Unfortunately, nothing in dentistry will last forever. Things will get worn down or begin to show signs of failure possibly. But observing for any symptoms such as pain and swelling will help to indicate any need for further treatment.
Also regular routine dental care and x-rays to observe the area is always encouraged.
If the root canal failed the first symptom according to me would be the tooth pain again. If there is no pain then I think it may not be the failure. Checkout some more details about root canal at root canal Rockville MD.
I have done my root canal previous year from a private hospital called zajacdental in Oakville .Still now its seems healthy(i meant no discoloring observed).Is that root canals are not permanent .Is it that it may last only for a certain period of time?Is there anything like that?
Discoloration could be the sign of failure of root canal treatment but then there are other more prominent signs which might help you reach a conclusion. Signs like swelling,discomfort and discoloration are pretty much prominent in such a case and so should be examined by a dentist immediately. This condition usually arises when the cleaning aspect of the tooth's procedure is incomplete or there is deterioration of the seal,which is usually because of extensive decay or gum disease.
How would I know if it was failing?
It could indicate that. But not necessarily. Teeth that are root canal treated tend to discolor over time.