First District Dental Society, State of New York. [Volume: 29, Issue: 1, January, 1887, pp. 41-65]

52

2 THE DENTAL COSMOS.

responding with the horizontal axis of the tooth. In such instances
the loss of tissue is generally greatest at or toward the cutting
edges, which finally become involved, until occlusion of the anterior
teeth becomes impossible, owing to the shortening occasioned by
loss of structure. This is probably but a more advanced stage of
the condition just described. Two other manifestations of erosion
are met with. The first one, which is most common, and which is
undoubtedly responsible for much of the difference of opinion and
confusion which exists as to the cause of the malady, is that which
occurs at the necks of the teeth, just at the free margin of the gum,
and the simplest expression of which is a narrow, transverse groove,
highly polished and varying in depth from a shallow depression to
a cavity which may nearly invade the pulp-chamber. It is noticeable in this expression of erosion that the enamel margins of the
eroded spots frequently project or overhang, presenting sharp edges
or points which may become sources of irritation to the tongue or
lips.
Also, when the disease has sufficiently advanced, the contour of
the margin, of the eroded area presents a ragged or irregular appearance, which in the earlier stages of the disease presented an almost
straight or an unbroken curved line, points or prolongations of the
eroded area extending in the line of the vertical axis of the tooth
towards its cutting edge. Lastly, erosion may cause loss of enamel
from the approximal surfaces, while the labial and lingual surfaces
are comparatively unaffected. This condition I have never observed
except in the lower front teeth, and then only when they were
somewhat separated from each other.
Any tooth in the upper or lower denture may be the seat of erosion, and pulpless teeth as well as those which are otherwise normal.
Whatever may be its origin, the disorder is progressive, the action
extending not only in the plane of the labial surfaces, but into the
deep structures of the tooth, until the pulp-chamber becomes invaded by the deepening of the eroded spots. Actual exposure of
the pulp from erosion is, however, a comparatively rare occurrence,
as the progress of the disease apparently induces a deposition of
secondary dentine in the pulp-chamber, and consequent recession of
that organ. Fracture of the teeth at their necks, however, is not
infrequent, when by reason of extension of the disease the tooth
becomes so thin that only slight mechanical violence is necessary to
induce a sudden separation of the crown from the root of the tooth.
The progressive character of erosion is fully and graphically shown
in those cases where in its early stages the pits or depressions
which are the seat of the disease have been carefully filled and the
contour restored with gold. These, after a length of time varying