Page 161 - My FlipBook

THE DECAY OF THE TEETH. 135

Peirce^'^' : "I am a firm believer in the fact that dental caries
cannot progress without these low forms of life."
Allan ^''- : " The germ theory is the only one so far that clearly
and satisfactorily accounts for the acid." " The germ theory
fnlly explains the distended tubules and the broken-down basis-
substance."
Black ^**^: "In this way the tubules become packed full of 7 .-
organisms, and the surrounding dentine is always decalcified in
advance of the growth of the fungus by the lactic acid produced.
That this is the true explanation of the etiology of dental caries,
there is no longer a reasonable doubt."

Electrical Theory of Decay.
A theory making decay of the teeth dependent upon galvanic
action was promulgated by Bridgman^"* in a prize essay before
the Odontological Society of Great Britain. The human mouth
is to be regarded as a galvanic battery ; the individual teeth
represent the difierent elements, and the secretions of the mouth
a common electrolyte. Under normal conditions the crowns of
the teeth are electro-positive, the roots electro-negative, "VYhen,
however, the roots become exposed by recession of the gums,
the exposed portion must be electro-positive. In like manner
the pulp is electro-negative to the dentine and to the enamel of
the crown. To be consistent, Bridgman should have gone further
and pronounced the dentine negative to the enamel, the cement
negative to the dentine, and the enamel positive to the cement.
The electric current generated between the two parts produces
an electrolytic decomposition of the fluids of the mouth; the
acids (electro-negative) are given oft" on the surface of the crown
of the tooth (electro-positive) and cause decalcification. Further-
more, inasmuch as the " formation of the dentine is due to elec-
tro-voltaic action," so, too, the dentine may be directly pulled
down elecirolytically and decomposed by the same force.
Bridginan's treatise won the prize oftered by the Odontological
Society for the best essay on dental decay ; it naturally excited
some notice at the time, but was not accepted with confidence.
We will not stop to consider the forty-five theses of Bridgman