Root canal treatment - The basics

Welcome. Our topic "Root Canal Treatment / Endodontic Therapy" is organized using the following subcategories.

What is root canal treatment?

What is root canal treatment?

Root canal therapy refers to the process by which a dentist treats the inner aspects of a tooth, specifically that area inside a tooth that is occupied by its "pulp tissue." Most people would probably refer to a tooth's pulp tissue as its "nerve." While a tooth's pulp tissue does contain nerve fibers it is also composed of arteries, veins, lymph vessels, and connective tissue.

For the purposes of this discussion, so to use terminology that people seem to be most familiar with, we will use the terms "nerve" and "nerve tissue" to refer to a tooth's pulp tissue.

Where precisely in a tooth is its nerve?

Teeth are hard calcified objects but their inner aspects are not completely solid. Inside every tooth there lies a hollow space which, when a tooth is healthy, contains the tooth's nerve tissue. Dentists use the following terms to refer to various portions of this nerve area

A) The pulp chamber.

This is a hollow space that lies more or less in the center of the tooth.

B) The root canals.

Each tooth's nerve enters the tooth, in general, at the very tip of its root(s). From this entry point the nerve then runs through the center of the root in small "root canals" which subsequently join up with the tooth's pulp chamber.

What is the function of a tooth's pulp tissue?

Initially a tooth's pulp tissue plays an important role in the formation and development of the tooth. Then, once the tooth has formed, the function of this tissue becomes one of helping to preserve the tooth's health and vitality. The pulp tissue keeps the organic components of the tooth's mineralized tissues (dentin and enamel) supplied with nutrients and moisture. The pulp tissue also produces new tooth structure (reparative dentin) as is needed so to help to wall off and protect the pulp from insult or injury (such as advancing tooth decay).

A tooth's nerve tissue does provide a sensory function but this role is probably different from what you expect. Under normal circumstances the nerves inside our teeth provide us with very little information. Yes, when activated by extremes in pressure, temperature, or severe insult (such as a cracked tooth or advancing tooth decay) teeth do respond with a painful sensation. But under normal circumstances the nerves inside our teeth remain relatively "quiet."

At this point you might be thinking that if you push on your tooth with a finger or close your teeth together you will feel a pressure sensation. Because of this you might assume that that sensation must come from the nerve inside the tooth. Well, in reality, that sensation comes from the nerves found in the ligament that binds the tooth to the jawbone, not from inside the tooth itself. This implies then, from a standpoint of the normal functions we perform with our teeth, that the presence of a live nerve inside a tooth is somewhat academic. If a tooth's nerve tissue is present and healthy, wonderful. But if a tooth has had its nerve tissue removed as a part of root canal treatment then that's fine too. You will never miss it.

Root canal treatment - The procedure

What is the purpose of the root canal procedure?

You could say that the purpose of root canal therapy is to create an end result where the tissues that surround a tooth's root will maintain a healthy status despite the fact that the tooth's nerve has undergone degenerative changes

How does root canal treatment accomplish this goal?

In a nutshell, the process of root canal treatment first removes (as thoroughly as possible) bacteria, nerve tissue, the organic debris left over from the breakdown of nerve tissue, and bacterial toxins from within the inner aspects of a tooth (the area originally occupied by the tooth's nerve tissue). Each of these items can produce tissue irritants that can cause your body to activate an inflammation reaction.

Subsequently, once this space has been cleansed the second half of root canal treatment involves filling in and sealing up the interior of the tooth.

Why go to all of this trouble?

The problem with teeth and infections is that once a tooth's nerve tissue has started to degenerate and bacteria have taken up residence in the tooth's nerve area, there is no effective way for white blood cells to get at the bacteria to combat them. The dying nerve's blood and lymphatic vessels used to transport white blood cells will have begun to degenerate too.

The net result of all of this is that the nerve space inside a tooth can provide a nice cozy cave-like location for bacteria to persist because it's a place where your body's defense mechanisms can't get at them effectively. With this scenario, at best your body will only be able to cordon off the infection caused by the bacteria living inside your tooth. At worst, this bacterial infection will overwhelm your body's defense mechanisms and pain and swelling will ensue (an acute tooth abscess).

