What Happens When You Eat After Brushing Your Teeth at Night?

Posted on: 14 February 2018

If you have a habit of snacking or eating supper after brushing your teeth at night, you should stop and consider the risks to your oral health. Although by brushing your teeth, you have removed most of the tooth decay-causing bacteria from your mouth, eating again before going to sleep allows those bacterial organisms to thrive once more.

The last thing you need while you are asleep is a few hundred million bacterial organisms eating and multiplying.

An All-Night Buffet for Bacteria

When you brush your teeth, then go to sleep, the remaining bacteria in your mouth have no choice but to go on a low-carb diet. Deprived of their favoured food—carbohydrates, harmful oral bacteria, such as streptococcus mutans, multiply more slowly and produce less lactic acid. Since lactic acid dissolves tooth enamel, this is a good thing.

However, if you sneak in a snack before going to bed, especially one that contains carbs or sugar, you are essentially throwing an all-you-can-eat buffet for tooth decay-causing bacteria. Streptococcus mutans and their partner in crime, streptococcus lactobacillus, will gorge themselves, doubling their numbers every 20 minutes while producing lactic acid.

In the morning, you'll wake up with bad breath and with a fresh bio-film brimming with bacteria on your teeth.

Out With the Good, in With the Bad

Not all the bacteria in your mouth are bad for your teeth. Some species of bacteria are beneficial to your oral health. For instance, when you brush your teeth, you remove dental plaque, a bio-film that is teeming with harmful species of bacteria. Shortly after brushing your teeth then, the good guys show up and begin to construct a colony.

In order to anchor themselves to your teeth, beneficial bacteria secrete a sticky substance that allows them to cling to your teeth. This sticky layer is called a "pellicle", and it protects your teeth from abrasion and acidic substances. However, if your diet is high in carbs and sugar—and you eat right before bed—you create an environment in which the bad guys can thrive.

Brush, Eat Supper, then Brush Again

If supper is a meal that you enjoy, the solution is simple. Brush your teeth as you normally would while preparing to wind down for the night. Afterwards, eat your supper, preferably one that is low in sugar and carbs, and then brush your teeth again. However, wait 20 minutes before brushing your teeth after supper—or in fact any meal.

This period of time gives your saliva time to neutralize any acids, an action which will lower its pH level, before returning to a healthy pH of around 7. Brushing too early could damage your teeth, the surface of which will have softened due to the higher acidity of your saliva.

You can eat before bed, and after brushing, but you may have to adjust your sleeping time to factor in the extra 20 minutes. For more information or assistance, contact a local dental clinic.