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Endodontics

What are Endodontic Treatments?

Endodontic treatment removes micro-organisms, relieves pain, and prevents reoccurrences.

If infectious micro-organisms get inside your jaw bone, they can cause swelling and significant discomfort. Endodontic treatment removes the micro-organisms, relieves pain, and seals the tooth against future bacterial invasion.

The most common type of endodontic treatment is root canal treatment. It is a procedure in which access to the hollow interior of the tooth (pulp) is made, in order to remove inflamed, infected or necrotic (non-living) nerve and blood vessel tissue. The root canals are disinfected, enlarged and hermetically sealed to the root tips with a rubbery filling material. Finally, the access hole into the tooth is filled with any of the available filling materials like silver amalgam, composite resin, porcelain or gold (usually at a separate appointment).

Your dentist may recommend that the tooth be crowned following endodontic treatment, especially if it has multiple cusps or multiple roots, and is structurally compromised. Normally the front six teeth in both jaws only have single roots, and many times those teeth don’t need to be crowned after endodontic treatment.

Endodontic treatment is prescribed for teeth that have been diagnosed with an abscess, irreversible pulpitis, chronic apical periodontitis, inflammatory resorption or are necrotic (filled with non-living blood vessel and nerve tissue). Endodontic treatment is also prescribed if the clinical crown of the tooth (the part that is visible protruding through the gum tissues) is badly broken down and would require structural posts to be placed in order to restore the tooth to normal function.

Sometimes a tooth that requires endodontic treatment will be obvious from an X-ray image, if there are obvious changes in the bone near the root tip(s)—even in the absence of symptoms. Sometimes teeth with deep decay (caries) require root canal treatment even though they may not hurt or be sensitive. A tooth that is particularly sensitive to hot temperatures, but is relieved by cold likely has gas from bacteria inside of it, most likely from an infection. Heating the tooth heats the gas, which, constrained by the hard shell of the tooth around it, cannot expand.

The result is that the pressure in the tooth increases and puts pressure on the nerve that you feel as pain. Teeth with such symptoms typically require root canal treatment to eliminate the infection. Teeth that produce continuous dull, achy pain frequently require root canal treatment. Teeth that have a prolonged, aggravated pain response to cold may need root canal treatment.

If you have been taking bisphosphonate medications, and require a tooth to be removed, you may not be a candidate for tooth removal without suspending the medication for a period of time in advance of treatment. In such cases, your dentist may recommend endodontic treatment of the tooth as an option, if it requires immediate treatment.

The process of endodontic treatment

Who will perform the procedure, and how will it be billed?

Before undergoing treatment, you should be aware that accessing the tooth, performing the root canal procedure, filling the access hole, and crowning the tooth (if necessary) are all separate, billable procedures. If the dentist who accesses the tooth is the same one who completes the root canal procedure, you will generally not be charged for the access separately.

The reason for this ambiguity is that one dentist may open up (access) your tooth to relieve the pressure (and pain) inside. Due to potential complexities, that dentist may elect not to complete the root canal procedure. Instead, you may be referred to an endodontist—a dentist with two to three years of additional training, who specializes in problems arising inside teeth. Both dentists have provided you with a valuable service for which they are entitled be paid.

If the same dentist performs the root canal procedure and the access filling, separate charges typically apply. However, you will generally not be charged separately when the same dentist accesses the tooth and completes the root canal procedure.

Many general dentists perform straightforward root canal procedures, referring to an endodontist only those patients whose root canals look especially difficult to treat. Some general dentists don’t perform root canal procedures at all. As with any dental treatment involving more than one dentist, it’s important to have a clear understanding of who will perform what treatment, and what the fees will be for each. If you’re not certain, ask your dentist or their care coordinator to clarify it for you.

Before the root canal procedure is started

When you have invasive dental procedures like root canal treatment done, the dentist will review your health history. If you have replacement joints (for example, total knee replacement, hip replacement, etc.), you may be pre-medicated with antibiotics for the procedure. If you have certain types of heart murmurs or replacement heart valves, you may also need to take an antibiotic pre-medication prior to the procedure.

If you are anxious about dental procedures, your dentist may recommend sedating you for the procedure. There are several methods of relaxing patients for dental treatment, including oral anti-anxiety pills; inhaled anti-anxiety medication like nitrous oxide; and intravenous anti-anxiety medication. Your dental plan may not pay benefits toward sedation.

The following describes the basic steps involved in root canal treatment. Your procedure may vary from the procedure described.

Anesthetic and X-rays

The tooth to be treated will be anesthetized by injecting local anesthetic around the nerve(s) that supply sensation to it. Discomfort from the injection can be minimized by use of a topical numbing gel for a minute or two prior to the injection.

