An abscessed, or infected tooth, is often the result of tooth decay. When the pulp becomes diseased or injured and cannot repair itself, it dies, exposing your teeth and mouth to even more serious problems down the road.
The most common cause of pulp death is a cracked tooth or a deep cavity. These problems can allow bacteria and other kinds of germs to enter and therefore compromise the pulp of your tooth. Left untreated, pus builds up at the root tip in the jawbone, forming a “pus-pocket” called an abscess. An abscess also can damage the bone around your teeth.