Pain after root canal treatment is very disappointing. You've already had toothache, gone through the root canal procedure, paid the fees and now you still have pain!
What on earth could be the matter?
There are a number of things that can cause pain after root canal. Some of them may be preventable, some of them can be treated and will get better, but there are a few that cannot be fixed.
Here are some possible causes of post root canal pain:
But if bacteria are still in the bone around the root, it will be inflamed and painful. This will normally settle down on its own, given a little time.
Without a source of infection (the dead nerve in the root canal), the bacteria have nowhere to hide, and your own immune system will deal with the infection. You can speed things up with a course of antibiotics. Take a look at tooth abscess antibiotics.
If you have had an infection in the root of the tooth for a while, the bone around the root resorbs a little, and there is a small empty space around the root tip. So if a little dental cement gets out of the root tip, it's unlikely to cause a problem.
At the other extreme, if a LOT of cement is forced out, it can set up an inflammatory reaction that can be very painful. This may take a few weeks to settle down. If there is a LOT of excess cement in the bone around the root, it may need to be surgically removed.
It kills most bacteria inside the tooth.
It dissolves any remaining tags of nerve tissue inside the tooth.
It washes away the slurry that builds up during root canal treatment.
But sometimes (rarely) some bleach solution can escape out of the root tip. Normally, this causes immediate extreme pain, even with the area numb. The dentist will normally flush the tooth out with distilled water, dress it, and prescribe antibiotics and painkillers. But the area will still be painful for some weeks.
It's tender to bite on, and the gum over it may be tender too. Unfortunately the only solution is to remove the tooth.
To see what this looks like, have a look at cracked tooth root photos.
The root treatment may be perfect, but if the tooth is being bitten on too much, it becomes painful. The solution is relatively easy - the dentist needs to adjust the filling or crown slightly. Once he removes the "high spot", the tooth will settle down, although it can take 3 to 5 days.
However, if used carelessly, it is possible (although rare) for a tiny bubble of air to be trapped under the root filling as it is pushed into place. This gets pushed out of the tip of the root, causing pressure for a short time. This can be painful for a few days until everything settles down.
It is possible for a dentist to miss a canal. This means that there will either be a little bit of nerve left behind inside the tooth, or else a small space where bacteria can live, causing an infection.
In the first case, the tooth will be sensitive to hot and cold, mostly to hot things. In the second case the tooth will be sensitive to pressure. This will not settle down on it's own. The root canal treatment needs to be re-done, preferably by an expert endodontist.
But after a bit, the tooth becomes painful to bite on. In a way, this is similar to the situation above, because it is due to tiny spaces harboring bacteria. But these are spaces that are microscopic, and there are several of them, in the 3 millimeters at the tip of the root.
Sometimes this can be successfully treated by an expert endodontist, either by re-doing the root canal, or else by surgically removing the tip of the root. More on this at root canal surgery. But only sometimes. Otherwise, the tooth will need to be removed.
These are the main causes of pain after root canal. There are some others, but they are rare. Post root canal pain normally only lasts a few days, and then settles down. If it lasts longer than 3 to 5 days, I suggest contacting your dentist again for a review.