A preliminary X-ray image (radiograph) is exposed to evaluate the length of the tooth, and study the root canals for obstructions, points of divergence, and other potential complexities. Additional images may be needed during the procedure, and a final radiograph will be exposed when the procedure is completed.

Tooth isolation and access cavity

Rubber dam and access cavity

A rubber safety dam is placed, and a high-speed dental handpiece is used to gain access into the tooth for the instruments that will be used to treat the infection.

The tooth to be treated is isolated from mouth structures like the lips, tongue and cheeks with a rubber dam (also called a dental dam), in order to prevent injuries from instrumentation, and to prevent the tooth from being contaminated with mouth moisture.

A hole is made into the tooth (called an access cavity), penetrating to the hollow pulp chamber and root canal(s) inside. If the tooth already has a crown, filling, or other restoration, the hole is usually made through it, and restored after the root canal procedure is completed.

Pulp removal

Cleaning, shaping, and enlarging the root canals.

A series of specialized instruments is used to clean, shape, and enlarge the hollow root canals where micro-orgnisms have established themselves.

Using specialized instruments, the nerve tissue and blood vessels (pulp) are removed from inside the tooth’s root canal(s). A common misconception is that “all of the tooth’s nerve tissue” is removed. However, the ligament fibers that connect the outer tooth root surfaces to the bone and gum tissues is also supplied with sensory nerve tissue that remains until the tooth itself is removed from the jaw, so the tooth will always be able to sense biting pressure as long as it remains.

There are two popular methods for establishing the proper length for instruments. The first involves insertion of a file to a depth equal to the root length as measured on the preliminary X-ray image, and exposing another X-ray image to check the file’s position. The file position could appear slightly inaccurate due to the angle at which the X-ray is exposed. The second involves use of a digital “apex locater”, which uses a low level electrical current applied to the root canal file. The microcircuit is closed when the file reaches the tooth’s apex.

Disinfecting, cleaning, shaping, and drying

Disinfecting a root canal.

Disinfecting solutions are used to flush away the microbes and lubricate the shaping instruments. The goal is to remove all infected tooth structure and to enlarge the canals enough so that the root canal filling materials can easily be placed.

Antibacterial agents like dilute Sodium Hypochlorite (household bleach), or chlorhexidine may be used to disinfect the root canal.

The root canal is further cleaned, shaped and enlarged by using flexible tapered files of successively larger diameter (debridement).

When the canals have been enlarged and shaped to the desired outcome, they are rinsed to remove the fillings and dried with absorbent paper points.

Sealing the root canals

Sealing the root canals with rubber points.

The root canals are filled with rubber points called “Gutta Percha,” which are coated with sealer cement for a hermetic seal. The rubber points are packed into the root canals and melted off, where they emerge from the canals into the crown of the tooth.

The root canals are sealed and filled with a biocompatible resin material (most commonly Gutta Percha) that hermetically seals the tooth against bacterial infection at a later date (obturation). The goal of endodontic treatment is to completely fill the inside of the canals all the way to the tip of the roots, and to seal any accessory; canals, which may be present. Accessory canals are smaller side canals that join the root canals mid-root.

Access Filling/Core Buildup/Final Crown

Root canal with structural posts.

Sometimes the dentist will enlarge one or more of the sealed canals to make room for placement of structural posts, if needed to help reinforce the core of the tooth. The posts usually extend to within 5mm of the root’s now-sealed apex. The posts are cemented into the canal, and the access hole of the tooth is filled.

Depending on which tooth required treatment, and the extent to which it was damaged, the final step can range from simply filling in the access cavity that was made into the tooth, to rebuilding all or most of the core of the tooth (core buildup), to covering the entire tooth with a crown or onlay. Normally these steps are not completed by an endodontist, and they are billed as separate procedures.

Multi-root, multi-cusp teeth (the back teeth) generally will have an onlay or crown prescribed following root canal therapy to prevent them from cracking in pieces and being lost. Studies have shown that the brittleness of teeth is unaffected by endodontic treatment, despite widespread beliefs to the contrary. However, the anatomic shape of, and heavier bite stresses on back (posterior) teeth makes them more susceptible to cracking than the front (anterior) teeth.

If cost is a concern, it may be possible to have a bonded or pin-retained filling placed, which can stabilize the tooth structurally long enough to allow the patient to budget for the cost of an onlay or crown. This is especially true if the enamel cusp anatomy of the tooth is reduced and covered with filling material, such that dividing forces cannot easily be developed that would split the tooth.

Your dentist is the most qualified to counsel you on the risk of your tooth fracturing following root canal treatment.

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Author: Thomas J. Greany, D.D.S. / Editor: Ken Lambrecht

This page was last updated on December 13, 2018.

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