"Nobody looks forward to having a cavity drilled and filled by a dentist. Now theres an alternative an antimicrobial liquid that can be brushed on cavities to stop tooth decay  painlessly. The liquid is called silver diamine fluoride or S.D.F. Its been used for decades in Japan but its been available in the United States under the brand name Advantage Arrest for just about a year. The Food and Drug Administration cleared silver diamine fluoride http for use as a tooth desensitizer for adults  and older. But studies show it can halt the progression of cavities http and prevent them http and dentists are increasingly using it offlabel for those purposes. Knox Urschel  had a liquid treatment silver diamine fluoride brushed on a decaying tooth. Studies have shown that the antimicrobial liquid can halt the progression of cavities and prevent them.CreditCaitlin OHara for The New York Times  The upside the great one is you dont need to drill and you dont need an injection said Dr. Margherita Fontana a professor of cariology at the University of Michigan. Advertisement Silver diamine fluoride is already used in hundreds of dental offices. Medicaid patients in Oregon are receiving the treatment and at least  dental schools have started teaching the next generation of pediatric dentists how to use it. Dr. Richard Niederman the chairman of the epidemiology and health promotion department at the New York University College of Dentistry said Being able to paint it on in  seconds with no noise no drilling is better faster cheaper. I would encourage parents to ask for it he added. Its less trauma for the kid. The main downside is aesthetic Silver diamine fluoride blackens the brownish decay on a tooth. That may not matter on a back molar or a baby tooth that will fall out but some patients are likely to be deterred by the prospect of a dark spot on a visible tooth. Until more insurers cover it patients also have to cover the cost. Still its relatively inexpensive. Dr. Michelle Urschel an anesthesiologist was happy to pay  to have Dr. Jeanette MacLean a pediatric dentist in Glendale Ariz. paint over a cavity that her son Knox  had recently developed. Editors Picks A cavity that had to be drilled cost . The liquid was very affordable Dr. Urschel said. The noninvasive treatment may be ideal for the indigent nursing home residents and others who have trouble finding care. And many anxious dental patients want to dodge the drill. But the liquid may be especially useful for children. Nearly a quarter of  to yearolds have cavities according to the Centers for Disease Control and Prevention httpwell.blogs.nytimes.comuntreateddentaldecayisfallingamongchildren. Some preschoolers with severe cavities must be treated in a hospital under general anesthesia http even though it may pose risks to the developing brain. S.D.F. gives us an opportunity to decrease the number of toddlers with cavities going to the O.R. said Dr. Arwa Owais an associate professor of pediatric dentistry at the University of Iowa httpsclinicaltrials.govctshowNCT. Dr. Laurence Hyacinthe a pediatric dentist in Harlem used silver diamine fluoride on eight uncooperative children whose parents wanted to delay a trip to the operating room. Dr. MacLean said People assume that parents will reject it because of poor aesthetics. But if it means preventing a child from having to be sedated or having their tooth drilled and filled there are many parents who choose S.D.F. she added. After Dr. MacLean treated Knox she gave him a sticker.CreditCaitlin OHara for The New York Times  After Dr. MacLean treated Knox she gave him a sticker.CreditCaitlin OHara for The New York Times Alejandra Bujeiro  was delighted that her yearold daughter Natalia didnt have to have two cavities filled in the back of her mouth. Instead Dr. Eyal Simchi https a pediatric dentist in Elmwood Park N.J. brushed silver diamine fluoride on the decay. Two front teeth however were drilled. Next time Ms. Bujeiro said shed opt for silver diamine fluoride. I would use it in baby teeth even if its in front she said. As for the discoloration You cant see it too much. Advertisement Silver diamine fluoride has another advantage over traditional treatment It kills the bacteria that cause decay. A second treatment applied six to  months after the first markedly arrests cavities studies have shown. S.D.F. reduces the incidence of new caries and progression of current caries by about  percent said Dr. Niederman who is updating an evidence review of silver diamine fluoride published in . Fillings by contrast do not cure an oral infection. Theres nothing that goes on in an operating room that treats the underlying problem said Dr. Peter Milgrom a professor of pediatric dentistry at the University of Washington who was instrumental in receiving F.D.A. clearance for silver diamine fluoride and has a financial stake in Advantage Arrest. Thats why some children must have dental treatment under anesthesia twice. Bacterial infections also cause acne but a dermatologist doesnt take a scalpel and cut off your pimples said Dr. Jason Hirsch a pediatric dentist in Royal Palm Beach Fla. Yet thats how dentistry has approached cavities. Dr. Hirsch has a Facebook page called SDF Action https where dentists can discuss individual cases. Knox getting a highfive from Dr. MacLean after being treated with silver diamine fluoride. The cost of the treatment . By comparison a filling would have run .CreditCaitlin OHara for The New York Times   Knox getting a highfive from Dr. MacLean after being treated with silver diamine fluoride. The cost of the treatment . By comparison a filling would have run .CreditCaitlin OHara for The New York Times In January Oregon became the first state to reimburse Medicaid providers for treating cavities with silver diamine fluoride. Its a completely new paradigm that offers significant savings said Dr. Bruce W. Austin the dental director of the Oregon Health Authority http You need only a drop to treat five teeth and it comes out to pennies per tooth said Dr. Scott L. Tomar a University of Florida dentistry professor who treats some Medicaid patients. Toddlers in lowincome families sometimes have to wait a year for fillings in an operating room. The new alternative is a huge deal said Dr. Tomar the chairman of the oral health section https of the American Public Health Association. Advertisement Silver diamine fluoride also may help nursinghome residents who often experience severe cavities if their teeth arent routinely brushed httpwell.blogs.nytimes.cominnursinghomesanepidemicofpoordentalhygiene. Transporting and treating frail patients assuming they can afford to see a dentist can be difficult. But now some patients can be quickly treated where they live. Still silver diamine fluoride is no silver bullet. Patients with mouth sores or a silver allergy cant use it. Severe cavities  huge holes that trap food and plaque  still require fillings. At dental conferences Dr. Tomar and Dr. Fontana lecture about the treatment. They ask audiences if they are using it so far just a few hands go up."