The idea behind having root canal treatment is that it provides the bulk of the clean up work for your body. It removes bacteria and tissue irritants that are present inside the tooth, especially those in the locations where your body would have the most trouble combating them. As an end result, once root canal treatment has been completed it provides your body with an environment where its mechanisms are able to clear away any residual bacteria and tissue irritants that may still be present, thus allowing complete healing (resolution of the inflammation) to occur.

What are the individual steps of root canal treatment?

The root canal treatment procedure: What steps are involved with endodontic therapy?

A) Gaining access to the nerve area of the tooth.

As a starting point for the process of performing your root canal treatment your dentist must first gain access to that area inside the tooth where the nerve tissue resides. This is accomplished by using a dental drill and making an "access cavity" that extends down to the pulp chamber of the tooth. On posterior teeth this hole is made on the chewing surface of the tooth. On front teeth the access hole is made on the tooth's backside.

B) Cleaning the tooth out.

The next step of the root canal treatment process is for your dentist to clean out the interior of your tooth (the pulp chamber and all root canals). As we discussed previously, this cleaning process removes any bacteria, toxins, nerve tissue, and related debris that are harbored inside your tooth.

For the most part the cleaning process is accomplished by way of using "root canal files" and copious irrigation. Root canal files look like straight pins but on closer inspection you would find that their surface is rough, not smooth. These instruments literally are files and are used as such.

Your dentist will work a series of root canal files, each of increasing diameter, up and down in your tooth while simultaneously using a twisting motion. This action will scrape and scrub the sides of the tooth's root canal(s), thus cleaning it out.

As an additional part of the cleaning process, your dentist will wash your tooth out periodically ("irrigate" the tooth) so to help flush away any debris that is present. Traditionally, a number of different solutions have been used for this purpose. Nowadays, sodium hypochlorite (bleach, Clorox) is commonly used. An added benefit of bleach is that it is a disinfectant.

The goal is for your dentist to clean the entire length of the tooth's root canal(s), but not beyond. As a means of determining the length of a canal your dentist may place a root canal file in your tooth and then take an x-ray. Once developed the x-ray picture will reveal if the file extends the full length of the canal or not. Alternatively, your dentist may have an electronic device that can make this same determination when it is touched to a file that has been positioned in a canal.

Traditionally the filing action of root canal files has been created by way of the dentist manipulating them with their fingers. There are, however, special dental drills (dental drills are called "handpieces") which can hold and twist these files, and your dentist may choose to use one.

C) Placing the root canal filling material.

Once the tooth has been thoroughly cleaned your dentist can fill in and seal up its interior by way of placing root canal filling material. Sometimes a dentist will want to place the filling material the same day that they have cleaned the tooth out. Other times a dentist might feel that it is best to wait about a week before completing the root canal process. In the latter case your dentist will place a temporary filling in your tooth so to keep contaminates out during the time period between your appointments.

What root canal filling material is used?

The most common root canal filling material being used by dentists nowadays is a rubber compound called gutta percha. Gutta percha comes in preformed cones that are sized to match the files which have been used to clean out the inside of the tooth.

A root canal sealer (a paste) is usually used in conjunction with gutta percha cones. It is either applied to the cone's surface before the cone is placed into the tooth's root canal, or else applied inside the root canal itself before the gutta percha cone is positioned. Sometimes several cones of gutta percha need to be placed before the interior of the tooth has been filled adequately.

At times a dentist will warm the gutta percha cones (either before or after they are placed into the tooth) so they become softened. This allows the gutta percha to more closely adapt to the precise shape of the interior of the tooth.

After your dentist has finished the filling and sealing aspect of the root canal process they will place a filling in the access hole they created at the beginning of your treatment. The individual steps of performing the root canal treatment have now been completed.

How long does root canal treatment take?

The total amount of appointment time that will be required for your root canal treatment can hinge on a number of factors. Some of these are:

Different teeth have differing numbers of root canals, each of which need to be located, cleaned, and sealed. As an example, front teeth typically just have a single root canal while molars often have three or more canals.

