Root canal treatment is done to remove the infection and to remove the pain. After root canal treatment, patient may experience mild pain or no pain. Many people wonder as to why the tooth causes pain after root canal treatment when the nerve of the tooth is already removed. If the tooth was very painful and infected before procedure, then pain is expected after root canal procedure. Infection in the tooth spreads from dentin to the pulp and when pulp is involved which has nerve, then the need of root canal treatment arises. Periodontal ligament and the bone which are the supporting structures of the tooth may also get involved in the infection if infection is severe and this leads to pain after root canal treatment.

Patient should get the root canal treatment done when he first experiences tooth ache. If treatment is taken at early stage, then chances of post-operative root canal treatment pain becomes less. If infection spreads to the bone and periodontal ligament, then it will take some time for pain to go. Patient may feel difficulty in chewing and sensitivity for few days after treatment.    

Pain after Root Canal is result of:

1.    Tooth Abscess

At the tip of the root, fluid concentration may occur. This fluid can be because of initial bacterial infections which were pushed beyond the root apex during root canal procedure or it can be sterile due to irrigation solution which is used to clean and disinfect the canal. Periapical abscess will cause pressure on the tissues which are surrounding the tooth structure and will cause pain on chewing and may also cause swelling. Pain can be relieved by removing the temporary medicated dressing from the access hole. It will allow abscess to drain and will cause relief. Before filling of the canals, dentist or endodontist will see to it that there is no fluid present around the root apex. If this fluid is not drained, then it can lead to severe pain after root canal procedure.    

2.    Irritation of Ligaments which are Surrounding the Tooth Structure

Acute infection in the tooth can cause inflammation of tissues around infected tooth and can cause pain. During root canal procedure, removal of pulp from the tooth can cause tissues to be pushed through the apex of the tooth into the bone and can cause irritation. Over instrumentation during cleaning and shaping of canals and pushing debris and fluids beyond apex of the tooth can cause mild pain after root canal treatment.

3.    Inflammation of Tissues adjacent to Root Canal Treated Tooth

Inflammation of tissues adjacent to root canal treated tooth can cause pain after root canal procedure.

4.    Hyperocclusion

Hyper occlusion of root canal treated tooth can cause pain after root canal treatment. If the occlusion is not correct, then dentist can correct the occlusion so that teeth make proper contact. Hyper occlusion if present causes severe pain and can also lead to TMJ disorder and generalized sensitivity of teeth.    
If patient is in the habit of clenching or grinding his teeth, then also it can cause pain post root canal treatment.  

If pain doesn’t regress in a week or two after root canal treatment, then it can be because of failed root canal procedure. If the tooth is sensitive to cold foods or in case of persistence of pain in the tooth, it signifies failure of root canal procedure. Patient should visit his dentist or endodontist if there is persistent pain.

Failure of Root Canal can occur:

A.    Failure of root canals can occur if there is one or more extra canal present in the tooth which is missed by the dentist. There may be small accessory canals present which may be missed by the dentist and can cause failure of root canal treatment. Branched out and curved canals are difficult to detect and might be missed and cause failure of root canal treatment. If infection is still left in the tooth that is in case of inflamed, infected pulp left in tooth can cause failure of root canal treatment and in such case, root canal is repeated.   

B.    Crack: Crack in the roots may occur during root canal procedure and cause failure of the root canal treatment.   

C.    Defective or incomplete restorations can also cause failure of root canal treatment.

Delayed Pain after Root Canal Treatment

Patient may experience pain few months or years after root canal treatment. This pain can be because of failed root canal treatment, fracture of root canal treated tooth or can occur because of gum infection in relation to root canal treated tooth. If patient experiences pain after months or years after root canal, then he should visit his dentist to get the tooth evaluated. In case of failure of root canal treatment, re-root canal treatment, Apicoectomy or tooth extraction may also be required.  

Pain Management after Root Canal

1.    For pain relief after root canal treatment, pain meds can be given to the patient. In case of swelling of the tooth, anti-inflammatory pain meds like ibuprofen can be given to the patient. If pain is severe, then dentist may prescribe a stronger analgesic.

 2.    If infection was severe before root canal treatment and spread to ligament and bone, then antibiotics will also be prescribed by the dentist to patient. Antibiotics will facilitate healing process of tooth.

3.    After root canal treatment, patient is advised to take soft diet for 2-3 days and should avoid eating from the side of root canal treated tooth. Patient should avoid intake of very hot or cold foods. 

Leave Comment


  • carolyne opiyo

    carolyne opiyo 19 - April - 2015, at 10:48 AM

  • I had aroot canal treatment and steel feel pain after 2 weeks

  • dr.mohammed

    dr.mohammed 19 - January - 2014, at 04:29 AM

  • temporary filling removed .. analgesics and antibiotics are given to the patient for precaution and still it have severe pain so what is the solution ?

  • Dr.rajesh

    Dr.rajesh 31 - January - 2012, at 13:45 PM

  • really very nice explanation regarding pain after rct..

  • dr ritz

    dr ritz 31 - December - 2011, at 02:06 AM

  • Shrinivas, if you have done over-instrumentation of canals, then you can tell your patient to take pain meds and antibiotics and do obturation after pain resides completely. Tell her to take soft diet for other few days and avoid eating from side of root canal treated tooth. Make sure to remove all the pulp tissue and necrotic tissue from canals before proceeding with obturation.

  • dr.shrinivas k

    dr.shrinivas k 30 - December - 2011, at 08:06 AM

  • 1 of my patient had resorbed mesiobuccal root of maxillary right 1st molar, n i thnk i had done ovrinstrumentation,so want 2 ask what i shd do nw 2 reduce her pain which is on biting only,n wen shd i obturate...i had disoccluded it,n rc cal has been placed, n put on antibiotic n pain killer

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