After twenty-five years of stubborn fight supporters of gold as a
filling for decayed teeth accept the possibility of plastic material
being in certain cases its superior; throughout this period I have
been content to hold my peace and act entirely on my own judgment in
the selection of material, as however, it seems to be the fact that
a man who uses plastic filling without danger of being termed a
“quack,” may speak, I would, through your kind agency, convey to
brother Dentists my method of preparing metallic amalgams, which has
saved me much trouble and my patients a large number of teeth.
In using amalgam, the first thing we ought to take into
consideration is whether that which we are using and calling by that
name is such, and I venture to say that in a very large number of
cases it is no amalgam at all, but a concrete admixture of solid
metals with liquid mercury. In the early days, when metallic
precipitate of silver was employed, perfect amalgamation was not
difficult to obtain, provided the precipitate had been in the first
instance properly washed and carefully stoppered, the minute
sub-division of the metal and absence of oxidation aiding largely to
this result. The fillings of the present day are of a totally
different character, coarse in grain, and of a nature to oxidize on
even momentary contact with air, they become difficult to amalgamate
with mercury, which, in itself, is a highly oxidizable metal, so
that recourse is often had to a glass tube and violent agitation to
produce that which is at best only a semblance of what it should
be—a thoroughly homogeneous mass, that upon setting will retain a
uniform texture and density proportionate to the constituents of
which the fillings are composed. If, however, to the fillings and
mercury be added a drop or less of sulphuric acid, either in the
palm of the hand or mortar, it will be found that the metals will
almost instantaneously amalgamate, whilst the oxides combining with
the acid leave a residuum which, by its quantity, clearly shows what
a very imperfect body could have been a so-called amalgam containing
only a small portion of them. Washing in pure water at once removes
all trace of acid, and a thoroughly reliable stopping can be at once
produced from materials otherwise worse than useless.
Introductory Lecture to Course on Dental Mechanics.