Drinking water after fruit to protect your teeth

My dentist claims it washes away the fruit acid - but that alkaline food does a better job. Can't back this up with evidence that isn't anecdotal though.

It sounds absolutely obvious to me that washing off the sugars and acids is a good thing. 

But then...  I've got a feeling that I've read somewhere that the opposite is true - that drinking water after has a negative effect.  But surely, surely I can't have read that could I?

hadf a quick google and the first thing was a mail article saying that eating apples was 4 times more dangerous to teeth than soft fizzy drinks............

Now that is one that I find hard to swallow ...............it does say that eating apples is best with milk or cheese to balance out the acids...or if not drink water afterwards........so it could be this bit of research that they are refering to.........

i would like to see if there are any further studies as this was based on adults and childrens teeth are most vunerable form 5 to 11 aren't they

I think it's the acid which weakens the enamal on teeth so if you brush after eating fruit you will brush that off. Interesting quote here.

"There has been a sporadic, but generally increasing caries prevalence over the past 5,000 years. During the first 4,000 years there is a gradual increase in caries prevalence ranging from 2 to 10 carious teeth per 100 teeth, followed by a sharp rise at about the year 1000 A.D. to 24 carious teeth per 100 for 3 out of 4 populations. The year 1000 A.D. is the approximate date for the introduction of sugar cane to the Western world."

http://www.uic.edu/classes/osci/osci590/11_1Epidemiology.htm

I can actually think of a reason NOT to drink water after eating fruit. When you eat, two important things happen within the mouth - plaque acid is produced by bacteria, and the flow rate of saliva increases. The acid (usually carbonic acid) dissociates into hydrogen ions and bicarbonate, the latter of which acts as a buffer to reduce the effects of the acid on the teeth. As salivary flow rate increases, so too does the concentration of bicarbonate. If you drink after eating, your essentially washing away/diluting the bicarbonate and thereby allowing an increase in the action of the acid.

Saliva typically has a pH around 6, so obviously having something more alkaline - milk, cheese, etc. will do more to neutralise plaque acid and/or fruit acids.

Whilst it is true that eating fruit can have a detrimental effect on the teeth, there are far worse foods to be worried about!

I usually take my teeth out to eat acidic things...