The hazards of smoking on teeth mainly include yellowing of teeth or oral diseases. 1. Teeth yellowing: because tobacco contains a lot of tar, nicotine and other substances, long-term smoking may lead to these substances adhering to the teeth, resulting in teeth yellow phenomenon, affecting the aesthetic. 2. Oral disease: tobacco contains a large number of chemicals, may affect the normal metabolic process of periodontal tissues, to a certain extent, may induce oral disease, resulting in ischemia of the gums, teeth loosening or soreness and other phenomena. In serious cases, it may destroy the oral mucosa and trigger oral cancer, tongue cancer, pulpitis and other lesions. Patients are advised to go to the hospital for regular oral checkups and should seek immediate medical attention once there is any abnormal condition.