Pain after root canal: How long will pain last?

Update in December 25, 2023

Pain after root canal

It’s not uncommon to need a root canal at some point in your life. Despite their reputation, most root canal procedures are no more painful than having a cavity filled. However, many people wonder if they will experience pain after a root canal. The short answer is that it is normal to feel some discomfort and tenderness following the procedure, but the level of pain or tenderness depends on the circumstances of the root canal and the cause of the discomfort.

Most of the pain or tenderness is temporary, and it generally responds well to over-the-counter pain medications. Below you’ll find a list of some of the most common causes of post-root canal pain in order from most common to least common. However, If you have severe pain or the pain lasts for more than a few days, you should contact your dentist immediately so that they can help you as soon as possible.

Is dental pain after root canal normal? 

Is dental pain after root canal normal

In the past, root canals were extremely painful. This is one reason why people sometimes avoided such procedures. Dentists now have pain-relieving measures that can be used to reduce the amount of pain you experience during the procedure.

Before the process begins, your dentist will apply a local anesthetic that minimizes pain. You might still feel pressure during the cleaning, but you shouldn’t be in pain during the actual procedure.

As the local anesthetic wears off after the root canal, you might experience mild pain and sensitivity. This is related to the cleaning process. During the cleaning process, your dentist makes a small opening in the crown of the tooth and cleans out diseased pulp inside the pulp chamber of the tooth. While uncomfortable, any pain and sensitivity following a root canal should only last a few days.

Since the pain experienced after a root canal is usually mild, you’ll likely only need over-the-counter pain medications for relief. These include acetaminophen (Tylenol) and ibuprofen (Advil, Motrin IB). You’ll want to check with your doctor before taking these medications to make sure they don’t interact with any supplements or prescriptions you already take.

You should also avoid chewing hard foods immediately following the root canal, as this can induce more pain.

When to see doctor?

Most of the time, a root canal is a relatively simple procedure that results in a mild to moderate amount of discomfort after treatment. The most common symptom is tenderness around the tooth for a few days after treatment.  You can minimize your tenderness after treatment by not chewing on the tooth and taking anti-inflammatory medications as prescribed.

A common complication after treatment is a “flare-up”.  If your symptoms increases 48-72 hours after treatment or you experience swelling your dentist may prescribe antibiotics in addition to pain medication.

If you are still experiencing tooth pain weeks after a root canal, contact your dentist right away. You may need follow-up treatment to alleviate your pain.  Having a root canal should remove the pain resulting from an infected tooth. Root canals eliminate the infection and the nerve tissue inside the tooth.

What can cause pain after a root canal?

What can cause pain after a root canal

The two main causes of pain after a root canal are infection and inflammation.  Infection is the presence of bacteria around or inside your tooth where it is not normally found.  Inflammation is the body’s way of signaling the immune system to initiate repair after injury.  To cause pain, both infection and inflammation require a living nerve to send a painful signal to the brain that something is wrong.  Painful symptoms after a root canal can be sent from:  unremoved nerves inside the tooth, nerves in the surrounding bone and ligament and nerves in affected muscles.


During root canal treatment, the nerves inside the tooth are removed.  Many teeth, including molars, can contain multiple roots with multiple nerves in each root.  If you dentist fails to remove all of the nerve tissue from the tooth, you may experience persistent pain.  The use of a dental microscope during treatment has shown to help dentists visualize hard to reach anatomy.  Additionally, a 3D x-ray of your tooth can reveal the presence of difficult anatomy.


Root canal treatment removes the nerve tissue from inside the tooth, however, the bone and ligaments around teeth remain highly innervated.  The mechanical instrumentation during a root canal and the presence of bacteria can irritate these nerves and cause pain. A fracture in your tooth may be a persistent source of bacteria that causes irritation in the surrounding bone.  Antibiotics and steroids may help to relieve your pain.


If your facial muscles become inflamed, you may experience prolonged pain after root canal treatment, especially if you clench or grind your teeth.  One likely culprit of facial pain is the masseter muscle.  The masseter muscle attaches from your cheek bone to your jaw and is one of the main muscles to help you chew.  Anesthesic injections and staying open for extended periods of time can irritate the masseter muscle. Pain from an irritated masseter muscle can often be difficult to differentiate from a painful tooth.  Warm compresses, facial massages and prescribed muscle relaxers can be helpful in resolving muscle.


