Painless Dentistry Is Here! But It Turns Your Teeth Black.

Via Alex Tabarrok, here’s a New York Times story about a “new” treatment for cavities:

Nobody looks forward to having a cavity drilled and filled by a dentist. Now there’s 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. It’s been used for decades in Japan, but it’s been available in the United States, under the brand name Advantage Arrest, for just about a year.

….Silver diamine fluoride has another advantage over traditional treatment: It kills the bacteria that cause decay. A second treatment applied six to 18 months after the first markedly arrests cavities, studies have shown.

Tabarrok’s reaction is the obvious one: the Japanese have been using this for decades but it only became available in the United States a year ago? What the hell is wrong with the FDA?

But wait. What about other countries? If this stuff is so great, is it being used in Canada and France and India and Spain? I looked around and found this (written three years ago):

Studies suggested that SDF is effective in preventing new caries and arresting caries both in primary teeth and permanent teeth….Although SDF has been used in Australia, Asian countries, such as China and Thailand, and South American countries, such as Brazil and Peru, are concerned that SDF is not yet cleared by the US Food and Drug Administration but is accepted to be used in many European countries and in USA. More well-designed clinical trials on SDF for arresting dental caries are necessary to provide sound and convincing evidence.

The big problem with SDF is that it turns your teeth black. That’s not too big a deal for a back molar or something, but it’s not so great for visible teeth.

As for the FDA, they can’t approve something until it’s submitted, so I’m not sure they really bear any fault for the nonavailability of SDF until recently. Apparently SDF is fairly well known in other countries but hasn’t caused any kind of revolution in dental care, which might explain why no one bothered with it here until recently. It’s used mostly for children, because (a) they hate getting drilled and (b) their teeth are going to fall out eventually, so black stains don’t matter so much.

SDF is certainly a quick and low-cost treatment, and I could see it being favored by roving dentists in poor regions of the world, or for indigent patients who can’t afford conventional treatment. Aside from that, dentists around the world still seem to use conventional fillings almost exclusively even though they know about SDF. I feel like there has to be more to this story, but it’s not immediately obvious from what I could find on Google. Are there any dentists out there who would like to weigh in on this?

POSTSCRIPT: Also, is it really not possible to cover up the black stains? If we could do this, would SDF become the primary treatment for most cavities?