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4 MECHANICAL DF.NTISTRY AND METALLURGY.
cieiitlv at the soft points, and (3) in securing a correct
articulation. 'J^ie plate line in this case, and the extent of
the carving is shown in the shaded portions of the illustra-
tion. We might mention that the relative position of the
jaws in this case was not normal there being a tendency
to a slight protrusion of the lower teeth. In the three
plates previously made, the normal articulation had been
adhered to, and as stated without success.
One of the most frequent deformities is the lack of sym-
metry in the alveolar ridge. For instance, in a large per-
centage of cases, it will be found that there is a greater de-
pression upon the left side of the mouth than upon the

Fig. 2.

right. Fig. 2 shows a base-plate which has been formed
over sucli a model. Dr. Eugene Talbot reports that out
of 298 examinations of models he found 268 wdth marked
depressions upon the left side, and 24 with the depression
upon the right side, and only 6 cases showing both sides
to be alike.
This depression is not so apparent upon a casual glance,
for it is not so much in the alveolar process as in the
maxillary bones. Dr. Haskell says of this, that a nlate