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TWENTY-SECOND LECTURE. :

March 13, 1901.
You will remember in my last lecture I spoke of the force
exerted by the teeth, the force of the bite. Some of you have
been experimenting since and have found out some things
and it might be just as well for some of you to tell them in a
practical way.
The following tests of the force with which the teeth may
be closed were then made with the gnathodynamometer
Mr. Reid, 265 pounds on molars.
Mr. Reid says his teeth are a little sore, so that he can-
not bite hard. He broke a piece ofi the rubber pad on the
instrument the other day and his teeth came against the steel
and gave him a severe jolt, an accident that does not very
often happen, and his teeth are a Httle sore from it; otherwise
I suppose he would have broken the machine again.
Mr. Cummins, 230 pounds on molars.
Mr. Errett, 220 pounds on molars.
Mr. Gray, 180 pounds on molars.
Mr. Jarrett, 270 pounds on molars (machine closed).
Mr. Kempter, 190 pounds on molars.
Mr. Jarrett, 90 pounds on incisors.
Mr. Schneider, 140 pounds on incisors.
This gives you a very fair idea of the usual differences in
the force of the bite. I have seen over 200 pounds* pressure
brought with the incisors, but that is rare. Now, I will still
leave this instrument with you that you may experiment fur-
ther, any of you who wish. I wish you to understand the
pressures against which you must work in making fillings,
bridges, etc. I want to say in this connection that if you will
try those teeth from which the pu]j)s have been removed you
will find generally that their power is very much reduced. Pa-
tients will not have the power with those teeth from which
pulps have been removed that they will have with neighbor-
ing teeth in the same mouth in which the pulps are alive.
That has been verv prominent in the trials that I have made.
Therefore, you will not have the power of mastication upon
bridges that are supported by teeth, the pulps of which have
been removed, that you will upon bridges supported by teeth

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