Excessive intake of tea/coffee,alcohol,illnesses,excessive intake of fluoride, excessive use of antibiotics during childhood can contribute to a change in the color of the dentine
and lead to
yellow teeth .Extrinsic stains cause color change on the enamel, or through cracks and fissures on the tooth surface. Poor dental hygiene, iron supplements, overuse of chlorhexidine mouth wash and some drugs can cause yellow stains. Brush your teeth after meals, flossing may also help.