What's the difference between tooth discoloration and tartar and plaque buildup?

Depends: Discoloration usually refers to an intrinsic stain which means it is deep into the tooth. Tartar and plaque is a build up on the surface of the teeth and can be polished and/or scrapped away by your dental hygienest. Discoloration usually means you would need bleaching or a new crown to change the shade of that tooth. See your provider for options.

See below: Plaque is the film which coats a tooth made up of bacteria and food particles. It is soft and easily removed and can have different colors. Tartar is when the plaque is not removed and calcifies - absorbs the minerals from saliva and is hard and must be professionally removed. It can be different colors too, but tooth discoloration usually comes from smoking, coffee, tea, soy sauce, red wine, etc.

Very different: Tooth discoloration is due to staining that can be due to drinks, food and so on plaque and tartar buld up is do to not cleaning your teeth.

Difference: Pigments in foods, beverages, and from bacteria, can cause surface staining of your teeth, easily removed by your Dentist. Plaque (bacteria + food) forms a sticky coating on your teeth, especially between teeth, and the bacteria can harm both teeth and gums. Easily removed by you with proper oral hygiene, especially flossing. Tarter is calcified tarter that promotes gum disease and requires Rx.