Will your root canal treatment be completed in just one sitting or will the process be broken up into two appointments? At times a dentist will feel it is best to clean out a tooth during an initial visit and then have you return for a second appointment when they will seal up the interior of your tooth. Equally commonplace, a dentist may feel that it is preferable to perform both tasks during the same appointment.

You will have to ask your dentist what amount of time is needed for your treatment. As a ballpark estimate however, it seems likely that any single appointment will last somewhere between 30 to 60 minutes and in some cases possibly as long as 90 minutes.

Do "root canals" hurt?

Will you experience pain during your root canal treatment?

We'd be the first to acknowledge that root canal treatment has a reputation for being painful, but we'd be the last to agree that this reputation is deserved. It seems most likely to us that the majority of derogatory remarks you hear in regards to "having a root canal" almost certainly must have included in them references to the pain and discomfort that the person experienced leading up to receiving treatment.

For the average person and the average case, root canal treatment is a nonevent and not any more uncomfortable than having a filling placed.

If you are unequivocally anticipating that all root canal treatment results in an excruciatingly painful experience then someone has led you astray.

Will your dentist numb up your tooth prior to performing your root canal treatment?

Almost certainly your dentist will 'numb up' your tooth before performing your root canal treatment. Especially if you ask them to.

Nobody likes a bad time. (Not just you but your dentist too.) So, just so things go as smoothly and uneventfully as possible, most dentists will go ahead and numb up any tooth on which they are performing root canal treatment.

Remember, your dentist is trying to perform treatment that will hopefully last you a lifetime. They need to be able to concentrate on their work and not on how you are reacting to it. By numbing up your tooth both of you will be more at ease and relaxed.

Root canal treatment is a "good thing."

There are many reasons why a person should be eager to begin root canal treatment.

In those cases where a person's tooth has been the source of pain or swelling it is the root canal therapy that will initiate the process by which the painful or swollen tooth can be settled down. In some cases just those beginning steps a dentist takes as a part of performing root canal treatment can provide instant relief.

Even in those cases where relief is not total the treatment should at least significantly reduce the pain, and also set the stage where the healing process can begin to take place much more rapidly than if root canal treatment had not been initiated.

In those cases where no pain or swelling has been experienced, a person should still be eager to initiate their root canal treatment. In the absence of pain and extensive infection the treatment will just go that much more smoothly. You will be relaxed and well rested. Your tooth will respond to the steps of the procedure more predictably. Additionally, any tooth that is in need of treatment, but has not yet received it, is unpredictable. Having your root canal treatment completed sooner rather than later reduces the chances that you will experience a painful tooth flare up (an acute tooth abscess).

What should be expected after root canal treatment?

Will there be any pain or discomfort after your root canal treatment has been performed?

The hope is that after your root canal treatment you will notice very little discomfort with your tooth. It can be common that for the first day or so after its treatment a tooth might feel a little tender. Whenever you have a question, in all cases, you should feel free to contact your dentist's office just to ensure that what you are experiencing seems to them to be within normal limits.

A tooth's sensitivity can often be minimized by using an over-the-counter analgesic, especially one that also possesses anti-inflammatory properties. Ibuprofen (Advil or Motrin) can be an effective choice for this type of discomfort. Of course you should always read the label, indications, and warnings of any product you anticipate using so to insure that it is an appropriate drug for you.

Should you chew on a tooth that has just had root canal treatment?

Don't look for trouble. It is usually best to exercise caution with a tooth that is undergoing root canal treatment or has just had its treatment completed. Until your dentist tells you otherwise you should minimize chewing on the tooth. Here are some reasons why:

In those cases where more than one root canal treatment appointment is needed the temporary filling that has been placed in your tooth might come out. If it does, saliva and debris will contaminate the interior of the tooth again. Your dentist will have to spend your next root canal appointment cleaning your tooth out a second time.

Sometimes, since the tooth receiving the root canal treatment feels so much better, a person is eager to make use of their tooth again. Until your dentist has had a chance to finish rebuilding your tooth it should be considered to be fragile. What a disappointment it would be to spend the time, effort, and money to have root canal treatment performed, only to have the tooth break or crack irreparably before it was fully restored.

