Page 63 - My FlipBook

EXCITING CAUSES OF CARIES. 59

The most common agents, however, that injure the
teeth, are originated in the mouth, by the decompo-
sition of animal and vegetable matter. By this pro-
cess, elements are eliminated, that form new combi-
nations and these operate with energy in the
destruction of the teeth. Favorable conditions exist
in the mouth for such decomposition, and also for
such new combinations ; for there is a sufficient amount

of heat and moisture; for both of these, especially
the former, facilitate the action of any acid upon the
dentine. The character of the saliva and mucus will
very much modify the decomposition of foreign sub-
stances in the mouth. If these secretions are both
acid, the decomposition will be much more rapid, and

more potent in its effect.
Again, it is sometimes the case that the salivary
glands are comparatively inactive, except when spe-
cially excited, and yet the mucous glands still effi-
cient, eliminating their secretion; so that the mouth
assumes an acid condition, because there is not saliva
sufficient to neutralize the mucus; in which condition
decomposition of foreign substances would be greatly
accelerated. There are many cases, however, in which
the flow of saliva is copious, and yet the decay very

rapid; which is in consequence of an acid condition of
both secretions, or of a rapid decomposition of foreign
substances in the mouth.