Root canal treatment is a common dental procedure aimed at saving a damaged tooth. While highly successful, root canals can occasionally encounter complications or “go bad.” Understanding why this happens and what steps can be taken is important for recognizing potential issues and seeking timely care.
Understanding Root Canal Treatment
A root canal procedure addresses issues within the tooth’s pulp, the soft tissue located inside the tooth. When this pulp becomes infected or inflamed, often due to deep decay, repeated dental procedures, or a crack, a root canal is performed to alleviate pain and save the tooth.
During the procedure, a dentist creates a small opening in the tooth to access the infected pulp. The diseased pulp is then carefully removed, and the inner chamber and root canals are cleaned, disinfected, and shaped. After thorough cleaning, the canals are filled with a biocompatible material, typically gutta-percha, and sealed to prevent further infection. Finally, the tooth is usually restored with a permanent filling or a crown to protect and restore its function.
Reasons for Failure
A root canal can fail if the initial treatment does not fully eliminate the infection or if the tooth becomes reinfected. One common reason is incomplete cleaning and shaping of the root canal system. The intricate anatomy of tooth canals can make it challenging to thoroughly clean all branches, potentially leaving behind infected tissue.
Another factor contributing to failure is undetected or missed canals during the initial procedure. Some teeth have complex structures, such as curved or very narrow canals, or more canals than typically expected, which can be difficult to locate and treat. This allows bacteria to persist and cause reinfection.
Reinfection can occur if bacteria enter the treated tooth. This might happen due to delayed or improper placement of the permanent crown or filling, allowing saliva and bacteria to contaminate the tooth’s interior. Additionally, a new cavity on the treated tooth or a crack or fracture in the tooth or its restoration can create pathways for bacteria to re-enter and compromise the root canal seal.
Recognizing a Failed Root Canal
Recognizing the signs of a failed root canal is important for timely intervention. Persistent pain or discomfort in the treated tooth, constant or intermittent, is a common indicator. This pain can range from mild to severe and might worsen when biting down or applying pressure.
Swelling and tenderness in the gums around the treated tooth can suggest an ongoing infection or inflammation. Sometimes, a pimple-like lesion (sinus tract or boil) may appear on the gum near the affected tooth, indicating a pus-filled abscess. This lesion may drain, relieving pressure temporarily.
Other signs include prolonged sensitivity to hot or cold, or a change in the tooth’s appearance, such as discoloration or darkening. In some instances, the treated tooth might become loose due to bone loss or a fracture. While some discomfort is normal immediately after a root canal, symptoms persisting for weeks or months, or new symptoms appearing long after the procedure, warrant a dental evaluation. Dental X-rays are often used to identify signs of persistent infection or structural issues that may not be visible otherwise.
Addressing a Failed Root Canal
If a root canal fails, several treatment options are available to address the issue and save the tooth. The most common approach is root canal retreatment, which involves reopening the tooth, removing previous filling materials, and thoroughly cleaning and reshaping the canals. This aims to eliminate any remaining infection or address missed canals. After recleaning, the canals are refilled and sealed, and a new restoration is placed.
When retreatment is not feasible due to blockages or if the infection persists at the root tip, an apicoectomy may be recommended. This minor surgical procedure involves making a small incision in the gum to access the root tip directly. The infected tissue and a small portion of the root tip are removed, and a small filling is placed to seal the end of the root canal. This is often considered when a root canal has failed and retreatment was unsuccessful or not advised.
If retreatment and apicoectomy are not viable, or if the tooth is severely damaged, extraction may be necessary. This is typically a last resort when other methods cannot preserve the tooth. Following extraction, various options are available to replace the missing tooth, such as a dental implant, bridge, or denture, to restore function and aesthetics. Consulting with a dentist or an endodontist is important to determine the most appropriate course of action based on the tooth’s condition.