The Most Important Number in Your Mouth Might Not Be 32

When we think about oral health, a few numbers tend to get all the attention.

32 adult teeth. Two minutes of brushing. Twice a day.

But there's another number quietly changing inside your mouth throughout the day that you probably never think about:

Your pH.

And understanding it can change the way you think about what happens in your mouth after you eat, drink and brush.

Your Mouth Is Constantly Changing

Your mouth isn't a static environment. Every time you eat or drink, you're introducing new compounds into an ecosystem already populated by hundreds of species of microorganisms.

Some bacteria in dental plaque can metabolize sugars and other fermentable carbohydrates and produce acids in the process. As those acids accumulate, the pH around your teeth falls. That's important because tooth enamel is constantly participating in a balance between losing and regaining minerals.

When the environment around a tooth becomes sufficiently acidic, minerals can begin leaving the enamel, a process known as demineralization. When conditions recover, saliva can help neutralize acids and provide minerals that support remineralization.

In other words, your teeth aren't simply either “healthy” or “unhealthy.”

There's a microscopic push and pull happening throughout the day.

What Does pH Actually Mean?

The pH scale measures how acidic or alkaline an environment is. A lower pH is more acidic. A higher pH is more alkaline.

Your oral pH naturally changes, particularly in response to what you eat and drink. After exposure to fermentable carbohydrates, plaque pH can fall quickly before gradually recovering.

This rise and fall is sometimes illustrated by what's known as the Stephan curve.

The goal isn't to make your mouth permanently alkaline. That's neither realistic nor the point. What matters is your mouth's ability to recover from acidic challenges and return toward a more balanced environment.

And one of the biggest players in that recovery is something your body already produces.

Saliva Is Doing More Than Keeping Your Mouth Wet

Saliva is one of your mouth's natural defense systems. It helps clear substances from the mouth, buffer acids and maintain an environment that supports the mineral balance of your teeth.

That's one reason oral health is about more than simply what touches your teeth. It's also about the environment surrounding them.

And that environment includes something else we've traditionally been taught to think of as the enemy:

Bacteria.

Some Bacteria Can Affect the Environment, Too

Not every bacterium in your mouth behaves the same way. Your oral microbiome is a complex community containing many different microorganisms with different characteristics and functions. That's where the science gets particularly interesting.

One strain researchers have studied for its potential role in oral health is Streptococcus salivarius M18, better known as BLIS M18®.

M18 has several characteristics that make it noteworthy. One is urease activity. Urease breaks down naturally occurring urea and produces ammonia, which can help counter acidity. Research into Streptococcus salivarius has shown that this urease system can generate alkali and raise pH under acidic conditions.

M18 can also produce dextranase, an enzyme capable of breaking down dextran, a component associated with the structure of dental plaque.

And research has examined M18 for its relationship with Streptococcus mutans, a bacterium strongly associated with the development of dental caries.

But newer research has made the pH story even more interesting.

A New Look at M18 and Biofilm pH

A 2026 study published in the Journal of Oral Microbiology investigated several probiotic bacteria in a complex, saliva-derived oral biofilm model. Researchers tested the biofilms under both low- and high-sugar conditions.

Under the low-sugar condition, biofilms supplemented with Streptococcus salivarius M18 had a significantly higher pH than untreated biofilms.

Under the high-sugar condition, however, the researchers did not observe a significant pH benefit from probiotic supplementation.

That distinction matters because it reinforces something that's easy to lose in the excitement around probiotics:

There is no magic ingredient that makes the rest of your oral-health habits irrelevant.

Probiotics don't replace brushing or flossing, and they don't make a high-sugar diet consequence-free.

Oral health is an ecosystem, and the environment we create still matters.

Why BLIS M18® Is in Evena

This is one of the reasons Evena contains BLIS M18®. Evena was designed around a different way of thinking about oral care. Most of our nightly routine is focused on removal.

We brush away plaque and debris. We floss between our teeth. We rinse. We spit.

Those habits remain foundational. But your mouth isn't sterile, and it isn't supposed to be.

So after cleaning, Evena takes a different approach: adding carefully selected beneficial bacteria, including BLIS M18®, to support a balanced oral microbiome.

Take it after brushing. Let it slowly dissolve. Don't rinse.

Brush. Evena. Sleep.

Oral Health Is About More Than What You Remove

For a long time, we've thought about oral care largely in terms of fighting what's bad: remove plaque, avoid excess sugar and control harmful bacteria. Those things matter.

But the emerging science of the oral microbiome gives us another way to think about the mouth: as an environment that we're constantly influencing. What we eat matters. Our saliva matters. Our habits matter. Our microbes matter. And yes, even our pH matters.

So the next time you think about the numbers associated with a healthy mouth, don't just think about 32 teeth or two minutes of brushing.

Think about the environment you're creating for all 32 of them.

Sources

Burton JP, et al. Journal of Medical Microbiology. 2013.

Salim HP, et al. “Randomized Clinical Trial of Oral Probiotic Streptococcus salivarius M18 on Salivary Streptococcus mutans in Preprimary Children.” International Journal of Clinical Pediatric Dentistry. 2023. View on PubMed Central

Reichardt E, Assar S, Kristensen MF, Lund MB, Schlafer S. “The effect of probiotic bacteria on community composition, microscale pH and matrix architecture in a saliva-derived model of oral biofilm.” Journal of Oral Microbiology. 2026. View on PubMed

Sissons CH, et al. “Urease activity in Streptococcus salivarius at low pH.” Archives of Oral Biology. 1993. View on PubMed

BLIS Technologies Ltd. “GRAS Notice 807: Streptococcus salivarius M18.” U.S. Food and Drug Administration. View FDA GRAS Notice