Page 238 - My FlipBook

210 THE MICRO-ORGAXISMS OF THE HVMAX MOUTH.

raw vegetable food is less fermentable than cooked. Should
further researches prove that this is indeed the case, the cooking
of food would have to be reckoned among those customs of
civilization which have a detrimental influence upon the teeth.
It is well enough known that acids, brought into the mouth
as medicines or with the foods, may have a deleterious action on
the teeth. An excess of sour fruit, grapes, lemons, etc., and the
continued use of acids or acid comj^ounds doubtless has a decal-
cifying action on the teeth, attacking first not the concealed but
the exposed parts.
Schlenker"- calls attention to certain substances which, coming
into contact with the teeth, either as food or as medicine, are
generally injurious, some to such an extent that their decalcify-
ing action becomes visible to the naked eye in the short space
of five minutes. I do not attribute too great an importance to
the influence of such substances, nor do I underrate them, since
a slight injury of the enamel or dentine caused b}' such agents
may give rise to decay at points which otherwise would have
escaped.
An acid reaction of the saliva is equally detrimental. This
is said to occur in rheumatism, gout, gastro-enteritis, diabetes
mellitus, dyspepsia, and various disorders of the alimentary
tract, in fevers (typhus, intermittent fever, etc.), in diseases of
the lungs, etc., and during pregnancy. According to some
authors, the mucus also, under certain circumstances, has an
acid reaction, and the attempt has been made thereby to explain
pathological phenomena, particularly at the neck of the tooth
(wedge-shaped defect, neck decay). Our knowledge of the
properties of mucus is unfortunately too limited to determine
accurately the part it plays in decay of the teeth. (See page 42.)
With less reason, it appears to me. Tomes, Black, and others
ascribe a destructive (probably meaning a decalcifying) action
on the neck of the tooth to the '' acid secretion" of the irritated
gums. No conclusive facts have been adduced for this supposi-
tion. On the other hand, it is well known that decay very
seldom occurs in cases of pyorrhoea alveolaris, in which the
gums are in a state of irritation for months together. T\"hen-
ever decay does accompany inflamed gums, we invariably find