The root canal system is located in the roots of each of your teeth. If it becomes infected, you may need root canal treatment to remove the bacteria and save the tooth. The practice of this dental procedure is known as endodontics.
In this article we will answer some of the most commonly asked questions about root fillings including:
- What is a root canal?
- What does the procedure involve?
- Does a root canal hurt?
- How long will it take to recover?
- How much is a root canal in the US?
We can't promise to make the procedure any more enjoyable, but at least you'll know what to expect.
Table of contents
- 1 What is root canal treatment?
- 2 The root canal procedure
- 3 How much does a root canal cost?
- 4 Is a root canal painful?
What is root canal treatment?
Dental root canal treatment, sometimes referred to as a ‘root filling' or just a ‘root canal', involves drilling right inside the tooth to remove decay deep down in the roots.
This type of infection can be a result of:
- Untreated tooth decay
- Faulty crowns or fillings
- A cracked or chipped tooth
- Repeated dental work on the tooth
- Damage from trauma (e.g. an accident or fall)
Once the root is treated, the root and tooth are filled to help preserve the remaining tooth. Teeth that have undergone root treatment are more fragile than healthy teeth. Your dentist may, therefore, recommend fitting a dental crown to help prevent further damage.
The tooth structure
Before we get into the details of what this procedure involves, let's take a look at the structure of a tooth.
The crown is the part that sticks up above the gum line. The section level with the gum line is called the neck, and the part below the gum is the root. The tooth root can be twice as long as the crown.
The hard white coating on the outside of the tooth crown is called enamel. This is the part you need to protect by brushing and flossing daily. A build-up of bacteria on the teeth resulting from poor oral hygiene can lead to dental caries (tooth decay).
If tooth decay erodes even a small amount of enamel, it leaves the rest of the tooth susceptible to infection. Once bacteria start eating away at the soft dental pulp inside the tooth it can quickly spread down the tooth root(s) through the root canal system. From here it can reach the surrounding bone and gum and cause irreparable damage.
Untreated root canal infections are likely to lead to an oral abscess.
How many roots and canals does each tooth have?
Each tooth usually has between one and three roots, although some may have four. Generally speaking, the larger the tooth and the greater the biting pressure it has to endure, the more roots it needs to keep it securely in place.
The table below shows the usual number of roots and canals for each tooth, but these are not set in stone.
|Type of tooth||Numbered position||Normal number of roots||Normal number of canals|
|Upper incisor||7, 8, 9, 10||1||1|
|Upper canine||6, 11||1||1|
|Upper 1st premolar||5, 12||2||2|
|Upper 2nd premolar||4, 13||1 or 2||1 or 2|
|Upper molar||1, 2, 3, 14, 15, 16||3||3, usually 4 or more|
|Lower incisor||23, 24, 25, 26||1||1 or 2|
|Lower canine||22, 27||1||1|
|Lower premolar||20, 21, 28, 29||1||1 or 2|
|Lower molar||17, 18, 19, 30, 31, 32||2||3, 4 or more|
Note that the molars in positions 1, 16, 17 and 32 (third molars) are wisdom teeth. Not everybody has these and they are often removed as a matter of course.
Since each individual root may have one or more canals, it can take several hours to properly clean and fill a single tooth. It's important for dentists to take the time to work on each canal carefully, though, because if any trace of infection remains or the hole isn't completely filled, there is a greater chance of complications.
When is a root canal needed?
If you have regular dental checkups your dentist should be able to identify and treat any tooth decay before it penetrates the root system. However, if you haven't been to the dentist for a while you may find the infection has already spread and you need root canal therapy to save the tooth.
Initial signs that you might need root canal work include:
- Your tooth is sensitive or painful when consuming hot or cold food and drink
- It hurts to bite down
- One of your teeth is loose
If you ignore these root canal symptoms, you may find they disappear over time. This isn't because the infection has healed itself; it just means it has destroyed the nerves contained in the dental pulp so you can no longer feel it.
Eventually, you'll notice these symptoms returning, possibly along with the following signs that the infection has spread much further:
- Swollen gums around the infected tooth
- Swelling in your face
- Pus oozing from your tooth or gum
- Discoloration of the tooth
Going to the dentist as soon as you experience any kind of tooth pain should help prevent the infection from spreading to this more serious stage. It won't heal itself, and the longer you leave it the less chance there is of root canal treatment being successful.
You also shouldn't rely on antibiotics to clear a root canal infection without any other dental treatment. Although you may be given antibiotics as part of your dental work, medicine alone won't be enough to kill the bacteria in your tooth.
