This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Stannous fluoride concentration used in topical fluoride is: 
Select and explain. 
A. 8%, B. 2%, C. 1.23%, D. 12%
A: 8%
Answer: A: 8% 
Explanation: 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