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gum septum. The general rule will be that the original form

of the teeth should be reproduced in the filling, but it often hap-
pens that the original form is not the best form, and in this case,
when practicable, the form should be improved. The most es-
sential features are that the contact point be well rounded, so
that it will touch the proximating tooth only at a small rounded
point, and that this be sufficiently prominent
to restore the
full normal
original tooth form, and therefore restore .the
breadth of the interproximate space. When the forms of
the teeth have been good their restoration reinstates the
normal conditions and cleanliness and health are readily main-
tained.
If, on the other hand, the mesio-distal breadth is not re-
stored, the two teeth will soon be crowded together, narrow-
ing the interproximate space and the crowding upon the gum
septum will cause its partial absorption. It will be shortened
and will fail to fill the narrowed interproximate space, af-
'fording opportunity for lodgments in a position difficult to
clean. The embrasures are also narrowed by reason of the
teeth falling together, which prevents the excursions of food
through them in mastication, increases the area of liability, or
'carries its borders further toward the angles of the teeth, so
as to place the margins of the filling in greater danger of
recurrence of decay.
When the proximate contact is not sufficiently prominent
to restore the mesio-distal breadth of the tooth, it is necessa-
rily flattened and broadened, and is in that degree less well
adapted to maintain the cleanliness of the space. If it is flat-
tened to any considerable degree, it will not only fail to be
.self-cleaning, but will grasp and hold stringy particles of food.
These will be forced upon the gum septum, causing pain in
mastication, which will be a grave annoyance, will cause the
absorption of the gum septum, forming a pocket that will
hold debris, which will decompose and cause recurrence of
decay at the gingival margin of the fiUing, or cause disease
of the peridental membrane, with final loss of the tooth, and
will endanger the neighboring teeth.
In practice, cases are frequently presented of teeth that
have been neglected. The contact points have been lost from
caries, and the teeth have crowded together, closing up the
normal interproximate space, until the necks of the teeth have

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