Page 477 - My FlipBook

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hature there is not one more frail and fugitive, in general
than the colours with which objects are shaded. "
Nimium ne
crede colori,"—" Boast not of the lustre of your colours," said
the prince of Latin poets, in speaking to a young nymph who
had a young child
: these words might be equally applied to
the colour of our teeth
! they fade and tarnish in proportion
as we advance in age
; the enamel becomes of a yellowish
hue by a diversity of causes which contributes to make
it
thin, and by the successive addition of calcareous phosphate
which it continually receives. When we wish to change, by
replacing a natural tooth for a porcelain tooth, we must be-
gin by giving it a hue like that of the Others ; and even choose
it of rather deeper colour, and see that its colour becomes
lighter in passing through the fire.
For this effect the shades are Sufficient Of which I have
indicated the composition. I could obtain a great number,
vary, and multiply them without end, although I have not
done it, because I did not think it useful ; but in attending
these compositions at different degrees of heat, they them-
selves present a multitude of variations, which increase
considerably, the number of shades.
The formulas which I have composed give shades suffi-
cient to suit every mouth : it might be easy for those who
would thus occupy themselves, to create new shades to suit
the necessity of the cases. The principal thing is to know
the oxides and other ingredients which are necessary for this
operation. I have named them, and I wish that my brethren
may use them.
We shall treat in a succinct manner, the properties of all
the substances we have just enumerated.

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