What does not contribute to the formation of extrinsic stains?

Tooth decay itself does not directly contribute to the formation of extrinsic stains on teeth. Extrinsic stains are primarily caused by external factors that stain the outer layer of the tooth enamel. These factors include the consumption of certain foods and beverages, such as coffee, tea, and red wine, which can lead to pigmentation on the enamel's surface. Additionally, smoking or tobacco use is another significant factor that leads to extrinsic staining due to the tar and nicotine present in tobacco products.

Poor oral hygiene can also result in extrinsic stains because a lack of proper brushing can allow plaque and tartar buildup, which can attract stains from foods, drinks, and other sources. In contrast, tooth decay is a process that leads to the demineralization of the tooth structure and cavities, rather than staining the enamel itself. While a tooth affected by decay may appear discolored, this is due to a different process that is not categorized as an extrinsic stain.