Brackets De Autoligado

Original Article

Friction of Conventional and Self-Ligating Brackets Using
a 10 Bracket Model
Simona Teccoa; Felice Festab; Sergio Caputib; Tonino Trainia;
Donato Di Iorioa; Michele D’Attilioc
Abstract: The friction generated by various bracket-archwire combinations previously has been
studied using in vitro testing models that included only one or three brackets. This study wasperformed using a specially designed apparatus that included 10 aligned brackets to compare the
frictional resistance generated by conventional stainless steel brackets, self-ligating Damon SL II
brackets and Time Plus brackets coupled with stainless steel, nickel-titanium and beta-titanium
archwires. All brackets had a 0.022-inch slot, and five different sizes of orthodontic wire alloys
used. Eachbracket-archwire combination was tested 10 times, and each test was performed with
a new bracket-wire sample. Time Plus self-ligating brackets generated significantly lower friction
than both the Damon SL II self-ligating brackets and Victory brackets. However, the analysis of
the various bracket-archwire combinations showed that Damon SL II brackets generated significantly lower friction than theother brackets when tested with round wires and significantly higher
friction than Time Plus when tested with rectangular archwires. Beta-titanium archwires generated
higher frictional resistances than the other archwires. All brackets showed higher frictional forces
as the wire size increased. These findings suggest that the use of an in vitro testing model that
includes 10 brackets can giveadditional interesting information about the frictional force of the
various bracket-archwires combinations to the clinician and the research worker. (Angle Orthod
2005;75:1041–1045.)
Key Words: Frictional resistance; Conventional brackets; Self-ligating brackets; Archwires

INTRODUCTION

bracket slot, wire section, torque at the wire-bracket
interface, type and force of ligation, use ofself-ligating
brackets, interbracket distance, saliva, and influence
of oral functions.2–6 Consequently, because these factors could influence friction, they are critically important when considering the clinical application of sliding
mechanics. Such a reduction in friction can help shorten overall treatment time, especially in extraction patients where tooth translation is achieved by slidingmechanics.2
However, low friction also may be desired during the
orthodontic phase of alignment, when all the teeth
move at the same time and the wire slides through 10
brackets and two tubes. However, to date, no studies
have evaluated the total friction produced by various
bracket-archwires combinations in a testing model that
includes 10 brackets simulating the alignment phase.Self-ligating brackets, introduced in the mid-1930s,7–9
are ligature-less bracket systems that have a mechanical
device built into the bracket to close off the edgewise
slot.2 They are generally smoother for the patients because of the absence of wire ligature10 and also do not
require as much chair time.11 Several studies have

Friction is the resistance to motion when an object
moves tangentialagainst another.1,2 In orthodontics,
many studies have used experimental testing models
that included only one or three brackets to evaluate
the factors that influence frictional resistance between
the brackets and the archwire. 2–6 These studies
showed that the more important factors involved in the
determination of the frictional level were bracket and
wire materials, surface conditions ofarchwires and
Graduate Student, Department of Oral Sciences, University
G D’Annunzio, Chieti-Pescara, Chieti, Italy.
b
Professor, Department of Oral Science, University G
D’Annunzio, Chieti-Pescara, Chieti, Italy.
c
Researcher, Department of Oral Science, University G
D’Annunzio, Chieti-Pescara, Chieti, Italy.
Corresponding author: Simona Tecco, DDS, Department of
Oral Sciences, University...