(1) Ulcers in the mouth that have not healed in more than 2 weeks. (2) White, red and darkened patches on the oral mucosa. (3) Unidentified lumps and enlarged lymph nodes in the mouth and neck. (4) Recurrent bleeding from the mouth with foul odor, site and cause unknown. (5) Unexplained numbness and pain in the face, mouth, throat and neck. If the above symptoms occur in people who have smoked and drank excessively for a long time and have not had regular checkups for many years after denture repair, seek medical attention as soon as possible.