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84 MECHANICAL DENTISTRY AND METALLURGY.
trimmed with the plate forceps and file to the exact dimen-
sions recjuired.
In partial cases, the margins of the plate adjoining the
necks of the teeth should be permitted either to lie closely
to them, or should be cut away, leaving a space equal to a
line or more between the plate and the teeth; for if but a
very narrow line of uncovered gum remains at these points,
injury to the parts immediately surrounding the necks of the
teeth is more liable to occur from strangulation of the inter-
posed gum than if the plate were further removed from the
teeth or rested directly against them.
If the portion of the plate which passes in between the
remaining teeth is quite narrow, as where but a single tooth
is to be supplied, it should be strengthened by doubling the
plate at such a point. It is also advisable in many cases,
in order to provide more perfectly against fracture or distor-
tion of the base in mastication, to wire or double the entire
border of the plate adjoining the necks of the teeth.
The edges of those parts of the plate occupying the
vacancies on the ridge should be filed thin to admit of a more
accurate adaptation of the artificial with the natural gum,
and should not, ordinarily, extend beyond the outer circle
of the adjoining teeth, allowing the gum extremity of the
artificial tooth to overlap and rest directly on the natural
gum above. If, however, the concavity between and above
the teeth on the external border of the ridge is considerable,
the interdentinal portions of the plate may overlap the bor-
der completely and underlie the porcelain gum or rubber, as
the case may be.
Adjusting Clasps to the Plate.—Having proceeded thus
far in the operation, the plate and clasps, when the latter
are to be employed, should next be united to each other, and
the utility and comfort of the appliance in the mouth, as
well as the safety of the natural organs used for the purpose
of support, will depend in a great measure upon the accu-