Root Canal Question: I had a root canal last Monday. Shortly after I returned home from the dentist, I leaned over and experienced a sudden gush of a watery substance from my left nostril. It smelled exactly like the sodium hypochlorite the dentist used to irrigate my canals. The drainage occurred several times that evening. The next day, nearly 24 hours later, while bending over and moving boxes, it happened again — this time the fluid was yellow and about a teaspoon in volume. I had no pain or swelling.
The root canal was on my left upper jaw; I believe it was tooth #13. The nasal drainage and the temple pain were only on the left side.
When I discussed this with my dentist, he seemed puzzled and said the drainage was unlikely to be related to the root canal and might be a coincidence or an allergic reaction. He said there is no way to drill into the sinus cavity.
Is it possible to drill through the root into the sinus cavity?
Answer: I’m sorry you’re dealing with this. I disagree with your dentist’s certainty that the two events are unrelated. The drainage you describe, especially its smell and taste, is strongly suggestive of sodium hypochlorite exposure from the root canal irrigation. Sodium hypochlorite has a distinctive odor that the body does not produce.
There are situations where a root can communicate with the maxillary sinus. Upper molar roots, particularly in that region of tooth #13, often lie very close to the sinus floor. Following chronic infection (abscess) or with age-related changes, the barrier between a root canal and the sinus can be thinned or breached, allowing irrigants to enter the sinus cavity. While outright drilling into the sinus is uncommon and usually associated with surgical tooth removal rather than routine root canal therapy, inadvertent passage of irrigant through an existing pathway is possible.
Small, accidental amounts of properly diluted sodium hypochlorite introduced into the sinus do not necessarily cause permanent damage. However, they can cause acute chemical irritation. In more severe cases patients can develop sudden, intense facial pain, swelling, or worsened sinus symptoms that may require emergency treatment and, rarely, surgical intervention. This condition, referred to as chemical sinusitis, can be serious.
For a case like yours, an appropriate immediate approach would include saline nasal irrigation (for example, with a Neti pot) to help flush the area, a short course of antibiotics if bacterial infection is suspected or to prevent secondary infection, anti-inflammatory medication to reduce tissue reaction, and decongestants to promote drainage. Close monitoring of symptoms is important. Definitive completion of the root canal should be done carefully, avoiding further sodium hypochlorite irrigation into the communication. Over time, a small communication between the tooth and sinus often heals on its own once the infection source is controlled.
Because your treating dentist did not acknowledge the possibility of a tooth–sinus communication, I recommend referral to an endodontist (root canal specialist) for completion and follow-up. An endodontist can evaluate for a persistent communication, take appropriate imaging if needed, and perform the remainder of the treatment with techniques that minimize the risk of further sinus exposure. If you remain uncomfortable with your general dentist’s approach, consider finding a new general dentist for ongoing care.
Good luck, and please follow up with a specialist if symptoms persist or worsen.
Mark Burhenne DDS
Learn More:Know Before You Go: Root Canals