This Is What Happens If You Don't Brush Your Teeth for a Day, Study Shows

Serious damage can occur in as little as 24 hours, according to new research.

With the various lockdowns we've been through this year, it's understandable that certain standards may have slipped a little. If you've made it through the last 12 months without attending a Zoom call wearing pajamas on your bottom half, eating leftovers for breakfast, or having a few days when you barely moved from the sofa, you're clearly stronger than most. However, there's one area of your daily routine where it's as important as ever that standards don't slip, and that's brushing your teeth. While the need for proper oral hygiene is impressed upon us from a young age, a new study shows just how much damage can be done to your teeth in as little as 24 hours without brushing them. For the full story on what happens if you don't brush your teeth for a day, read on, and for more everyday health advice you need to know, check out If You're Doing This in the Shower, Doctors Say to Stop Immediately.

There's a steep decrease in "good bacteria."

Young man looking in mirror at his mouth and teeth in bathroom, checking their health state

This new research out of China, led by scientists from Procter & Gamble Company and the Single-Cell Center, Qingdao Institute of BioEnergy and Bioprocess Technology of the Chinese Academy of Sciences, was published in the journal mBio on Mar. 9. The researchers studied 40 participants whose oral hygiene routine was interrupted over the course of a month.

They found that in between 24 to 72 hours of abandoning their normal routine, there was a steep decrease in the amount of "good oral bacteria" (rothia species) along with the anti-inflammatory chemical betaine. And for more oral hygiene advice, check out This Is What Happens to Your Body When You Don't Floss Your Teeth.

And there's a sharp rise of "bad bacteria."

Woman looking her self in mirror, she has toothache
Vesna Andjic / iStock

As the good bacteria decreased, there was simultaneously a sharp rise in the amount of "bad bacteria"—specifically multiple salivary cytokines, which are the proteins and other molecules produced by immune system cells and connected with inflammation in the body. The researchers also found significant quantities of the kind of bacteria usually found in patients with peridontitis (the gum infection that can ultimately lead to the loss of teeth), even before any symptoms of this condition were present. And for another tip on keeping your teeth healthy, check out How Often You Should Really Change Your Toothbrush, Dentists Say.

Plaque starts to decalcify your teeth.

Man brushing teeth and in pain
Motortion Films / Shutterstock

In addition to these bacterial changes, after just one day of not brushing your teeth, actual physical damage starts to occur, too. "Plaque functional profiles already resemble that of the severe gingivitis stage within 24 [hours]," the study authors write.

Shafer's Textbook of Oral Pathology warns that built up plaque starts to decalcify the lower layer of dentin, the protective material that sits below the surface enamel. Once this is penetrated, damage can start to occur to the teeth, which can't be reversed by resuming regular brushing. Unlike enamel, dentin also has nerves running through it, meaning any damage to it is more likely to result in pain. And for more health news delivered right to your inbox, sign up for our daily newsletter.

The effects worsen the longer you go without brushing.

Distressed woman sitting in a dentist's chair, holding her cheek and enduring a terrible toothache

After the initial sharp change in the bacterial makeup of study participants' mouths, researchers noticed more damage occurring. "We also found a sudden 'aging' of the bacteria in the mouth," the study's senior author XU Jian, director of Single-Cell Center, said in a statement. "Their oral microbiome had aged the equivalent of about a year in less than a month."

Previous studies have shown that a person's oral microbiology can be given an "age" as the amount of healthy rothia typically declines naturally with the passing of time. A separate 2019 study in the European Journal of Preventive Cardiology also found a possible link between poor oral hygiene and heart disease.

So the message is clear—even if you're not leaving the house or seeing many people lately, brushing your teeth is something you shouldn't be cutting corners on, even for 24 hours. Of course, you know twice a day is key, but Here's What Happens When You Only Brush Your Teeth Once a Day.

John Quinn
John Quinn is a London-based writer and editor who specializes in lifestyle topics. Read more
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