Page 163 - My FlipBook

FILLING TEETH 147
an average durability of eighteen months before
needing to be replaced in the mouth—that is all.
It is considered that a steel spatula should not be
used for making the mix ; it should be heavily
nickel-plated, or, better still, made entirely of
nickel.
Gutta- Percha.— The gutta-percha specially pre-
pared for filling teeth is a very valuable material
but requires judgment in using. The softer kinds
are of great general utility as coverings for dress-
ings, and the harder or more permanent prepara-
tions, if used in cavities that are not exposed to
the force and friction of mastication, probably give
better results, taking one case with another, than
any other material ; a good deal, however, depends
on the quality of the material. Gutta-percha
deteriorates with age, and dentists would therefore
be benefited if manufacturers would put the date
of preparation on each packet.
Small cavities in incisors and canines are readily
filled witht his material, and such fillings will usually
last for some years ; but a medium or large-sized
approximal cavity is better filled with oxyphos-
phate, when gold or a porcelain inlay is contra-
indicated but when the cavity does not extend
;
either to the lingual or labial surface, gutta-
percha will last longer than a white cement, and