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CHAPTER XXVIII.
COMBINATION FILLINGS

Definition, A eoinbination filling is a filling composed of two or
more distinct substances introduced into the cavity separately.
Objects of a Combination. The object of combining various ma-
terials in the filling of a tooth's cavity is to secure a perfect fill-
ing, one possessed of all virtues, and no faults. Many such com-
binations of material meet this demand in a large measure by
bringing into service the strong features of each material, and at
the same time nullifying the faults of all material entering into the
construction.
Since dentistry has been raised to the dignity of a science there
has been a diligent search to discover a filling material which pos-
sesses the virtues of all and the faults of none in present use. At
the present time this is more nearly reached by the various com-
binations possible with the usual distinct materials. If perchance
the ideal filling is ever produced, dentistry will at once become
much simplified as to methods of procedure.
Single Materials Used as a Filling. There are only two filling
materials now in use Avhicli are used in their pure state, pure gold
and pure tin, and there are many instances where these combined
with each other or with other materials, will produce better results
than when used alone.
Gold and Tin Combination. This combination is of service in
large cavities of Class Two which are subgingival and in large
occlusal cavities in molars, where the pulpal wall is deep and
rounded. In this combination the tin should be placed in the cav-
ity first and thoroughly condensed, and the filling completed with
cohesive gold.
In Class Two the tin should cover the gingival wall at least one
millimeter deep and be condensed to place with the matrix in
position.
Benefits derived. Dentine upon which has been built a thor-
oughly condensed tin filling does not readily decay. By com-
pleting the filling with gold the discoloration of tooth substance
is avoided and the gold will better resLst the force of mastication.
Gold and Cement. The object of this combination is to produce
a filling that is adhesive, will protect weak walls, and resist the
fluids of the mouth and the force of mastication.
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