Table 1. Characteristics of included studies.

Author, year	Control group	Intervention group/whitening ingredient	Sample size	Brushing duration	Type of outcome measures	Key conclusions
Bolay 2012	• Control group brushed with water without dentifrice • Colgate Total (control)	• Natural White	8 in each group	Exposed to 20.000 brush strokes	Surface roughness and microhardness	Toothbrushing with whitening dentifrice increased surface roughness values but had no effect on hardness values.
Feitosa 2013	• Colgate Total Advanced Clean (control)	• Colgate Total Advanced Whitening • Colgate Whitening Oxygen Bubbles	12 in each group	Brushed for 20,000 cycles to simulate 10 hours	Surface roughness	Whitening dentifrices increased the surface roughness of enamel.
Rahardjo 2015	• Pepsodent Regular (control)	• Pepsodent Whitening • Formula Sparkling White	20 in each group	Brushed for 840 seconds to simulate 3 months	Surface roughness and microhardness	Tooth brushing with whitening toothpaste for a prolonged time increased enamel roughness and decreased enamel microhardness.
Shamel 2019	• Close Up (control for close up white now) • Sensodyne (control for Sensodyne true white) • Colgate (control for Colgate optic white) • Control with no tooth paste application	• Close up White now • Sensodyne True White • Colgate Optic White	10 in each group	Brushed for 420 minutes, simulating 4 weeks	Surface roughness	Blue covarine containing toothpastes produced less surface abrasion in comparison with blue covarine-free toothpastes.
Alpan Lektemur 2020	• Control group (water brushing only)	• Sensodyne True White • Splat Special Blackwood • Colgate Optic White • Signal White Now • Ipana 3D White • Paradontax Whitening	20 in each group	Brushed for 5 seconds per day for 30 days.	Surface roughness	The two whitening toothpastes i.e., Splat Special Blackwood and Colgate Optic White, reduced enamel roughness, whereas no significant changes were seen with the other whitening toothpastes.
Maden 2021	• Colgate MaxFresh (control)	• İpana White Power	30 in each group	Brushed for 2 min twice a day for 1 week	Surface roughness and microhardness	Ipana White Power toothpaste increased surface roughness and reduced microhardness.
Vural 2021	• Colgate Total (control)	• Body Kingdom • Curaprox Black is White • Colgate Optic White	12 in each group	Hundred and sixty-eight cycles of brushings to simulate 12-weeks.	Surface roughness and microhardness	Except for the Curaprox Black is white, all other toothpastes showed increased surface roughness, while microhardness was not affected in any of the groups.