Root Canal Treatments - Treatment

Authored by Dr Ben Williams, 09 Jul 2017

Reviewed by:
Dr Hayley Willacy, 09 Jul 2017

The RCT procedure will usually involve the following stages:

  1. Pre-operative X-ray: before starting RCT your dentist should always have a current X-ray to show:
    • The extent of any bone destruction at the root apex.
    • The shape, patency (whether the canals are open or blocked) and length of the roots.
    • The presence of any decay in the tooth.
  2. Local anaesthetic (LA) and placing a rubber dam: the LA may not be necessary if your pulp is already dead or was removed at an earlier appointment. All RCT should be completed under rubber dam; this helps to ensure you don't swallow or inhale any of the small RCT instruments or cleaning solutions. It also prevents saliva and germs (bacteria) from re-contaminating the root canal after it has been disinfected.
  3. Access the pulp chamber: this is achieved by drilling a hole in the top of the tooth, often through an existing filling to preserve tooth tissue. The dead or dying pulp remnants are removed and the small holes of the root canals are identified. The length of each root canal will be carefully calculated using an X-ray or an electrical measuring device.
  4. Canal disinfection and preparation: bacteria are killed and infected debris is removed by repeatedly flushing the canal, usually with dilute solutions of sodium hypochlorite (bleach). It is not possible to remove 100% of the bacteria from an infected canal but the aim is to remove as many as possible. The canals are also prepared using specialised screw-shaped instruments called endodontic files. These may be handheld or used in a slow-speed dentist's drill. The purpose of shaping is to remove infected dentine and form the narrow canal into a cone shape which is easier to fill.
  5. Assess level of infection: if your dentist suspects there is too much infection in the tooth or bone it may be necessary to place an antibacterial temporary filling for a few weeks. When the infection has healed, your toot canal treatment can continue. If there is little or no infection when the pulp was removed, your dentist might be able to complete the RCT in a single appointment.
  6. Placing the root filling: the final stage of RCT involves packing the root canal space, usually with a rubbery filling material and cement. This is done as tightly as possible to ensure that any remaining bacteria in the root canal are unable to get to a food source or spread out inside the root. Without food they should die off over time.
  7. Final X-ray and tooth filling: an X-ray is taken to assess whether the root filling material has been placed and packed correctly to the apex of the root canal. If necessary, adjustments can be made. A final tooth filling will then be placed to seal off the root filling and restore the tooth.
  8. Possible crown placement: if it is necessary to place a crown on the tooth, your dentist will often wait for several months after the RCT was completed. This provides some reassurance that the RCT has been successful before commencing with the crown treatment.

As well as the standard RCT outlined above there are several other treatments which relate to the root canal and dental pulp.


If a first attempt at performing RCT on a tooth has failed, it may be possible to remove the root filling material and attempt a retreatment. The success rate for re-RCT is slightly lower than for a first RCT on a tooth but there are many instances where they can be effective. For example, if an RCT failed because one of the root canals in a molar tooth was not identified and cleaned then a second attempt which filled all the canals might be more successful.


If a tooth has been root filled to a high standard but there is still ongoing infection in the bone at the tip of the root it might not be possible to attempt a re-treatment without damaging the tooth. In these cases a dentist might raise a flap of gum and remove bone to expose the tooth root. The leaking root tip can be then be cut off and the root canal sealed directly to ensure that no bacteria can leak from within the remaining root canal. This procedure usually takes about an hour and is performed under local anaesthesia.

Pulp cap and pulpotomy

If decay removal or a tooth fracture results in a small part of a healthy pulp becoming exposed, your dentist may try to retain the pulp vitality, or keep the pulp alive. This is achieved by placing a special layer of material, which promotes the formation of new dentine, on top of the exposed pulp before placing a filling. This technique is called a direct pulp cap. Alternatively, if only the exposed part of the pulp appears to be infected or inflamed then just the top half of the pulp can be removed, from within the pulp chamber. This leaves the healthy pulp still alive in the root canals which can be sealed off and protected before the tooth is filled. Follow-up X-rays and vitality tests are necessary to monitor the success of these 'vital pulp' techniques.

Further reading and references

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