Journal of Dental Research, Vol 65, 118-122, Copyright © 1986 by International & American Associations for Dental Research Online Journals
The effect of intermittent forces on eruption of the rabbit incisor
W. R. Proffit and K. T. Sellers
Rabbits were prepared so that a variable capacitance displacement
transducer (VCDT) could be used to monitor the eruptive movements of a
previously-amputated lower incisor, and a strain gauge transducer mounted
on a relay-controlled plate was used to place precisely controlled
intermittent forces opposing the erupting tooth. Forces of one or three g
were applied under time conditions of one second on, nine seconds off
(1:9); one second on, three seconds off (1:3); and one second on, one
second off (1:1). The data indicate that with force present for 10% of the
time (1:9), there was little or no effect on eruption rate. In contrast,
50% time (1:1) produced essentially the same intrusive effect as continuous
force, and 25% time (1:3) gave an intermediate response. The data are
consistent with the hypothesis that force duration is more important than
force magnitude for the vertical equilibrium, as is the case for
facio-lingual equilibrium.