If your root canal pain comes on suddenly and over-the-counter painkillers have no effect you should book an emergency dentist appointment. They may not perform an emergency root canal on the spot but can at least give you stronger pain relief until you are able to have the treatment you need.
Do I need a root canal or extraction?
The main priority of your dentist should be to preserve your natural teeth for as long as possible, rather than extracting them. When a tooth is removed it can affect how you eat and put extra strain on the surrounding teeth.
If the bacterial infection has spread through a lot of the tooth and the remaining structure is not enough to support a filling or crown, extraction may be the only option.
Your dentist will usually begin by taking x-rays of the affected area to determine the extent of the infected root canal. From these images, they will be able to see how many canals the affected tooth has, where they are positioned, and how many of them require treatment. They can then plan your course of treatment and let you know what to expect.
Note that if you have an infected wisdom tooth, there are certain situations where your dentist may opt to extract it rather than perform a root filling. If the tooth hasn't fully erupted, for example, or is in a position that's difficult to clean, your dentist may recommend extraction.
If the work you require is especially complex your dentist may refer you to a root canal specialist, known as an endodontist.
The root canal procedure
There are four main root canal treatment steps needed to restore a deeply infected tooth. These usually take place over one or two visits to your dentist. The number of visits required will depend on which tooth is being treated and the complexity of its root system.
Dental x-rays will give your dentist a good idea of the length of your visit(s). However, they can't know for certain how complex the treatment will be until they actually access your tooth roots.
Front tooth root canals tend to be more straightforward because they are easier to access and the canals are generally straighter and wider. This means that a root filling on a front tooth is usually quicker to complete than on a tooth at the back of the mouth.
The exact root canal treatment procedure will vary slightly from one clinic to another, but here is a basic outline of the steps involved:
After taking x-rays to plan your treatment, your dentist or endodontist will administer a local anesthetic. This numbs the area being treated so you shouldn't feel any pain.
It's good practice for dentists to fit a dental dam (cofferdam) while doing root canal work. This rubber sheet fits around a single tooth to isolate it from the rest of your mouth.
This serves three purposes:
- It protects the inside of the tooth from bacteria in your saliva
- You can swallow normally during treatment
- If the dentist drops a tool or some debris falls into your mouth, there is no risk of you swallowing it and choking
It's possible to perform this work without a dental dam, but professional endodontists should use one as a matter of course. When choosing a dentist to treat your infected root canal, ask whether they use a rubber dam to keep the tooth sterile. If not, consider finding one who does.
Opening the tooth
Using a drill, the dentist will make a hole in the top of your tooth (or at the back of a front tooth) through which he can access the pulp chamber and root system. Tiny little files are used to clear away the damaged and dead pulp and nerve tissue from inside the tooth and roots.
Root canals are very thin and are often curved, so it can take some time for the dentist to locate all of the canals and ensure all traces of infected material are removed. They often use special microscopes and bright lighting to help them see right inside the tooth.
If you have an abscess at the end of your tooth root, it will be drained at this point.
The narrow and irregular shape of root canals makes them difficult to fill properly. That's why your dentist will also use those little files to enlarge and shape each canal in the tooth. This process can take a few hours for teeth with several roots and canals.
Next, the inside of the tooth is cleaned thoroughly using water and an antibacterial solution (this may be done several times during the filing process, too).
Your dentist uses a syringe to squirt the cleaning solution into your tooth, then it is sucked back out. This is repeated several times to ensure the area is completely sterile.
If your treatment is too complex to complete in one visit, your dentist will fill the roots with some medication to kill any remaining bacteria. He will then apply a temporary filling to protect the tooth in between visits. This filling is removed when you return to complete your treatment.
Once all the canals have been cleaned and widened, it's time to fill them. This is often done with a thermoplastic material which, when heated, softens to fit the exact shape of the chamber. Dentists insert a number of thin cones into the canal and then compress them under heat to ensure complete filling.
It's important that the root canal filling totally fills the space inside the tooth, otherwise, it's more likely to become re-infected.
Once the roots are filled, the remaining space in the tooth is filled and restored just like a normal filling. This provides an extra seal to protect the roots from any more bacteria.
Because a tooth is more fragile following root treatment, your dentist may recommend you have a root canal and crown. A crown (also called a ‘cap') is a protective covering made from porcelain or metal. It covers the entire tooth to protect it from further damage.
