Does root canal treatment hurt a lot?
“I heard root canals are really painful. Does it hurt even with anesthesia?” This is the first thing people ask before root canal treatment. Root canal treatment (endodontic treatment) removes the inflamed nerve (pulp) inside the tooth, then cleans and disinfects the canals inside the root and seals them. Because it is done under anesthesia, during treatment you often feel little more than pressure and the sound of the instruments.
In fact, it often hurts more before treatment. Throbbing that starts on its own at night and pain that lingers after cold or hot water are signs that the nerve is full of inflammation, and relieving that pressure is the first step of root canal treatment.
When does it hurt even with anesthesia?
When the nerve has severe acute inflammation, anesthesia sometimes doesn't work well. This is especially true for lower molars. In that case, we add more anesthesia or give anesthesia in another spot, and if the tooth is still sensitive, that day we only relieve the pressure and place medication to calm the inflammation, then continue at the next visit. There's no need to put up with pain. Raise your hand and let us know.
How many days does it hurt after the first and second visits?
| Stage | What is done | Common feeling afterward |
|---|---|---|
| 1st visit | Remove the nerve, open and disinfect the canal entrances, place medication and seal temporarily | Throbbing for 1–3 days, dull ache when chewing |
| 2nd visit | Measure the canal length, widen, rinse and disinfect | Discomfort when chewing for a few days; often less than after the 1st visit |
| Final (filling) | Fill and seal the cleaned canals with material | A dull ache may remain for a few days |
Pain after treatment mostly comes not from inside the tooth but from the tissue around the root tip being irritated. That's why it aches more when you chew or tap the tooth than with cold water. Clinics name the stages differently, and the number of visits varies from tooth to tooth. How many times you'll need to come in is covered separately in how long root canal treatment takes.
The guide is not how many days it hurts, but whether it gets less each day.
When should I come back to the dentist?
- When the pain doesn't ease each day and instead gets worse
- When your gums or cheek swell and you have a fever
- When it hurts so much you can't sleep even after taking painkillers
- When the temporary filling comes out or the tooth breaks
Rarely, inflammation flares up suddenly during treatment and causes swelling. Rinsing the canals again and changing the medication calms it down. Don't wait until your next appointment—contact us.
What should I be careful about during treatment?
A tooth under treatment is sealed with temporary material, so it is weak, and a tooth whose nerve has been removed has thin remaining walls and breaks easily. Until the final crown or filling, don't chew hard or tough food on that side. If you stop treatment because the pain is gone, bacteria get back in through the opened canals and it ends up worse than at the start.
What if it hurts years later?
A tooth that has had root canal treatment can hurt again. This happens when bacteria get back in through a gap in the crown or restoration, when a thin canal that was hard to find at first was left behind, or when the root has cracked. We look at the cause on X-rays and decide whether to retreat the canals, treat the root tip, or whether the tooth is hard to save. For inflammation at the root tip, see Can an inflamed tooth root be saved without extraction?
How we do it at Wonjin Dental
Root canal treatment is covered by Korean National Health Insurance. At each visit, we tell you how far we got that day and how many days it may ache, and if the pain doesn't ease, we have you come in even before your appointment. A molar that has finished root canal treatment is usually covered with a crown. Materials are summarized in types of crowns.
Frequently asked questions
Can I take painkillers after the first root canal visit?
Yes. Take the prescribed medication or the painkiller you usually take, as directed. If it hurts so much you can't sleep even with painkillers, contact us.
My tooth feels raised after root canal treatment.
When the tissue at the root tip swells, the tooth can feel slightly lifted and touches first when you bite. This often settles within a few days, and if it continues, we lower the biting height to let it rest.
Can I drink alcohol during root canal treatment?
It's better to avoid it while the inflammation is settling. This applies even more while you are taking painkillers or antibiotics.
Why does a tooth darken after root canal treatment?
A tooth whose nerve has been removed can become dull in color from the inside. For a front tooth, internal bleaching done from inside the tooth (non-vital whitening) can brighten it. Whitening methods are described in types of teeth whitening.
