A comparison of the static frictional forces between stainless steel brackets and various types of orthodontic wires at different angulations in the wet state

Authors :

• Pornpetch Rujitwattana D.D.S.
• Vachara Phetcharakupt D.D.S., Dip. In Orthodontics (Bergen), Thai Board of Orthodontics
• Piyarat Apivatanagul D.D.S., M.Sc. (Orthodontics)

Abstract :

Objective To compare the static frictional forces measured in 37 ± 1 ÌC artificial saliva between
stainless steel brackets and 4 types of orthodontic wires when the angulations between the brackets
and the wires are 0, 1 and 2 degrees, respectively.

Materials and methods The static frictional forces of the 0.018 inch slot canine standard edgewise
brackets and 4 types of 0.016 x 0.022 inch wires which were stainless steel, Sentalloy^® medium,
Sentalloy^® heavy and TMA^® COLOR^TM (honeydew) were measured by using the Lloyd universal
testing machine at the second-order angulations of 0, 1 and 2 degrees. The measurements were
made in the artificial saliva at 37 ± 1 °C. Two-way ANOVA was used to test for significant
differences of the static frictional forces among the groups of specimens at the significant level
of .05.

Results There was no difference in the static frictional forces between the brackets and the 4 wire
groups when the second-order angulation was equal. However, the static frictional forces were
increased when the second-order angulation increased. The significant difference was found when the
angulation rose from 0 to 2 degrees only (p-value = .004, .028 and .002, respectively) except for the
stainless steel wire group which the significant difference of the static frictional forces when the
second-order angulation increased was not found.

Conclusion There was no difference in the static frictional forces between the brackets and the 4 wire
groups. However, except for the stainless steel group, the static frictional forces rose significantly when
the second-order angulation increased from 0 to 2 degrees.

(CU Dent J. 2008;31:169-78)

Keywords :
beta-titanium wire; nickel-titanium wire; second-order angulation; stainless steel bracket; stainless steel wire; static frictional force