Tea is certainly one of the major culprits of external teeth stains. Such dyschromias are due above all to its high content of tannins, brownish polyphenolic compounds. These substances have the ability to bind tenaciously to proteins, including those present in the oral cavity, for example in tooth enamel, saliva and bacterial plaque.
Therefore, all foods rich in tannins tend to stain teeth. For example, you are more prone to dental discoloration if you consume black tea instead of the green one, since the latter is generally less rich in tannins. These substances are typical of the vegetable kingdom and also abound in red wine and in many medicinal plants used for decoctions or infusions against diarrhea.
Coffee contains much less tannins than tea, but still tends to stain your teeth because it is rich in dark pigments that are retained by plaque, tartar and the porosity of dental enamel.
