An abscessed tooth is one that has become infected. Tooth decay is often the cause advancing deep into the tooth, which causes destruction of the pulp(the life core of the tooth). When this happens, the pulp gets infected and swollen and pus builds up at the end of the tooth's root within the jawbone. Left untreated, infected pulp can cause more serious problems, including damage to surrounding tissue and bone.
Root canal treatment is the most common form of treatment for an abscessed tooth. Root canal treatment involves removing the infected tissue, cleansing and sealing the canals of the tooth and restoring the tooth with a crown, or cap. At times root canal treatment is not an option and the tooth will need to be removed.