Comparison 2. CP gel in tray versus placebo.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Tooth whitening ‐ assessed by the dentist	2	109	Risk Ratio (M‐H, Random, 95% CI)	6.74 [3.15, 14.40]
1.1 10% CP gel ‐ 6 months	2	109	Risk Ratio (M‐H, Random, 95% CI)	6.74 [3.15, 14.40]