AW: Uranium in dental crowns

["Franz Schoenhofer" <franz.schoenhofer@CHELLO.AT>]

-----Ursprüngliche Nachricht-----

Von: owner-radsafe@list.vanderbilt.edu

[mailto:owner-radsafe@list.vanderbilt.edu]Im Auftrag von Otto G. Raabe

Gesendet: Freitag, 15. August 2003 23:06

An: Joey Michael; 'radsafe@list.vanderbilt.edu'

Betreff: Re: Uranium in dental crowns





August 15, 2003



Pure depleted uranium should not be used in dental crowns, and it probably

isn't a good material for dental crowns since it is too dense and easily

oxidizes. Surface beta radiation exposure from depleted uranium can be

significant.



Otto,



Nobody ever got the idea to use whatever uranium metal in metallic crowns!!!

Your misunderstanding is a direct consequence of the sloppy use of

"uranium", "zinc", "magnesium" etc. when "compounds of" U, Zn, Mg.... should

be mentioned.



The "uranium" with regard to dental crowns are uranium compounds used in

porcelain crowns, in order to produce a beautiful "white". They can easily

been identified by using UV light - they would fluorescence. This might be

one reason, why they are outdated, because in disco-UV-light they will give

the same unnatural blueish colour like white shirts having been washed with

certain UV-active whiteners. The European Union and I believe also the USA

have limited the use of uranium compounds in these crowns in order to

restrict the dose.



I have just interrupted writing for a few minutes and checked my teeth with

an UV source. The result is interesting:



Only one of my porcelain crowns showed a weak fluorescence. It is at a

place, where no disco-light would could enter (if I would go to one.....).

But all of the modern plastic fillings showed significant fluorescence!



I wonder whether anybody knows about this effect. I am not an expert in

uranium fluorescence and know it only from historic vaseline glass of which

I have a large collection and certain uranium minerals. So I heavily doubt

that the fluorescence of the plastic fillings could originate from any

admixture of uranium salts. Any explanation?



Best regards,



Franz















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