Page 261 - My FlipBook

ways, that the eroded surface is smooth and hard, presenting
none of the character of decay whatever.
As to frequency of occurrence, erosion may he said to he
rare. It does not occur in one person in a thousand, perhaps
not in one person in two thousand. I don't know how to
estimate that, however, hut [ know that a dentist may practice
for many years and never see a case of erosion. In a practice
of about forty years I think about twenty cases were as many
as came to me, i e., that leg-itimately belonged to my practice.
However, I have observed a great many more cases in cases
sent by other dentists. So that I have observed some hundreds
of cases of erosion. Every year there are a number of cases
presenting here in the school, but not sufficient in number, I
sometimes think, for all of you to become familiar with the
appearances. Yet, by the examination of these specimens, and
remembering distinctly that these eroded surfaces are smooth
and hard and free from) discoloration, and sensitive when the
dentin is reached, you will be able to distinguish them when
they are presented to you.
it may cease
The progress of erosion may be continuous ;
spontaneously at any time without apparent cause; it may he
intermittent—beginning, going on for a time, then stopping,
then beginning again, going on for a time and then stopping,
and in that way continue for a long time. There is this sign
that will tell you plainly whether or not an erosion is in prog-
ress or stationary—wdienever erosion is in progress upon teeth
with living pulps the dentin afifected is extremely sensitive;
this is universal. If the progress stops for a time that sensi-
tiveness disappears, and if it stops for a considerable time the
eroded dentin will begin to discolor and occasionally decay
may become implanted in the eroded surface. If the erosion
begins again the surface quickly becomes of the normal color
and the sensitiveness reappears. So that whenever an ero-
sion has reached the dentin in a living tooth we may know
by an examination whether or not the erosion is progress-
ing.
The cause of erosion we know nothing about. You will
find articles in the literature assigning this and that cause for
erosion. It was supposed at one time that there was something
in the motions of the lips or of the parts that created a current
of acidulated material along the teeth, and in this way these

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