 [ Symptoms ] 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 [ Disease ] 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 