Have you ever heard of the "3-3-3" brushing rule: brush three times a day, within three minutes after eating, and for at least three minutes?

Surprisingly, this rule actually lacks medical evidence.

The 3-3-3 rule originated from an oral hygiene campaign slogan created in Japan in the 1950s.

While health authorities in Japan have long since discarded it, the rule is still widely used in public service advertisements and schools in South Korea.

Experts note that properly brushing all of your teeth actually requires about 10 to 15 minutes, rather than just three.

Particularly in the summer, brushing your teeth immediately after consuming carbonated beverages or ade can wear away weakened tooth surfaces.

It is safer to rinse your mouth with plain water first and wait about 30 minutes before brushing.

If you are short on time, experts recommend skipping the front teeth, thoroughly cleaning the chewing surfaces of your molars along with the gumline, and using dental floss together.