Can a Sinus Infection Be Caused by a Tooth?

A couple of years ago, I wrote a post discussing sinus infections, prompted by my wife’s experience.  She had severe tooth pain caused by a sinus infection.  While that post discusses how a sinus infection can cause tooth pain, it never addressed the opposite question: Can a tooth cause a sinus infection?

Sinuses are simply chambers in your head that allow air to circulate to get warm and moist before it travels down to  your lungs.  Normally, the body is able to keep the sinuses clean and healthy, despite the dark, moist environment that bacteria love.

However, when conditions are right, bacteria can grow out of control in the sinuses, causing a sinus infection.  One cause of sinus infections is the common cold. Interestingly enough, teeth can also cause sinus infections.

Before we get into a discussion on how teeth can cause sinus infections, we’ll talk about where the sinuses are located.

Where Are Sinuses Located?

There are a few different sinuses located in the facial area — around the cheeks, nose, and above the eyes.  The sinuses around the nose are known as the maxillary sinuses. While there are several sets of sinuses, the maxillary sinuses are the only sinuses that can also be infected by a tooth-related problem.

How Often Do Teeth Cause Sinus Infections?

Hupp’s Contemporary Oral and Maxillofacial Surgery textbook states, “Periapical or periodontal infections of maxillary posterior teeth may erode superiorly through the floor of the maxillary sinus.  Approximately 20% of cases of maxillary sinusitis are odontogenic.”

Basically, that’s a fancy way of saying that tooth and gum abscesses of the upper back teeth can eat through the bone and invade the maxillary sinus.  It further says that about 20% of all maxillary sinus infections are caused by tooth infections, rather than another cause.

A Case of an Abscess Close to the Sinuses

Here is an x-ray that I took of an upper first molar.  I have outlined some of the important structures below for those of you who are not accustomed to reading x-rays.

In this case, the root of the upper first molar is inside of the maxillary sinus. This is a perfect example of how close the maxillary sinus is to the upper teeth.  Sometimes there is only a thin membrane separating the roots of the upper teeth and the sinus, making it very easy for an infection to travel into the sinuses.

Although this person wasn’t exhibiting any symptoms of a sinus infection, they are susceptible to infections of the sinus cavity infecting the teeth.

Teeth Can Cause Sinus Infections

It is important to remember that unhealthy teeth are just one cause of sinus infections, and that there are several other causes.  If you suspect your sinus infection is caused by a tooth, you should see your dentist to confirm this.