Leukoplakia is a reaction to an irritant, like rough teeth, badly fitting dentures, smoking, and smokeless tobacco. It can show up as white patches or plaques in the mouth, is usually painless, and can not be scraped off. Leukoplakia can also be a precancerous condition. Persistent patches or other changes in your mouth need a dentist’s evaluation. See a dentist if you think you may have Leukoplakia for an evaluation and treatment.