How Long Does a Root Canal Take?

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At Omega, Dr. Pedram Bohluli and Dr. Parastou Terrany, endodontists, handle root canal treatment.

How Long Does a Root Canal Take? The Short Answer by Tooth

It depends mainly on how many canals the tooth has and whether it's been treated before, so a front tooth is usually the quickest, and a molar or a retreatment takes longer.

A root canal removes the pulp from inside the tooth, then cleans, disinfects and seals the canals it sat in. A canal is the narrow channel inside each root, and the pulp is the soft tissue that holds the tooth's nerve and blood supply.

A front tooth usually has one canal. Molars have three or four, and some have more, so there's simply more to find, clean and seal.

For most teeth, the appointment itself runs 60 to 90 minutes. A molar with four canals takes longer than an incisor with one. Redoing an old root canal, called retreatment, takes longer than a first treatment, because the old filling material has to come out before the canals can be cleaned again.

The table below shows typical times and visits at our office. Your endodontist, a dentist with two or more additional years of specialty training, confirms your time once they've seen your X-rays. Canal shapes vary a lot from one tooth to the next, and much of that only shows up on X-rays or under the microscope.

If your appointment is already booked, our checklist on how to prepare covers eating beforehand, what to tell us about your medications, and what to have at home.

Times vary with the tooth, its canals and how infected it is. Your endodontist confirms your time and number of visits once they've examined the tooth and seen your X-rays.

What Happens During the Appointment

Every root canal follows the same order, whatever the tooth: X-rays, numbing, isolating the tooth, opening it, cleaning the canals, then filling and sealing them.

It's the same sequence the American Association of Endodontists describes. Here's what each step looks like from the chair.

• X-rays. We take X-rays if we don't already have recent ones, and on most cases a CBCT scan, a 3D X-ray, including every molar and every retreatment. It shows root shapes that a flat X-ray hides.

• Numbing. Local anesthetic goes in, we give it a few minutes to take hold, and we test the tooth before we start. A numb lip isn't proof of a numb tooth, so we check the tooth itself.

• Isolating. A rubber dam, a small sheet held by a clip around the tooth, keeps saliva out of the canals and rinsing solution out of your mouth. You can swallow normally the whole time.

• Opening and cleaning. We make a small opening into the tooth and remove the infected or inflamed pulp. Then we clean, shape and disinfect each canal. This is the step that grows with the number of canals.

• Filling and sealing. The canals are filled and sealed, and a temporary filling goes on the tooth until the crown or final filling is placed.

Our endodontists in Houston, Dr. Pedram Bohluli and Dr. Parastou Terrany, work under a surgical microscope. That's the difference between seeing a canal and estimating where one ought to be, and it's how a hidden canal gets found rather than left to ache afterward. At Omega, the microscope is used on every root canal, and the CBCT scan on most of them, including all molars and retreatments.

All of this is done under local anesthetic. If nerves are the bigger problem, we also offer nitrous oxide, which takes the edge off and wears off within minutes, and oral sedation, a tablet taken before the appointment that leaves you drowsy. Neither adds much time to the appointment, but with oral sedation you'll need someone to drive you home. For patients who find dental treatment genuinely difficult, IV sedation is available too; you won't remember the procedure, and you'll need a driver and the rest of the day off.

If what you really want to know is whether it hurts, read Is a root canal painful? for the honest version, including why a badly inflamed tooth can take extra numbing.

One Visit or Two?

Most teeth are finished in one visit; some, particularly badly infected teeth that need time to settle, are done across two, and that doesn't mean something went wrong.

A two-visit root canal goes like this. On the first day the canals are cleaned, medication is left inside the tooth, and it's sealed with a temporary filling so you leave comfortable. Once the infection has settled, you come back and we fill and seal the canals.

Molars with several canals, and retreatments of root canals done elsewhere, occasionally need a second appointment too. At our office, though, nearly every root canal is finished in one visit.

If you were told you need a root canal or a retreatment somewhere else and want another look before you decide, you can book a second-opinion consultation.

Studies comparing one-visit and two-visit treatment haven't found that either one works better, according to a 2022 Cochrane review of the research. What matters more is that the canals end up clean and the tooth gets its final restoration on time.

