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Comment by jacobolus | Hacker News Reader

Has anyone here closely investigated the research that led to recommendations to brush teeth after every meal or at least two times a day, as e.g. suggested on toothpaste containers, and to floss frequently, etc.? Any idea how well designed / how complete the relevant studies were? Have there been more recent improved studies? In the last few years I’ve heard second-hand some alternative recommendations to brush before meals rather than after, but I haven’t ever done my own research review.

I’ve long suspected that a good diet + brushing the teeth very carefully a few times per week would be more effective than drinking soda and sweet and starchy foods + brushing after every meal, just based anecdotally on how my own teeth feel to my tongue depending on my diet and toothbrushing frequency.

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> Has anyone here closely investigated the research that led to recommendations to brush teeth after every meal or at least two times a day, as e.g. suggested on toothpaste containers, and to floss frequently, etc.?

http://www.cochrane.org/CD009857/ORAL_cleaning-between-the-t...

http://www.cochrane.org/CD008829/ORAL_flossing-to-reduce-gum...

http://www.cochrane.org/CD002281/ORAL_poweredelectric-toothb...

Very interesting, because we teach dental hygienists that flossing + brushing is vital, while powered toothbrushes are for those with dexterity issues (children, elderly, or otherwise). Mind you, brushing and flossing studies have less moral hazard.

>There is some very low-quality evidence that using interdental brushes plus toothbrushing is more beneficial than toothbrushing alone for plaque and gingivitis at one month. There is also low-quality evidence that using interdental brushes reduces gingivitis (gum inflammation) by 52% when compared with flossing at one month. There was insufficient evidence to claim a benefit for either interdental brushing or flossing for plaque.

>There is some evidence from twelve studies that flossing in addition to toothbrushing reduces gingivitis compared to toothbrushing alone. There is weak, very unreliable evidence from 10 studies that flossing plus toothbrushing may be associated with a small reduction in plaque at 1 and 3 months. No studies reported the effectiveness of flossing plus toothbrushing for preventing dental caries.

>The evidence produced shows benefits in using a powered toothbrush when compared with a manual toothbrush. There was an 11% reduction in plaque at one to three months of use, and a 21% reduction in plaque when assessed after three months of use. For gingivitis, there was a 6% reduction at one to three months of use and an 11% reduction when assessed after three months of use.

From my own experience Brush Picks are the ultimate interdental tool. I keep a small container full of them at my work and home desk and it's become a passive activity to fully clean all of my teeth, multiple times a day.

From adding Brush Picks to my already solid regimen of brushing 2-3 times a day depending on how much I've eaten I've achieved something I never had before in my ~30 years of living: Real compliments about my teeth from my dentist. No but's, no side note, no complaints. Just an unexpected compliment followed by questions of how I achieved such a feat.

Images: http://www.guildent.com/Products/brush_picks.jpg http://cdn.luckyvitamin.com/site/images/item_descrip/74499/7...

> Very interesting, because we teach dental hygienists that flossing + brushing is vital, while powered toothbrushes are for those with dexterity issues (children, elderly, or otherwise).

For what it's worth, every dentist/hygienist I've ever had has told me that electric toothbrushes are better.

> I’ve long suspected that a good diet + brushing the teeth very carefully a few times per week would be more effective than drinking soda and sweet and starchy foods + brushing after every meal

That seems like a false dilemma. Those two things are never at odds with one another. People don't eat sugar because it is part of their brushing regimen, they eat sugar because they like/are addicted to the stuff.

So if you're eating sugar for reasons that have nothing to do with promoting teeth health, then brushing more often to combat that damage makes a lot of sense.

Could you eat less bad stuff and brush less? Potentially, but if people wished to drop sugar from their diet the list of benefits to doing so is so long that brushing less is just a minor footnote at best.

I feel the same way. A few years ago I became convinced that any well known brand name toothpaste was doing more damage to my teeth than help. I switched to using clay based tooth pastes as well as some other powders, and sometimes Ill take some tea spoons of cod liver oil. I grew up with cavities every visit and now it seems like going to the dentist is pointless. They tell me my teeth look great and I must be brushing and stuff, but really I just don't eat much sugar and brush my teeth with toothpaste that is edible, floss occasionally. I think dropping the listerine was the hardest part and also the most helpful. But ultimately it just makes sense in my own mind to brush with a paste that won't poison me if consumed.

It is interesting, my NHS dentist recommended I avoid alcohol-based mouthwash (which is the majority) since it dries out gums and also whitening toothpastes (because they're abrasive by design).

Both things are extremely common on supermarket aisles (even in the UK). But yet dentists suggest you avoid them. That's a rather interesting state of affairs.

Actually my dentist recommended Sensodyne (non-whitening) and a fluoride mouthwash without alcohol (the brand escapes me).

I stopped eating all sugar for 3 years (all carbs actually).

My dentist loved me. My dental visits consisted of me walking in, getting briefly looked at, the dental hygienist doing a quick go over my teeth, complementing me on how clean they are, and sending me on my way.

When I want back to eating sugar, my dental visits suddenly got a lot longer. The cleaning of plaque alone is now at least twice as long.

Why did you go back to eating sugar?

Dropping the low carb thing I can understand. I do low carb paleo on and off as my fiscal and lifestyle circumstances dictate... but I keep my sugar intake low regardless.

If you cut back on sugar a lot, that almost surely is the most major factor in the change. Sugar is amazingly bad for your teeth, and many sugary beverages (like soda) are also naturally acidic, which leads to erosion of enamel.

That said, you're right to have some skepticism about heavily marketed tooth pastes. For instance, I have four veneers and my dentist recommended against using any "whitening" toothpastes, because they're naturally abrasive against your teeth and can very slowly damage them over time. I just use Sensodyne and follow-up with a non-alcoholic flouride mouthwash, and I've had no dental issues since, even with a sugary diet. But I brush/rinse three times a day.

I can't understand how it would make sense to brush before rather than after meals. What's the logic behind that?

This is doubly so if the meal is sugary. By not brushing afterward, you're just letting bacteria process all that sugar and produce plaque and acid.

My dentist has advised me not to brush after a sugary meal or drink for at least an hour, otherwise you are effectively brushing the sugar into your teeth. Perhaps this also applies (but with a lesser timeframe) for meals that aren't so sugary.

It's more that your enamel is weakened temporarily by acids (which get produced by bacteria in your mouth as a side effect of their consuming the sugar). It is true that you shouldn't brush immediately after a meal -- waiting 30 minutes to an hour is a good practice.

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