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376 RESTORATION OF TEETH BY CEMENTED INLAYS.

on gold, these of necessity requiring so large a percentage of glass that
they, like the fillings of Herbst, lacked permanence of gloss and color.
From this discovery of Land dates all effective porcelain filling. Before
this, pieces of porcelain had been ground to fit labial cavities, with
fairly good results, and pieces of enamel from extracted teeth had been
inserted in a similar fashion, but the accurate adaptation of porcelain to
approximal cavities as far back as the molars was impossible until the
metal matrix was evolved.
At present the advocates of porcelain fillings are represented by two
distinct parties : those who advocate a low-fusing porcelain that can be
melted in a gold matrix, and those who advocate a porcelain of a fusing-
point and resistance at least equal to Close's continuous-gum body,

Fig. 352.

I

12 3 4 5 6

Diamond points, Nos. 1 to 6
; a, copper disk charged with diamond dust.
necessitating the use of platinum for the matrix. It is claimed by the
advocates of low-fusing porcelains that gold can be more perfectly
adapted as a matrix than platinum. This, if true, is a very important
advantage. But, on the other hand, those advocating high-fusing
porcelains believe that they can get as perfect an adaptation with
platinum as with gold, and that their porcelains have a better color,
are stronger, more durable, and more easily manipulated, thus giving to
the work a far wider range than seems possible with any low-fusing
bodies yet devised, for porcelains seem to have strength and durability
in direct proportion to their fusing-points. In this connection we should
remember that when brilliant men of the past, through long series of
experiments, were perfecting the process of continuous-gum work, they
would undoubtedly have adopted the low-fusing bodies had they found
any that would melt on gold and remain permanent. That they
finally resorted to platinum and made durable porcelain bodies at their
present fusing-points would seem to indicate that low-fusing porcelains