What are the main causes of oral cancer? Can you avoid it if you do not drink or smoke?

The greatest risk factors are smoking and drinking, and doing both is known to raise the risk further. You can still develop it without either, however. 1) Chronic irritation, where an ill-fitting denture or a sharp tooth or restoration rubs the same spot for a long time, 2) human papillomavirus (HPV) infection, and 3) very poor oral hygiene can also contribute. So even a non-smoker with a sore or patch in the mouth that has not healed in 2 weeks needs an examination, and if you have a denture that does not fit or a tooth that jabs your tongue or cheek, do not leave it - have it adjusted.