Polymers in water at dentist can prevent aerosol mists that spread germs

Aug. 25 (UPI) -- Dental office tools, some of which spin and vibrate can quickly turn water and bodily fluids, such as saliva, into a mist that can spread a virus or other pathogen, according to a new study.

Researchers say the addition of food-grade polymers to water solutions, such as polyacrylic acid, can prevent misting.

In lab experiments, small amounts of polyacrylic acid eliminated aerosolization entirely, they say.

"What was surprising is that the very first experiment in my lab completely proved the concept," researcher Alexander Yarin said in a news release.

"It was amazing that these materials were capable of so easily and completely suppressing aerosolization by dental tools, with significant inertial forces involved. Nevertheless, the elastic forces generated by small polymer additives were stronger," said Yarin, a professor of mechanical and industrial engineering at the University of Illinois.

Before testing the effects of food-grade polymers, researchers observed the aerosolizing effects of several dental tools. The tests showed that the rapid vibration of cleaning tools and the centrifugal force of dental drills efficiently form and propel tiny pockets of water.

When the researchers irrigated model teeth and gums with a polymer admixture, they found the high elongational viscosity of the polymer macromolecules -- an ability to stretch like rubber bands -- prevented the formation and propulsion of water droplets.

Instead of bursts of tiny water droplets, the solution encouraged the formation snakelike threads, which during tests were quickly pulled toward the tip of the tool before they could be flung into the air.

Researchers detailed the results of their dental tool experiments in a new paper published Tuesday in the journal Physics of Fluids.

"When droplets try to detach from a liquid body, the droplet tail is stretched. That's where the significant elastic forces associated with the coil-stretch transition of polymer macromolecules come into play," Yarin said. "They suppress tail elongation and pull the droplet back, completely preventing aerosolization."