Is it true that if the dentist did pulpectomy 3 months ago, they have to do it again to complete root canal treatment?

"repeat" root canal. The misunderstanding is that the inside of the tooth canals are "cleaned" out. In many cases the dentist will wait and not "fill" them with a "final" material so that any gas or liquid will have a chance to dissipate, especially for "hot" (painful) teeth. At a second separate appointment, the canals are again cleaned and then "sealed". However, not all teeth cooperate, and some do require removal.
Yes but......... A pulpectomy merely means removing the tissue contents of a root canal within the tooth. That first step is just a basic cleaning out of the canal. This has to be followed by: 1. A refined and complete cleaning after measurement are taken, shaping of the canal(s) 2. Sterilization of the canals 3. Filling of the canals. If this is not done, the procedure will fail.
No. I believe you may have misunderstood what was to be accomplished at the visit after the pulpectomy. Once the pulp is removed it can't grow back however further treatment is required to complete the root canal therapy. Incomplete treatment can result in a continuous infection, pain and possible loss of the tooth. I suggest returning to have it completed in a timely fashion. Good luck -.
Root canal. In most cases a pulps tommy is an emergency treatment intended to relief pain until the root canal can be completed. All of the disease peep tissue. Ends to be removed and then the root needs to be filled and sealed so you have long term success a deli instead pain.