When a tooth experiences severe damage or infection, a root canal procedure is performed to save it. This treatment involves removing the infected or inflamed pulp, which contains nerves, from the tooth’s interior. While the pulp is gone, the tooth remains connected to surrounding living tissues. This means the common idea that a tooth without a nerve cannot feel pain is often inaccurate.
Understanding a Tooth Without a Nerve
The dental pulp houses the nerves and blood supply that give the tooth its sensation and vitality. During a root canal procedure, this dental pulp is removed from the tooth’s interior. The internal space is then cleaned, disinfected, and sealed with a filling material, preventing further bacterial invasion.
Despite the removal of the internal nerve, the tooth is still firmly anchored in the jawbone by the periodontal ligament. This ligament surrounds the tooth’s root and connects it to the bone. Both the periodontal ligament and the surrounding jawbone contain their own network of nerves and blood vessels. These external structures remain sensitive and can transmit pain signals.
Sources of Pain in a Treated Tooth
Even after a successful root canal, pain can emerge from several sources. One common reason is persistent or new infection in the surrounding tissues. This might occur if some infected material was missed during the initial procedure, or if new bacteria enter the tooth due to a compromised filling or crown. These bacteria can then irritate the periodontal ligament and bone, leading to inflammation and pain.
Another frequent cause of discomfort is a cracked tooth or root fracture. Cracks can result from biting on hard objects or excessive forces. These fractures can create pathways for bacteria to penetrate the tooth’s internal structure or irritate the surrounding ligament, causing sensitivity.
New decay can also develop on a root canal-treated tooth. If cavities form around the existing filling or crown, bacteria can eventually reach the tooth’s inner structures or the surrounding bone, triggering pain. Additionally, if the biting surface of the tooth or its crown is too high, it can create excessive pressure on the periodontal ligament, causing pain when biting. Pain can also be referred from other areas, such as adjacent teeth, the jaw joint (TMJ), or even sinus issues, which can be perceived as originating from the treated tooth.
Identifying the Root of the Discomfort
When a patient experiences pain in a root canal-treated tooth, a dentist undertakes a diagnostic process to pinpoint the cause. This begins with a thorough review of the patient’s history, including details about the type, intensity, and duration of the pain, along with any associated symptoms. A clinical examination follows, involving visual inspection of the tooth and surrounding gums for swelling or discoloration, gentle palpation of the gum tissue over the root, and tapping on the tooth to assess sensitivity.
Imaging techniques help visualize structures. X-rays, such as periapical and panoramic views, help identify bone loss, signs of infection around the root tip, or undetected fractures. For more complex cases, three-dimensional imaging like Cone Beam Computed Tomography (CBCT) provides a detailed view of the tooth’s internal anatomy, allowing for the detection of missed canals or subtle cracks. Specialized tests may also be performed, including bite tests to evaluate pain upon chewing, thermal tests on adjacent teeth to rule out referred pain, or selective anesthesia to isolate the source of discomfort.
Paths to Pain Relief
Once the cause of pain in a treated tooth is identified, various treatment approaches can provide relief. If the original root canal was incomplete or a new infection has occurred, a root canal re-treatment may be recommended. This involves reopening the tooth, removing previous filling material, cleaning and reshaping canals, and then resealing them.
For persistent infection or inflammation at the root tip that cannot be resolved with re-treatment, a minor surgical procedure called an apicoectomy might be performed. This procedure removes the very end of the root and any infected tissue, then seals the root end. If a crack or fracture is the underlying issue, treatment depends on its severity; minor cracks might be addressed with bonding or a crown, while severe fractures extending deep into the root may necessitate tooth extraction.
If the pain is due to an uneven bite, adjusting the tooth’s surface to reduce pressure on the supporting structures can resolve the issue. For referred pain, addressing the originating problem, such as decay in an adjacent tooth or a temporomandibular joint (TMJ) disorder, is necessary. While short-term pain relief can be managed with over-the-counter medications like ibuprofen or acetaminophen, or prescription antibiotics for infection, these are not long-term solutions without addressing the underlying cause.