Page 171 - My FlipBook

that have had faulty enamel with decays spreading over
and removing the whole occlusal portion of the crown with-
out extending very deeply.
Interglobular spaces of less extent often give rise to
irregular forms of cavities by giving opportunity for inva-
sion by micro-organisms in unusual directions.
Following this again a number of illustrations were
given photographed with high powers of the microscope
showing the micro-organisms in the individual tubules of
the dentin. With these the enlargement of the tubules as
the process of decay advanced was illustrated. It was
shown that the micro-organisms crowded into all available
space and that the tubules were enlarged by the gradual
solution of their walls until the septi between them were
destroyed, leaving a confused mass of micro-organisms with
irregular shreds of basis substance. This disintegrates and
washes away, leaving a cavity.
This practically closed the hour, but a few photographs
illustrating the wearing of the contact points between proxi-
mating teeth by the rubbing movements in mastication were
hurriedly shown and explained.

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