Oral cancer is a common malignant tumor of the head and neck, although the treatment effect of many tumors has been greatly improved in recent years, the 5-year survival rate of oral cancer has always hovered around 60%. The treatment of oral cancer often brings about the loss of speech and swallowing functions as well as the change of maxillofacial appearance, which is an important physical feature, thus affecting the social communication of patients. Therefore, prevention and early diagnosis of oral cavity is important. The following are the common risk factors of oral cancer: 1, smoking and alcohol consumption: it is recognized that the occurrence of oral cancer is closely related to tobacco intake and excessive alcohol consumption. Filter can not reduce the risk of tumor caused by tobacco. Oral cancer is closely related to precancerous lesions of oral mucosa, among which the more common ones are oral submucosal fibrosis, lichen planus and oral mucosal leukoplakia. If the above mucosal lesions are present, close observation and follow-up are needed. 3. Bad restorations, that is, crude dentures, can lead to oral cancer due to long-term stimulation, which has been seen many times. So don’t be careless with dental implants. 4.Infection: Chronic infection, especially human papilloma virus infection is one of the factors of oral cancer. hpv is a recognized causative factor of cervical cancer, how can it cause the occurrence of oral cancer? Obviously, change in sexual habits is the main one. 5.Other: poor oral hygiene is one of the important reasons, so please brush your teeth properly and clean them regularly.