This new treatment could make your next trip to the dentist more bearable

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• Willaim Brangham:

  But first, there's long been a big push to promote better dental health through fluoridation and telling people to eat less sugary foods.

  Despite those efforts, tooth decay remains a major public health issue. In fact, it's the most common chronic childhood disease, and 90 percent of all adults have cavities.

  As many of us know, traditional treatments can often be painful, but a new pain-free, low-cost dental treatment could help all that.

  Special correspondent Cat Wise has the story.

  It's part of our Breakthrough reporting for our weekly series about the Leading Edge of science and technology.

• Cat Wise:

  It's an unmistakable, stomach-churning sound- the high-pitched whir of the dentist's drill. For more than a century, it's been one of the main tools in the battle against tooth decay.

  The standard drill-and-fill treatment is not a lot of fun for anyone. But for some patients, especially young children who often have to be sedated or put under, it can be very challenging and even dangerous.

  But the silvery liquid in this little bottle has started to lead to some big changes in the way some tooth decay is being treated.

• Dr. Frank Mendoza:

  We started in 2013 using this, and it's — in 35 years, I have not seen anything that's worked as well.

• Cat Wise:

  Dr. Frank Mendoza is a pediatric dentist on the Warm Springs Indian Reservation in Central Oregon.

  He is one of a small, but growing number of dentists who've begun using silver nitrate, a widely used liquid antimicrobial medical treatment, with fluoride varnish, a widely used dental product, to stop tooth decay.

  The treatment is for cavities which haven't reached the pulp of the tooth.

• Dr. Frank Mendoza:

  The silver kills the bacteria, and stops new bacteria from growing. The fluoride re-mineralizes, or hardens, what's left. That hardened material then can be used to — you can actually bond or stick a lot of filling material to that.

• Cat Wise:

  On a recent morning, 13-month-old Zavion Wallulatum and his siblings paid a visit to Dr. Mendoza. Zavion has eight teeth so far, and despite his family's best efforts to keep them healthy, four have cavities.

  Three months ago, Dr. Mendoza began the first of several treatments. The cavities have been stopped and, as of now, no new ones have formed. The black spots on his teeth are actually the silver doing its job on the decay. The staining is the main drawback of the treatment, which has been used in other countries, and which has been shown to be safe in studies.

  Six-year-old Sylvia is also getting treatments, and, so far, her cavities are under control too.

  But older brother Frederick, who developed cavities as a toddler before Dr. Mendoza began using silver in his practice, ended up under general anesthesia in the hospital. That's a common story for young children in Warm Springs and in tribal communities around the country, which have high rates of dental decay.

• Dr. Frank Mendoza:

  Over half of the kids went to the hospital, up until we started this silver nitrate project four years ago.

  We have seen about half as many kids requiring O.R. treatment since then, and we have changed nothing, other than add this to our program.

• Cat Wise:

  The dark spots can eventually be covered with tooth-colored material. And when the baby teeth fall out, the stains go away too.

  Mom Nancy Wallulatum says she doesn't like the stains, but she believes the treatment has kept her younger children from having more invasive work done.

• Nancy Wallulatum:

  It's really fast. They just come in and out, and then we're done. I think that it's really helping them, preventing them to not go through surgery.

• Cat Wise:

  Preventing kids from being put under, or sedated, has become a priority in the dental world. The authors of a recent article in the journal Pediatrics wrote, an estimated 100,000 to 250,000 pediatric dental sedations are performed annually in the U.S., and they highlighted the case of a 4-year-old boy who died after sedation in his dentist's office.

  But they noted it's difficult to track adverse events or deaths because there's no mandated reporting. The article's authors joined an expanding group of dental experts, including the American Academy of Pediatric Dentistry, who say a treatment that combines silver and fluoride can be effective in appropriate cases.

  The formula, called silver diammine fluoride, or SDF, was cleared by the FDA last year for reducing sensitivities in teeth, but its so-called off-label use for stopping cavities is now its main use. The treatment is much cheaper than drilling, typically about $30 per visit.

  Some state Medicaid plans and an increasing number of private insurance providers are now covering it. But a lot of questions remain, including why SDF works only about 80 percent of the time.

• Dr. Jeremy Horst:

  It works on most cavities. The problem is, it doesn't work on all cavities.

• Cat Wise:

  One of those on the front lines of SDF research is Dr. Jeremy Horst, a pediatric dentist and a post-doc fellow at the University of California, San Francisco.

  He and his colleagues are studying, among other things, the structural and chemical changes in teeth before and after they have been treated with silver products.

• Dr. Jeremy Horst:

  We completed a short-term study, which blew our minds. It didn't look like the bacteria changed very much at all. There were just dramatically less of them. So, it decreased the infection dramatically.

  That was when it worked. So we need to look longer-term, and we need to look at cavities that didn't stop. Are there other certain bacteria that are making the infections, cavity in the tooth, still grow?

• Cat Wise:

  Dr. Horst is also studying how often silver products need to be reapplied to be effective, and he's using extremely high-res X-rays of treated teeth to uncover how the silver and fluoride, seen in red in this photo, work their magic.

• Dr. Jeremy Horst:

  So this is a bit of a tooth we have imaged, so the dark area is the cavity. The surprising thing is that the silver penetrates down into the inner part of the tooth pretty well as far as the cavity goes, or sometimes beyond, and reinforces it, strengthens it, increases its hardness.

• Cat Wise:

  And that's a good thing.

• Dr. Jeremy Horst:

  That's a good thing. Teeth should be hard.

• Cat Wise:

  UCSF is teaching both pediatric and general dentistry students about SDF, but it's not universally taught or practiced around the country yet.

  There others, though, who could benefit if the treatment spread.

  Sixty-one-year-old Keizer, Oregon, resident Robert Block had a stroke 12 years ago that made it difficult to care for himself and his teeth. Dental decay is a problem for many older adults, especially those in nursing homes, where it can be tough to get dental care.

  Block began getting treatments from a local dentist, who was one of the first to try using silver more than a decade ago, Dr. Steve Duffin.

• Dr. Steve Duffin:

  We just put silver compounds on all of his teeth. And I will never forget. He came back three months later, I looked in his mouth, and he had no plaque on his teeth. His gums were healthy. He looked like a different person.

• Cat Wise:

  Dr. Duffin, who discovered in an old dental textbook that silver nitrate was actually used in this country for a time in the early 1900s, believes what was old is new again for everyone.

• Dr. Steve Duffin:

  I personally believe that this is the appropriate treatment for every person who has tooth decay, because it is the most effective way to treat the disease, regardless of income.

• Cat Wise:

  In Oregon, the treatment has been approved to be used by hygienists and qualified dental assistants, and Dr. Duffin says that could have a major impact on access to dental care.

  Back in Warm Springs, Dr. Mendoza says prevention of cavities should always be the focus, but, when needed, silver is making a difference.

• Dr. Frank Mendoza:

  I won't ever go back to the same way of doing it. I don't think parents would allow me to, because they know that there's another way to do it. It's not a silver bullet. It's not going to stop everything. You need follow-up. You need to start it early.

• Cat Wise:

  Later this year, the American Dental Association plans to release a clinical practice guideline on all non-surgical approaches to cavities, including SDF.

  For the PBS NewsHour, I'm Cat Wise in Warm Springs, Oregon.

• Editor’s Note:

  Photos courtesy of Dr. Jeanette MacLean