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

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Conventional Ligation Orthodontic ligatures existed prior to the use of the modern fixed appliance. In 1728, Fauchard published a book called “Le Chirurgien Dentiste” in which he described his “Bandeau” device. Ligatures were extended from this horseshoe-shaped device to facilitate simple tooth movement. Angle’s edgewise appliance was introduced in 1925, and the original design has evolved to the most commonly used orthodontic appliance today. It was the first fixed appliance to feature ligatures as an essential part of the appliance. Early ligatures were materially precious metals. 49,50 In modern clinical orthodontics, the conventional methods of tying archwires into bracket-slots are with either small stainless steel wires or elastomeric ties. These ligatures, although relatively inexpensive and easy to place, have been criticized with the recent interest in orthodontic friction. Studies have shown a relationship between normal forces of ligation and resistance to sliding. Using a pneumatically controlled surface to simulate the force of ligation on a sliding wire, Stannard et al. 17 discovered a proportional increase in friction with increasing ligating force. Keith, Jones and Davies, 51 with three magnitudes of ligating force, found a similar 20
ligation-friction relationship. The importance of ligating technique was demonstrated by Frank and Nikolai 5 ; they found ligature-tie force to be the greatest contributor to friction at small wire-slot angulations. Berger 52 also concluded that, at nonbinding angulations, ligature-force was a major contributor to frictional resistance. Of the two conventional methods of archwire-ligation, elastomeric ligatures have been the more popular because of the ease and speed at which they can be placed and removed. In addition, patients have enjoyed selecting from the numerous colors available. In terms of their effect on friction, however, the difference between stainless steel and elastomeric ligation has not been so clear. Some studies have been unable to show a difference in frictional forces generated between these two methods of ligation. 5,53 Others have reported that elastomeric ties produced less friction. 45 Another group of studies found stainless steel ligatures to show less friction. 54-57 The inability to obtain consistent results might be blamed on differences in experimental methods. 56 In addition, it is possible that the difficulty in controlling and maintaining ligating forces could be another cause of the inconsistency. 17 Stainless steel ligating forces have been reported to range between 0 and 300 grams, depending upon how tightly the 21
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 and 12: CHAPTER 1: INTRODUCTION The special
Page 13 and 14: CHAPTER 2: REVIEW OF THE LITERATURE
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 wire stiffness. As bracket widt
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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