Root canal procedures have a terrible reputation for being painful. Perhaps the reputation is from the pain a patient experiences before a root canal treatment. Or perhaps people have heard bad stories of unskilled dentists performing root canals. In any case, in my 15 years of experience, once a patient is numb, the procedure is much like any other dental treatment. In addition, root canals are typically uneventful for the patient, even when it is challenging for the dentist. This article and the accompanying video will discuss what happens during the root canal procedure.

What Are The Steps of a Root Canal Procedure?

1. Numb the tooth.
2. Isolate the tooth.
3. Make an access opening into the tooth pulp chamber.
4. Locate all the main root canals.
5. Clean and shape canals with files. (Includes removing the nerves)
6. Irrigate the canals with NaOCl.
7. Seal root canals.
8. Seal off access opening temporarily or permanently.
9. Place a post and crown, if needed.
Deep Decay in Tooth to Pulp chamber ttoth Needs Root Canal Procedure

Numbing a Toothache for a Root Canal Procedure

While numbing may seem straightforward if a tooth has a severely painful infection, it can interfere with achieving profound anesthesia. Therefore, the dentist may need to drain the infection or prescribe a round of antibiotics first to achieve numbness for a hot tooth, which dentists call a very painful tooth. However, if a root canal is needed urgently, most times, you can obtain profound anesthesia even with a hot tooth.
Amoxicillin 500mg Bottle Antibiotics for a Dental Abscess

Does a Root Canal Need a Rubber Dam?

A rubber dam is almost always necessary for a root canal procedure. Its purpose is twofold. It prevents infection from getting in your mouth, and more importantly, it creates a barrier to stop what is in your mouth from getting into your tooth. We call this isolating the tooth, which keeps the inside of the tooth as clean as possible during treatment. Dentists always try to use a rubber dam but can’t use it in every case. For example, the rubber dam is intolerable for some people, and we can do a root canal procedure without it, but using it increases the chance of a successful root canal.
Rubber Dam Placed Over Tooth for Root Canal Procedure

How Do You Access Endodontics For Root Canals?

Endodontics is the name for treating the interior of the tooth. To treat the inside of a tooth, you must make an access opening or hole in the upper portion to expose the tooth's root canals. The access opening extends through the tooth's crown to the pulp chamber. The opening needs to be wide enough to gain access to every canal in the tooth but not wider than that. The tooth can become excessively weakened and fracture if the opening is too broad. The final crown often prevents these fractures, but a dentist must take some care not to widen the opening excessively.
Tooth with An Access Opening In Root Canal

How Do You Find The Root Canals?

With the pulp chamber now open, we look for all the canals in the tooth, which present as small holes in the floor of the pulp chamber. We find the holes using a long pointy metal instrument called an endo explorer. When you find a canal, this tip will stick slightly in it when you try to pull it out. Finding all the canals can be challenging as these canals constrict, calcify and become smaller in time; in other words, the older you are, the smaller they get. Sometimes they become so narrowed that they seal off completely.

It isn’t straightforward how many canals each tooth will have. Dentists have a good idea about how many and where the canals are, but it can vary quite a bit for each individual. For example, look at the image of the tooth in this section. This tooth usually has three canals, but this one has four canals. Can you find the canal openings? Probably not. I could only find them by feeling with the endo explorer at first. But You can see where they are once I have filled them.

Can you find the root canals in a molar toothWhere the 4 canal are in the tooth pulp floorFilled Root Canals with Guttapercha

How Do You Clean And Shape A Root Canal?

After finding the root canals, we clean and shape them with a series of files. When healthy, each of these canals has a nerve and blood supply. If this blood supply dies, your body cannot fight an infection that gets into these canals. So the reason we are doing the root canal is to seal off the canals from bacteria. To do this, I remove the nerve and tissue in the canals with a long, rotating mechanical file. Luckily in this example, when I remove the nerve from the tooth, it wraps around this file instead of getting torn to shreds. You can see that in the accompanying video to this article. Unwrapping the nerve is one of the few joys of being a dentist.

After removing the nerve, we use a series of mechanical and manual files to unclog and shape each canal nicely so we can fill them. This part takes a lot of skill as there are a lot of challenges. If you go too fast or hard, the instruments can break, which isn’t too bad if it seals off the canals adequately, but it can also be a problem that requires attention. Either way, taking it slow and avoiding broken files is best. Also, if a dentist is too aggressive, the files can make a hole in the side of the root called a perforation or leave the roots so weak that they break in the future. In addition, these canals can become blocked, and unclogging them is a big hassle. Lastly, you must ensure you file within 1 millimeter from the tip of each root, or the root can become re-infected.
GIF of mechanical File clean and shape root canal

Why Do You Irrigate The Root Canals?

Once we clean and shape the canals, we irrigate them with sodium hypochlorite or bleach. If you shape the canals sufficiently, the bleach irrigation will kill all the bacteria in the canals. However, for some people with significant infections, this can burn when bleach travels through the abscess far past the root tip. The burning sensation will subside but can leave the tooth tender as it has spread far to kill off the infection.
Irrigating Root Canal Bleach Sodium Hypochlorite NaOCl

How Do You Seal Off The Root Canal Procedure?

To seal off the root canals, we fit these long rubber-like cones made of gutta-percha into the canals. These cones are the same size and taper as the mechanical files, so they should fit in the canals just like the files you used. Before we finish, we take a quick x-ray of the cones in the tooth to confirm that they fill the canal to the correct length. Our x-ray looks good. So we irrigate with the bleach one more time, and then we take paper cones of the same size and dry the canals. After drying them, we mix the sealer, coat the canals and cones with the sealer, and place the gutta-percha cones back in the canals. After all that, we melt off the excess gutta-percha sticking out of the canal openings.
Tooth with An Access Opening In Root Canal and filled Guttapercha diagram copy

How Do We Seal Off The Access Opening?

After a root canal treatment, there are a few possibilities to seal off the access opening. We commonly place a piece of cotton and a temporary filling to seal off the tooth for a few days while we monitor the root canal healing. Then a few days later, we will permanently seal off the tooth. The dentist should replace the temporary filling within 14 days because it can start to leak saliva, bacteria can reenter the canals, and the root canal can fail. To avoid this scenario, some dentists opt to seal off the root canal right away permanently.

 To permanently seal off the opening, the tooth will need either a build-up or a post with a build-up. A build-up is a material that fills in the access opening and strengthens the upper portion of the tooth so it is not too fragile. If the remaining upper portion of the tooth is exceptionally susceptible to fractures, the dentist may use a post in addition to the build-up. The post will support the upper part of the tooth by drawing strength from the root portion.
Tooth Diagram An Access Opening fill guttapercha cotton

Does A Tooth Need a Crown After A Root Canal?

Some anterior teeth and every posterior tooth with a root canal will need a crown to prevent it from breaking. The picture in this section is a fractured tooth a few months after a root canal because he didn’t have a crown placed on it.

 A dentist will normally evaluate a front tooth to decide if has enough strength after a root canal to avoid a crown. However, every premolar and molar should have a crown after a root canal, even if it feels stable. This study reveals teeth with a root canal, build-up, and crown on average last 20 years. With only a crown or build-up, the teeth, on average last about 11 years, With neither a crown nor filling, they last about 6.5 years.

Watch my video on cosmetic crowns. Crowns can look very beautiful and even better than natural teeth for some people.

Tooth Diagram Access Opening In Root Canal Guttapercha Post Filling Crown

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