Alexander Yarin: How can polymer science protect dentists from COVID-19

COVID-19 presented a major dilemma for dentists. The ultrasonic tools they use to clean teeth kick up a shower of airborne droplets that can spread SARS-CoV-2, the virus that causes COVID-19.

Alexander Yarin isn't in the dental field. But given his decades of experience studying fluid and solid mechanics, the UIC College of Dentistry turned to him for help during the early days of the pandemic.

"On the first day of lockdown, they contacted my department with a question," said Yarin, a UIC Distinguished Professor of mechanical and industrial engineering. Was it possible to alter ventilation in the exam room to cut down on the aerosols dentists were exposed to when they used ultrasonic cleaning instruments?

But when Yarin reviewed the problem, he had a different idea. "Because of my previous experience with polymeric liquids, I proposed to not hunt for droplets, but to completely eliminate them," he said.

An applied physicist by training, Yarin uses principles of fluid mechanics, solid mechanics, polymer science and combustion in innovative applications. For the problem at hand, he proposed adding small amounts of a high-molecular weight, FDA-approved polymer to the water used with the ultrasonic cleaning tools. The solution would be viscoelastic, meaning it would have both fluid-like and solid-like qualities. It would flow like water when pumped through the pipe, but its solid-like elastic properties would dominate, suppressing aerosolization at the tool tip.

"This prevents the formation of droplets," Yarin said. "They are pulled back, because even a few polymer macromolecules introduce huge elastic forces in strong stretching." That prevents droplets from detaching and showering the surrounding area, he explained. When viewed under high resolution with a high-speed camera, it looks like the mythical head of Medusa, said Yarin. The droplet tails extend like the snakes on Medusa's head and retract before they can escape.

Through multiple studies, the researchers confirmed the success of this idea in preventing aerosolization. With the support of UIC's Office of Technology Management and help from Dr. Lyndon Cooper, formerly the associate dean for research and head of the department of oral biology at the College of Dentistry, UIC patented the invention and licensed it to the dental products company Ivoclar. It hit the market in summer 2024 under the name VivaDent Aerosol Reduction Gel.

Yarin, a fellow of the American Physical Society, has published hundreds of peer-reviewed research papers and is an inventor of 11 other patents. Over the course of that prolific career, Yarin has remained guided by advice of his former mentors he received as a student.

"One of my mentors long ago told me that happiness is that when you want to go to work in the morning - and want to go back home in the evening. I'm trying to follow that."