Even in 1600s, Dutch scientist knew to use alcohol-free mouthwash

In the late 1600s, a sharp-minded and hard-working Dutchman was seeing wonders in a droplet of water. His discoveries would echo in later advancements in microbiology, bad breath technology and even mouth rinses.

This is the tale of how Antoni Philips van Leeuwenhoek discovered that alcohol-free mouthwashes work best.

Tiny spheres, tiny animals

A Dutchman from Delft, Leeuwenhoek had an unparalleled curiosity about the natural world, which had led him to tinker with a relatively new instrument, which natural philosophers and members of the English Royal Society (with whom he corresponded) called the "microscope".

This invention allowed scientists to see unusually small things, objects that escaped the naked eye. And Leeuwenhoek discovered a way to make the microscope even more powerful.

His method was to heat a glass rod in a fire and pull its ends, creating a strand thinner than a hair. By then placing one of these strands back in the flames, he could create tiny glass spheres, which he found made excellent microscope lenses.

And what he saw using these lenses was astounding. Droplets of river water contained tiny one-celled beings, which he dubbed "animalcules". (Today, we call them microorganisms). Blood, too, was full of small, donut-shaped cells.

And samples of gunk taken from teeth were crawling with microbes.

Alcohol doesn't make a dent

Leeuwenhoek, enterprising individual that he was, decided to test certain liquids to see if they killed the "animalcules" found in dental plaque. He applied vinegar and brandy to the microorganisms in a dish and then observed as they reacted to it.

What he saw was rather surprising. Vinegar should have killed the bacteria, since it was commonly used for pickling and preserving - yet it didn't. Neither did the alcohol in brandy, according to a paper published in the Journal of the American Dental Association.

Next, he tried gargling with vinegar and brandy himself, and then examining his dental plaque afterward. Again, these liquids - both of which had been used as mouthwashes over the centuries - failed to kill the microbes on teeth.

The Dutch innovator concluded that alcohol and vinegar either couldn't eliminate oral bacteria or did a poor job of it.

And he was right

He had discovered what today we take for granted - namely, that alcohol-based mouth rinses are exceedingly bad at eliminating oral microbes or neutralizing bad breath.

What breath experts now know, thanks in part to Leeuwenhoek, is that only specialty alcohol-free mouthwashes can effectively dispel oral odor and kill the bacteria that cause halitosis.