What other dental work may a 'root canaled' tooth require?

Restoring a tooth after root canal treatment has been completed.

What additional dental work is needed for a tooth that has had root canal treatment?

After your tooth's root canal treatment has been completed your dentist will need to discuss with you what additional dental work will be required so to make the tooth fully functional again.

Many times a tooth that has required root canal treatment is one that has a big filling or else has large portions missing due to decay or breakage. These teeth, in this state, are not as sturdy as they once were and for this reason it is commonplace that a dentist will recommend that a tooth that has had root canal treatment should be restored with either a dental crown or else a dental crown in combination with a dental post. Of course your dentist will need to determine what treatment is appropriate in your situation.

The dental restoration that is chosen for rebuilding a tooth that has had root canal treatment provides another function also. It provides a seal protecting the interior of the tooth. This barrier helps to prevent seepage of bacteria and contaminates from the oral cavity into the interior aspects of the tooth (a phenomenon termed "coronal leakage"). Your dentist will need to advise you as to what they think is best for your situation but, in general, the sooner arrangements can be made to have the permanent dental restoration placed (thus creating the best possible seal) the better.

Placing a post in a tooth that has had root canal treatment.

A "post" is a rod that a dentist has positioned and then cemented in the canal space in a tooth's root. Typically, but not always, dental posts are made out of metal.

Posts are usually only placed in those teeth which have extensive portions of their natural tooth structure missing. Dentists know, in general, that the greater the amount of a tooth that can extend up into the center of the dental crown, the more stable the crown will be. In those cases where a great deal of tooth structure is missing a dentist will "build up" the height of the tooth using dental filling material. A dental post provides a way for the dentist to securely anchor this filling material core to the tooth.

How does a dentist place a post in a tooth?

When placing a post a dentist will first use a drill and remove some of the gutta percha filling material that was placed during the tooth's root canal treatment. They will then cement the post and subsequently place a core of filling material around the post's upper portion, so to increase the overall amount of structure that will extend up into the crown.

Placing a dental crown on a tooth that has had root canal treatment.

A dentist will use a dental crown as a means of improving the appearance of a tooth, restoring a broken tooth to its original shape, and/or strengthening a tooth. Additionally, and very importantly, dental crowns create an excellent seal over a tooth. By this we mean that a crown cemented in place provides a barrier that is helpful in preventing bacteria and contaminates from seeping back into those inner aspects of a tooth where the root canal treatment has been performed. After a tooth has had its root canal treatment completed, any or all of these qualities which a crown can provide may be needed.

What can cause a 'root canal' to fail?

How long will a tooth that has had root canal treatment last?

No doubt it is the hope of your dentist that the root canal treatment they provide for you will allow your tooth to last a lifetime. This can certainly be the case and hopefully the outcome you will experience.

What can cause root canal treatment to fail?

Previously we described some of the goals of root canal treatment:

  • It removes bacteria, toxins, unhealthy nerve tissue, and irritants that are present in a tooth.
  • It fills in and seals off the nerve space inside a tooth so physically there is no location where bacteria and tissue irritants can exist and be out of effective reach of your body's defense mechanisms.
  • If after root canal treatment has been performed a tooth still harbors bacteria or irritants which keep the tissues surrounding the root of the tooth from being healthy (inflamed), then the treatment has not been successful. Some signs of failed root canal treatment can include tooth pain (ranging from very mild to extreme) and tenderness or swelling in the gums in the area near the tooth (ranging from very slight to pronounced). These signs can either:

  • Persist from the time of the root canal treatment.
  • Be transient (varying week to week or month to month).
  • Appear even though the tooth has been asymptomatic for years.
  • In other cases a tooth may have been, and continues to be, without symptoms but the tissues surrounding the tooth are identified as having the presence of persistent inflammation by way of a x-ray examination by a dentist.

In general, the presence of problems indicates that, despite your dentist's best efforts to clean and seal up the tooth, bacteria or tissue irritants have found some location in which to persist beyond the reach of your body's defense mechanisms. As a result there is persistent inflammation in the tissues that surround the tooth's root. Here are some of the reasons why this scenario might occur:

The shape of any tooth's root canals can vary greatly. As an example, there can be root canals that have branches or forks in them. This branching can be hard for a dentist to detect and, as a result, one branch may be cleansed and sealed while the other branch is left untreated.

