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288 THE TECHNICAL PROCEDURES IN FILLING TEETH.

expression of the lamination in lines tliroiigli the filling, as was
shown in Figure 355, is also an expression of the order of plac-
ing the filling. There are two points, however, in which the par-
ticular order of advance in building the gold is very important
to the highest success, in making perfect adaptation and in the
strength of the gold to breaking stress. These points are found
in incisor proximal fillings ; in building over the gingival wall,
which must be used in all proximal cavities ; and in building on,
or restoring, angles with gold. These are illustrated in connec-
tion with the two series sho'wing the building of angles with
gold, including the Figures 273-280. The gradual building out
over the gingival wall is especially shown in the diagonal lines
from the gingival to the axial wall in Figure 279, each line indi-
cating a layer of gold condensed into the angle formed by these
walls, and extending out gradually, layer upon layer, until the
gingival wall is fully covered. This will be seen to be precisely
similar and is for the same purpose as was fully explained in
the article on filling proximo-oeclusal cavities in bicuspids and
molars. The second purpose, i. e.. the strength of the gold built
on in restoring angles, is shown by the lamination in Figure 280.
In this a thin angle of gold is built on, forming an angle, three
sides of which are without support by cavity walls. It. there-
fore, depends entirely on the strength of the gold to endure the
stress brought upon it in usage. Considerable difficulty has
occurred from the breaking of these angles. This may be avoided
by using due care in the building. First, the greatest care must
be taken that the annealing is perfectly done and that the weld-
ing property of the gold used is perfectly developed, in order
that no portions of gold may be introduced that do not properly
weld. Second, after the walls of the cavity have been well cov-
ered for a space, the central ]iart of the filling should begin to
be raised in a ridge running from mesial to distal, looking to
the formation of the restored portion of the incisal edge of the
tooth. As this is raised more and more by adding most gold
on the center of this ridge, gold is also being added on its lal)ial
side and its lingual side extending in layers over the raised edge
and down its slopes, as shown in the illustration, Figure 280.
until the building is finished. When built in this way, the
restored angle will have the maximum strength, and will seldom
break.
In other particulars than this one, fillings for the restora-
tion of lost angles require no especial methods of l)uilding. In
the nature of things, a filling that will be subjected to the heavy