A root canal treatment involves drilling a hole into a decayed tooth and removing the soft centre, known as the dental pulp. The dental pulp is made up of connective tissue, nerves and blood supply, and extends into the roots of the tooth. The crown, or surface of the tooth that is used for chewing, may also be replaced if necessary. A root canal treatment can save a badly infected or damaged tooth. The tooth may have become infected or damaged by decay, repeated dental work, wear and tear, gum disease, cracked fillings or an injury to the tooth.