A root canal is a filling that is placed inside of the tooth where the nerve used to be. It is placded there due to changes in the nerve that can lead to inflammation, pain or infection to the nerve. Symptoms of a painful nerve or toothache can heal given time and/or medication, or sometimes if a tooth continues to be painful. Even if the nerve dies without pain, a root canal is still necessary to seal the dead space in the tooth, which will help to prevent future infection in the tooth. Most patients are relieved and amazed to learn that root canal therapy is much easier and more straightforward than they imagined it to be.