When a tooth has either been traumatized or has a very deep cavity into the nerve, often, root canal therapy is needed. This time-tested therapy is a way that a once doomed tooth can be saved. Root canal therapy is the removal of diseased or damaged nerve and blood vessels from the interior of the tooth. After the root canal is complete the entire hard structure of the root as well as a portion of the crown (the part you see in your mouth) remains. The crown of the tooth is usually weakened at this point and often the root canal therapy is followed by placement of a crown over the top of the tooth for the purpose of strengthening the tooth. In the end, an injured or badly decayed and painful tooth can be brought back to full function and if lovingly cared for, will perform for you as though nothing had ever happened to it.