Endodontic
Endodontics is the branch of dentistry that deals with diseases of the tooth's pulp. The pulp is found in the center of the tooth and in canals (called root canals) inside the root of each tooth. Pulp includes connective tissue, nerves and blood vessels. Pulp nourishes the tooth when it first emerges through the gum. Once the tooth matures, the pulp can be removed without destroying the tooth. That's because each tooth also is nourished by a blood supply in the gums.
Why would a tooth need root canal treatment?
Root canal treatment is needed for two main reasons. The first is infection. An untreated cavity is a common cause of pulp infection. The decay destroys the enamel and dentin of the tooth until it reaches the pulp. Bacteria then infect the pulp. Antibiotics can't get to infections inside teeth. The inflammation caused by the infection reduces the blood supply to the tooth. The reduced blood supply also keeps the pulp from healing.
The second reason for a root canal is damage to the pulp that can't be fixed. A fracture in a tooth can damage the pulp. So can a less severe blow to the tooth (trauma), even if there's no visible damage. Multiple fillings or other restorations on the same tooth also can damage the pulp.
Sometimes, common dental procedures can hurt the pulp. One example would be if a tooth is cut too close to the pulp while it's being prepared for a crown. Then the tooth might need a root canal.
When the pulp is inflamed but not infected, it may heal on its own. Your dentist may want to see if this will happen before doing root canal treatment. If the pulp remains inflamed, it can be painful and may lead to infection.
An infection in the pulp can affect the bone around the tooth. This can cause an abscess to form. The goal of root canal treatment is to save the tooth by removing the infected or damaged pulp, treating any infection, and filling the empty root canals with a material called gutta percha.
If root canal treatment is not done, an infected tooth may have to be extracted. It is better to keep your natural teeth if you can. If a tooth is missing, neighboring teeth can drift out of line. Keeping your natural teeth also helps you to avoid other treatments, such as implants or bridges. Also, if you ignore an infected or injured tooth the infection can spread to other parts of your body.
Having root canal treatment on a tooth does not mean that the tooth will need to be pulled out in a few years. Once a tooth is treated, and restored with a filling or crown, it often will last the rest of your life.
Procedure
First, your dentist or endodontist will numb the area around the tooth. You also may receive sedation, such as nitrous oxide. Your dentist also has other ways to reduce your anxiety. Before your first appointment, ask what is available.
A small protective sheet called a dental dam will be placed over the tooth to keep the area free of saliva. Then the dentist will make a hole in the top or back of your tooth to get to the pulp chamber. He or she will remove some of the diseased pulp.
Then the root canals have to be measured. Your dentist needs to know how long the canals are to make sure the entire canal is cleaned. He or she also needs to know how much filling material to put in the cleaned canals.
To measure the root canals, dentists use X-rays or an electric device called an apex locator. For an X-ray, your dentist will place a file into the canal and then take an X-ray. An apex locator measures a root canal based on its resistance to a small electric current. Many dentists use both methods.
After the canals have been measured, your dentist or endodontist will use special tools to clean out all of the diseased pulp. Then the canal is cleaned with antiseptic. This helps treat and prevent infection. All the canals within a tooth must be cleaned. Teeth have different numbers of canals:
- The top front teeth have one canal.
- The bottom front teeth have one or two canals.
- The premolars have one or two canals.
- The molars have three or four canals.
The location and shape of the canals can vary quite a bit. Some endodontists look inside the tooth with a microscope to make sure all the canals have been cleaned out.
Once the canals have been thoroughly cleaned, the roots are filled. A temporary filling is placed over the tooth. The top of the tooth should then be covered with a permanent filling or crown. The temporary filling you receive is not meant to last.
In most cases, the tooth will need a crown. A crown will help to restore the tooth's strength and protect it from cracking. If a crown is indicated it should be placed soon after having root canal treatment.
The pulp that was removed during root canal treatment is the part that responds to temperature. Your tooth will no longer be sensitive to hot or cold after the root canal is treated. There still are tissues and nerves around the tooth, however, so it will respond to pressure and touch.