A tooth extraction can cause a sinus infection, which is a recognized complication in dental surgery. The potential for a sinus infection following the removal of an upper back tooth stems from a specific anatomical relationship within the skull. When this close connection is disrupted, it can create a pathway for bacteria from the mouth to enter the typically sterile sinus cavity. Understanding this anatomical risk is important for anyone undergoing the extraction of a posterior upper tooth.
Understanding the Maxillary Sinus Proximity
The reason a tooth extraction can affect the sinuses lies in the intimate structural connection between the upper jaw and the maxillary sinuses. These sinuses are pyramidal spaces located within the cheekbones, situated just above the roots of the upper back teeth. The floor of the maxillary sinus is formed by the alveolar process, the bone that holds the upper teeth. The roots of the upper molars and premolars often lie in extremely close proximity to this sinus floor, separated only by a very thin layer of bone, which can range from 0.5 mm to 4.5 mm in thickness. This close spatial relationship means that when a molar or premolar is removed, the protective barrier between the mouth and the sinus is easily compromised.
How Extraction Creates a Pathway for Infection
The complication that directly links a tooth extraction to a sinus infection is known as oroantral communication (OAC). An OAC is an opening created between the oral cavity (“oro”) and the maxillary sinus (“antral”) during the tooth removal process. This usually occurs when the thin bone forming the sinus floor fractures or is perforated as the tooth’s root is extracted, especially if the tooth was deeply rooted or had a pre-existing infection. Once this communication is established, the sinus is exposed to the bacteria-rich environment of the mouth. Bacteria and oral fluids can easily migrate through this new opening and colonize the sinus lining, which can lead to oroantral sinusitis. If an OAC is not managed promptly, it may become lined with tissue from both the mouth and the sinus, forming a chronic, non-healing tunnel known as an oroantral fistula (OAF). The risk for this complication is highest when extracting upper first and second molars, whose roots are most commonly closest to the sinus floor.
Symptoms That Indicate Sinus Involvement
Identifying a post-extraction sinus issue often depends on recognizing symptoms that differ from typical recovery pain. One of the clearest indicators of an OAC is the sensation of air escaping through the extraction site when the patient breathes or speaks. Patients may also experience a foul taste or smell, which results from bacteria and oral fluids entering the sinus. A patient may also notice fluid leaking from the mouth into the nose, particularly when drinking. Common signs of developing sinusitis include a persistent feeling of pressure or pain in the cheekbone area, directly above the surgical site, and nasal congestion or discharge, often affecting only the side where the tooth was removed. If these symptoms appear, especially the movement of air or fluid, it signals a communication that requires professional attention.
Resolving the Communication and Infection
The treatment for post-extraction sinusitis involves addressing both the bacterial infection and the anatomical opening. The infection is managed with a course of antibiotics, such as amoxicillin with clavulanate potassium, to eliminate the bacteria that have entered the sinus. Nasal decongestants or steroid sprays may also be recommended to help reduce inflammation in the sinus lining and promote drainage. Small oroantral communications, typically those under 2 to 3 millimeters, may close spontaneously if the patient strictly follows post-operative instructions, such as avoiding forceful nose blowing, sneezing with the mouth open, and using straws. For larger or non-healing communications, or those that have progressed to a chronic fistula, surgical closure is necessary. The most common surgical technique involves using a local soft tissue flap, such as a buccal advancement flap, where tissue from the cheek is moved over the opening and sutured shut to create a durable, watertight seal.