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

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combinations of bracket-slot and wire materials, ligature type, slot-positioning and other pertinent parameters. Research designs have recently attempted to simulate clinical environments with multiple crown-attachments placed in series or in an archform. The present research was designed to answer several timely questions about friction in orthodontics. Apparently no studies have been published to date that compare friction across categories of self-ligating brackets with third-order positioning controlled. The purpose of this study was to determine the effect of wire- slot torque on friction in self-ligating brackets with an engaged, 0.019- x 0.025-inch, stainless steel archwire. In addition, the influence of the design of various ligating mechanisms on kinetic friction with active torque present in the wire and/or slot was also evaluated. 2
CHAPTER 2: REVIEW OF THE LITERATURE Classical Friction In the orthodontic literature, friction was discussed as early as 1960 when Stoner 1 warned of the difficulty in determining the amount of force to be applied to a tooth because of the role of frictional resistance. Our current understanding of friction impairing tooth movement is based largely on long-standing theories, not directly related to orthodontics, by Leonardo Da Vinci, Guillaume Amontons, and Charles-Augustin Coulomb. Although Da Vinci’s work was not published until the other investigators had carried out friction experiments, he left behind the earliest known studies on the subject in a collection of journals in which he detailed his research. 2 Collectively, these scientists are credited with establishing the classical laws of friction, or the Amontons-Coulomb laws, which state the following: 1. Frictional force is proportional to normal force; 2. Frictional force is independent of contact-area; 3. Frictional force is independent of sliding velocity. 2,3 Friction is defined as the resistance to motion when one object moves or tends to move tangentially relative to another object. 4 The total contact-force 3
Page 1 and 2: THE EFFECTS OF THIRD-ORDER TORQUE A
Page 3 and 4: of torque, all five attachment sets
Page 5 and 6: COMMITTEE IN CHARGE OF CANDIDACY: A
Page 7 and 8: ACKNOWLEDGEMENTS The author wishes
Page 9 and 10: LIST OF TABLES Table 2-1: Partial O
Page 11: CHAPTER 1: INTRODUCTION The special
Page 15 and 16: surfaces. 6 The magnitudes of the c
Page 17 and 18: Since the introduction to orthodont
Page 19 and 20: that the application of the Amonton
Page 21 and 22: archwires. At binding angulations,
Page 23 and 24: A phenomenon known as “cold weldi
Page 25 and 26: of round wire with the slot created
Page 27 and 28: acket and the gold-lined Luxi brack
Page 29 and 30: and wire stiffness. As bracket widt
Page 31 and 32: ligation-friction relationship. The
Page 33 and 34: designs have been introduced to the
Page 35 and 36: otated tooth or a twisted rectangul
Page 37 and 38: to incisor irregularity after initi
Page 39 and 40: added. Similarly, Bunkall 15 noted
Page 41 and 42: couple, resulting in the delivery i
Page 43 and 44: Another factor that influences brac
Page 45 and 46: References 1. Stoner MM. Force cont
Page 47 and 48: 19. Kusy RP, Whitley JQ, Ambrose WW
Page 49 and 50: 37. Kusy RP, Whitley JQ, Mayhew MJ,
Page 51 and 52: 56. Khambay B, Millett D, McHugh S.
Page 53 and 54: 75. Tecco S, Festa F, Caputi S, Tra
Page 55 and 56: 93. Thorstenson GA, Kusy RP. Effect
Page 57 and 58: Tables Table 2-1: Partial Overview
Page 59 and 60: significantly less friction than th
Page 61 and 62: optimal clinical results. Fixed-app
Page 63 and 64:
self-ligating bracket systems to ma
Page 65 and 66:
unconstrained rotation around the l
Page 67 and 68:
surface of a tooth-crown. The const
Page 69 and 70:
0.025-inch NuBryte Standard Arch st
Page 71 and 72:
test-archwire in place and ligated,
Page 73 and 74:
aseline values at 0 degrees of torq
Page 75 and 76:
increased to only five degrees. The
Page 77 and 78:
tension on one edge of the wire and
Page 79 and 80:
set, when the torque angle was incr
Page 81 and 82:
with active, self-ligating sets. Th
Page 83 and 84:
11. Kusy RP, Whitley JQ. Effects of
Page 85 and 86:
33. Andreasen GF, Quevedo FR. Evalu
Page 87 and 88:
54. Downing A, McCabe JF, Gordon PH
Page 89 and 90:
76. Thorstenson GA, Kusy RP. Effect
Page 91 and 92:
Table 3-2: Significance levels (α
Page 93 and 94:
Table 3-4: Mean differences in fric
Page 95 and 96:
Figure 3-3: Control of the third-or
Page 97 and 98:
Figure 3-9: Victory bracket Figure
Page 99 and 100:
Figure 3-12: Cross-section diagrams
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The effects of third-order torque and self - Saint Louis University

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