Does having root canal therapy hurt?

- Root canal treatment has a reputation for being painful. But this page explains why that belief isn't necessarily valid. | What's your potential for feeling pain? - Statistics | Steps your dentist will take, and can take if needed, to minimize procedure discomfort.


Link to Numbing Your Tooth section.

When covering the topic of root canal procedure discomfort, the discussion needs to be broken down into subcategories. That's because the possible pain issues associated with each of the different aspects of having endodontic therapy are different and varied.

Here's how we've subdivided this topic. This page discusses pain management as it applies to:

  • Regularly scheduled appointments. - (Managing discomfort while performing the steps of endodontic therapy.)

    For the average person and average case, experiencing root canal treatment isn't all that much different from having other routine dental procedures performed (like having a filling placed). Here's information and statistics about what you can expect and why.

  • Postoperative pain or sensitivity. - (Managing after-visit problems.)

    While it's not the norm, there is the possibility that a patient will experience some degree of discomfort after having root canal work performed.

    Use this link for an explanation of the causes, treatment solutions and statistics associated with post-op issues.

  • Emergency visits / Flare-ups. - (Managing the discomfort that has signaled the need for endodontic therapy, or in the case of previously treated teeth, case failure.)

    Some people will experience an acute tooth flare-up during which they experience mild, moderate or even excruciating pain.

    When these types of situations occur it can be a challenge for a dentist to painlessly treat the severely inflamed tissues involved. This link explains why and what can be done.

1) There's no reason to expect that regularly scheduled appointments will hurt.

When it comes to having root canal performed, what you've heard may not necessarily be accurate.

As evidence of the level of misconception that abounds, a survey conducted by the American Association of Endodontists (root canal specialists) found that people who had actually had root canal therapy were 3 times more likely to say the process was painless as opposed to those who had never had a tooth treated. (AAE 1995) (Reference sources.)

Yes, for the majority of people, having endodontic therapy is a routine dental event (see Statistics section below).

For simple cases, it may not seem all that much more involved than having a relatively large dental filling placed. And when compared to a tooth extraction (the only other alternative to having this procedure), while it does take longer it's certainly a more civilized process.

Comfort management.

Your dentist is just as eager for you to have a pleasant experience as you are. Toward this goal, here are some of the things they can do to help to insure that that happens.

a) The timing of your appointment.

Regular visits (as opposed to emergency ones) are generally targeted for a period when your tooth is expected to be relatively "quiet" (having no or just minimal symptoms). That's because this time frame offers a window during which the tissues involved with your treatment will respond most predictably.

For people whose tooth has never been bothersome, this point isn't much of an issue. But if a recent flare-up has occurred, the dentist will want to wait until a point when the inflamed tissues involved have had a chance to settle down substantially.

Takeaways from this section.

That doesn't mean that if your tooth is hurting when you show up for your appointment that your dentist won't take steps to make it feel better.

But they'll want to delay the completion of your treatment until a time when your tooth doesn't respond painfully to tapping or finger pressure, and there are no obvious signs of lingering infection (like a foul odor or pus coming from inside the tooth).

So, when your dentist first greets you and asks how you and your tooth are doing, they're not just being polite. They're also looking for information that will help them decide how much/what aspect of your tooth's procedure they'll perform that day.

b) Numbing your tooth.

A dentist giving a dental injection.

Of course, your dentist will numb up your tooth for its procedure (that involves giving you a "shot"). And so you don't feel the pinch of the rubber dam clamp that they'll place, they'll also need to anesthetize the surrounding gum tissue too.

The good news is that once this has been accomplished the remainder of the appointment should be easy going (see Statistics section below), even to the point of being boring.

Things to know.

Of course, getting shots can be an issue in itself. And in an effort to be complete, we should mention the following points.

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  • It will likely take giving you more than one injection (stick of the needle) to adequately anesthetize everything that needs numbing. (One or more for the tooth itself and one or more for the surrounding gum tissue.)
  • The injections used to numb the gums on the palate side of upper teeth do tend to pinch, that's just life. (Why some dental shots hurt more than others.)
  • Numbing lower teeth is usually more of a challenge than uppers. But even so, the routine techniques used with lower teeth generally have a 75 - 90% success rate right off the bat. (Rosenberg 2002)
  • Anesthetics tend to be less effective when used with inflamed tissues (Rosenberg 2002). That's one reason why your dentist will want to give your tooth some time to settle down before initiating its procedure.
Takeaways from this section.

Knowing these last two points may not be all that comforting. But dentists know how to handle difficult cases and have additional techniques they can use to make sure you are comfortable (see our Emergencies section below). After all, managing painful situations is what being a dentist is all about.

