When a tooth becomes badly decayed, infected(abscess), or if the pulp/nerve of the tooth becomes injured, we perform a procedure called root canal therapy.
Root canal procedures involves removal of the pulp/nerve tissue inside of the tooth, therefore removing any sensation of pain associated. The tooth is then cleaned and sealed before placing a permanent restoration like a crown to help preserve its fragile state.
Root canal procedures have the reputation of being painful. Actually, most people report that the procedure itself is no more painful than having a filling placed. The discomfort experienced is typically from jaw soreness from having to stay open during the procedure, not the root canal procedure itself. We are aware of this and take precaution to give our patient periodic breaks to rest their mouth.