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

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produced about 40% to 45% less friction than slots of cast brackets. Ceramic brackets are a popular choice for many adults because of their esthetic appearance. Like stainless steel brackets, ceramic brackets are also available in multiple designs. Whether they (including the slots) are single- crystal sapphire, polycrystalline alumina or zirconia, these brackets have generally been found to produce more friction than stainless steel brackets with the same wires at nonbinding angulations. 4,25-27,36,51,54,80-82 Some investigators have not found a difference in frictional resistance between stainless steel and ceramic brackets. 35,83 In an effort to maintain the esthetic advantages of ceramic brackets, but reduce the friction potentials associated with them, some polycrystalline alumina brackets are manufactured with metallic slots. One of these, with a stainless steel slot, the Clarity bracket (3M/Unitek Corporation, Monrovia, CA), was compared by Cacciafesta’s group 36 with conventional ceramic and stainless steel brackets. They reported that the steel-slot/ceramic bracket produced less friction than the conventional all- ceramic bracket, but more than the stainless steel bracket with stainless steel, nickel-titanium alloy or ß-titanium alloy wires. Kusy and Whitley 84 found that both the Clarity 16
acket and the gold-lined Luxi bracket (Rocky Mountain Orthodontics, Denver, CO) exhibited frictional resistances similar to that of stainless steel brackets. In general, ceramic brackets with metallic slots were found to be acceptable alternatives to all-ceramic brackets. 36,84 Orthodontic brackets have been manufactured from other materials for various reasons. Esthetic plastic brackets are available with or without metallic inserts. These brackets have generally been found to produce less friction than ceramic brackets, although deformation with tight ligation (i.e., toward torque control) has been a problem. 7 Titanium brackets were introduced in response to concerns about corrosion and potential sensitivity to the nickel in stainless steel. These brackets were found to be very similar in frictional resistance to stainless steel brackets. 19,85 Bracket Width and Slot Size There is conflicting information in the literature as to the effect of bracket width on friction in the fixed appliance. Andreasen and Quevedo 44 measured the friction produced with three brackets of different slot widths and six wires at four second-order angulations and found no significant differences in frictional resistance across the 17
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: of round wire with the slot created
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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