Page 166 - My FlipBook

METHODS OF FILLING TEETH.
152
itself showing no signs either of deep decay or of superficial softening.
A seems contraindicated in the absence of a the
filling cavity, yet
patient may insist upon having relief.
In order that the condition may be thoroughly appreciated, as well
as the remedy which I shall advise, it will be necessary to enter some-
what into the etiology of the condition. I have never seen enamel
sensitive upon its outer surface. If others have noted such a phenom-
enon, it is sufficiently anomalous to be unconsidered in this connec-
tion. I have never seen cementum sensitive. Sensitive dentine, how-
ever, is common. Thus, dentine being the only hard tissue of the
tooth which is responsive painfully, it would seem to follow logically
at the neck of a tooth must be due to an
that pain exposure of the
dentine. Fig. 173 represents a sectional view through a cuspid. It
FIG. 173.

but is nevertheless
is diagrammatical, sufficiently accurate, since in
making the original of the illustration I have produced the various
which I made from
parts by copying drawings microscopic specimens
of Dr. Carl Heitzmann.
in the laboratory
The first point of interest to be noted is that normally, at the neck
of the tooth, the cementum, c, overlaps the enamel, e, just beneath the
free margin of the gum, g. As this gum recedes, possibly as far
as the line a, the cementum becomes exposed and gradually dis-
thus the dentine at b. soon thereafter
appears, leaving exposed Very
the part may become excessively sensitive. This leads to a considera-
tion of the dentine, d, especially at this point. Sensitiveness in den-
tine, has long been attributed to the dentinal fiber. This fiber, though
traced as far as the odontoblastic layer of the pulp, has not been posi-