To fit a crown, your dentist first has to shave some of the enamel off the outside of your tooth. Once fixed in place it should feel and function just like a natural tooth. Fitting a crown will, of course, add to the cost of your treatment.
Your dentist may wait a few weeks before beginning the process of crowning your tooth, just to be certain that the root canal filling was successful.
The video below from the American Association of Endodontists gives a quick summary of the procedure:
How long does treatment last?
Endodontics is a common dental practice with a relatively high success rate. Around 85% of treatments last for at least 8-10 years if the patient maintains good oral hygiene. Many go on to last a lifetime. Giving up smoking (if you currently smoke) will help prolong the effectiveness of any dental work while improving the overall state of your teeth.
If you experience problems with a tooth years after having a root filling, it may be possible to perform a root canal re-treatment and preserve the tooth for even longer.
One side-effect of root treatment is the tooth may darken over time. If this happens, especially with a front tooth, you may consider getting it chemically whitened so it's not as obvious.
How much does a root canal cost?
The cost of a root filling with a private dentist will depend on:
- Your dentist's location and private rates
- The extent and complexity of the damage
- Tooth size (specifically, the number of roots and canals)
- Tooth position (those at the back tend to cost more)
Dentists and root canal specialists probably won't be able to give you a fixed root canal price until they have examined your mouth and possibly taken x-rays to assess the condition of your teeth. You may still be able to get an idea of root canal costs by phoning around different clinics though, and it's worth doing this as prices can vary quite substantially from one to another.
To give a rough idea, private root canal treatment costs around $700 for a front tooth and $1,000 for a molar.
If you need extensive restoration work, you may find it more cost-effective to visit an overseas dentist for your treatment.
Patients from North America usually travel to Mexico or Costa Rica for low-cost dental work. If you live close to the border you can get your teeth done in a day and save hundreds or thousands of dollars in the process.
Many dental insurance plans cover endodontic work to some extent. If you have one, find out what percentage of root canal costs it will cover.
Is a root canal painful?
Many patients worry about root canal treatment pain and may put off getting the treatment they require because they fear it will hurt. Fortunately, the anesthetic technology used by dentists these days means the procedure can be performed with minimal discomfort. It should feel no different than getting a regular filling, except it will take longer.
For patients experiencing significant root canal pain prior to treatment, endodontic therapy provides considerable relief.
Many patients report having greater discomfort in their jaw (as a result of holding it wide open for so long) than in the treated tooth.
Your dentist should administer an anaesthetic before starting any work. Due to the length of treatment, this numbing medicine may need to be “topped up”. Ask your dentist for a way to signal if you start feeling pain at any point during the treatment. Often, all you need to do is raise your hand to let them know if you're not comfortable.
If you're feeling particularly nervous about your root canal treatment, you may be able to have an IV sedative while the work is done. This doesn't knock you out completely, like a general anaesthetic would, but it deeply relaxes you so you don't feel anxious and barely remember the experience.
Managing pain after root canal surgery
Root canal recovery shouldn't be painful, but your restored tooth may swollen or sensitive for a few days. During this time you can take ibuprofen or paracetamol to ease any discomfort.
You may find it more comfortable to only eat soft foods until your mouth feels back to normal.
If you experience continuing pain after taking painkillers or notice any other side-effects you should contact your dentist straight away. This is a sign of a failed root canal procedure and you may need extra dental care.
Root canal complications and problems
Despite the relatively high success rate of endodontic treatment, some patients do experience problems. Root canal complications can occur anywhere from a few days to a few years after the initial treatment.
A failed root canal can be the result of:
- The dentist missing a canal during initial treatment
- A canal being incompletely treated (i.e. the tip of the canal left untreated)
- Tissue left inside the tooth
- A fracture to the root
- Leakage of bacteria
If any of these complications arise, your dentist or endodontist will assess your tooth to see whether root canal re-treatment can be performed. The process for this is much the same as the original treatment, although it is complicated by the presence of the artificial tooth filling.
In most cases, the alternative to root canal re-treatment is extraction. Patients who don't wish to undergo further root canal therapy may instead choose to have the problem tooth replaced with a dental bridge or implant.
If a root canal fails because of re-infection at the tip of the root, it may be possible to perform endodontic surgery. This involves making a small incision in the gum to access the root tip directly. This allows the original structure from previous treatment to remain in place.
If you are concerned you may have a failed root canal, contact your dentist as soon as possible. The earlier it is treated, the less opportunity there is for the bacteria to cause more damage.
And remember, having regular dental checkups and maintaining good oral hygiene will reduce your chances of getting a tooth infection in the first place.