Page 222 - My FlipBook

194 IHE MICRO-ORGANISMS OF THE HUMAN MOUTH.

a progressive superficial dissolution of the cement, or the cavities
of the cement become infiltrated with bacteria, giving rise to
a parenchymatous dissolution,
l^"^' '^^- accompanied by phenomena
i > very similar to those of dentine-
:.._
%i Z^'^:\}^?H y, decay. Its similarity to the lat-
!'
\^\ yi-/ i // . ter is esijecially striking in
'^{.-^^^^Ifen places where Sharpey's fibers
'^^'^ y^'oW. developed. Immedi-
^^'''"'^^^fe*^^-^;y^^^.#
'\ '"' ately following decalcification
p'-X''
these fibers, or rather canals, are
Decay of Cement. ' '
Enlargement of the lacuna; and gradual infiltrated and enlarged by bac-
liquefaction of the basis-substance ^gp^.^ which gradually liciuefy
by bacteria. 800 : 1. . ° . J ^ V J
.
the intervening tissue (Fig. 97).
In this way the tissue is rarefied, and finally totally destroyed.
I possess several specimens in which this form of cement-caries
has been artificially produced.
When cement-corpuscles are present, they or their oftshoots
(as far as 1 have had opportunity to examine such cases) are infil-
trated with bacteria and swollen (Fig. 98). I was not able to
determine any such inflammatory reaction on the part of the
cement as occurs, say in bone or cartilage.
Decay of Teeth worn on Plates.

Some authors state that decay of human teeth, worn as arti-
ficial teeth, just as decay of natural teeth devoid of living pulps,
is exactly identical with and shows all the phenomena of decay
of living teeth. Other eminent authors, on the other hand,
describe appearances (transparency, thickening of ]Sreumann's
sheath, etc.) wdiich, they claim, occur in living teeth only. My
observations lead me to believe that all the phenomena of decay,
with the exception of transparency, which, strictly speaking,
cannot be regarded as a phenomenon of decay, occur in dead as
well as in living teeth. In fact, I have reproduced all artificially.

Artificial Decay.
The attempt to procure artificial decay has been made by many
investigators. Magitot made extensive experiments in order to