A periodontal abscess is caused by an infection in the periodontal tissues. This infection is usually the result of long-continued irritation by food debris; deep deposits of calculus; or a foreign object such as a toothbrush bristle or a popcorn husk being tightly packed into the interproximal spaces or between the tooth and the soft tissues. Periodontal abscesses almost always happen in people who have existing periodontal disease that is advanced enough to have resulted in some loss of bone around the root of the tooth. An area in which bone is missing around a tooth root is called a periodontal pocket, and a periodontal pocket can be very hard to clean. The bacteria living in the pocket change in time and more destructive species move in. Byproducts of the bacteria cause more bone to dissolve.
Periodontal infection can be present without pain. If there is pus forming, and it is trapped under the gum, the pain can be quite bad. The infection can spread and seem like it is going into your ear or under your lower jaw and down into your neck. It may be hard to open your mouth because of the inflammation and swelling. If your problem seems to be a periodontal abscess, the dentist will probably place you on an antibiotic. The gum area may be cleaned out, debris removed and the pus allowed to drain. You should start to feel better relatively quickly but it is important to realize that there was an underlying periodontal problem that needs to be addressed.