Is it true that a root canal retreatment is more painful than the original root canal?

Not necessarly: Whenever you are having root canals done you will be given local anasthesia which will block and pain. Usually patients feel nothing. There should be no feeling weather its an original or a retyreatment.

Sometimes: the pain could be very slight but will go away in 1-3 days. root canal is very complex and pain slight is always possible and expected. its a normal process.

False, painless: Fortunately, with Modern Dentistry, the root canal treatment or re-treatment procedure is painless. Good luck.