Track down the culprits
Stains are areas of darkened tooth enamel. You can be affected by both internal (caused by fluorides, certain medication, tooth death, etc.), and external discolouration, referring to staining on the surface. It is way easier to find the culprit in cases of external discolouration – staining is often caused by highly pigmented ingredients in foods and drinks. When accompanied by insufficient dental hygiene, teeth can become yellow, yellowish-brown or even black – and your bright smile will be nowhere to be found.