Preschoolers, elderly people and others who are ill-suited to go under a dentist’s drill have an alternative that proponents say will stop their tooth decay quickly, painlessly and cheaply.

A subsidiary of Advantage Dental of Redmond has been marketing since last spring a silver fluoride product called Advantage Arrest, which the U.S. Food and Drug Administration approved to treat dental sensitivity. Its real purpose, however, is to stop tooth decay, and it’s about to become even easier for dentists in Oregon and across the country to use it.

The American Dental Association approved a new billing code that can be used for silver fluoride treatments starting in January, said Gary Allen, dental director for Advantage, which is a statewide network of clinics that treats 340,000 Oregon Health Plan members.

Also starting Jan. 1, OHP, which is the state’s version of Medicaid, will cover silver fluoride treatment for cavities up to two times per year.

Advantage is already using silver fluoride, which the FDA approved in August 2014. Before then, Advantage used a controversial compound called silver nitrate in conjunction with fluoride varnish. Both compounds are applied in tiny drops to the decayed area to stop infection and, dentists hope, avoid the need for a filling.

“It’s new, it’s revolutionary, it changes the way dentistry is practiced,” said Mike Shirtcliff, president and founder of Advantage.

Shirtcliff acknowledges that there was not much current research to support the use of silver nitrate. That’s why he joined forces with University of Washington oral health professor Peter Milgrom to push through approval of silver fluoride.

Silver, which is the antimicrobial agent, comes at a slightly higher concentration in silver fluoride, which has been used and studied extensively in Asia and other places around the world, said Milgrom, director of the Northwest Center to Reduce Oral Health Disparities at UW.

He specializes in working with fearful or otherwise difficult-to-treat patients.

Advantage and Milgrom formed a small business, won a grant to support their own research and received FDA approval for silver fluoride as a medical device.

The next step, Milgrom said, is to conduct further research that would support FDA approval of silver fluoride as a drug, which would be marketed directly for treatment of cavities. That’s a much more expensive and rigorous process, he said.

Gaining approval for silver fluoride to this point took seven years, Milgrom said. He estimates that he donated $500,000 of his time, and Shirtcliff said Advantage invested $1 million of time and cash.

Advantage Arrest is such an inexpensive product, Shirtcliff said he doesn’t expect it to become a moneymaker.

Advantage Arrest comes in a small bottle that costs $125. A single drop can treat more than one cavity.

Shirtcliff said he took on the project so that Advantage could get access to silver fluoride. If silver fluoride begins to generate substantial revenue, he said it will go toward developing more products that fight infection rather than rebuild teeth. “We’re looking at (cavities) as a chronic disease,” Shirtcliff said. “We’re taking a medical approach, not a restorative approach.”

Like the controversial silver nitrate, silver fluoride leaves a black crust on the place of decay. The discoloration can be mitigated or covered up, Milgrom said.

The silver compound can also damage tissue if misapplied. That’s one reason silver nitrate was controversial when in 2013 Advantage asked the Oregon Board of Dentistry to allow it to be applied by dental assistants and hygienists. The board declined.

Dental assistants and hygienists are allowed to administer fluoride, and that includes silver fluoride, said Stephen Prisby, executive director of the dentistry board. Prisby noted that silver nitrate and silver fluoride, also called silver diamine fluoride, are different compounds.

The off-label use of silver fluoride for cavity treatment is already gaining interest in dentistry, Milgrom said. The University of California San Francisco School of Dentistry studied the effectiveness and developed a protocol, which will be published in January in the Journal of the California Dental Association. The UCSF program is recommending silver fluoride for people at extreme risk of developing cavities, who are challenging to treat because of medical or behavioral problems, who have too many cavities to address in one visit, or whose cases are too difficult for a dental-school clinic.

The UCSF study found that one round of silver fluoride doesn’t have a substantial effect on tooth decay, but that “annual reapplication results in remarkable success.”

The authors said longer studies are needed to determine whether the arrest and prevention of decay can be maintained after two to three years and with decreasing treatment.

Milgrom began using silver fluoride in the late 1990s after reviewing papers from Japan and China. “I started smuggling it into the U.S. and using it,” he said. “I take care of fearful and mentally ill people. These people are real hard to work with.”

Milgrom said one of his patients is a 40-year-old who was treated for oral cancer with radiation, and as a side effect developed tooth decay in every part of his mouth. The silver fluoride left dark spots around his gum line, which is where cancer patients are most susceptible to decay.

“He hasn’t gotten one new cavity,” Milgrom said.

­— Reporter: 541-617-7860,