Patient Information


Endodontics is the branch of dentistry concerned with the morphology, physiology, and pathology of the human dental pulp and peri-radicular tissues. The study and practice of endodontics includes the biology of the normal pulp and peri-radicular tissues and the aetiology, prevention, diagnosis and treatment of diseases and injuries that affect these tissues.

General overview

Endodontic treatment is a specialised branch of dentistry known also as root canal therapy. Endodontics is carried out by general dentists and specialists endodontists to relieve dental pain and resolve infection or a disease process in teeth. The aim is to save teeth by locating the infected or irreversibly inflamed dental pulp in the root canals. The canals are thoroughly cleaned, then sealed to prevent re-infection.

Toothache can arise from a number of causes and appropriate treatment options can only be considered after a detailed mouth examination, x-rays and other tests in order to make a diagnosis. Factors such as a patient's medical history, oral cleanliness and health of the gums, and the amount of tooth and bone support remaining are important considerations in deciding whether a tooth has a reasonable long-term future or whether extraction should be considered. Replacement options for extracted teeth continue to improve but are generally much more expensive and less satisfactory than natural teeth.

What's Inside a Tooth?

The outermost layer of the tooth material is called "enamel", which is hard and solid. The inner layer of the tooth material is called "dentine". Both are hard and mineralised layers. Inside the tooth there is a small, delicate space called the "dental pulp" or what people normally refer to "tooth nerve". The dental pulp is a delicate structure that contains nerves and blood vessels that help nourishes the tooth and provides the tooth with sensation. The pulp is also responsible for most of the early growth and development of the tooth in childhood. See the illustration bellow which describes these structures.


Cross section of a tooth

What is endodontic treatment?

Endodontic treatment is a procedure carried out to preserve a tooth that may otherwise require extraction. There are many advantages of saving natural teeth including;

  1. Proper function, appearance and ability to talk.
  2. Natural teeth maintain the height, thickness and shape of your jaw bone. Loss of natural teeth can compromise the bony support for face muscles, affecting face shape.
  3. Loss of a single tooth that is surrounded by natural teeth would allow the adjacent teeth to drift into the space that is created by the lost tooth. That can create problems with the bite or open spaces between the adjacent teeth that may contribute to gum problems.

What caused the problem with my tooth?

The most common cause of pulp damage is deep tooth decay. Other factors could also damage or expose the pulp to bacteria that cause pulp inflammation or infection. Among the other causes are tooth fracture, traumatic injury such as a blow to the mouth, a cracked or loose filling or repeated restorations, and less frequently periodontal (gum) disease.

How many appointments are necessary?

Endodontic treatment is usually completed over two or three visits. In some cases it could be completed in one session.

How long will the tooth last?

With proper restoration and care endodontically treated teeth can last as long as any other tooth. There are many factors that determine the long-term survival of a root filled tooth including, but not limited to, the condition of the tooth before treatment, the type of tooth restoration following the treatment, the way teeth bite together and habits such as grinding or clenching teeth. Good oral hygiene, avoidance of a high sugar diet and periodic dental check-ups facilitate the long term survival of endodontically treated teeth.

Does endodontic therapy hurt?

Root canal procedure is usually carried out under local anaesthetic. The procedure should not be painful. However, when tissues are very inflamed causing severe toothache, this is the most difficult situation in which to achieve complete relief of pain. In these situations more than one method or technique for administering local anaesthetic may be required to achieve good pain control.

Will there be pain after procedure?

The majority of patients experience no or very minor discomfort. Sometimes teeth may be tender to bite on for 2-3 days after treatment. This is not uncommon and should be controlled by ordinary pain relief. Some teeth take more time to settle however, if the pain persists you should contact your dentist or endodontist.

How much does endodontic treatment cost?

The cost of root canal procedure can vary depending on several factors. The front teeth are usually easier to treat and therefore treatment may be less expensive than treatment of back teeth. The factors that determine the cost of the procedure are the difficulty of the treatment, complexity of procedure, time required for the treatment and the materials used for the procedure. You need to discuss cost with your dentist or endodontist. Generally, endodontic treatment is much less expensive than extraction and replacement of teeth with a bridge or an implant.

What are the alternatives to endodontic treatment?

The alternative to endodontic treatment is usually tooth extraction. The options after extraction are to accept a gap or replace the tooth with an artificial replacement to restore function and aesthetics. The prosthetic or artificial replacement options include implant-supported crown, bridge restoration or removable partial denture (Plate). It may be important to confirm that a replacement option is possible before electing to have a tooth extracted.

Can all teeth be treated endodontically?

With the recent advances in this field, endodontic treatment options can be offered for an increasing number of teeth that were traditionally considered not treatable. Even back teeth that are difficult to access can be effectively and satisfactorily treated. An individual assessment needs to include consideration of the medical history, acceptance/tolerance of the procedure itself, a detailed assessment of the tooth in question, the long-term outlook for the tooth and each individual patient's wishes.

Can endodontic treatment fail?

