Dental biotechnology

[bomba923]

Some background information first:

*Hydroxyapatite (i.e., Ca5[(PO4)3OH]) comprises 97-98% of human tooth enamel. It will demineralize at pH 5.5.

*Fluoride ions are usually added to drinking water and are found in fluoride toothpastes (commonly via NaF).
According to Wikipedia (http://en.wikipedia.org/wiki/Fluoride),

Fluoride ions can replace hydroxide ions in hydroxyapatite (Ca5[(PO4)3OH]), forming fluorapatite (Ca5[(PO4)3F]), which is more chemically stable and dissolves at pH 4.5. This is generally believed to lead to fewer cavities, since stronger acids are needed to attack the tooth enamel.

According to the University of Vermont (http://www.uvm.edu/~swgordon/131-01/131web/caseymorley/discussion.html),

The difference in solubility products between hydroxyapatite and fluorapatite is important to consider when examining their resistance to cavities. As discussed in demineralization, hydroxyapatite is more dissociated in equilibrium than fluorapatite, which assumingly allows acids to penetrate the crystal structure more easily.
Perhaps the most important property of fluorapatite in its resistance to cavities is the F- itself. When F- ions are released, they help kill cavity-causing bacteria.
Sweet happppy
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Now here is my question:

-What if the formation of fluorapatite (for our teeth) did not require drinking water, and fluoride toothpaste? What if...say, we could synthesize fluorapatite ourselves (biologically speaking)?
-Is there a genetic basis for the synthesis of hydroxyapatite?→Can we alter this...to produce fluorapatite instead :)?

(*I am not certain, however, as to where the body might 'obtain' these fluoride anions...early on...(But I like biotechnology))

[Melody]

ha, interesting question. seems simple enuff, and genetic alteration would be wise in beginning with simple things like this

im guessing ur foot question explains why we dont have fl.patite: all the hy.patite constituents are relatively common

the engineering problem i would see is that the hy.patite construction would need to be 'overloaded' by the fl.patite construction so that if the person is not getting enuff fluoride, the original hy.patite architecture will be in place as backup. i wonder how insanely complex that would be to implement O.o -- and im not sure if there are even any such 'overloaded' systems in our body to begin with... hmmm.... *thinking thinking*

tho im guessing if someone is the subject of such engineering... they would be sure to take necessary amounts of fluoride or w/e O.o

chemistry currently outta my field of understanding tho =o so w/e


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ur question about whether it has a genetic basis is interesting... i wonder, would the genetic system be so sophisticated that just by eating fluoride tofu as a baby [or something like that] the tooth growth system automatically creates fl. instead of hy.patite? ie the genetic system has generic parameters for what can serve as enamel, and any minerals -- and even better -- the strongest minerals -- which fall within those parameters are automatically used. HAHAHA that would be so powerful, i doubt that is the case tho

imo, genetic engineering at its prime will result in feats of this kind -- imagine the adaptability of such systems

[eyebyte_atWork]

bomba923 - Wouldn't that just be the hard way to do things? I mean its not unlike trying to raise cows just to get some steaks when you could easily buy steak at the store.

On the other side it may have some military applications if you could get it to work.

[kuranes]

There may be unwanted side effects too, as Fluorine proper ( the element ) is one of the most harmful of them all in terms of its ability to burn/destroy. Hydrofluoric acid, for example, is one of the few that will actually dissolve glass.

However salt has Chlorine seemingly safely locked away inside it with Sodium, stabilizing both. Perhaps the apatite performs this function with Fluorine. When snails get dissolved by salt, you wonder what the mechanism was that allowed something to be UNlocked.

[Architectonic]

However salt has Chlorine seemingly safely locked away inside it with Sodium, stabilizing both. Perhaps the apatite performs this function with Fluorine. When snails get dissolved by salt, you wonder what the mechanism was that allowed something to be UNlocked.

Salts generally disassociate into their respective ions in water. ;)


-What if the formation of fluorapatite (for our teeth) did not require drinking water, and fluoride toothpaste? What if...say, we could synthesize fluorapatite ourselves (biologically speaking)?

For the body to form fluroapatite, it has to get the fluoride/fluorine from somewhere. Otherwise, you can only form it via a nuclear process, which is somewhat unlikely in the body.
But we do end up naturally ingesting fluorine in trace amounts anyway.


-Is there a genetic basis for the synthesis of hydroxyapatite?→Can we alter this...to produce fluorapatite instead :)?

I'm not sure exactly. The real question is why the body synthesises hydroxyapatite in the first place.
As a speculation, I'd say probably not easily. At least not very easily, without affecting other biochemical systems.
But it really depends on the method in which it is formed.
When altering the gene, you would basically be altering the shape a protein, (inc functional groups) to make it a more effective catalyst.

But on the topic of fluoridation of drinking water, toothpaste and so on, it is potentially a very stupid idea. (I'm guessing this is why you suggested genetic alterations as an alternative.)
The process of forming fluorapatite is just one of many biochemical processes in the body. Think about all of the other biochemical processes that may be affected due to the high intake (relative to what the body is used to) of fluorine? Secondly, the dental benefits of the mass fluoridation of drinking water have still not been conclusively proven after many years.