A tooth may have more root canals than is normally anticipated. In these cases, especially when the unexpected root canals are very tiny, your dentist may not discover them and as a result not clean and seal them.

There is a crack in the root of the tooth. These cracks can be very small or else in a location in which your dentist cannot detect them.

The tooth has a defective or inadequate dental restoration and as a result bacteria have been able to seep past this restoration on into the inner aspects of the tooth and recontaminate that area originally cleansed and sealed off by the root canal treatment. This phenomenon is termed "coronal leakage."

Even though a tooth has been expertly cleaned and sealed, with the passage of time the integrity of this seal can degrade, thus allowing bacteria to recontaminate the interior aspects of the tooth.

Your dentist will have to evaluate your specific situation and advise you as to if they think the retreatment of your tooth is likely to resolve your problems. They may offer to perform this treatment themselves or they may feel that the expertise of an endodontist is warranted for your case. If retreatment is not a possibility then the tooth should be extracted.

Other problems and complications that can occur with teeth that have had root canal treatment.

It is possible that your tooth's root canal treatment has been successful but the tooth itself has experienced problems which have compromised it severely.

The tooth has broken in a fashion that cannot be repaired.

Teeth that have had root canal treatment are seldom as structurally strong as they once were. These teeth often require a dental crown so to adequately strengthen and protect them.

The tooth has extensive decay or gum disease.

Teeth that have had root canal treatment are not impervious to tooth decay and gum disease, both of which can lead to the loss of the tooth. You must brush and floss your teeth effectively so to prevent the occurrence of these problems.

Alternatives to having root canal treatment performed for a tooth.

Are there any alternatives to having root canal treatment?

If root canal therapy is indicated for a tooth there really is no alternative treatment other than an extraction. Root canal treatment deals with the inner aspects of a tooth unlike any other dental procedure. If it is required, no other dental work can suffice. If root canal treatment will not be a possibility for a tooth then it should be extracted.

Should you have an extraction rather than root canal treatment?

The cost or simplicity of a tooth extraction might seem attractive in comparison to having root canal treatment performed. But this solution might not be the easiest or least expensive treatment choice in the long run.

When a tooth is missing its neighboring teeth will tend to shift, sometimes significantly. This in turn can have a major impact on your dental health. Even losing a single tooth can lead to problems with your chewing ability or your jaw joint. Teeth that have shifted because of a lost neighboring tooth can be more likely to have dental problems themselves.

So to avoid these complications, in most cases your dentist will probably recommend to you that you have any tooth that has been extracted replaced. Replacing a tooth that has been extracted with an artificial one (using either a dental bridge, removable partial, or implant) can easily cost as much (and usually more) than ideal treatment for your tooth beginning with root canal therapy.

Don't make the decision to have a tooth extracted quickly. Make sure that you and your dentist have discussed and explored all of the benefits and detriments of all of the treatment options that are available to you before you make a decision.

Timing your root canal treatment.

In those cases where root canal therapy is needed it is always best to go ahead and make plans to have the treatment performed sooner rather than later. Sometimes, however, root canal treatment must be delayed because of scheduling conflicts, the need for other dental work, or else financial considerations. Delays such as these can usually be managed, at least to some degree. Often a dentist can perform the initial aspects of root canal treatment, the ones that can make it so your tooth feels better, and then schedule an appointment for you at a later date for the completion of the work.

You should not make a decision to delay root canal treatment unilaterally but instead discuss matters with your dentist. Any tooth that is in need of root canal treatment, but has not yet received it, is not predictable. A tooth could remain asymptomatic for an indefinite period of time or, at the other extreme, could abscess and cause you pain and produce swelling. Even in those cases where a tooth remains asymptomatic, the infection associated with the tooth could cause damage to the bone that surrounds it. Discuss matters with your dentist. Let them explain to you what they would consider a reasonable time frame for the treatment of your tooth.