What defines an extrinsic stain?

Extrinsic stains are primarily characterized by their formation on the surface of the tooth enamel due to the accumulation of external substances. This includes various agents such as food, drinks, tobacco, or bacteria that adhere to the enamel and result in visible discoloration. Unlike intrinsic stains, which stem from internal factors or occur during the development of the tooth, extrinsic stains can typically be removed through professional dental cleaning or polishing.

By focusing on the processes involved, it becomes clear that the adherence of these agents to the enamel is key to defining an extrinsic stain, effectively highlighting why option B is the most accurate representation of this type of stain. Additionally, understanding that extrinsic stains do not originate from within the tooth itself, but rather external sources, helps further clarify their nature in a clinical context.