Probably the most important takeaway here is understanding that: 1) Having treatment isn't always uneventful. 2) There are things your dentist can do to help. 3) But only if they're aware that a problem exists.

This last one is the key. Set up a hand signal with your dentist at the start of your appointment. One that you can give that clearly expresses that there is a problem and you require attention. (Just making grunts and groans usually isn't a very effective way to communicate.)

Statistically speaking.

Study #1 -

We found a research paper (Segura-Egea 2009) that specifically evaluated the issue of pain experienced by patients during their root canal procedure.

Its findings were that 54% felt no pain. Of the remaining subjects, 34% experienced slight, 9% moderate and 3% felt intense pain. No cases involved unbearable discomfort.

All of the cases in which subjects reported intense pain involved teeth that were acutely inflamed (the tooth was painful before the procedure was begun). Of the cases involving teeth that had no symptoms, very few patients experienced moderate and none reported intense pain.

Root canal without anesthetic?

You might be surprised to learn that many teeth that require root canal therapy could, without the use of any anesthetic, be drilled on and the patient would feel no pain whatsoever. And, in fact, it's conceivable that in some isolated cases the person's entire procedure could be completed without any anesthetic or pain.

Why? Simply because in these cases the nerve tissue in the tooth has died (dead nerve tissue can't transmit pain sensations) and there's no active inflammation associated with the surrounding tissues.

Should you expect that your treatment can be performed without numbing you up? No, that's not realistic. But, if you have a mind set that all root canal appointments are excruciatingly painful, well, that's not realistic either.

Study #2 -

Lobb (1996) followed up with patients one year after they had had their root canal procedure completed.

  • 90% of subjects stated that they would choose to have endodontic treatment again.
  • Cost, which was distantly followed by pain, was the most important factor for the 10% who would not opt for this treatment approach again.

From this, one would have to conclude that undergoing this procedure is not all that bad for the vast majority of patients.

Pre-procedure numbness testing your dentist can do.

Each type of injection that a dentist gives produces effects in a characteristic way. For example, when lower molars are numbed up, the corner of the patient's lip on the same side feels numb too.

So if the patient confirms that "lip signs" are present, the dentist can generally assume that the tooth's nerve is numb too. However, and as discussed above, this isn't always the case.

More conclusive testing.

In cases where the tooth slated for endodontic therapy has some remnant of vital (live) tissue remaining in it, the profoundness of its anesthesia can be evaluated directly, and more accurately.

Thermal (cold) and electric pulp testing are two common methods dentists use to evaluate the status of a tooth's nerve (teeth with live nerve tissue typically respond to both tests).

The plan would be one where the tooth due to receive treatment is tested before its anesthetic is given (so the dentist has baseline readings) and then after. If the repeated tests are negative (nothing is felt), it's a strong indication that profound pulpal anesthesia has been achieved.

c) Anxiety management may help to improve your experience.

Different from pain management is the issue of patient management (a behavioral issue).

Research has shown that there is a relationship between the degree of pain experienced and the level of stress, anxiety or pessimism that the patient holds.

The higher the level, the more likely the patient is to interpret the sensations they feel as pain.

Don't keep your dentist in the dark.

That means you need to be up front with your dentist about your fears or concerns. Doing so will give them a chance to figure out a solution. Here are some of the things that can help.

  • Conscious Sedation. - This technique involves the use of medications (laughing gas, oral or IV sedatives) that help to place the patient at ease.

    You remain awake, in the sense that you can respond to questions and commands, you just care less about what's going on.

    As a side note, you'll still also respond to pain sensations. And for that reason your tooth and gums must still be numbed up. However, if getting an injection is the hard part for you, ask if the sedation medication can be administered first.

  • Hypnosis. - The use of hypnosis as a means of relieving anxiety has a long history in both medical and dental practice. At an extreme, the use of mediation-hypnosis has been documented as the sole anesthesia used for a root canal case (Morse 1979).
  • Information. - Knowing the details about your upcoming dental procedure can be an important anxiety reduction technique. (Looking for this type of input may be one reason why you're reading this page right now.)

    But don't just read; ask your dentist questions too. If concerns about pain are an important consideration for you, let them explain what steps they plan to take and why it's unlikely to become an issue.

  • Distraction. - Coming up with ways to take your mind off your procedure can help to alleviate anxiety and as a result minimize the level of discomfort you experience.

    As a plan, take your music player or favorite video game (and headphones please) with you to your appointment.

Takeaways from this section.

Any of the above can prove to be a valuable adjunct and may be just what it takes to tip the scales so your experience is a totally pleasant one.

While a decision to use laughing gas (nitrous oxide) can be made at the time of your appointment, the use of hypnosis or oral or IV sedation will likely require making some pretreatment arrangements.

