The effects of third-order torque and self - Saint Louis University

ackets. Peterson’s group 31 also found that bracket width
had no effect on friction. Frank and Nikolai, 5 however,
found that frictional force increased as bracket width
increased. This outcome was allegedly due to decreased
interbracket distance and to the wider bracket binding at a
smaller angulation. Other researchers found a similar
effect, but thought the cause was the mesiodistal slot
dimension of the wider bracket resulting in greater
stretching of the ligature, which in turn, lead to
increased normal forces of ligation. 23 A third group of
studies found that narrower brackets produced more friction
than wider brackets. 21,22,81 Drescher’s group 22 believed that
the increased tipping seen in narrow brackets resulted in
greater frictional forces. Using biomechanical analysis
and mathematical formulations, Schlegal 86 determined that
neighboring brackets had an extraordinary influence on
friction within a bracket, and, due to this influence,
single-bracket studies could not accurately determine how
bracket width affected friction. He concluded that
interbracket distance, wire stiffness and relative bracket
position must also be considered when determining the ideal
slot width.
Bracket width may have an indirect influence on
friction due to its relationship with interbracket distance
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