One more thing people mix up: the root canal and the crown are two different pieces of work. The canal work cleans and seals the inside of the tooth; the crown protects a back tooth from the outside. At Omega the crown can be placed right after the root canal treatment, so the tooth isn't left for weeks on a temporary filling.

Not sure how long your tooth will take? Our endodontists can examine it and tell you at a consultation. Book a consultation  ·  (713) 322-7474

What Makes a Root Canal Take Longer

Extra time comes from more canals, narrow or curved canals, active infection, a tooth that's hard to numb, or an old root canal that has to be taken apart first.

• Extra canals. The upper first molar often has a fourth canal that's easy to miss without magnification. Finding it takes time, and it's time worth spending.

• Calcified canals. Calcified means the canal has narrowed or partly filled in with hard tissue. It's common in older teeth and in teeth that were injured years ago, and these canals are slower to find and shape.

• Curved or unusually shaped canals. A sharply curved canal has to be cleaned carefully along its whole length. A CBCT scan can show these shapes before we start.

• Active infection. A tooth that's already abscessed, meaning there's a pocket of infection at the root tip, often needs the infection brought under control first. Sometimes that's the reason for the two-visit plan above.

• A tooth that's hard to numb. A badly inflamed tooth, often a lower molar, can need extra anesthetic by a different route before we begin. We don't start until it tests numb.

• Retreatment. Redoing an earlier root canal means working back through the existing filling or crown and removing the old filling material before the canals can be cleaned again.

Of these, the one that most often stretches an appointment at Omega is an active infection.

If your case is likely to be a long one, we'll say so and plan for it. Lying still with your mouth open is the part most patients find tiring, so we build in breaks.

How Long Recovery Takes

The numbness wears off in two to three hours, most people go back to work the same day, and the tooth is usually tender to bite on for two to four days.

Don't eat until the feeling has fully come back. It's very easy to bite your cheek or tongue without knowing.

The tooth is tender rather than disabling, so a normal workday is realistic. Most of our patients go back to work, and kids back to school, the same day. Take the rest of the day off if you're having oral or IV sedation, since you won't be driving or working. Do the same if the tooth was badly infected and the pain has been costing you sleep, since an infected tooth tends to take longer and you'll be tired afterward.

The soreness comes from the ligament around the root, which the instruments irritated; the inside of the tooth is settled. Your jaw may ache a little from staying open.

If the tooth was badly infected before we started, expect the tenderness to sit at the longer end of that range while the bone around the root heals. That's healing, not a sign the treatment failed.

Over-the-counter anti-inflammatories usually handle the soreness if you can safely take them. If you're not sure which one is safe with your other medications, ask us or your pharmacist.

Once the numbness is gone, eat soft food for the first day or two and chew on the other side. Rice, pasta, eggs and soup are all fine. Keep hard or crunchy food off that tooth until the crown or final filling is on. A temporary filling isn't built for a steak.

Two small problems are worth a call at (713) 322-7474 rather than a wait. One is a bite that feels high on that tooth, which makes it ache constantly and takes minutes to adjust. The other is a temporary filling that comes out.

How Long a Root Canal Lasts

A treated tooth that gets its crown or final filling on time can last many years, often for the rest of your life, though nobody can promise that about any tooth.

That's a different question from how long the appointment takes, but people ask both, so here it is. What decides the outcome more than anything is getting the tooth properly restored. A treated back tooth has lost structure inside and has an opening through its biting surface. Left on a temporary filling, it can crack under ordinary chewing.

A back tooth left without a crown after a root canal fractures at a much higher rate, and the ADA's patient site makes the same point: a crown protects a tooth that root canal treatment has weakened.

Most back teeth need a crown or onlay afterward. A front tooth sometimes needs only a bonded filling.

We don't put a percentage on it. With its crown on and normal care, a treated tooth usually lasts many years, often for life, though results vary from person to person.

The one problem a root canal can't fix is a vertical root fracture, a crack running down the root. When a treated tooth starts hurting again months or years later for another reason, it can often be saved with retreatment, so don't wait it out. The signs are covered in failed root canal symptoms.