The purpose of this leaflet to discuss the risks and benefits of endodontic or root canal treatment (RCT).

Teeth are the hardest substance in your body but have live tissue inside them. Trauma or irritation from decay will cause inflammation, and as the tissue is unable to expand, severe toothache can result.

If the pulp tissue then dies, it can become infected, which will then give rise to a dental abscess. Teeth can have a varying number of roots ranging from 1 to 4, and occasionally more. They are all different shapes and sizes.

Endodontic treatment aims to remove all the organic debris from inside a tooth and then fill the space.

It is a technically demanding treatment and requires skill and training of a high-level from the dentist.

What are the Options if I have an Abscess or Severe Toothache?

If you have a tooth that in the dentist's opinion needs root filling, there are a variety of options:

  • Do nothing: antibiotics will resolve an abscess for usually 2 to 3 months: however, they do not reach the bacteria inside the teeth and so the abscess will recur.
  • Extract the tooth: this is reliable but if the tooth is important for chewing or appearance it can be difficult to replace. While it can be costly to root fill a tooth, it can be more expensive to replace it in other ways such as a bridge, denture or implant. At the same time if the tooth is so badly damaged it cannot be reliably restored then it is better off extracted, and an alternative solution pursued.
  • Endodontic treatment: as detailed above this has a relatively good success rate but will only work reliably if enough of the bacteria can be removed from the inside of the tooth, and then the tooth can be sealed against further bacterial contamination. Bacteria are very small (in the region of 2/1000 of a mm) so it is impossible to guarantee success.

What Can Cause Problems with the Treatment?

Endodontic treatment becomes more difficult to perform successfully for the following reasons:

  • More difficult on multi-rooted teeth
  • the length of time the tooth has been contaminated with bacteria
  • if the tooth has developed internal cracks
  • if the canals are severely curved or heavily calcified or sclerosed (backfilled)
  • Tooth location: the further back in the mouth the tooth is

A wide variety of problems can arise during treatment which can decrease the likelihood of success. The most common are:

  • The dentist may not be able to locate all the canals
  • An instrument can fracture in the tooth
  • the tooth can be perforated
  • the canal can become blocked

In some cases, it may be advisable to refer you to a specialist to undertake or complete the treatment. You can always ask to be referred if you wish.

Minor Problems During Treatment

There can be problems of a transient nature associated with the treatment.

It is quite common for the tooth to be slightly tender after treatment and occasionally there can be pain and swelling, although in most cases this will resolve without intervention. The temporary dressing that is placed in the tooth between appointments is important to prevent bacterial recontamination of the inside of the tooth. If you feel it is failing, then an urgent appointment is advisable.

To avoid further bacterial contamination of the tooth during treatment, it is nearly always done with a ‘rubber dam’ in place, which is a thin sheet of rubber stretched over the tooth to keep your saliva out of the tooth and isolate the area.

We usually take at least one or two x-rays during treatment to assess the shape of the tooth and the root structure; the x-ray is also used to assess the final root-filling.

Longer Term Problems

Another factor to consider is the prognosis of the tooth in the future.
It is pointless doing a root filling if the tooth cannot be rebuilt properly; at the same time, doing a root filling damages the tooth further as more tooth structure has to be removed.
All teeth that have been root treated should receive protective full coverage restorations, crowns or onlays in the medium term to avoid bacterial leakage and catastrophic fracture of the remaining structure.

The evidence shows that root-filled teeth with crowns or onlays survive far better than those without.

A survey in America looked at 1.4 million root filled teeth in 1.1 million people over eight years. The study found that 97% were still in place at the end of eight years. The 3% of teeth that had need of further treatment had usually required it in the first three years. 85% of the teeth that were extracted had not been protected against mechanical failure of the remaining tooth structure.

Another UK study using NHS data showed that a crown on the tooth gave better survival no matter how good or bad the root filling was on x-ray.

The charge for root fillings includes around £30-40 to cover the cost of the single use instruments we use. It is also for the time and expertise we spend doing the treatment - there is no guarantee of a positive result, but we do the best we can to ensure a successful outcome.

Success Rates

Studies have shown that in simple cases with no pre-existing infection, success rates can be as high as 96%. This drops to 86% where infection has been present for some time. Where retreatment is involved, success can be as low as 68%.

Success is higher in teeth that are crowned, and poorer overall in molars, single standing teeth and where the root-filled teeth are used to support a denture or bridge.

The main points are:

  • Root fillings work very well in many cases, but not all
  • If the tooth is very broken down, it may not be worth doing
  • If a tooth needs root filling, antibiotics will not ‘fix’ it
  • Root filled teeth are usually heavily filled and will often need crowns or onlays in the medium term to avoid mechanical failure.
  • Root filled teeth are more unreliable if single-standing or if they are used to hold up bridges or dentures as they are under more stress.