US trial backs drill-free liquid that stops childhood cavities

Overview

Every year, untreated tooth decay sends thousands of small U.S. children to emergency rooms, and fixing a cavity in a toddler often means a drill, a needle, or sedation. A new University of Michigan trial points to a simpler option: a liquid brushed onto the tooth in seconds.

In 830 children under six, one coat of silver diamine fluoride stopped about 54% of treated cavities from getting worse after six months, against roughly 22.5% for a placebo. The result, published in JAMA Pediatrics, is the large U.S. efficacy evidence the treatment has lacked.

Why it matters

Tooth decay is the most common chronic disease in U.S. children; a cheap brush-on liquid could stop it without a drill.

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Key Indicators

54%

Cavities halted with treatment

Share of treated cavities that stopped progressing six months after one application.

22.5%

Cavities halted with placebo

Share that stopped progressing in the comparison group.

830

Children enrolled

Kids under age six recruited across Michigan, New York, and Iowa.

Permanent

Dark stain on treated spot

The main tradeoff: the liquid turns the arrested decay black for good.

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People Involved

Margherita Fontana

Lead author of the JAMA Pediatrics results

Organizations Involved

University of Michigan School of Dentistry

Academic research institution

Led the Phase III trial

The dental school that ran the multi-state trial of silver diamine fluoride in young children.

U.S. Food and Drug Administration

Federal agency

Holds the approval pathway for SDF as a cavity drug

The federal regulator that clears medical devices and approves drugs, including any future SDF cavity indication.

Timeline

January 1969 July 2026

4 events Latest: Yesterday

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July 2026
Pivotal U.S. trial results published
Latest Research

University of Michigan researchers report in JAMA Pediatrics that one coat stopped about 54% of treated cavities in kids under six, versus 22.5% with placebo.
Yesterday
January 2016
Breakthrough therapy status granted
Regulatory

The FDA gives SDF breakthrough therapy designation for arresting cavities, signaling interest in a faster review path.
January 1st, 2016
January 2014
FDA clears SDF as a device for sensitivity
Regulatory

The FDA clears SDF as a Class II device to treat tooth sensitivity. U.S. dentists start using it off-label to arrest cavities.
January 1st, 2014
January 1969
SDF first studied in Japan
Background

Researchers in Japan begin studying silver diamine fluoride, which reduces tooth sensitivity and appears to stop decay.
January 1st, 1969

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

January 1945

Grand Rapids water fluoridation (1945)

Grand Rapids, Michigan became the first city to add fluoride to its drinking water in a controlled study. Over the next decade, tooth decay in local children fell sharply, by roughly 60% in some measures.

Then

The results convinced public health officials that cheap, community-wide fluoride could cut cavities dramatically.

Now

Water fluoridation spread across the U.S. and became a standard, if sometimes contested, public health tool.

Why this matters now

Like SDF, fluoride was a low-cost preventive proven in Michigan that reshaped cavity care once the evidence was solid.

1970s to 1980s

Dental sealants gain ground (1970s–1980s)

Thin resin coatings painted onto children's molars were shown to prevent decay in the grooves where cavities often start. Studies confirmed they worked, yet insurance and Medicaid coverage lagged for years.

Then

Sealants became a recommended preventive measure, especially for kids at higher risk.

Now

Coverage eventually widened, but uptake stayed uneven across income and geography.

Why this matters now

It shows how a cheap, proven dental tool can still take years to reach the children who need it most.

1994 onward

WHO promotes atraumatic restorative treatment (1990s)

The World Health Organization backed atraumatic restorative treatment, using hand instruments and glass ionomer to fill cavities without electric drills or power. It was designed for places short on dental equipment.

Then

The method expanded basic cavity care in low-resource settings worldwide.

Now

Drill-free approaches gained acceptance abroad faster than in the well-equipped U.S. market.

Why this matters now

SDF is another drill-free approach long used overseas that is only now getting rigorous U.S. validation.