This smart device sniffed my morning breath to check for gum disease

The human mouth is a disgusting place, capable of emitting awful smells. Viruses, fungi, and possibly more than 1,000 species of bacteria live inside this dark, moist orifice. Nestled into the crevices between your gums and teeth, these microbes can sometimes cause serious health problems like tooth decay and gum disease. These conditions can also make breath smell putrid, so one quick, easy way to check on your oral health is to smell your own breath. If it stinks, it could be a clue that something’s wrong.

The human mouth is a disgusting place

But smelling your own breath is anatomically challenging. I’ve tried breathing into my cupped hand and sniffing the escaping fumes as fast as I can, but it doesn’t work very well. A Silicon Valley startup called Breathometer wants to solve that problem. Its FDA-approved class I medical device, called Mint, looks like a giant Altoid with a removable mouthpiece. It syncs with an app via Bluetooth, it “works with your smartphone to help you understand and improve your oral health,” the Mint website says.

Breathometer began selling Mint for $99.99 at the end of September. They loaned me a device that I test drove for about a month. Here’s how it works: following the instructions in the app, you keep your mouth shut for 30 seconds to give the noxious gasses a chance to accumulate inside. Then you bite down on Mint’s removable mouthpiece, but you don’t actually blow into it. Instead, the Mint sucks out a sample of mouth air and runs it past electrochemical sensors that detect certain sulfur-containing molecules. Those measurements are then converted into an oral health grade: an ‘A’ means your oral hygiene routine is working just fine. And an ‘F’ means make an appointment with your dentist. Like, now.

Vjeran Pavic/The Verge

There are a lot of things that make breath stink, including forgotten food and gastrointestinal disorders. But Mint only measures what are called “volatile sulfur compounds,” which can give bad breath that distinct eau de swamp aroma of overcooked cabbage and rotten eggs. Scientists have long associated these sulfur compounds with a serious gum disease called periodontitis. It affects nearly half of adults over 30, and while it’s still not exactly clear how it starts, what seems to happen is that bacteria accumulate in between gums and teeth. Those bacteria and the body’s immune response to them can make gums swell, bleed, and pull back from the teeth. Eventually, periodontal disease can destroy the bone and gum tissue that keep teeth from falling out.

It’s hard to evaluate how well the Mint app’s algorithm actually predicts gum disease from the presence of these sulfur compounds. There haven’t been any peer-reviewed studies with Mint yet, and the algorithm hasn’t been publicly released. But the premise behind Mint is pretty sound, says Terence Risby, the chair of the International Association of Breath Research. Risby is not affiliated with Breathometer, although he is collaborating with an Italian company that manufactures a breath sampler. “There are a lot of molecules in your breath and there are a lot of sulfur compounds in your breath — and clearly, if you have periodontal disease you will have sulfur compounds in your breath,” Risby says.

Smelling your own breath is anatomically challenging

Breathometer also touts the benefits of oral hygiene for staving off other, horrible, life-threatening diseases. In its press materials and on its blog, the company links mouth bacteria and periodontal disease to conditions like premature birth, cardiovascular disease, and Alzheimer’s disease. But the science is still pretty uncertain about what these connections actually are, and it’s too early to say that improved oral hygiene can reduce the risk of disease in the rest of your body.

“What has been done is lots, and lots, and lots of academic work and clinical work, but not trials that have related oral health to these other diseases,” agrees Breathometer’s chief technology officer Tim Ratto, who says the connection to Alzheimer’s might be “stretching it a bit.”

Vjeran Pavic/The Verge

Devices like the Mint could help drive this kind of research forward though, says Katrine Whiteson, a biochemistry professor and breath researcher at the University of California, Irvine. “We’re not going to get enough information to really answer those questions unless we have cheap devices that we could deploy like this,” she says.

So, I wasn’t worried about what the Mint would say about my risk for dementia, but I was worried it would reveal that I was much smellier than I suspected. The first time I used Mint was in a demo, in front of Breathometer’s founder and CEO Charles Michael Yim. I felt like I was about to be scolded by my dentist about my poor oral hygiene in front of an audience. But my results came back in the ‘A’ range.

There are a couple different programs within the app you can use to track your oral hygiene progress: there’s a one-week breath exploration for you to get to know your mouth odors, which is the main one I played with. There’s also a savvy “prepare for the dentist” two-week program to get your mouth in shape for dental judgment. And there are two longer three-month and six-month monitoring programs — but those commitments were too much for me.

My mouth tasted like a blooming onion had molted in it

As I used Mint, I kept getting good readings — even with morning breath. I thought the device might be malfunctioning, so I looked for a second opinion. I asked someone I trusted to smell my morning breath. His response: “I don’t know, it smells like morning breath.”

That’s an advantage of the Mint, Ratto says: “It doesn’t judge you, and it’s more accurate than a spouse or colleague.”

But I still wasn’t convinced, so I did what any good scientist would do: I tested a positive control. Onions contain sulfur compounds, so I loaded up a spoon with onion powder and gagged it down with a tiny bit of water. My eyes watered. My mouth tasted like a blooming onion had molted in it. It was foul. I stuck the Mint in my mouth, certain I would destroy its circuitry with my breath. The readout on my phone lit up with an ‘F’ in bright red. It politely suggested I go see a dentist.

“It doesn’t judge you, and it’s more accurate than a spouse or colleague.”

So, my Mint was working. But my positive control also revealed a potential problem: onions might be giving me bad breath, but they aren’t giving me poor oral health. Breathometer’s Ratto says that the smelly compounds in onions degrade quickly, so they shouldn’t be skewing my results even if I ate an onion-heavy diet. In fact, after I raced to the bathroom gagging to brush my teeth and swish with mouthwash, I tested again and the results were back to normal.

After using it for about a month, my conclusion is that Mint seems like a good way to check in on oral health. It was easy to use, and the way this giant Altoid whined and whirred as it analyzed my mouth air was weirdly endearing. I liked the reassurance it gave me that my brushing routine was adequate and that my partially erupted wisdom teeth weren’t decaying in my skull. But everyone’s mouth ecosystem is different, and I worried that my problems were simply going unnoticed. It also couldn’t reassure me about other concerning issues like oral cancer.

The other problem was that incorporating Mint into my morning and evening routine went about as well as my yearly resolution to floss more: not well at all. Most mornings, I forgot to use it or, if I remembered, I resented the minute it took. I never remembered at night.

It was hard to tell if the device helped improve my dental hygiene and oral health, since I was lucky enough to have a decent baseline. But I have a lingering suspicion that the secret to a healthy mouth isn’t a device, but good nutrition, fluoridated water, and, especially, accessible and affordable dental care. Given that our country still hasn’t managed to provide these basic services for every person living here, it’s a lot to ask of a cute little device.