What type of stain originates outside of the tooth in response to environmental agents?

Exogenous stains originate outside of the tooth structure and are the result of various environmental agents. These stains can occur due to factors such as certain food and beverages, tobacco use, or exposure to certain medications. Unlike intrinsic stains, which are formed from within the tooth, exogenous stains are typically surface-level discolorations that can often be removed or managed through dental cleanings, whitening treatments, or good oral hygiene practices. This distinction makes exogenous stains the correct answer, highlighting how external influences contribute to the staining of teeth.

Intrinsic stains, on the other hand, develop from within the tooth structure, often due to factors related to genetics, developmental issues, or trauma. Endogenous stains refer specifically to those that arise during the tooth's formation, often tied to systemic health issues. Systemic stains relate to broader health factors impacting the body as a whole or developmental concerns rather than localized environmental agents.