The side effects most people have
Tenderness when biting is the commonest. The ligament around the root is inflamed from the infection and from the instruments, and it takes a few days to settle. The tooth may feel slightly high or bruised. Our guide on whether a root canal hurts covers the first days in more detail.
Numbness from the local anaesthetic lasts a few hours. Do not chew on that side until feeling returns, because it is easy to bite your cheek or tongue without noticing.
A sore jaw and a dry, cracked lip are common after a long appointment with the mouth held open. Both ease within a day or two.
Side effects that appear later
Tooth darkening. Once the nerve and blood supply are gone, a root-treated tooth can gradually turn grey or yellowish, more often in front teeth and in teeth that were infected or traumatised for a long time. It is a colour change, not a sign of failure. Options include internal bleaching or a crown.
Brittleness. A root-treated tooth has lost internal structure and the access cavity weakens the biting surface. This is the real long-term risk, and the reason a back tooth usually needs a crown, as explained in do I need a crown after a root canal.
Reduced sensitivity. With no nerve, the tooth no longer warns you about hot, cold or decay underneath, so regular check-ups and X-rays matter more, not less.
Rare complications worth knowing about
A flare-up, meaning increased pain or swelling in the first few days, happens in a small number of cases, particularly when the infection was already active. It is usually managed with a review and sometimes a second visit.
A missed canal, a crack in the root or a separated instrument fragment can leave infection behind and cause symptoms that return. These are known risks of any root canal, and magnification, X-rays and careful technique reduce them without removing them entirely. If symptoms return, re-treatment is often possible, as described in why a root canal tooth can hurt years later.
Medicines used in the canal and rubber dam latex can trigger allergy in a few people. Tell the dentist beforehand about any allergy to latex, local anaesthetic or medicines.
What helps, and what is not normal
For tenderness, paracetamol or ibuprofen as directed on the label is usually enough. Avoid ibuprofen if you have a stomach ulcer, kidney disease or asthma that reacts to it, and check with your doctor if you are pregnant or take blood thinners. Chew on the other side until the tooth is permanently restored.
Contact the clinic if pain increases after the third day, if the bite feels progressively higher, or if the temporary filling falls out. Swelling of the face or gum, or a fever, needs care the same day. If swelling affects your breathing or swallowing, go to a hospital emergency department immediately.
The treatment itself is described step by step in root canal treatment steps, and our root canal treatment page explains when it is recommended.
Common questions
Is it normal for a root canal tooth to feel high when I bite?
Yes, in the first few days. Inflammation around the root makes the tooth sit proud and feel bruised. If it persists beyond a week or gets worse, tell the dentist, because a small adjustment to the filling can fix a genuinely high bite.
Will my tooth turn dark after a root canal?
It can. Without a living pulp, some treated teeth gradually turn grey or yellow, mostly front teeth and those infected for a long time. It is cosmetic rather than a failure, and internal bleaching or a crown can correct it.
Can a root canal make me ill or cause other diseases?
No. The idea that root canals cause illness elsewhere in the body comes from a discredited theory from a century ago. Mainstream dental and medical bodies find no reliable evidence for it. Untreated infection is the greater risk to general health.
How long does the numbness last after a root canal?
Usually two to four hours, a little longer after lower jaw injections. Avoid hot drinks and chewing until normal feeling returns, since you can burn or bite your lip without noticing. Numbness lasting beyond a day should be reported to the clinic.
When should I call the dentist after a root canal?
Call if pain worsens after day three, the temporary filling comes out, or the bite keeps feeling high. Facial swelling or fever needs same-day care, and a hospital emergency department if breathing or swallowing is affected.
About this page
This page is general information, not a diagnosis or a quotation. Prices are prevailing Lucknow market ranges. Your own treatment and cost are determined after an examination. For questions about your own case, call +91 83036 12717.