peroxide gel in tray vs 17% carbamide peroxide gel in tray	Most commonly used concentrations
Li 2003	6.5% hydrogen peroxide strips 7.5% hydrogen peroxide gel in tray 16% carbamide peroxide gel in tray	Bleaching agent vs bleaching agent 6.5% hydrogen peroxide strips vs 16% carbamide peroxide gel in tray	Most commonly used concentrations
Li 2004	18% carbamide peroxide 2x paint‐on gel 18% carbamide peroxide 3x paint‐on gel 18% carbamide peroxide 4x paint‐on gel	Bleaching agent vs bleaching agent 18% carbamide peroxide 2x paint‐on gel vs 18% carbamide peroxide 4x paint‐on gel	Most commonly used concentrations
Matis 2006	10% carbamide peroxide gel in tray 15% carbamide peroxide gel in tray 20% carbamide peroxide gel in tray	Bleaching agent vs bleaching agent 10% carbamide peroxide gel in tray vs 15% carbamide peroxide gel in tray	Most commonly used concentrations
Wong 2004	6% hydrogen peroxide strips 18% carbamide peroxide paint‐on gel Placebo: non‐whitening toothpaste	Bleaching vs placebo 6% hydrogen peroxide strips vs placebo Bleaching agent vs bleaching agent 6% hydrogen peroxide strips vs 18% carbamide peroxide paint‐on gel	Most commonly used concentrations
Xu 2007	6% hydrogen peroxide strips 5.8% hydrogen peroxide paint‐on gel Placebo: negative control (water rinse)	Bleaching vs placebo 6% hydrogen peroxide strips vs placebo Bleaching agent vs bleaching agent 5.8% hydrogen peroxide paint‐on gel vs 6% hydrogen peroxide strips	Most commonly used concentrations

vs = versus; 2x = twice; 3x = 3 times; 4x = 4 times.