Page 75 - My FlipBook

ATROPHY OF THE TEETH. 21

square end of the upper piece. This was broken in the effort
to extract and the root pulled apart on the line of the area of
interglobular spaces, the line representing the lines of the pi-oc-
ess of growth.
The patient failed to keep his appointment for further treat-
ment and was not seen again. The opportimity to inquire into
the nature of the nutritional disturbance that had caused this
rare form of injury was lost. The specimen, however, tells its
own story clearly. This case shows that the root of a tooth may
also be injured by atrophy, though such an extreme occurrence
as this must be rare.
I have noted a considerable number of cases in which a zone
of injury occurred in the dentin beginning below the gingival
line, as in the case shown in Figures 21, 22, though they are far
more rare than those occurring in the crown of the tooth. In
Figure 11 there is such a zone of injury which may be seen even
in that slight amplification, in the disturbance of the outlines of
the enamel and some faint shadows representing the lines of
interglobular spaces. With medium powers of the microscope,
these latter are prominent objects.
Figure 23 represents another case of atrophy of the graver
sort, occurring in a central incisor, in which but little discolor-
ation is apparent. The wide overlapping of the new onto the
older enamel, the complete breakage of the enamel rods along the
line of junction of the two, the change in the course of the enamel
rods in the two formations of enamel and the profound disturb-
ance of and recurving of the labial dento-enamel junction, all
point to a long suspension of nutrition and account for the grave
distortion of the form of the tooth. This is much like that shown
in Figure 13. The line of interglobular spaces is sharp and
severe, but very narrow, and the dentin is normal immediately
on either side. The incisal edge had been ground away in the
endeavor to improve the appearance before the tooth, with the
other incisors, was extracted. About one-third of the normal
length of the crown had been missing.
Figure 24 represents another similar case, but with rather
more discoloration. The incisal edge of this had also been
groimd away in the effort to improve the appearance before
resorting to extraction. In this the main features are again
repeated; it shows the same line of demarkation between the
old and new enamel, the same distortion by recurve of the
labial dento-enamel junction and the same sharp line of inter-
globular spaces. In this particular case the character of the