During your procedure, your dentist has to isolate the tooth using a rubber dam. The metal clamps used to hold the dam in place can cause slight trauma to the periodontal tissue, commonly known as gum tissue, surrounding the tooth being worked on. This trauma can include pinching, bruising, and cutting. This type of pain should heal within a few days and have no lasting effect.


The most common source of pain in the tooth after a root canal is inflammation of the tissues surrounding the root of the tooth. Inflammation can occur if the dentist’s root canal files poke beyond the tip of the root or if debris escapes in this area. While a good dentist does everything they can to prevent this from occurring, it can happen. An over-the-counter pain medication with anti-inflammatory properties (e.g. ibuprofen or aspirin) can help alleviate pain caused by tissue inflammation.


If the tooth was infected before your root canal, the pain can sometimes linger as the infection heals. On occasion, a tooth can be infected without much pain occurring before a root canal procedure. Unfortunately, in this instance, the infection can sometimes be activated by the procedure, which can result in a painful, acute infection. This scenario is less likely than simple inflammation, but it does occur. Your doctor will generally prescribe an antibiotic and, if the pain is severe, a prescription pain reliever.


Hyperocclusion refers to a tooth that is longer than it should be. After your procedure, inflammation can actually cause temporary hyperocclusion. Another cause is when the restoration (filling or crown) of your tooth is improperly fitted. When this occurs, your dentist will need to correct it by shortening the tooth to correct your bite. This is done to relieve the pain and to prevent the tooth from fracturing due to undue stresses.

Pain management

Pain management

Pain beyond a root canal should be addressed with your dentist. Beyond taking medications temporarily, there are other things you can do to manage pain from a root canal. Taking care of your teeth is a must, and you should avoid hard and crunchy foods until your pain improves. Quitting smoking can also help.

You may even consider stress-relieving activities as a method of pain management. Meditation, yoga, and tai chi are all practices that can also take your focus off of your pain.

How do I know if a Root Canal has failed?

Symptoms will affect the same tooth that was treated, or a surrounding area, such as the nearby gums. The common signs and symptoms of a failed root canal treatment include –

  • Tenderness or swelling
  • Pain on biting
  • A blister or pimple-like bump inside the mouth
  • Increased tooth mobility

What causes a Root Canal to fail?

A root canal failure occurs because bacteria remain present in the root canal, or find a way to re-enter the tooth after treatment. Causes of root canal failure vary. Some reasons are listed below.

  • Incomplete cleaning– Narrow or curved canals can be complicated for a dentist to access, but if the infection isn’t completely removed, root canal treatment can fail.
  • Undetected canals– Sometimes, the channels in a tooth are uncomplicated, or a dentist might not see an additional canal. Undetected canals are still infected.
  • Improper restoration– If a patient or dentist delays restoring a tooth after root canal treatment, saliva and bacteria can leak in and infect it. Your tooth can get infected again if your dentist doesn’t restore it correctly.
  • Damaged restoration– If your filling or crown is damaged, the tooth can get infected again.
  • Cracked tooth root– When a dentist doesn’t notice that a tooth root is cracked—or if the root is damaged during root canal treatment—root canal failure eventually results.

Just like your other teeth, a tooth that has received a root canal is susceptible to decay and needs to be maintained with good oral hygiene. Your mouth is full of bacteria, and if appropriate oral care is not maintained then there is a risk that decay can develop. This decay can provide the access for bacteria to re-enter your tooth.A tooth that has had root canal therapy no longer has an active nerve, and unlike a normal tooth, this means that a cavity won’t be felt or exhibit pain.

“This means that after root canal treatment, it is beneficial to take extra care to keep your teeth free of decay, and to maintain your regular dental appointments so that the health of your teeth can be ensured.”

What happens at a root canal re-treatment?

What happens at a root canal re-treatment

Before your root canal is re-treated, your dentist will assess your tooth to determine any of the potential causes for the failure of your first treatment. The endodontist will examine your tooth and take digital x-rays. In complex cases, a referral to an Endodontic specialist may be deemed necessary.

During re-treatment, your dentist will :

  • Access the tooth by taking the crown or filling out
  • Remove any of the previous material from RCT
  • Clean & re-apply antibacterial dressing
  • Refill the Root Canal
  • Reseal and finish treatment

In other circumstances, a form of root canal surgery called an Apicoectomy may be considered. This involves accessing the root canal via the gum using surgical techniques and allows your dentist to clean and seal the area directly without removing the filling or crown. Don’t give up quickly if the specialist offers to try saving your tooth. dentists recommend saving a natural tooth and restoring it whenever possible.

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