Wait a half hour before brushing your teeth?

I’m guessing here that this might be more of a GQ question than an IMHO question. I’m not specifically asking for personal health advice for myself here.

I just saw this article: Eek! Why it Might Be Time to Step Away from the Kale, Lauren Le Vine, REDBOOK, January 16, 2013, as re-published on Yahoo.

The gist of the article is that too much cruciferous veggies might not be so good for you after all. Tangentially, it mentions that too much fruit juice will rot your teeth, from way too much sugar.

But then there was this remark:

Why does it matter (indeed, why is it better ) to wait half an hour after eating or drinking before brushing your teeth? That’s one I haven’t heard before. And do fruit juices have much more sugar and acid that the fruit they’re made from, that they should rot your teeth worse?

I Googled the question and came up with this explanation: (bold mine)

From: http://health.howstuffworks.com/wellness/oral-care/products/wait-to-eat-after-brushing-teeth1.htm

i asked at a dental checkup about when to brush. i was told that plaque starts being formed at about after 20 minutes.

Do teeth have recovery mechanisms? They’d have to be doing something to make waiting better, right?

I don’t think teeth have any particular recovery mechanisms - it’s just that the pH in the mouth will return to normal from the acidic state with sufficient saliva production, re-hardening the enamel.

Yes, I believe that after tooth enamel has lost calcium due to acid etc. in food it subsequently becomes re-mineralized, absorbing calcium from the saliva, which has quite a high concentration of calcium salts. This depends on saliva being slightly alkaline, which it is naturally, once any acids either in foods themselves or produced from sugars in teh mouth after eating, have been dissipated (or swallowed).

Incidentally, I suspect that the advice to wait half an hour before brushing is not really very good advice, or, rather is likely to be a case of the perfect becoming the enemy of the good. A lot of people who take the advice to wait to brush are probably, often, in practice, going to then forget to brush altogether.

Actually I asked my friend who is a dentist this, because when I worked in a children’s home this was very difficult: you have a schedule for when 50 children brush their teeth and if everyone eats an orange and then needs to wait half an hour it’s chaos.

Her response was that if it’s between not brushing or brushing right after eating an orange she would pick not brushing! That’s how much it damages teeth.

Being a dentist, that pick was very, very hesitant and hedged in lots of brushing promotion. On her advice we actually ended up putting some toothpaste in the mouth and swilling with water, and then hopefully managing to get 50 children to brush later on.

Enamel can remineralize and dentin can regenerate. That is my impression.

When ph gets below 5.5 teeth start to demineralize. I was told by a dentist that if I drink or eat something acidic to rinse my mouth with tap water to get my oral ph back up.

What about using dental floss immediately after eating? I’m guessing the abrasion wouldn’t be as harmful as even a soft-bristled brush. Certainly the dislodging of residual food particles might aid the restoration of normal pH levels, so that brushing twenty minutes afterward can be considered safe.