A low-cost liquid known as silver diamine fluoride, or SDF, may offer a much simpler option. Dentists apply it directly to a cavity with a small sponge-tipped applicator, a process that takes only a few seconds for each tooth. The treatment can stop decay without drilling, injections, or sedation.

A Long-Used Treatment Gains Stronger Evidence

SDF has been used successfully in many countries for decades. In the United States, dentists have used it off-label since 2014, when it was approved as a medical device for reducing tooth sensitivity.

However, researchers had not yet completed the large U.S. clinical trials needed to demonstrate its safety and effectiveness as a cavity treatment. That evidence would be necessary for the Food and Drug Administration to approve SDF as a drug for treating tooth decay.

A clinical trial led by the University of Michigan has now supplied those data.

The Phase III study, published in JAMA Pediatrics, included 830 children younger than age 6. Participants were recruited through dental offices, pediatric medical practices, Head Start and Early Head Start programs in Michigan, New York and Iowa.

SDF Stopped Decay in Many Baby Teeth

The researchers found that 38% SDF stopped tooth decay in more than half of the affected baby teeth when the treatment was applied every six months.

Traditional cavity treatment usually involves removing damaged tooth material and placing a filling. SDF requires no removal of the tooth. Instead, the liquid is painted directly onto the decayed area.

“This is a very effective and safe treatment — even in children as young as 1,” said Margherita Fontana, professor of dentistry at the University of Michigan School of Dentistry and the study’s lead investigator.

Tooth decay is the most common chronic disease among children and affects more than 40% of children in the United States. Cavities that are not treated can lead to intense pain, infections, difficulty sleeping or eating, missed school days and repeated medical appointments.

A Potential Option for Hard-to-Treat Patients

Fontana said SDF could be particularly useful for very young children, older adults, people with developmental or physical disabilities, and patients with severe dental anxiety. It may also help people who have limited access to conventional dental care or cannot easily tolerate standard procedures.

The treatment does have a visible drawback. The silver permanently turns the decayed part of the tooth dark.

“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. 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,” Fontana said.

The research began in 2018 and continued despite disruptions caused by the COVID-19 pandemic.

“In medicine, clinicians want high-quality evidence before changing practice,” Fontana said. “It is important to have data they can refer to because young children often see pediatricians years before they ever visit a dentist; broader acceptance could allow many more cavities to be treated while a referral to a dental home is successful, and before they become painful, infected, or require surgery.”

Findings Could Support FDA Approval

Fontana worked with researchers from New York University, the University of Iowa and Indiana University, as well as the NIH’s National Institute of Dental and Craniofacial Research. The institute provided more than $12 million to support the study.

The trial generated the clinical evidence the manufacturer needs to submit a dental caries drug application to the FDA. Elevate Oral Care supplied Advantage Arrest 38% SDF, the product tested in the study.

Amr Moursi, professor of pediatric dentistry at New York University College of Dentistry, said the findings could help expand access to the treatment.

“Our results support FDA approval of SDF for managing arrest of tooth decay in young children. Removing SDF from off-label status would be an important innovation which could lead to increased utilization by providers, enhanced payments by insurers and more consistent product quality,” said Moursi, a co-principal investigator on the study.

A Bridge or Long-Term Treatment

For some children, applying SDF again every few months may control the cavity until the baby tooth falls out naturally. In adults, it could function as a long-term treatment or provide temporary protection until a restorative procedure becomes affordable or practical.

“For almost anyone, this can arrest the decay and stop the infection and the pain it causes,” Fontana said. “This could benefit many people.”