Endodontic treatment has high success rate. The success rate of this procedure varies depending on several factors. Generally, and if performed to high standards, root canal procedure does enjoy high success rate in the long term. Problems, however, do occur with root filled teeth. If the root filled tooth develops decay or its restoration fails or leak it could lead to endodontic treatment failure. In some other cases and despite good care the tooth may not heal as expected. Further endodontic treatment or surgery may be indicated if appropriate to deal with the treatment failure. A tooth that develops vertical crack or fracture can also fail, which often require extraction.

Will I need to return for any additional treatment?

It is usual for healing to be reviewed about 6 months after root canal treatment to determine whether healing has occurred. Sometimes, more than six to twelve months are required to confirm that healing has taken place. You may need to return back to your dentist for the permanent definitive crown restoration if healing has been confirmed and your tooth needs a crown.

Want to know more?

If you have more questions before, during or after your treatment, your dentist will be happy to answer your questions.

What do I do after endodontic treatment is completed?

Following your root canal treatment, the crown of the tooth should be restored with a permanent restoration which protects the remaining tooth from the risk of fracture. Your dentist may suggest you have a crown to protect a tooth where it has been heavily filled.

What is Endodontic Retreatment?

Teeth that have had root canal treatment can last for a very long time, however, in some cases the treatment can fail or signs or symptoms of infection or inflammation can persist. This could happen shortly after the treatment has been performed or many years following the treatment.

In these cases it may be possible to repeat root canal treatment. This procedure is called endodontic retreatment. Endodontic retreatment involves the same steps of root canal treatment with the additional step of removing the old root filling material.

Why does the treatment fail?

Endodontic treatment may fail for a few reasons. The most common cause of endodontic treatment failure is residual infection inside the root canal system. In some cases bacteria can survive the initial cleaning and disinfection protocol. The root canal system is quite complex and it may not be technically possible to eradicate bacteria completely from this space.

Secondary infection or re-infection of the root canal space is another common cause of root canal treatment failure. If the final restoration was not placed quickly enough or leak due to poor fit, fracture, shrinkage or recurrent decay, bacteria can re-enter the canal space. If left long enough that can cause treatment failure.

There are other biological reasons for endodontic treatment failure including apical lesion of cystic nature. Some of these lesions do not respond favourably to endodontic treatment. Bacteria surviving outside the confines of the root canal space in the bone around the root is another cause of treatment failure. The options in the event of endodontic treatment failure are re-treatment of the root canals, or a surgical approach to the problem or extraction of the tooth in question.

Is retreatment more complicated than initial root canal treatment?

Endodontic retreatment is usually more difficult and complicated than the first root canal treatment. It follows the same principles or steps of conventional root canal treatment with the additional step of having to remove the existing root filling material. This may involve gaining access through a crown and/or, require removal of a post that had been inserted prior to restoring the tooth after the initial root canal treatment.

Who does the retreatment procedure?

Most dentists carry out endodontic treatment and some carry out endodontic retreatment. Patients requiring endodontic retreatment procedures may be referred to an endodontist.

A specialist endodontist is a dental practitioner who has obtained post-graduate qualification approved by the Dental Council of New Zealand to register as a specialist in the field of endodontics. Endodontists can perform a wide range of endodontic procedures and have the right training, knowledge, experience and equipments to deal with these more difficult situations.

What will happen if I am referred to an endodontist?

You will need an initial consultation as appropriate treatment options can only be considered after a detailed mouth examination, x-rays and other tests in order to make a diagnosis. Factors such as a medical history, oral cleanliness and health of the gums, and the amount of tooth and bone support remaining are important considerations in deciding whether a tooth has a reasonable long-term future or whether extraction should be considered. You can expect to be advised what the problem is, the options open to you, the costs involved and the likelihood of success.

What will happen during endodontic retreatment?

Endodontic retreatment is usually commenced by gaining access to the root canal space. That would often necessitate removal of the complex coronal restoration and in some cases poorly fitted or old crown and root post. Once the previously treated canals are identified, the old root fillings should be removed, and the root canal space is fully explored. The canals are then cleaned and medicated with antibacterial dressing and the access cavity is sealed with temporary restoration. Subsequently, and usually at a later appointment, the canals are sealed with new root fillings and the crown of the tooth is finally restored with appropriate restoration.

Will the retreatment be successful?

Because of the latest advances in endodontics, endodontic retreatment can be carried out with high degree of predictability. If the cause for previous treatment failure can be identified and corrected, then endodontic retreatment would have a high chance of curing the associated disease process. For more information about likelihood of success you need to discuss this with your dentist or endodontist.

How much will the procedure cost?

The cost of endodontic retreatment varies depending on the complexity of the procedure and the time required to complete the treatment. Because of some of the additional steps involved, endodontic retreatment may be more costly than the initial endodontic treatment.

What are the alternatives to retreatment of the root canals?

In most instances endodontic retreatment is the treatment of choice where initial endodontic treatment has failed. Endodontic surgery can in some instances be used as an alternative to or in addition to endodontic retreatment. Endodontic surgery is a minor surgical procedure that allows surgical access to the tooth root(s) and surrounding bone. You should ask your dentist or endodontist about the advantages, disadvantages and likelihood of success for this option. The other alternative to endodontic retreatment is extraction of the tooth.







NZSE Endodontic Symposia 


Online starts Feb 23rd 2022


Trans-Tasman Endodontic Conference

(TTEC) 2022  

Sydney, Australia  2-4 June 2022