Intrinsic stains within the tooth:

Intrinsic stains are those that occur within the structure of the tooth, often due to factors such as genetics, trauma, certain medications, or excessive fluoride exposure during tooth development. Unlike extrinsic stains, which form on the surface of the teeth and can typically be removed through polishing or professional cleaning, intrinsic stains are embedded within the tooth enamel and dentin. Because they originate from internal conditions of the tooth rather than surface factors, they cannot be eliminated through standard cleaning procedures.

They require more invasive treatment options for improvement, such as whitening agents that penetrate the tooth structure or more extensive procedures like veneers or crowns, depending on the severity of the staining. This distinct characteristic of intrinsic stains makes them a category apart from more easily treatable extrinsic stains.