One of the main reasons why someone goes directly to the dentist is the intense and constant toothache, which sometimes does not go away even with painkillers. In most cases, this pain is treated with endodontic treatment of the responsible tooth.
However, this does not mean that a tooth that does not hurt cannot benefit from endodontic treatment. In any tooth there is microbial infiltration in the pulp chamber (the cavity inside the tooth where the pulp of the tooth is located) in most cases endodontic treatment is needed.
This includes the exfoliation of the tooth (or root canalization as is common) if the pulp still exists and is not dead, the disinfection of the pulp chamber and the roots and their final occlusion.
Endodontic treatments, if done relatively soon after the tooth is affected, have a fairly high success rate and can often be done in a single appointment, unlike in the past.