the human body is constantly changing. a root canal that has lasted 17 years can get re-infected. there could be a leak around the crown that is allowing bacteria to re-infect the area. there could be a fracture in the tooth or root system. it may even be another neighboring tooth. i recommend seeing the dentist as soon as possible to have an x-ray and an evaluation. .
about a month and a half ago i started getting throbbing unbearable pain from a capped tooth. what should i do? . i had a root canal 17 years ago and had the cap replaced for cosmetic reasons all with no problems.