A root canal procedure removes infected or damaged tissue from inside a tooth to alleviate pain. While some discomfort is common afterward, this sensation is usually temporary, indicating the body’s natural healing. However, persistent or severe pain can signal an underlying issue requiring further attention.
Expected Discomfort Versus Concerning Pain
Following a root canal, mild sensitivity to pressure or a dull ache is considered normal. This discomfort often results from inflammation in the tissues surrounding the treated tooth and subsides within three to five days. Over-the-counter pain relievers like ibuprofen or acetaminophen are often sufficient to manage these sensations.
Conversely, certain symptoms suggest a more concerning problem requiring immediate professional evaluation. These include severe, throbbing, or persistent pain that worsens over time, especially beyond the initial few days. Swelling in the gum or face, fever, or pus drainage also indicate a potential complication.
Common Reasons for Persistent Pain
Incomplete Cleaning or Missed Canal
A root canal involves thoroughly cleaning a tooth’s internal chambers. However, complex tooth anatomy can lead to missed areas. Teeth, particularly those with multiple roots, may have extra or very narrow, calcified canals difficult to locate and clean completely. If a tiny canal or nerve tissue remains, it can harbor bacteria, leading to continued infection and pain.
Re-infection
Even after a successful root canal, a tooth can become re-infected if bacteria enter the treated area. This can occur if the temporary filling or permanent crown is not placed promptly, or if the restoration’s seal breaks down over time. Poor oral hygiene can also contribute to bacterial re-entry, leading to renewed inflammation and discomfort.
Cracked Tooth or Root
Microscopic cracks in a tooth or its root can be present before or develop after a root canal, causing pain. These fractures are challenging to diagnose, even with advanced imaging like three-dimensional scans. Common signs of a root fracture include isolated periodontal pockets and a sharp pain progressing to a dull throbbing sensation, especially when chewing or applying pressure.
High Bite or Occlusal Trauma
An uneven bite, where a new filling or crown is too high, can place undue pressure on the treated tooth. This increased force during chewing can inflame the periodontal ligament, the tissue surrounding the tooth root and connecting it to the bone, causing persistent pain. Even though the tooth’s internal pulp has been removed, the periodontal ligament remains sensitive to pressure.
Referred Pain
Pain felt in a root canal-treated tooth might not originate from that tooth. It can be referred from adjacent teeth, jaw muscles, or other structures like the temporomandibular joint (TMJ) or sinuses. In rare cases, non-odontogenic conditions such as nerve pain (e.g., trigeminal neuralgia) or certain systemic conditions can manifest as tooth pain, making accurate diagnosis important.
Nerve Damage
Irritation or damage to surrounding nerves can occur during a root canal procedure. This can lead to neuropathic pain, sometimes described as “phantom tooth pain,” where discomfort persists even after the original infection source is removed. This type of pain is rare but can be challenging to manage, as it stems from the nervous system’s response to the procedure.
When to Contact Your Dentist
Contact your dentist promptly if you experience severe or worsening pain that does not improve after a few days, even with over-the-counter pain relievers. Swelling in the gum or face that increases or does not subside is a clear indicator of a potential problem. Other concerning symptoms include pus or drainage from the treated area, a fever, or persistent sensitivity to hot or cold temperatures in the treated tooth.
If your bite feels uneven or “off” after the procedure, contact your dentist; a simple bite adjustment can often resolve this discomfort. While some initial tenderness is expected, any sensation of the tooth feeling loose or discolored should also be reported. These signs suggest the healing process might not be progressing as anticipated, and a professional evaluation is necessary.
Diagnosing and Addressing the Pain
When you visit your dentist for post-root canal pain, they will begin with a thorough clinical examination of the treated tooth and surrounding tissues. This includes taking new X-rays to assess the tooth’s internal structure and surrounding bone for missed canals, fractures, or signs of re-infection. The dentist may also perform percussion tests, gently tapping on the tooth to gauge its sensitivity, and apply cold or heat to differentiate pain sources.
Based on the diagnosis, various treatment approaches may be considered. If an incomplete cleaning or missed canal is identified, a root canal re-treatment may be performed to thoroughly clean and seal the remaining areas. For re-infection, medication might be prescribed, or the tooth may need to be re-opened for further cleaning and sealing. If a high bite is the cause, a simple adjustment of the filling or crown can relieve the pressure.
In cases of cracked roots or severe, persistent infection that cannot be resolved with re-treatment, a surgical procedure called an apicoectomy, which involves removing the root tip, may be considered. In severe situations where the tooth cannot be saved, extraction might be the only viable option.