Page 38 - My FlipBook

METHODS OF FILLING TEETH.
24
bibulous paper used for smoothing the filling. If a fair-sized rose-bur
is used, all corners will be well rounded and accessible. It will some-
times happen that by following two nearly parallel sulci to their ex-
tremities we leave between a narrow strip, vhich, if left, is apt to
crumble under the blows of the mallet. In such cases the intervening
bit should be cut out, and the two sulci thus united. .
In a few rare instances the border of a cavity may be so placed that
a becomes a support to a frail wall rather than dependent upon
filling
it. A case from practice will well explain this. A patient once came
into my hands having a first bicuspid which was positively black.
This was before the days of the perfection of artificial crowning. Ex-
amination showed the tooth to have been filled with amalgam. The
cavity occupied a large space directly through the tooth from the
anterior to the posterior approximal surface. Fig. 41 shows how the
dentist had formed the cavity. It will be seen at a glance that the fill-
ing offered no support whatever to the weakened walls. On the con-
in mastication, a of food as a between the
trary, piece acting wedge
cusps would have a tendency to drive the labial and palatal walls apart
and away from the filling. A slight elasticity of the dentine allowed
this. Thus the filling leaked badly, and discoloration was largely
due to decay between the amalgam and surround.'-*^ dentine. Great
care was required to remove this but when accomplished, and
filling,
all the decay removed, the tooth was far from being unsightly in color.
I filled this tooth with gold, anchoring the filling in the root-canal,
and so became a and com-
shaped the borders that the filling strong
plete support to the walls. This is shown in Fig. 42. It is plain now
that all mastication must be upon the gold. The ends of the cusps
have been removed and the upper extremities of the remaining walls
strongly beveled, so that the gold built over them holds them firmly
from any tendency to bulge outward.
Similar treatment is required in cases shown in Fig. 43, where
abrasion against the lower teeth has worn away the palatal surface of
the upper incisors or cuspids, leaving frequently a knife-edge. This
incising-edge should be ground down to a well-marked bevel and gold
contoured over it as shown in Fig. 44.
ENAMEL MARGINS.
A great deal has been written and preached upon this subject, and,
as in other matters, the theorist has advanced several erroneous
prop-
ositions. The desideratum in all is that when
fillings polished the
line of contact shall be as fine as a hair. Examination with a
jeweler's
lens should not reveal marked the
any raggedness. Considering
arrangement of the margin from this aspect alone, there is but one
method of producing the result desired. The margin must be smooth,