Tooth yellow and brush not white, may not pay attention to oral hygiene, long-term smoking, etc., as follows: 1, do not pay attention to oral hygiene: may be because usually do not pay attention to oral hygiene, did not brush teeth, rinse, so that food residues accumulate on the surface of the teeth for a long time, the formation of soft tartar, tartar, plaque, etc., thus causing yellow teeth. 2, long-term smoking: patients with a long-term smoking history, due to the cigarette in the 3, other reasons: it is also possible that usually like to drink tea, coffee or eat food with color, etc., resulting in exogenous staining, can be manifested as yellowing teeth. There is also the possibility that the water contains too much fluoride and cause dental fluorosis, or have taken tetracycline drugs, etc., can also lead to yellowing teeth. Therefore, if the phenomenon of yellow teeth can not be brushed white, it is recommended to actively seek medical examination, according to the specific situation for targeted treatment.