After you finish brushing your teeth, swishing aroundsome water before spitting ensures that you rid yourmouth of all that frothy toothpaste. But as it turnsout, having a little toothpaste residue left in yourmouth isn’t a bad thing—in fact, it’s an importantpart of keeping your teeth healthy.
This is because toothpaste contains fluoride. “Fluoride is the single most important ingredientin toothpaste,” Dr. Nigel Carter, dentist and CEO of the UK’s Oral Health Foundation, explained on the organization's website. “It greatly helps oral health by strengthening the toothenamel, making it more resistant to tooth decay. It also reduces the amount of acid that thebacteria on your teeth produce.”
If you rinse your mouth with water immediately after a brush session, you’re also rinsing awaythe fluoride, which doesn’t give it much time to work its magic. Instead, many expertsrecommend simply spitting out excess toothpaste. The Oral Health Foundation evenlaunched a campaign called “Spit, Don’t Rinse” in 2016 to encourage the habit.
The need to completely clear your mouth after brushing can be strong, especially if you’verinsed with water for your entire life. Some people rinse with mouthwash as a workaround—butthat may not be such a great idea either, since toothpaste has a significantly higherconcentration of fluoride than mouthwash does. The UK's National Health Service advisesgargling with mouthwash at a different time of day, like after a meal.