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 diagram below gives you a little better idea of where the sinuses are, and how they look when they are healthy, versus how they look when they are infected.

If you look at the diagram above and imagine a row of upper teeth, you can see how the roots of the upper teeth come into close contact with those sinuses on each side of the nose. These sinuses 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.

Below, you’ll find a couple of examples of how tooth infections or abscesses can cause sinus infections.

A Case of an Abscess Close to the Sinuses

Here is an x-ray of a tooth that had a root canal and crown done previously, but the infection at the roots had never quite healed. I have outlined some of the important structures below for those of you who are not accustomed to reading x-rays.

Abscess Near Sinus in a Molar

I colored the sinus blue and the tooth infection red in the x-ray below:

As you can imagine, the infection and the sinuses do overlap, as you can see in the x-ray below.

Abscess Near Sinus in a Molar Abscess and Sinus Outlined

Although it looks like the sinus and the infection are overlapped on the x-ray, it doesn’t necessarily mean that the infection has broken into the sinus and causing a sinus infection. It could be that the abscess is either in front of or behind the sinus in this x-ray, because the x-ray is simply a snapshot of the whole area and doesn’t tell us if things are closer to the front or the back.

If you take a look at the x-ray above, you can see 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, but the x-rays do a good job of showing just how close the abscess is to the sinus.

A Case of Sinusitis Caused by a Tooth

This person had chronic sinusitis for the last few years, that started shortly after she had a metal post put into one of her upper back teeth. Upon looking at her x-rays I noticed that the metal post that was put in one of her upper teeth looked like it had pierced through edge of the tooth and gone slightly into the bone. This caused an abscess that was leaking into her sinus.

Here’s the x-ray of her upper right teeth:

Sinus Infection Caused by a Tooth Abscess

To make the x-ray below easier to see, the tooth is green, the infection is red, and the sinuses are blue:

Sinus Infection Caused by a Tooth Abscess with Abscess, Tooth, and Sinuses Outlined

Sadly, due to the fracture in the tooth caused by the large metal post, the tooth had to be extracted.

The oral surgeon who extracted the tooth told me that the tip of the tooth broke off just above the metal post, causing the root fragment to get pushed into the sinuses during extraction. He had to open up the sinus to retrieve the root and he was able to suction out a lot of the infection — he said it was a pretty bad infection.

Teeth Can Cause Sinus Infections

While sinus infections can cause teeth to to hurt, hopefully this post has helped you see that infections from the upper back teeth can easily make their way into the sinuses and 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.

Do you have any questions, concerns, or comments? Feel free to leave a comment in the comments section below. Thanks for reading!