Your dentist uses root canal treatment to find the cause and then treat problems of the tooth's soft core (the dental pulp). Years ago, teeth with diseased or injured pulps were removed. Today, root canal treatment has given dentists a safe way of saving teeth. The pulp is the soft tissue that contains nerves, blood vessels and connective tissue. It lies within the tooth and extends from the crown of the tooth to the tip of the root in the bone of the jaws. When the pulp is diseased or injured and can't repair itself, it dies. The most common cause of pulp death is a cracked tooth or a deep cavity. Both of these problems can let germs (bacteria) enter the pulp. Germs can cause an infection inside the tooth. Left without treatment, pus builds up at the root tip, in the jawbone, forming a "pus-pocket" called an abscess. An abscess can cause damage to the bone around the teeth. When the infected pulp is not removed, pain and swelling can result. Certain byproducts of the infection can injure your jaw bones. Without treatment, your tooth may have to be removed. Treatment often involves from one to three visits. During treatment, your general dentist or endodontist (a dentist who specializes in problems of the pulp) removes the diseased pulp. The pulp chamber and root canal's) of the tooth are then cleaned and sealed.