Page 226 - My FlipBook

19i HISTOEY OF DENTAL SURGERY

"The teeth are strongest in youth and early adult age, diminishing some-
what in strength with advancing age.
"Teeth that have lost their pulps and have become discolored lose strength
in a marked degree, apparently from a deterioration of the organic matrix.
"Teeth that have become badly worn from mastication, and in which the
pulps become so nmch calcified as to cut off the nutrition of the crown
portions of the dentine, lose strengtli apparently from deterioration of the
organic matrix.
"Teeth of old people, and especially those in which much calcification of
the pulp occurs, deteriorate in strength.
"There is no basis for the supposition that the teeth of children under the
age of twelve years are too soft to receive metallic fillings.
"Differences in density or in the percentage of lime salts in the teeth is
not the controlling factor in the strengtli of the teeth nor their hardness, this
seeming to depend upon the condition of the organic matrix.
"Differences in the strength of the teeth have no influence as to their lia-
bility to caries. Difference in the density, or in the percentage of lime salts
in the teeth, have no influence as to their liability to caries.
"The active cause of caries is a thing apart from the teeth themselves acting
upon them from without, and from a consideration of the facts thus far
developed, the logical inference is that the cause of the differences in the
liability of individuals to caries of the teeth is something in the constitution,
operating through tlie oral fluids, and acting upon the active cause of caries,
hindering, or intensifying, its effects.
"Caries of the teeth is not dependent upon any condition of the tissues of
the teeth, but on conditions of their environment. Imperfections of the teetli,
such as pits, fissures, rough or uneven surfaces, and bad forms of interproxi-
mate contact, are causes of caries only in the sense of giving opportunity for
the action of the causes that induce caries.
"The objects to be attained in filling teeth are the perfect exclusion from
the tissues of the causes of caries by sealing the cavity, and securing such form
as will prevent lodgments of debris about the margins of the filling, and thus
prevent the further action of the cause of caries.
"There is no basis for the supposition that some teeth are too soft, or too
poorly calcified, to bear filling with gold, or other metal in use for that pur-
pose, since all are found to be abundantly strong.
"There is no basis for the selection and adaptation of filling materials to
soft teeth, hard teetli, frail teeth (in structure), or poorly calcified teeth.