What causes yellow stains on teeth?

The accumulation of plaque is a significant contributor to yellow stains on teeth. Plaque is a soft, sticky film that consists of bacteria, food particles, and saliva. When plaque builds up on the surface of teeth and is not removed through regular brushing and flossing, it can harden into tartar, leading to further discoloration. The bacteria in plaque can produce acids that not only contribute to tooth decay but can also cause staining. Over time, if plaque is not adequately managed, it can lead to a yellow appearance that detracts from the natural whiteness of tooth enamel.

In contrast, drugs and metals can contribute to discoloration, but they do so in different ways and usually result in more specific stains rather than general yellowing. Intrinsic factors typically involve the internal structure of the teeth and may lead to discolorations that are not primarily yellow. Dental calculus deposits, which result from hardened plaque, can also contribute to yellow staining but are often more associated with a brownish color. The primary mechanism for the yellowing seen from daily habits and insufficient oral hygiene is indeed the buildup of plaque.