Dentistry startup gets FDA clearance
Mesosil, founded by alum Cameron Stewart, sees its antimicrobial hit the market
By Diane Peters
When Mesosil’s anti-infection biomaterial earned Food and Drug Administration (FDA) clearance recently, founder and CEO Cameron Stewart — an alum of the Faculty of Dentistry who has maintained strong ties — had to be told by his board to stop and celebrate.
“I’m still a scientist at heart. I don’t get super excited or happy about things. I know there’s more to do. Sometimes I need that push to acknowledge that this is a big thing we should broadcast and celebrate and talk about.”
Mesosil’s team of six did indeed go out to a restaurant to give proper due to an innovation that’s been over a decade in the making.
Stewart began his master’s at the Faculty and with what is now called the Institute of Biomedical Engineering in 2013. He switched over to the PhD program at the urging of his supervisors, professors Yoav Finer from Dentistry and Benjamin Hatton of the Faculty of Applied Science & Engineering.
He worked on solving a core problem in dentistry. In the microscale space between a filling and the tooth, bacteria can grow that can lead to infection and also break down the filling itself, especially those made from tooth-coloured composite resin. Most restorations fail in between five and seven years, and replacement fillings cost Canadians about $3 billion a year.
In the lab, early on, Stewart formed porous silica particles around an antimicrobial. He showed this combination could slowly release infection-fighting materials around a filling.
“By year three of my PhD I was convinced that it worked and there was a need for it,” says Stewart, who looks back on that realization as a career highlight. In time, as a bonus, he found his material slowed the biodegradation of fillings plus preserved the bond strength between the restoration and the tooth.
He patented the material in 2015, launched Mesosil and wrapped up his PhD in 2018 — following that up with a postdoc at Dentistry that lasted four years. Meanwhile, Stewart looked around U of T for support for launching a startup.
“I liked the business side of things,” he says, embracing entrepreneurship wholeheartedly. He went through the University of Toronto Early-Stage Technology (UTEST) program and worked with the Health Innovation Hub (H2i). “Those programs were pretty pivotal.”
His business skills helped him navigate funding — Mesosil brought in $2.3 million in investment in 2024. Now, Stewart is using savvy strategies to get his product to market. While a competitor has been selling directly to dentists, an approach that has proved difficult, Mesosil instead opted to be a technology and additive provider to established companies working in dentistry. That's how the technology got FDA 510(k) clearance.
Well-run businesses diversify, and Stewart has plans to do just that. He’s looking into the larger medical device market and is in early talks with potential partners. “Anything that’s internal and just mucous membrane interfacing is going to be a significant technical challenge,” he admits.
As well, Mesosil has developed high-quality nanomaterials without antimicrobial properties that could have uses outside medicine.
While Stewart graduated years ago, his connections to U of T endure. He rents space at U of T Mississauga’s SpinUp lab and at 124 Edward St. and is a regular client of CAMiLod. He and his employees manage Finer’s lab, help his students and are engaged in his academic research.
“It’s a mutually beneficial relationship,” says Stewart. “We are an antimicrobial company, and the process of getting a lab approved to work with Risk Group 2 bacteria is quite arduous.”
Finer, who is also the George Zarb/Nobel Biocare Chair in Prosthodontics, works on research that spans the development of a larger dental restorative system that includes an improved composite and adhesive. He says these efforts have earned ongoing funding and led recent patents, but are a few years behind Mesosil’s market-ready invention.
“Most dentists, we want our work to last,” says Finer, so he expects improved dental materials will be in demand. He calls Stewart’s success so far “encouraging” and plans for the larger restoration system to be ready for clinical trials in a few years — animal studies have already been promising.
As for Stewart, he’s looking ahead to ramping up production, which may require setting up a small-scale chemical manufacturing facility.
He’s also trying to pause and enjoy what he and his small team have accomplished. “I have seen pictures and read reports of people benefitting from our materials. That’s extremely exciting. I love that we're helping people,” he says.
On the business side, there is much to celebrate, too. “As a company with this technology, we have so many paths in front of us and options we can choose from.”
Top photo: The team at Mesosil