Comparison 12. CP tray versus CP tray.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Tooth whitening ‐ assessed by the dentist	1		Mean Difference (IV, Random, 95% CI)	Subtotals only
1.1 10% CP versus 15% CP ‐ 2 weeks	1	52	Mean Difference (IV, Random, 95% CI)	1.65 [0.22, 3.08]
2 Tooth whitening ‐ assessed by the dentist	1	25	Mean Difference (Fixed, 95% CI)	2.22 [1.29, 3.15]
2.1 10% CP versus 15% CP ‐ 2 weeks	1	25	Mean Difference (Fixed, 95% CI)	2.22 [1.29, 3.15]
3 Tooth whitening ‐ assessed by the dentist	2	58	Std. Mean Difference (IV, Fixed, 95% CI)	0.32 [‐0.20, 0.84]
3.1 10% CP versus 10% CP + KN + NaF ‐ 2 weeks	2	58	Std. Mean Difference (IV, Fixed, 95% CI)	0.32 [‐0.20, 0.84]