Do you brush your teeth before you go to bed? Always? Without fail?
If you can answer an unequivocal “yes,” you’re in the majority — but just barely.

According to a recent poll in Britain, 45% of adults admitted to sometimes skipping their nightly tooth brushing. They blamed being too tired or simply forgetting. Furthermore, only 24% said that they floss regularly, and nearly 20% responded that they don’t usually use toothpaste.

Many of us are aware that we could (and should) take better care of our teeth. In fact, dentists strongly recommend brushing your teeth twice a day, not just before bedtime. But is it really that big of a deal to skip one of your regular brushings?

Of course, the big problem is that bad habits build up over time. Forgiving a missed tooth-cleaning here and there can lead to missing them more and more often, which can lead to serious problems.

But even if we’re talking about one single, isolated instance of going to sleep with dirty teeth, the answer is yes — it’s pretty gross, and it is a big deal. So what’s really happening inside your un-brushed mouth while you’re sleeping? We’ll walk you through it.

First of all, your mouth is full of bacteria all the time. This isn’t a good or bad thing, it’s just natural. Bacteria excrete their wastes, which are highly acidic substances. Acid is what’s really bad for your teeth, wearing down your enamel and leading to cavities and root decay. Additionally, if not removed promptly, this waste substance calcifies into plaque, a hard substance that can’t be taken off your teeth by brushing and flossing alone.

So, brushing accomplishes two things: it removes these acidic waste products from your teeth before they can harden and become much more problematic plaque, and it also sweeps away the extra bits of food remaining on your teeth — which otherwise would be consumed by the bacteria, creating more waste products that would eventually turn into plaque.

Failing to brush your teeth impacts your gums, too. If plaque begins to build up, your body recognizes it as an infection, triggering inflammation in your gums. This is actually your body’s normal response to the presence of harmful elements, but in this case, it can end up doing damage to healthy gum tissue. Over time, inflammation will cause your gums to pull away from your teeth — known as gingivitis — which can worsen into periodontitis, a more harmful condition that can do lasting damage.

While one night of not brushing your teeth won’t ruin your oral health for life, it should still be avoided at all costs. Next time you find yourself tempted to just hit the sack without first cleaning your teeth, try imagining all the bacteria in your mouth and the acids and plaque that will be collecting in your mouth while you snooze. Then consider what a tiny percentage of your time in the day is actually required to brush and floss, and see if that doesn’t help you make the healthy choice when it comes to your regular brushings.