Root Canal Treatment

Root canal treatment is needed when the blood or nerve supply of the tooth (known as the pulp) is infected through decay or injury. If the pulp becomes infected it may spread through the root canal system of the tooth eventually causing an abscess.

The tooth is numbed and cleaned using special instruments in combination with antibacterial medicines. Once the tooth is cleaned and dried it is sealed and filled to prevent re-infection of the tooth.

Root canal treatment weakens teeth as you have to hollow out the tooth to access the internal chamber of the tooth which is known as the pulp. This is where the blood vessels and nerves are located.  Posterior teeth are more likely to fracture after root canal treatment if they are not crowned. One study quoted that posterior teeth are six times more likely to be lost if they are not crowned following root canal treatment.

Anterior teeth can generally be filled with white filling material after root canal treatment unless there is not enough tooth left.

With any medical or dental procedure there are risks and complications that can happen. We have broken this down into expected, common and rare below.

Expected complications

• Numbness lasting a few hours as a result of the local anaesthetic.
• Discomfort will often occur after the anaesthetic has worn off. A number of patients have no discomfort but about 60% of patients require some analgesics such as paracetamol or ibuprofen. A very small number of patients (<10%) have post-operative pain which is more severe and lasts more than 5 days. If this is the case please contact your dentist.

Common risks and complications

• Weakening of the tooth being treated meaning it might require further work in the future such as a crown, to strengthen it.
• Darkening of the tooth.
• Inability to locate, clean and seal all parts of the root canal resulting in failure to remove all pain and/or infection. In some cases, even if the treatment is done to a high standard, the infection will not resolve. The anatomy of the tooth may be complex or some patients do not heal as well as others in general. The success rate of root canal treatment is often quoted at around 90% but if the treatment is unsuccessful it may necessitate the need for further treatment such as apical surgery or removal of the tooth.

Rare risks and complications

• Fracture of the tooth resulting in extraction being required.
• Separation (fracture) of an instrument within the tooth – the instruments used within the canals can fracture, especially if the anatomy of the root is narrow and/or curved. If the canal was cleaned out prior to the fracture occurring often there is no effect on the outcome. If the fractured instrument blocks the cleaning then it may need to be bypassed or removed to allow cleaning of the canal to be finished, which may require referral to a specialist. A fractured instrument is an obstruction but it does not in itself cause disease.
• Perforation – if a canal cannot be located then a hole might accidentally be made in the floor or root of the tooth by a dental instrument. This is called a perforation and can often be repaired using a modern cement. If it cannot be repaired the tooth will require extraction.
• Trauma to tissues underneath the tooth including bone, sinus, nerves supplying other teeth etc. This can be caused by one of the irrigants or medicaments used during the procedure.
• Allergic reaction to something used during the procedure.

There is a high risk of further pain and infection from the affected tooth. This infection can cause swelling and can spread to other parts of the body, potentially becoming life-threatening in some cases.

The only alternative option to root canal treatment to remove infection is to have the tooth extracted. This will leave a space which can be left or filled with either a denture, bridge or implant.