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146 FILLING MATERIALS

PLASTIC FILLING MATERIALS

Gutta-percha—Cement—Amalgam

GUTTA-PERCHA

Origin.—The purified concrete juice obtained by tapping
the Isonandra Gutta, an evergreen tree found principally in
the Malay Peninsula and Archipelago.

Characteristics.—Color, almost white, or rose, or grayish
white. Inodorous. Slightly elastic. It contracts on harden-
ing or cooling. It is very bland and unirritating to the soft
tissues, and is an absolute non-conductor. It in time becomes
porous and disintegrates in unclean mouths. Freely soluble

in chloroform, while oil of eucalyptus, eucalyptol and oil of
cajeput have a softening effect on it. Heat softens it, but it
hardens again on cooling. /
Varieties of Dental Gutta-percha.—Gutta-percha is not
used in dentistry in its pure state, but is combined with other

materials to give it desirable working qualities. Of these,
the principal ones are white wax, zinc oxid, or calcium oxid.
Gutta-percha for dental use may be classified under one of
the^following headings
1. Low heat—softens below 200° F. (i part Gutta-
percha, 4 parts Zinc Oxid).

2. Medium heat—softens from 200^ to 212° F. (i
part Gutta-percha, 6 or parts Zinc Oxid).
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3. High heat—softens from 210° to 225° F. (Zinc
Oxid to saturation).

There are a number of varieties of Gutta-percha in use
for dental purposes, among which are the following:
1. Excelsior Gutta-percha—high heat — (softens at 225°
F.).
2. Premium Gutta-percha—medium heat- — (softens at

208° F.).