Why does my tooth still hurt when I bite down after a root canal?
Cited to 3 sources. Reviewed 2026-08-25.
Pain that only happens when you bite usually comes from one of two things: the filling sits a fraction too high so that tooth takes the whole bite, or the periodontal ligament around the root is still inflamed from treatment. The ligament version fades over three to five days. The high filling version does not fade, because every bite re injures it, and it is corrected in a couple of minutes with a drill and articulating paper.
- Inflamed ligament
- Fades over 3-5 days
- High filling or crown
- Does not fade, needs adjusting
- Pain on releasing a bite
- Suggests a crack
- AAE lists uneven bite
- As a reason to call
How to tell which one you have
The distinguishing question is whether it is getting better. Ligament inflammation improves day on day because nothing is re injuring it. A high restoration produces the same intensity of pain on day six as it did on day two, sometimes worse, because you have been hammering it thousands of times a day.
| Clue | Inflamed ligament | High filling | Cracked tooth |
|---|---|---|---|
| Trend over a week | Improving | Flat or worse | Erratic, comes and goes |
| Feels like | Bruised, tender all round | That tooth hits first | Sharp jolt |
| Worst moment | Firm biting | Any closing together | Releasing the bite |
| Fix | Time, chew elsewhere | Bite adjustment | Assessment, often a crown |
Why a high spot hurts so much
Teeth are suspended in bone by the periodontal ligament, which is exquisitely good at detecting pressure. It can register a difference measured in fractions of a millimetre. When a filling sits proud, that one tooth absorbs force meant to be shared across the whole arch, and the ligament under it stays permanently bruised.
This is very common after a root canal because the tooth was numb when the filling was placed, so you could not test the bite properly, and because a numb, tender tooth does not close the same way it will once it settles. The American Association of Endodontists specifically lists an uneven bite as a reason to phone them after treatment.
The bite pain that is a crack, not a filling
There is a third pattern that gets missed. If the pain is a sharp jolt on releasing a bite rather than on applying it, and it comes and goes unpredictably, that is the textbook description of a cracked tooth. The AAE describes erratic pain when chewing, sometimes on release of biting pressure, as the hallmark.
Root canal treated teeth are more crack prone because they are hollowed out and often already had a large filling. This is one of the main reasons a crown gets recommended rather than a plain filling, and it is a reason to bring this pain up rather than assume it is normal healing.
Call your dentist or oral surgeon if
- Bite pain that has not improved at all after five to seven days
- The tooth feels visibly or obviously taller than its neighbours
- A sharp jolt when you let go of a bite rather than when you press down
- Any swelling, a gum bump, or a bad taste alongside the bite pain
- The pain spreads to the jaw or ear, or you cannot chew on that side at all
Related questions
Will a high filling wear itself down?
Not reliably, and not before it does damage. Weeks of overloading a freshly treated tooth keeps the ligament inflamed and can crack the tooth. Get it adjusted.
Does an adjustment hurt?
No. They put coloured paper between your teeth, you bite, and they take down whatever marks up. It takes a couple of minutes and does not usually need anesthetic.
My permanent crown went on and now it hurts to bite. Same thing?
Very often yes. A new crown can be a touch high in exactly the same way. It is worth checking before assuming the root canal has failed.
Sources
- Root Canal Post Treatment Care (American Association of Endodontists)
- Cracked Teeth (American Association of Endodontists)
- Root Canal Treatment Patient FAQs (American Association of Endodontists)
Reviewed against the sources above on 2026-08-25. General information only, not dental advice. Your own provider's aftercare instructions come first.
Keep reading
Most root canal discomfort settles within three to five days. It typically peaks in the first 24 to 48 hours, when the tooth is tender to bite on, then drops off steadily. Roughly a quarter to a half of patients report some pain afterwards, and most of it is mild. Pain that is severe, that lasts more than a few days, or that is climbing rather than falling is the version worth calling about.
A mild throb in the first day or two is common and settles. Throbbing that begins after a quiet start, that wakes you at night, or that is worse today than yesterday is not the normal curve and should be reported. The AAE says to call if severe pain or pressure lasts more than a few days. Most of these cases are a flare up or a high filling, and both are fixable without redoing anything.
Weeks, not months. The permanent crown or filling should follow the root canal as soon as your dentist can arrange it, usually within a few weeks. A long delay leaves the tooth sealed only by a temporary filling, which leaks over time and lets bacteria back into the canals, and leaves the hollowed out tooth unsupported. Root fracture is the most common reason root canal treated teeth end up extracted, and a fractured root cannot be repaired.
No. A temporary filling is a short term seal, not a chewing surface. The AAE is direct about it: do not chew or bite on the treated tooth until it has been permanently restored by your dentist. Chewing on a temporary can dislodge it, which lets bacteria back into the cleaned canals, and it can crack the hollowed out tooth underneath. Chew everything on the other side until the crown or permanent filling is in.