If oral or IV sedation technique is used, you'll need someone to help you home and monitor your activities after your appointment.

2) There is some potential for post-treatment pain.

We wouldn't be telling the whole story if we didn't mention that after your root canal appointment there is some potential that your tooth might hurt (it really should just be minor). We've dedicated a page to this subject: Root canal aftercare and precautions.

3) Pain management during emergency visits.

It seems likely that many of the remarks that you hear about how painful having root canal therapy is should really be attributed to those events that initially signaled that it was needed and not the procedure itself. And when this type of tooth flare-up occurs, an emergency trip to your dentist's office is indicated.

Acute flare-ups.

In some instances, the final (and possibly only) sign that a tooth needs root canal treatment is a painful toothache.

It would be dishonest to suggest that during this type of event (a time when you are stressed and your tooth and its surrounding tissues are inflamed and possibly involved with an active infection) that the steps your dentist must take to provide pain relief and to set the stage for the healing process can always be accomplished with absolutely no discomfort.

a) Problems associated with inflammation.

One big problem associated with acute tooth flare-ups is that local anesthetics are much less effective when used with tissues that are inflamed. In fact, there's an 8-fold higher failure rate as compared to when teeth are numbed under normal circumstances. (Rosenberg 2002)


That means a dentist must use other strategies to manage their patient's pain.

  • In some cases, simply allowing more time for the anesthetic to take effect may be all that's needed. Your dentist may ask you to arrive 20 or 30 minutes early so they can employ this technique.

    Other times the solution may lie in modifying the way the anesthetic is given or simply using more of it (although there are specific dosing guidelines that must be followed).

  • As an alternative, your dentist may employ a technique where the anesthetic is placed directly between the tooth and surrounding bone, or in the jawbone in the region of the root's tip. These methods are respectively termed intraligamentary and intraosseous injections. And while they can be, they aren't usually used to numb up teeth for routine procedures.
  • It may be that things have been going just fine with your procedure, until that point where your dentist starts to work directly with your tooth's nerve. If so, they may utilize an intrapulpal injection.

    This type of shot is given directly inside your tooth. And interestingly enough, it's not the anesthetic that's used that's the effective factor. It's the pressure created by the injection process that deadens (conks out) the tooth's nerve (so really, even just injecting water could be successful).

    While this sounds like a horrible injection to get, it's more of a good news, bad news type of situation. Yes, you will feel the injection (a sharp pain) but just for a split second. Then, that's all. Your dentist should then be able to continue with your procedure painlessly.

  • Your dentist may ask you to take an NSAID (nonsteroidal anti-inflammatory drug) prior to your appointment. Ibuprofen (Motrin, Advil), ketorolac or diclofenac have a history of being used for this purpose.

    Studies suggest that with cases where teeth with inflamed nerve tissue are being treated, pretreatment dosing with an NSAID helps to create an environment where the local anesthetic used will be more effective. (Hargreaves 2002, Nagendrababu 2018)

  • Experiencing an acute tooth flare-up can be a stressful event. And patients that have are usually tense and exhausted, and typically respond to pain more so than under normal circumstances.

    As discussed above, the use of sedation technique (laughing gas, oral or IV medications) can help to relax these types of patients, and as a result decrease the amount of discomfort they experience.

The point here ... isn't necessarily what will be done with your tooth (that's for your dentist to decide) but rather to understand that a painful tooth does present challenges and that your dentist does have ways to overcome them.

Takeaways from this section.

Don't overlook the fact that your dentist can't respond to your needs unless they know you're having a problem.

As mentioned above, lots of patients make grunts and groans during their procedure but that's not a very effective means of communication. It's a great idea to have a prearranged hand signal that you can give if you do feel pain so your dentist knows for certain that an issue exists.

b) Difficulties associated with infections.

Tooth flare-ups that involve a significant amount of swelling will complicate pain management.

  • It may be that the swelling limits your ability to open your mouth, thus preventing any type of treatment directly involving your tooth.
  • As a general rule, dentists don't inject quantities of anesthetic into areas of swelling (for fear of spreading it). With teeth that hurt, this may mean that no direct treatment is possible.


Even if your dentist can't work directly with your tooth, they can initiate treatment that will help your infection to clear up more quickly so later on they can.

  • Placing you on antibiotics will help to bring your infection under control more quickly.
  • If the swelling has localized, your dentist may be able to make an incision in the affected tissue that allows the trapped pus to drain.

To keep you comfortable until that time when your tooth can be worked on, your dentist will likely have you take some type of oral analgesic (pain pills), either prescription or over-the-counter.


Written by: Animated-Teeth Dental Staff

Last revision/review: 9/10/2018 - Minor revision, content added.

Content reference sources.


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