As my colleague Austin Frakt pointed out recently, for adults without apparent dental problems, there’s little evidence to support the use of yearly dental X-rays. This still doesn’t prevent many dentists from recommending them for everyone.

With respect to flossing, this shouldn’t have been news either. A systematic review in 2011 concluded that, in adults, toothbrushing with flossing versus toothbrushing alone most likely reduced gingivitis, or inflammation of the gums. But there was really weak evidence that it reduced plaque in the short term. There was no evidence that it reduced cavities. That’s pretty much what we learned recently.

What about everything else? It turns out there’s a whole journal dedicated to the idea that we could use more rigor in dental recommendations. Evidence-Based Dentistry either publishes systematic reviews or summarizes reviews from other organizations, like the Cochrane Collaboration.