Page 42 - My FlipBook

12 PATHOLOGY OF THE HAKD TISSUES OF THE TEETH.
features of these marks. Certainly, hereditary syphilis comes
in for its full share of these cases.
On the other hand we can not say, at least I can not, that
marked teeth will result from this or that illness. If the hair
falls out or the finger nails show a groove after an illness we are
apt to find the teeth marked also. Very many of the cases that
I have noted and watched for the coming of the permanent teeth
have presented teeth without a blemish. Indeed, among all of
the cases that I have noted and watched, the marked teeth have
been the exception rather than the rule. Still, it remains true
that when I have been able to obtain a satisfactory history, the
marked teeth have coincided in time with some form of disease
that might well have interfered seriously with the nutritive proc-
esses. The history is not always easy to get, even among intel-
ligent people. I once remarked to a lady in my chair that she
had been very sick with scarlet fever when she was about two
years old. She was very sure she had not, for she had never been
told of such an occurrence. When I explained that accurate
knowledge of the facts was of considerable scientific value she
said she would question her mother regarding it. The next day
I received a note saying her mother's story agreed with my sup-
position, both as to the particular disease and the date of the
illness. I have seen many of these cases, however, in which I
could find no history of the illness causing them.
To assist in searching for the cause that has led to this
deformity in cases coming before us, I introduce a diagrammatic
chart, or index, indicating by lines across the incisors, cuspids
and first molars, the positions the grooves across the teeth
assume because of disease occurring at different ages of the
child. Figure 9. These lines have been varied a little from the
true contemporaneous calcification lines to suit better the appar-
ent positions upon teeth that are shortened by severe atrophy.
This chart will point out the age at which any injury occurred
as well, perhaps, as it can be done in a chart of this character,
which, of course, is founded upon averages. Pretty wide varia-
tions will occur in the time of the calcification of the teeth of
individuals, and also between the several teeth of the same indi-
vidual. There is certainly as much variation as eighteen months
in the time of the beginning of the calcification of the central
incisors, and a greater range possibly with all of the other teeth,
except the first molars. These latter are perhaps the most con-
stant. But these certainly vary from the twenty-fifth week of
uterine life to something near six months after birth.
The chart is intended to give only a general average as to
the time of the illness that has caused these injuries.