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Root canal filling

author icon By Dr. George Ghidrai

Root canal filling is the final step of any endodontic treatment.

After the root canals are cleaned, shaped and disinfected, the dentist fills each of the root canals and the pulp chamber with an inert material and seals up the opening.

root canal filling

a proper root canal filling on a dental x-ray

For the endodontic therapy to be successful, all root canal passages have to be completely filled, without voids. Canal fillings have to fully extend to the apex of each root.

Normally, root-filling materials are radiopaqueRadiopaque refers to a material or tissue that blocks passage of X-rays, and has a high density. It is the opposite of radiolucent tissue or materials, which allow the facile passage of X-rays, have a low density (air, liquids) and appear black or near black on X-rays., allowing verification afterward on a dental radiograph. Radiopaque structures are white or nearly white on conventional X-rays.

Root filling materials

  1. Gutta-percha

    Gutta-percha is the standard filling material. Gutta-percha is a natural polymer prepared from latex from a specific tree (the percha tree).

    Gutta-percha is manufactured and delivered in specific sets of gutta-percha cones (or points) of various sizes, color-labeled. White color has the smallest diameter while black the greatest.

    gutta-percha cones

    gutta-percha cones

    a set of gutta-percha cones, color-labeled

    a set of gutta-percha cones, color-labeled

    There are various techniques of placing gutta-percha inside root canals :

    • The standard endodontic technique involves inserting a gutta-percha cone (or a "point") into the cleaned-out root canal along with a sealing cement.

    • Another technique uses melted or heat-softened gutta-percha, which is then injected or pressed into the root canal passages.

    • The lateral condensation technique uses cold gutta-percha, which is pressed along the root canal with a specific instrument (the spreader).

      gutta percha lateral condensation technique

      lateral condensation technique

    Because all techniques have some unreliable aspects, many dentists use a combination of techniques.

  2. Root canal sealers

    Root canal sealers are paste-like materials which are inserted inside the canal passage with spiral (or carrier) files at low speed.

    Lentulo spiral file

    Lentulo spiral file

    There is a wide variety of root canal filling materials, from inert cement sealers to active materials, which aim to sterilize the canal passage.

    Normally, these materials are used in combination with gutta-percha and their main goal is to fill the remaining voids so that the root canal filling is as compact as possible.

Root canal filling procedure

Root canal therapy can be performed in a single appointment. However, there are situations when a medication is placed inside root canals for a week or more to disinfect canal passages and reduce inflammation in the surrounding tissues.

In these cases, the definitive root filling is performed after several appointments, depending on how long it will take for the tooth to heal.

Procedure steps

  • Many dentists will like to isolate the tooth from the other teeth with a rubber dam. This will keep the tooth dry and the root canal filling can be performed in an optimum environment.

    rubber dam

    a rubber dam is placed to isolate the tooth

  • The root canals are dried and a small quantity of root canal sealer can be placed into the canal passages with a spiral file at low speed.

    root canal filling

    a spiral file can be used to place root filling materials into root canals

  • Gutta-percha is inserted inside root canals using one of the techniques described above. As mentioned, many dentists prefer a combination of techniques.

    gutta percha placement

    a gutta-percha cone is inserted into the root canal

  • After the root filling is completed, an X-ray can be performed to verify the accuracy of the root canal filling.

Follow up

After "receiving a root canal", the tooth should be restored either with a filling or a dental crown. A conventional filling is the cheaper solution.

However, many practitioners argue that the tooth should be protected with a crown. Otherwise, over the years the tooth can fracture, since root canal treatments remove tooth structure from the tooth and undermine the tooth's structural integrity.

Another reason is that a crown has the best ability to seal the root-canaled tooth. If the tooth is not perfectly sealed, the root canal may leak, causing eventual failure of the root canal therapy.


Many people wrongly believe that once a tooth has had a root canal treatment it cannot get decay. A tooth with a root canal treatment still has the ability to decay, and without proper home care, the tooth structure can become severely decayed often without the patient's knowledge since the nerve has been removed, leaving the tooth without any pain perception.

Therefore, besides a proper oral hygiene, it is very important to have regular X-rays taken of the root canal to ensure that the tooth is not having any problems that the patient would not be aware of.

Last review and update: November 2022

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