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Yes, it is possible to have an infection in the old root canal treated tooth but is usually does manifest as pain! However if you don’t pain at this point of time but an itchy or somewhat different feeling in the gums around your tooth than probably it can be an indicative of an abscess formation. Your gums might appear swollen or red which might later worsen and progress into symptoms giving rise to pain or swelling!Though one cannot be sure about it without an x-ray or by clinical evaluation ,I would therefore suggest you to make an early appointment with your endodontist.
Also there can be various reasons attributed for this condition. Things can go wrong after the treatment that won’t become apparent for a long time after the treatment. The final reason that root canals have such a poor reputation is that they don’t always work!! Sometimes in spite of the best technical skills the tooth never really ceases to be painful or bothersome in some way.
It is not for possible for me to give the pin-point diagnosis to what exactly might have gone wrong with your tooth without looking at the x-ray. But, here are the lists of possibilities that can be attributed to it, i.e. it can happen due to any one of the following reasons:
1) Presence of an Extra canal in the tooth which was not identified by your dentist and thus not cleaned.( most common in mutlirooted teeth i.e. molars)
2) There can be possibility of Fractured/broken instruments during the the root canal therapy that can cause ledge formation (while using the endodontic files used for cleaning and shaping the canal).
3) Inadequate instrumentation in removing the infected tissue or decay at the first place i.e the root canal is not cleaned properly.
4) Inadequate or Improper sealing of the root canals i.e. either end of the root canal was not sealed properly, either the tip of the roots or junction of the pulp chamber and the canals, then this tissue can possibly spread to either end of the tooth and start an infection thereby causing pain. (Another most common cause)
5) Sometimes a Root fracture after filling can also happen as after filling the roots tend to become brittle.
I will therefore suggest that you make an appointment with your Endodontist and discuss the above points with him.
Get an X-ray made for the same tooth, your dentist can evaluate the tooth conditions and can re-fill your tooth. Sometimes placing a Post and Core is the procedure that is required in order to rebuild and strengthen a tooth that had root canal treatment. It adds the proper support necessary to restore a tooth with a crown.
This link will help you to find an Endodontist in your area please check the following link :
I hope this helps!
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