Page 231 - My FlipBook

HISTORY OF DENTAL SUEGERY 199

witli amalgams that did uot slirink, and these two caiises, in the opinion of the
writer, will account for most of the instances in which amalgam fillings did
service for a long tei'ra of years without failure or repair. Tlie work of Dr.
Black resulted in jratting the manufacture of amalgam alloys upon a scientific
basis and a number of manufacturers have since that time lieen furnishing
alloys of uniform and trustworthy character, which do not shrink or ex-
pand, or expand only in minutest amount, and which are strong enough
to withstand mastication without appreciable change or "flow."' The old,
and what ought to be considered worthless amalgams, are still largely sold and
used. They are more plastic and work more easily, but there is no sutticient
excuse for any intelligent man who really desires to make good operations to
neglect the amalgam alloys that are honestly made upon scientific principles
and each ingot carefully tested. Experience and observation indicate that the
average durability of amalgam fillings has very greatly increased in the
practice of those men who have for about ten years past been using these
good amalgams.
I will quote a paragraph or two aliout gold fillings from the last paper.
"A careful review of the strength of the fillings presented in this exhibit,
together with a review of the article on the force exerted in the closure of the
teeth in the June issue of the "Cosmos," will, I think, convince anyone that
many of the gold fillings have not strength enough to stand continuously in oe-
clusoproximate surfaces, or in any positions in which they are supported by the
cavity walls on two or three sides only. It is doubtful if the weaker ones are
strong enough to stand continuously in occlusal cavities where they have the
support of four good walls. We should provide, certainly, for a stress of one
hundred and fifty pounds on our fillings, and in extreme cases for a greater
stress. It is true that in many eases such a stress will not be brought upon
fillings, but it is equally true that in the present state of our knowledge of
individuals and their liabits in mastication, we cannot certainly determine
when a weaker filling will bo successful. In reasonably favorable cases, gold
fillings ought to be made to stand indefinitely. Tlie teeth are strong enough,
and the gold can he made strong enough. It can also be perfectly adapted to
the walls of the cavities so as to be water-tight, and perfectly exclude the agents
that produce caries, and protect the tissues of the tooth.
"A review of the fillings of the exhibit shows a very large per cent of
failures to prodiice fillings that ai'e sufficiently strong. Clinical observation
teaches the same thing in terms that seem to me definite and decisive. T would
not 1)0 understood, however, as placing all failure of fillings at the door of