Page 263 - My FlipBook

looked as though a round file had been run between them—the
central incisors first, then between the central and lateral, then
between the lateral and cuspid and between the cuspid and
bicuspid, progressing to either side in that way. I observed
these from time to time until these teeth were cut off ; or they
were cut so thin that there was about a millimeter thickness of
tooth structure from; mesial to distal left, and then they broke
away, leaving the roots of the teeth in position. In this case
there was no mucous memibrane coming in contact with them.
So that that disposes of that idea of the causation of erosion.
Every suggestion as to its cause I have traced in a similar way,
and it has become clear to my mind that we know nothing of
its cause. I hope future generations will find out why this
occurs and some remedy for it.
There is one other hypothesis that perhaps I should speak
of, with reference to the cause of erosion, and that is the
hypothesis that it is caused by the tooth brush. I will only
speak of it to say that experiments have been made on this
point by a number of persons, and that we regard it as utterly
impossible that that could occur. I have seen a few cases that
were very much undercut toward the gingivae; I have seen
some cases that were considerably undercut toward the oc-
clusal ; I have seen cases that were cut directly across the
crowns of the incisors, not more than one and a half milli-
meters wide. We cannot imagine such forms to have been
cut with a tooth brush, even if the tooth brush, loaded with
pumice or loaded with various other gritty substances, would
cut away the teeth. We have been unable to produce any such
cutting with a tooth brush or by any form of artificial cleaning
whatever.
Erosion presents peculiar characters zvith reference to the
pulp of the tooth. There is something in the peculiar irrita-
tion of the fibrils in the progress of erosion that causes reces-
sion of the pulp, or, in other words, that causes a deposit of
secondary dentin, obliterating the bulb of the pulp in the crown
portion of the tooth. It is exceedingly rare to see a pulp ex-
posed by erosion. Before the erosion has reached the pulp of
the tooth the pulp will have receded by the deposit of second-
ary dentin and the erosion will go on through that just the
sarqe as any other of the hard tissues, until the tooth is cut off.
Thermal sensitiveness of the teeth does not occur, al-

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