Page 107 - My FlipBook

EROSION" OF THE TEETH. 45

this country many years ago, who have been very much devoted
to the maintenance of their especial set. From the descriptions
first given of erosion among these people, it was expected that
much of it would be of one character as to form, but the examina-
tion of the casts revealed a wide variety of form, so much so
that one could not say that any one particular form prevailed
to the exclusion of others. There were among them two cases
of marked erosion of proximal surfaces, cutting holes between
the bicuspids.
I have also supposed from my reading of the literature, and
especially from examination of illustrations, and from inquiry
in certain localities in this country and abroad, that certain forms
prevailed in certain localities.
FORMS OF EROSION
ILLUSTRATIONS : FIGURES 48-62.
Dish-shaped areas. One of the very common forms of
erosion we may describe as a dish-shaped excavation, in which
the center of the eroded area is deepest, and from this it rounds
up to the surface of the enamel in every direction. This may
attack a central incisor first and spread to the teeth at either
side of the tooth first attacked, hardly ever exactly bilateral,
but usually more extended on one side of the mouth than the
other, destroying the labial surfaces. Its place of beginning
varies from the middle of the gingival third to the mid-length
of the crown. Mesio-distally it is usually about the center, but
if there are irregularities in the positions of the teeth it is most
likely to begin on the most prominent part.
It first forms a little facet upon the enamel, then destroys
more and more, and finally passes through to the dentin, cutting
without any distinction whatever between the dentin and enamel,
and increasing the size of these facets until the whole labial
surface has been removed, not touching the proximal surface,
and not touching the incisal except as it is approached from the
labial. This form is represented in Figure 48. There is fre-
quently an offshoot from the true dish shape toward the incisal,
particularly in the central incisors and cuspids above and below,
and sometimes in other teeth.
Figure 49 also presents the dish shape of the eroded areas,
but in this case it has two complications. There is recession
of the gums and the dish-shaped portion of the erosion is largely
in the cementum, but cutting the cementum, enamel and dentin
without distinction. This complication of recession of the gums
with erosion is not uncommon. The erosion never passes under
the free margin of the gum, and while the gum may be tumified