Other brown stains can be associated with which of the following agents?

Stannous fluoride is identified as a key agent associated with brown stains on teeth. This fluoride compound, used mainly for its cavity-preventive properties, can sometimes lead to discoloration. The stains occur because stannous fluoride can precipitate with various substances in the mouth, leading to the formation of stain materials that can adhere to the tooth surface, especially if oral hygiene is insufficient.

In contrast, while antibiotics can cause discoloration, particularly tetracyclines, they are less commonly associated with brown stains compared to stannous fluoride. Acids primarily contribute to enamel erosion rather than direct staining. Cosmetic products may temporarily stain teeth but are not typically linked to the long-lasting brown stains associated with stannous fluoride. Thus, the connection of brown stains to stannous fluoride is well documented in dental literature, making it the most fitting answer.