Comparison 15. HP strip versus HP tray.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Tooth whitening ‐ assessed by the dentist	2		Mean Difference (IV, Random, 95% CI)	Subtotals only
1.1 14% HP strip versus 9.5% HP tray ‐ 22 days	1	29	Mean Difference (IV, Random, 95% CI)	‐1.4 [‐2.35, ‐0.45]
1.2 5.3% HP strip versus 5% HP tray ‐ 18 months	1	28	Mean Difference (IV, Random, 95% CI)	‐0.06 [‐2.36, 2.24]
2 Patient comfort	1		Mean Difference (IV, Fixed, 95% CI)	Subtotals only
2.1 5.3% HP strip versus 5% HP tray	1	28	Mean Difference (IV, Fixed, 95% CI)	1.27 [0.13, 2.41]