There are quite a few more small sample studies out there, like I said it's just something that is hard to accurately case study at a large scale because it relies primarily on participants accurately reporting a specific habit.

It's anecdotal, but most dentists claim they can tell if someone flosses regularly. It makes sense, as people who floss more regularly will have less plaque and biofilm building up between teeth.

I don't really see why people are so skeptical about it. If the main benefit of brushing is to mechanically remove plaque and biofilm from the surface of teeth, it would make sense that mechanically removing the plaque and biofilm between the teeth would also be effective.

Just because there is an absence of a study that encompasses thousands of people for a claim, doesn't mean there is no supporting evidence. I mean who would even pay for that large of a study for research for flossing anyways, and how would it be conducted?