Has My Root Canal Failed? | A Guide to RCT Success & Failure

Has My Root Canal Failed? | A Guide to RCT Success & Failure
November 6th, 2017 | Dental, Dr Robinson, Root Canal

What does a successful Root Canal feel like?

Is your root canal still giving you troubles after treatment?

It is normal for the tissue around the root of your tooth to be disturbed after root canal treatment (RCT), and the surrounding area to feel tender and sore. So, how do you know if this discomfort is a normal part of the recovery process or something you should be concerned about?

“Following a successful root canal treatment, the tooth should begin to settle and any pain should resolve. However, if your pain continues to increase after treatment or returns after your recovery, then an assessment by your dentist can help work out any underlying causes,” says Dr Stephen Robinson.

Root canal treatment is quoted as having a greater than 90% chance of success. So, what can go wrong? Below, we break down some of the ways a root canal can fail, and the symptoms you may experience in the case of a failed RCT.

How do I know if a Root Canal has failed?

Symptoms will affect the same tooth that was treated, or a surrounding area, such as the nearby gums. The common signs and symptoms of a failed root canal treatment include –

  • Tenderness or swelling
  • Pain on biting
  • A blister or pimple-like bump inside the mouth
  • Increased tooth mobility

What causes a Root Canal to fail?

A root canal failure occurs because bacteria remain present in the root canal, or find a way to re-enter the tooth after treatment.

Some of the reasons for a root canal failure include –

  • A leaking, or dislodged dental filling or dental crown
  • A cracked or fractured tooth
  • Dental decay, cavities or Periodontal disease
  • Incomplete removal of bacteria due to varying size and shape of root canal

Just like your other teeth, a tooth that has received a root canal is susceptible to decay and needs to be maintained with good oral hygiene. Your mouth is full of bacteria, and if appropriate oral care is not maintained then there is a risk that decay can develop. This decay can provide the access for bacteria to re-enter your tooth.

“A tooth that has had root canal therapy no longer has an active nerve, and unlike a normal tooth, this means that a cavity won’t be felt or exhibit pain,” says Dr Stephen Robinson.

“This means that after root canal treatment, it is beneficial to take extra care to keep your teeth free of decay, and to maintain your regular dental appointments so that the health of your teeth can be ensured.”

The Complexity of the Root Canal

Another common reason for the failure of a root canal treatment is that your root canals are not located or are only partially treated.

“Root canals can vary in size and shape, and this can make some canals harder to locate and treat in entirety. RCT is much more likely to fail if only part of the root is treated, and your dentist may choose to refer to an Endontics Specialist (Endodontist) in complex cases,” says Dr Stephen Robinson.

Root canals (shaded red above) can display a range of different complex structures and shapes,
as shown by these different diagrams of the same tooth.1 

Dr Stephen Robinson adds that some teeth can have ‘extra’ canals – for example, in most cases incisors typically have just one canal, but may also have a second canal in some teeth. These ‘extra’ root canals are known as accessory canals, and if they are not located appropriately, they can provide a site for bacteria to flourish.

What happens at a root canal re-treatment?

Before your root canal is re-treated, your dentist will assess your tooth to determine any of the potential causes for the failure of your first treatment. In complex cases, a referral to an Endodontic specialist may be deemed necessary.

During re-treatment, your dentist will –

  • Access the tooth by taking the crown or filling out
  • Remove any of the previous material from RCT
  • Clean & re-apply antibacterial dressing
  • Refill the Root Canal
  • Reseal and finish treatment

In other circumstances, a form of root canal surgery called an Apicoectomy may be considered. This involves accessing the root canal via the gum using surgical techniques and allows your dentist to clean and seal the area directly without removing the filling or crown.

My Crown Broke (or Dental Filling).
Will this affect my Root Canal Treatment?

It is important that you tell your dentist immediately about any issues with the crown or filling on any teeth that have had root canal treatment. As discussed previously – a dislodged filling or crown provides easy access for bacteria to re-enter your tooth, which is the primary cause of root canal failure.

“Any damage to your tooth, or the restoration that seals the tooth, should be reported to your dentist promptly. Discussing these issues with your dentist as early as possible can prevent the need for more complex re-treatment,” says Dr Stephen Robinson.



1 Root Canal Images @ http://rootcanalanatomy.blogspot.com.au/

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