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.

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.

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.

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.

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.