A root canal is a common dental procedure designed to save a tooth that has been severely damaged or infected. This treatment removes the compromised pulp, which contains nerves and blood vessels, from inside the tooth. The interior of the tooth is then cleaned, disinfected, filled, and sealed to prevent further infection. While the procedure aims to alleviate pain and preserve the natural tooth, a question that often arises is whether a tooth that has undergone a root canal can still hurt.
Understanding Initial Discomfort
Some discomfort following a root canal procedure is common and expected. This temporary pain typically manifests as mild tenderness around the treated tooth or surrounding gum tissue, which can be managed with over-the-counter pain relievers. The discomfort usually subsides within a few days to a week as the tissues around the tooth heal from the manipulation during the procedure. This healing process is a normal response of the body, and persistent severe pain is not typical.
Reasons for Persistent or New Pain
Although root canal treatment is successful in saving teeth, pain may persist or develop months or even years after the procedure. Research indicates that between 4% and 6% of teeth treated with root canals can experience lingering pain. This discomfort can stem from several underlying issues.
Incomplete cleaning or filling of the root canal system can cause continued pain. Intricate tooth anatomy, with tiny canals or branches, can make thorough cleaning difficult. Remaining bacteria can lead to residual infection and persistent inflammation. Delayed permanent restoration, such as a crown, can also allow bacteria to re-enter the tooth.
A new infection can also cause pain in a previously treated tooth. Bacteria can re-enter the tooth or surrounding tissues due to new tooth decay, a cracked or loose crown, or a failed restoration that no longer seals properly. Poor oral hygiene can also contribute to new infections, allowing bacteria to thrive and spread. These new infections can sometimes lead to the formation of an abscess, a pocket of pus at the root tip.
Root fracture is another potential cause of pain. Root-canaled teeth can become brittle over time, especially if not adequately restored with a crown. A crack or fracture can develop from biting on hard foods, trauma, or teeth grinding, creating pathways for bacteria to enter. These fractures can be difficult to detect and may cause intermittent or biting pain.
Pain in a root-canaled tooth can sometimes originate elsewhere, known as referred pain. This means discomfort is felt in the treated tooth but caused by an issue in an adjacent tooth, the jaw joint (temporomandibular joint or TMJ), or sinus problems. For example, sinus inflammation can cause pain perceived in upper teeth due to root proximity to the sinus cavities.
A periapical lesion, such as an abscess or cyst, at the root tip is another reason for pain. This occurs if an infection persists or returns, leading to localized inflammation and bone destruction around the root end. These lesions indicate that the initial infection was not fully eradicated or a new infection has taken hold.
When to Seek Professional Help
If a root-canaled tooth begins to hurt, especially if the pain is severe, worsening, or accompanied by other symptoms, seek professional dental evaluation. Signs of concern include persistent or throbbing pain not subsiding with over-the-counter medication, or pain more severe than initial post-procedure discomfort. Swelling in the gums or face, a visible pimple or boil, or pus drainage indicate potential infection requiring immediate attention. Sensitivity to hot or cold temperatures, or pain when chewing or biting down that continues for over a week or two, warrants a dental visit.
Management and Treatment Options
When a root-canaled tooth causes pain, a dentist will diagnose the exact cause. Diagnosis often involves a clinical examination, symptom review, and dental X-rays to visualize the tooth’s internal structure and surrounding bone. More advanced imaging, such as cone-beam computed tomography (CBCT), may be used for complex anatomy or subtle fractures.
Treatment options vary depending on the diagnosis. Root canal retreatment is a common approach, involving reopening the tooth, removing old filling material, thoroughly cleaning and disinfecting canals, then refilling and sealing them. This procedure aims to address missed canals, persistent bacteria, or new infections. If retreatment is not feasible or successful, an apicoectomy may be recommended.
This surgical procedure involves a small gum incision to access the root tip, removing infected tissue and the root end, then sealing it. If other treatments are not viable or the tooth is severely damaged, extraction may be the only option to remove the problematic tooth and prevent infection spread. Following extraction, various tooth replacement options, such as dental implants or bridges, can be considered.