Stannous fluoride concentration used in topical fluoride is:
Stannous fluoride has been used at 8% and 10% concentrations in solutions equivalent to 2 and 2.5% fluoride. Although the 10% solution is usually used for adults and 8% for children, there is no evidence of an actual clinical difference between the two. However, the most commonly used is 8% stannous fluoride preparation.
Essentials of preventive and community dentistry 
Soben Peter 
5th edition
8%
2%
1.23%
12%