Re: Could you explain a previous statement about fluoride?

Hello, Matthew.

I wasn't involved in the earlier question/answer to which you refer, but I 
will try to add another perspective to the role of fluoride in preventing 
tooth decay.

As a Food Technologist, I am more familiar with using halogens as 
sanitizers in food production but the bacteriacidal activity of this group 
- fluorine, chlorine, bromine and iodine - will be similar whether in a 
food production or cavity prevention.

The activity of the halogen compound varies depending on its form.  For 
example, hypochlorous acid is the most active of the chlorine compounds.  
And the susceptibility of the microbial population is related to 
microbe type, age, spore formation and other physiological factors.

There are a number of possible halogen actions against bacteria: 
- as you suggested, by inhibiting glucose oxidation of certain enzymes 
(thought to be primarily aldolase) that are vital to carbohydrate 
metabolism;
- disruption of protein synthesis;
- oxidative decarboxylation of amino acids;
- reaction with nucleic and amino acids;
- irregular metabolism after the destruction of key enzymes;
- loss of DNA transforming abilities;
- inhibition of 02 uptake and oxidative phosphorylation;
- formation of toxic halogen derivatives; and
- creation of chromosomal defects.

Studies with chlorine indicate that there is a permeability change to the 
cell membrane which allows two things:
1) the chlorine penetrates and acts in one or more of the above ways; and
2) cell contents begin to leak out.
Neither of these is a good thing from the microbes perspective.

Whether it is stannous fluoride or sodium fluoride in your toothpaste, as a 
halogen compound, the fluoride will act similarly against bacteria on 
teeth, as outlined above.

(The bacteriacidal activities of the halogens are excerpted from 
"Principals of Food Sanitation", 2nd Edition, by Norman G. Marriott, Van 
Nostrand Reinhold, 1989.)  

Carol Crouse
Food Technologist
The Food Chain Ltd.