WEDNESDAY, Feb. 22, 2023 (HealthDay News) -- Children can be spared cavities, and possibly painful dental work, with a simple treatment that is brushed onto the teeth, a new clinical trial finds.
The study tested the effects of the topical treatment, called silver diamine fluoride (SDF), in 47 New York City elementary schools. The researchers found that a single SDF application was as effective as standard dental treatments in preventing cavities and keeping existing cavities from worsening for two years.
SDF is a clear liquid that combines the antibacterial properties of silver with the ability of fluoride to "remineralize" and strengthen the tooth surface.
Since SDF is easy to use and relatively cheap — and could be provided by nurses rather than dentists — experts said it's an ideal fit for school dental programs.
"Being able to see such an impact is great," said Ryan Richard Ruff, co-principal researcher on the trial and an associate professor at NYU College of Dentistry in New York City.
The trial, which began in 2019, was disrupted by the pandemic. So the nearly 3,000 children involved were only able to receive one dental treatment, instead of the planned twice-yearly frequency.
Despite that, SDF prevented cavities for two years in more than 80% of the children who received it — right on par with their peers who received standard treatment, including dental sealants. And for children with existing cavities, both SDF and standard care kept about half from worsening.
The findings were published online earlier this month in JAMA Network Open.
In the United States, conventional dental care is pricey, and many Americans cannot afford it. An estimated 77 million U.S. adults do not have dental insurance, according to a 2022 survey by the nonprofit CareQuest Institute for Oral Health.
And as in other areas of health care, there are disparities: Black and Hispanic people and low-income Americans have a particularly hard time getting dental care, and are more likely to have cavities and gum disease.
So schools are seen as one place to fill the gap, by bringing dental care to kids where they already are, Ruff said.
But that also underscores the need for alternatives to the traditional "drill and fill" variety of cavity care.
"It's time to move on and use materials that are simpler and inexpensive," said Dr. Peter Milgrom, an emeritus professor of oral health sciences at the University of Washington in Seattle.
Milgrom, who was not involved in the trial, introduced SDF in the United States when he began using it in his own practice in the 1990s. SDF was first developed in Japan decades ago, and Milgrom learned of the treatment after researchers in Hong Kong put it to the first rigorous test in a clinical trial.
But it wasn't until 2014 that the U.S. Food and Drug Administration cleared SDF, as a tooth desensitizing agent. In the real world, it's also used off-label to stop early cavities in their tracks.
At this point, Milgrom said, SDF has been widely adopted by pediatric dentists in the United States — but awareness is still lacking among general dentists.
The new trial, Milgrom said, "absolutely" supports broader use of SDF in school programs.
For the study, Ruff's team randomly assigned 47 elementary schools to one of two groups: In one, kids in kindergarten through third grade received "simple" dental care that involved applying SDF plus fluoride varnish.
Kids in the comparison group received fluoride varnish plus a standard glass ionomer dental sealant — a paste containing glass powder that is painted onto the back teeth as a protective coating. When needed, they also had existing tooth decay scraped away with hand instruments.
In the end, Ruff's team found, both approaches worked equally well.
The findings are "really exciting," according to Dr. Jeremy Horst Keeper.
He's a pediatric dentist and director of clinical innovation for CareQuest Innovation Partners, in Boston — the for-profit subsidiary of the nonprofit CareQuest Institute.
The trial shows that even a one-time, "easy and painless" SDF treatment can arrest half of cavities for two years — during a pandemic, when Americans' diets often took a turn for the worse, Horst Keeper pointed out.
The fact that SDF was just as effective as standard care, he said, is "astounding."
That's not to say SDF is without drawbacks. When it's applied to cavities, it leaves behind a dark stain. For that reason, Ruff said, kids in the trial received SDF only to their back teeth.
"That's where decay most often happens anyway," he noted.
Ideally, all three experts said, every child should have access to care from a dentist. But that's not the reality for many U.S. kids, as well as adults.
So it's critical to have treatments that allow dental care to be provided by other health care professionals, and in non-traditional settings like schools and nursing homes.
"Overall, what we're seeing now is that minimally invasive treatments in dentistry work," Horst Keeper said. "And people should have access to them, wherever they are."
The research was funded by the nonprofit Patient-Centered Outcomes Research Institute.
The American Dental Association has more on silver diamine fluoride.
SOURCES: Ryan Richard Ruff, PhD, MPH, associate professor, department of epidemiology & health promotion, NYU College of Dentistry, New York City; Jeremy Horst Keeper, DDS, PhD, director, clinical innovation, CareQuest Innovation Partners, Boston; Peter Milgrom, DDS, emeritus professor, oral health sciences, University of Washington, Seattle; JAMA Network Open, Feb. 9, 2023, online