Pain Under Crown Months After Root Canal?

Though it is rare, there are times when a tooth that has had a root canal can produce discomfort.  One of several things could be happening.

1.  The tooth has an accessory (extra) nerve that is small and perhaps was not found.

2.  The tooth has a crack that is usually between the roots.

3.  The existing crown may not be fitting as well as it could.  

I would have your dentist do an evaluation and take an X-ray.  He/she can then give you  possible causes of the pain and solutions to correct it.  Good luck.   

If pain after placing a crown on a root canal tooth, upon chewing, the best dental treatment is to see your dentist for possible bite (occlusal) adjustment, and an xray. Usually after bite adjustment the pain subsides, however if the root canal was not properly done, usually after placing a new porcelain crown, especially the more stronger porcelain crowns, such as E max, or Zeronia crown,the tooth can flare up, and even cause infection. Meaning a tooth that had no pain or discomfort, got agitated due to new biting forces. An expert dentist must always anticipate this problem when crowning a tooth with unsatisfactory root canal, so that is why he will usually refer you to an Endodontist to redo an unsatisfactory root canal prior to placing a new crown.If You do have sensitivity to hot and cold, it is very possible that an adjacent tooth or an opposing tooth may need dental treatment, in which this can be verified by xray, and clinical examination.

It is possible that one of the canals was missed when the root canal was done if the tooth is sensitive to cold.  It is also possible that an adjacent tooth is causing the sensitivity.  It can be very hard to localize pain from cold because of the type of nerve fiber that perceives the pain.  

You would need a 3D Cone Beam Scan to determine if there is another canal that might have been missed during the root canal treatment or there is a root fracture. Regular x-rays is two dimensional and sometimes the dentist will miss the additional canal during treatment.  
Typical fracture does not have throbbing pain. Usually one cannot bite down on it. Or it hurts upon releasing from the bite force.  Throbbing pain indicates either a very advanced fracture or beginning of another root infection.

Root canal treatments are performed when a tooth is sufficiently decayed or damaged to have caused an inflammation or infection in the roots.  During the process, we essentially remove the soft tissue (nerves and blood vessels) inside, clean, disinfect it and expand/shape the canals as needed, to allow us to fill and seal them up well. If the treated tooth is a premolar or back molar, it will likely have two or three roots, each one containing one or two root canals. If any part of the treatment goes wrong-- either because root canal spaces were not accurately determined, the canals are not thoroughly cleaned and disinfected, or they are not filled completely and densely with an airtight seal-- reinfection can occur, causing pain such as the one you describe. Patients requiring root canal treatment ought to always ensure they are treated by an Endodontist who is appropriately trained and equipped to perform the treatment, or an experienced dentist, with top notch imaging, obturation and apex locating technology at their facility. It may seem costlier at first, but if it avoids re-infection, it is the always the safest, smartest bet.

2 Possibilities of pain after Root canal treatment.

1. 8 months after root canal treatment, also throbbing pain, sensitivity to cold. Likely possibility that one of the Adjacent tooth or Opposing tooth on the same side of the arch may be having pulpitis. This could be more like a Referred pain originating from one of the teeth close to the root canal treated tooth. Your dentist can diagnose with an X-ray pic of the root canal treated tooth if that is the culprit or some other tooth near that.
2.  You can also have throbbing pain if the Pulp is not completely removed from the canals in the root canal treated tooth. The reason for pain is due to Pulpitis (inflammation). Your dentist can take an X ray pic to see if the root canal treatment is done well. If root canal is perfect and the tooth is Non - Tender to Percussion then the dentist will look for some other tooth with pulpitis near this tooth. He can therefore make a proper diagnosis and treat the cause.

If you are having pain in a tooth after 8 months of having the procedure done and a crown placed, it is probably due to one of the following reasons
1. There is probably an accessory canal that has been been missed.
2. The infection has not completely resolved in one of the existing canals and has possibly increased.
3. There is a crack in the tooth leading to pain on biting.
In either of these situations your dentist would probably want to do an x ray to evaluate the cause of the pain and treat it accordingly. There are times however where inspite of our best efforts as dentists, root canals fail and the tooth has to be removed.

There may be several reasons why a tooth may still experience discomfort after a root canal. One reason may be due to accessory canals where the nerve tissue was not completely removed in its entirety. Another reason may be a hairline crack in the tooth, which can lead to a vertical fracture although the tooth is still crowned. The best way to identify any potential problems is to get a CBCT (3D X-ray) of the area. This way your dental provider may have more information to further diagnose any problems.

Several possibilities exist as to your sensitivity and pain under your crown. Perhaps there was an additional canal that was not treated during the root canal procedure and is now causing your sensitivity because there may still be some vital tissue left. Additionally, the discomfort could possibly be coming from an adjacent tooth that has an issue going on. Sometimes it is difficult to discern exactly where the discomfort is coming from. My suggestion would be to visit an endodontist and have them make a diagnosis and hopefully resolve your problems

If you experience pain immediately after a crown is placed, usually that can indicate that a bite adjustment is needed. Since you are saying that you're having pain 8 months after the crown was placed, that can indicate that their needs to be follow up with the root canal. When root canals are done, there is a chance that small "accessory" canals can be missed due to their small size and difficulty in locating them. If this is the case, it may mean that your root canal is incomplete. Another possibility is that a fracture exists in the tooth. In both cases, you should see your dentist for follow up. If the treatment was done by a general dentist, you may need to go to a specialist to have the root canal evaluated. Hope this helps!