Extrinsic discoloration refers to the staining or discoloration of the outer surface of teeth caused by external factors. Common sources include food, beverages, tobacco, and poor oral hygiene. These stains can affect the appearance of teeth, making them look yellow or brown. The discoloration is typically superficial and can often be removed through professional dental cleanings or at-home whitening treatments. Maintaining good oral hygiene practices, such as regular brushing and flossing, can help prevent extrinsic discoloration and keep teeth looking bright and healthy.