Abstract
Aims: To determine the effect of different points of force
application on dimensional positions and the ratio of space
closure of maxillary canine using sliding mechanics. Mater–
ials and Methods: The study included eight groups which
were categorized according to the differences in the points
from which the retraction force was applied. A 180 gm was
applied by short elastic chain to retract the right maxillary
canine on 0.018_x0001_0.025'' rectangular stainless steel (SS) wire
and along 13mm available space. In both vertical and
horizontal direction, photographs were taken by digital camera
and the angle between canine extension bar and bite plane
extension bar was measured by protractor to determine tipping
and rotation whereas rate of space closure was measured by
digital vernia. Results: The results showed that the maximum
rate of space closure was achieved when elastic chain was
attached between molar hook to canine hook and the
minimum degree of tipping was achieved when elastic chain
attached between premolar bracket to canine hook while
minimum rotation occurred when the attachment was between
premolar hook to canine hook. Conclusions: Changing the
distance between the points of force application significantly
affects the rate of space closure, tipping and rotation. The use
of hook significantly increases the rate of space closure and
decreases tipping and rotation.
