Dental gold re-melting hazards

This is a question for Peter (who seems to know a lot of
things), Skip and other dentists on the list. I have heard that
dental golds may contain chromium and other metals that it is
hazardous to breathe when re-melting, and that it is wisest to
return dental golds to the refiner rather than risk the dangers
of breathing toxic fumes (ie chromium). Can you comment please?

Thank you. Charles

Charles Lewton-Brain/Brain Press
Box 1624, Ste M, Calgary, Alberta, T2P 2L7, Canada
Tel: 403-263-3955 Fax: 403-283-9053 Email: @Charles_Lewton-Brain

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Hello Charles:

For what it’s worth. When I was in active practice, I cannot
recall using a gold alloy containing chromium. The constituents
of the alloys varied depending upon the particular purpose for
which it was being used. For example, if we were constructing a
fixed prosthesis (bridge),which required strength and wear
resistance, aType C gold was prescibed. This was a designation
of a gold that had the requisite physical properties deemed best
for the situation at hand.

The exact formulation was a guarded secret of the manufacturer
of the alloy, but they had to meet certain specifications laid
down by our professional organization. The usual constituents
were: Gold ----to yield between .667-750 fine (16-18K)

                                    Copper
                                    Silver 
                                    Nickel --% varied depending upon hardness desired
                                    Palladium )--not always
                                     Platinum )        "
                                     Zinc--- small amounts

However, I was never aware of Cr. being used. I’m sure Skip can
throw some light on this.

           Best regards      Joe Dule