Page 330 - My FlipBook

328 PLASTIC FILLING MATERIALS.
wedging; and :il-;() the cavities to be subsequently tilled with metal. A
mass of the material may l)e packed into such spaces and be permitted
to remain for months if desired, the gum in contact with it after its
prolonged presence exhibiting no indications of irritation, Masses of
gutta-perc^ha may be packed in interdental spaces where there is not
sufficient space for the introduction of contour fillings, with the purjwse
of having the teeth gradually separated by the impact of mastication;
the gutta-percha acts as a persistent and very gradual wedge.
When it has been determined that an excavated cavity is unfit for
the reception of a permanent filling, gutta-percha is the filling material
par excellence.
Although it is stated that gutta-percha shrinks markedly in harden-

FiG. 295.

Fluf ;\itta-percha softener and tool-heater.

ing, cavities in which it has been properly placed exhibit no evidences
of softening after the material has been worn for months, or it may be