Can a tooth that has had a root canal become abscessed?

A root canal procedure can be started while an infection (abscess) is present but but probably not completed until another day, and it may be quite painful.The reason it will be painful is if the infection is located in such a way that it prevents the effective use of local anesthetics. Local anesthetics do not work well in infected tissues. During the procedure, the nerve of the tooth is exposed, touched directly, and removed. Local anesthetics are extremely necessary.

Once the tooth is opened there will be a large quantity of exudate (pus) present as well as blood. In order for the root canal to be completed properly, the bleeding and the exudate need to be gone. The long term success of the root canal is dependent on this.

An alternative would be to go on a regimen of antibiotics for a few days to knock down the infection and reduce the blood supply to the infected tooth. The root canal can then be completed, and it should be a lot more comfortable.

Ask your dentist about your options.