Dentists might soon have an easier option on hand to treat the dreaded cavity.
Researchers at the University of Michigan conducted a large-scale Phase III trial testing out a liquid form of fluoride on children’s cavities. Compared to placebo, the treatment was significantly better at preventing further tooth decay and avoiding the need for more invasive options like fillings or surgery.
The findings show that liquid fluoride can be an effective “noninvasive treatment for young high-risk children and [support] its consideration for FDA drug approval,” the researchers wrote in their paper, published in July in JAMA Pediatrics.
Currently off-label
Cavities (also called caries) are holes caused by bacteria that erode the protective surface of our teeth. Though people these days might be taking better care of their teeth than in the past, more than 40% of children in the U.S. still develop some level of teeth decay. Cavities are usually treated using fillings, but in more severe cases where the decay penetrates deeper and causes an infection, people will need a more invasive root canal or even a complete removal of the affected teeth.
Fluoride has long been known to help prevent cavities, which is why governments in many parts in the world add small amounts of it to their drinking water supply. It also seems to be effective at preventing, or arresting, the further progression of existing cavities. Many countries have approved certain fluoride-based treatments, such as silver diamine fluoride (SDF), to prevent worsening cavities. Notably, however, this list doesn’t include the U.S.
In 2014, the Food and Drug Administration did approve SDF for treating tooth hypersensitivity, which allowed dentists to use it as an off-label treatment for cavities. Two years later, in 2016, the FDA designated SDF as a “breakthrough” therapy, a label intended to speed up the review process for treatments that can meet an urgent need. Without high-quality evidence of its safety and effectiveness, though, the FDA is unlikely to ever approve SDF for this use.
This current trial, funded in part by the U.S. National Institutes of Health, is meant to help provide that evidence.
Solid evidence
The trial involved 830 children under the age of six with severe early childhood cavities. Half of the children were randomized to get a placebo, and the remaining were given a 38% formulation of SDF, applied directly to the affected teeth via a small sponge-filled tip. People received treatment at the start of the study and a second dose six months later. The children were evaluated for cavities over the next eight months.
Ultimately, 70% of children completed the study in full. By the eight-month mark, about 50% of the children treated with SDF showed no progression of their cavities, compared to 17% of children given a placebo.
SDF is known to cause a permanent darkening of the teeth (an effect of the silver). That said, reported adverse events were similar between the two groups. This cosmetic side effect is also likely to be less worrying for children who will eventually lose their baby teeth.
The team’s findings should help strengthen the case for the FDA’s approval of SDF, the researchers say.
“If we want more children and families to benefit from this treatment, we need rigorous evidence showing both that it works and that it’s safe,” said lead author Margherita Fontana, professor of dentistry at the University of Michigan School of Dentistry, in a statement from the university. “From a public health perspective, if we want broader implementation across the United States, including in medical settings, we need carefully collected data in U.S. populations, and we now have that.”
Though the primary use of SDF is likely to be for very young children, it might also be a helpful stopgap for adults who are unable to get or afford other treatments.
“For almost anyone, this can arrest the decay and stop the infection and the pain it causes,” Fontana said. “This could benefit many people.”
