Page 60 - My FlipBook

56 CARIES OF THE TEETH.

and especially when the material used is not of the
right quality.
Lack of proper exercise in mastication induces a
condition favorable to decay, both by favoring the

action of injurious agents upon the teeth and by with-
holding the stimulus of normal exercise. Tartar and
other deleterious substances are much more rapidly
deposited when the teeth are idle.
The teeth cannot, with impunity, undergo great and
sudden transitions of temperature, or even such vari-
ations as may be endured by the surrounding parts.
By these, inflammation of the dentine may be induced,
and the vitality of the teeth diminished. And in
friable teeth, checking of the enamel may occur, and

thus a condition arise that will facilitate decay.

EXCITING CAUSES OF CARIES.

When there is a predisposition to caries, any of the
exciting causes act with more effect. Well organized
teeth of unimpaired health and vitality, withstand
influences that, in less favorable circumstances, des-
troy them in a very short time. The immediate
cause of decay is the action of agents chemically upon
the teeth. It is not here proposed to enter upon an
investigation of the manner in which these various

agents operate ; for that would open up a vast field