[Content note: This post seems to have ended up somewhere between a very long question and a very uncertain post, so I'm not sure where it belongs.]
I don't floss, and have never managed to maintain any interdental cleaning habit for more than a few weeks. Apart from enduring the standard admonitions from the dentist every six months or so, this has not yet caused me any issues. However, I'm starting to feel I should either start flossing (or using some alternative method) or decide not to, rather than just feeling vaguely guilty about it. So here I am to seek advice.
The main reason I'm not sure what I should do here is that when it comes to flossing, we seem to be in the unusual situation where the preponderance of evidence runs squarely against the very strongly stated position of basically every dentist and dental association in the world.
The dental profession seems to be unanimous in its belief that everyone should absolutely floss, and its stated reasons for believing this make intuitive sense: the bacteria that damage your teeth and gums don't care where they grow, and if you don't clean in between your teeth they'll happily accumulate there and cause progressive damage over time. Also flossing is cheap and easy and, like, teeth are really important y'all, don't take the risk.
The trouble is, the empirical support for this position just isn't there. There doesn't actually seem to be much evidence that flossing improves, well, anything really. The biggest recent story on this is this AP broadside from 2016, which claims that there is little evidence for any benefits from flossing, and what evidence there is is weak and low-quality; you can find links to the most-relevant recent studies there. But there seem to have been concerns about the evidence base for flossing going back decades, which dentists have ignored because the impact of flossing seems so obvious to them.
Last time I looked into this a few years ago I found a great post from some dental association being like "okay we admit we're really confused about the results coming out of these studies, but seriously we dentists can all tell the difference between people who floss and those who don't and the mouths of those who do look much better". I can't find it now, which makes me sad, because 100% of the rest of the response to these evidentiary concerns is dreadful. "[W]hile the effectiveness of flossing isn’t proven, it’s also not disproven, at least not yet". "We know there’s a possibility that it works, so we feel comfortable telling people to go ahead and do it". And so on. I know reversed stupidity is not intelligence, but it's hard for me not to take responses like these, often from very highly-placed dentists, as evidence that the pro-flossing position is very flimsy.
One point made in that post I can't find (which is also referenced here and here, is that there is some evidence for (fairly small) benefits from regular professional flossing, but much less for either regular amateur flossing or irregular professional flossing. This might resolve some of the confusion: really good flossing might have benefits (though I'm guessing smaller ones than dentists seem to think), but only if it's done well, and people are bad at it. But since we have yet to reach a post-scarcity society where everyone has their own professional robot dental hygienist, this seems to be a point for the anti-flossing side.
Finally, I think it's worth pointing out that flossing is certainly not cost-free: it's unpleasant for lots of people, requires substantial time investment to learn the technique, and imposes a significant aggregate time cost when aggregated over your life. Alternatives that are easier to use, like interdental brushes or easy-picks, are much more expensive. And that's excluding the effort required to emplace a lasting habit. Despite the universal and loud exhortations of dentists everywhere, a lot of people (one-third of Americans, two-thirds of Brits) don't floss, which seems to belie the claim that the costs of flossing are trivial.
All of this may suggest that I'm coming down hard on the anti-flossing side. Certainly my best guess is that the benefits of flossing are substantially smaller than dentists seem to think, and that the loud claims about it being essential to basic dental hygiene are overblown. But it does make me pretty uneasy to set myself so strongly against the beliefs of what seems to be a large majority of direct subject experts in this domain, and despite what I said in the previous paragraph the cost of not flossing if they're right does seem higher than the cost of flossing if they're wrong. More generally this seems like a good case study in making decisions in the face of uncertainty: probably people who already have a flossing habit should keep it, but what about people who have never flossed, or those like me who have repeatedly tried and failed to build a lasting habit? I'm interested in hearing the community's views on this.