In the rare event that a tooth fails to respond to root canal therapy and root canal retreatment is not a viable option, root canal surgery is necessary to save the tooth. This procedure is apical surgery, or apicoectomy. It is also known as root-end resection, because it is, quite simply, the removal of the root tip (and the surrounding infected tissue) of an abscessed tooth. This procedure also provides the opportunity to detect possible root fractures.