I am not a dentist, but based on my understanding (derived from reading commentaries by dentists) the "best" would be floss -> brush. Never mouth wash (except when recommended by your dentist for specific conditions).

That's derived from the idea that brushing is not about cleaning the teeth. It's about disrupting bio-films and depositing fluoride on the teeth. That's the reason why dentists recommend not rinsing your mouth after brushing. If brushing were about cleaning then clearly you would want to rinse to remove everything from your mouth. But since brushing is more about applying fluoride to your teeth, it makes more sense not to rinse as that would remove all the fluoride that you just worked to apply. (The recommendation is to brush, then take a teaspoon or two of water into your mouth to form a toothpaste slurry, swish around, then spit.)

I thus argue that flossing should come before brushing because flossing would remove the food from between your teeth, allowing fluoride to penetrate those areas.

And with regards to Listerine/mouth wash, the alcohol based stuff causes mouth cancer and hasn't shown any benefit to the reduction of cavities (I don't recall its effectiveness with respect to bad breath or gum disease). There is fluoride based mouthwash, which dentists do recommend to certain patients, but for most people there's no point since they're getting all the fluoride they need from the toothpaste. And of course there are mouth washes medicated for specific conditions, which again will be recommended by your dentist when needed.

My understanding is that, although possible, if the cancer risk does exist, it's very small; here's an article placing it at 3-4 cases per 1,000,000: http://aaem.pl/fulltxt.php?ICID=1011054 (They cite a 2012 meta-analysis which showed no statistically significant effect of mouthwash) Here's a recent large-sample statistical study: https://healthcare.utah.edu/huntsmancancerinstitute/research... They find an 1.15 odds ratio of cancer for mouthwash users, but in the non-smoking non-alcohol-drinking cohort this effect goes the opposite direction (OR 0.83); statistics is hard and there isn't high-quality data to give a real conclusion. But since the overall incidence of oral cancer is roughly 1 in 10000 (http://www.nidcr.nih.gov/DataStatistics/FindDataByTopic/Oral...) I wouldn't be too worried; all these show is that the effect is tiny. (Of course, if you only remember the big headline from ten years ago with a tiny sample size...)

There's a clear line of research showing benefits in mouthwash: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4948552/ It's true that the fluoride in mouthwash does little, and there are some stupid mouthwashes that don't have any real ingredients, but essential oil mouthwashes (like Listerine) and several others (as mentioned in the review) have been shown to have significant gum benefits.

There's also some interesting research with tetrapotassium pyrophosphate and tartar buildup: http://periogen.com/periogen-studies.html Although I expect these studies are manufacturer-funded and thus overstate the effect, it seems pretty hard to deny that it helps.

Note: I'm not a dentist either, but I read this book my dentist recommended: https://amzn.com/B009LPLMRU. It's well-referenced for everything except water fluoridation and her conflict of interest (xylitol products).

Here is the author saying flossing is useless, a few years ago: http://www.medicaldaily.com/dental-floss-useless-dentist-say...

Goddamn it, my dental hygienist told me to use mouthwash after brushing + flossing :(

I'd probably listen to someone with actual dental training over someone who opened their comment with "I am not a dentist" :)

I don't really think there's a difference. My thoughts is that brushing pushes most of it off, but pushes some stuff into small holes and stuff, which is then removed by flossing.