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

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Abstract Few studies have evaluated the effect of wire-slot torque on sliding friction. Apparently, no studies have been published to date that compare friction across categories of self-ligating brackets when third-order positioning is controlled. The purpose of this study was to determine the effects of wire-slot torque and type of self-ligating bracket on the average kinetic friction in sliding mechanics with a 0.019- x 0.025-inch stainless steel archwire. Five sets of crown-attachments (including In-Ovation R, Time2, Damon 3MX, SmartClip and Victory brackets) were tested for frictional resistance in a simulated posterior dental segment with -15, -10, -5, 0, +5, +10, and +15 degrees of torque placed in the maxillary right second-premolar bracket. Increasing the torque from 0 to ±15 degrees produced significant increases of frictional resistance in all five of the tested attachment-sets. At 0 degrees of torque, the sets with passive self-ligating brackets produced less friction than the sets with active self-ligating brackets, and all four self-ligating bracket sets produced significantly less friction than the set with elastomerically ligated Victory brackets. At ±10 degrees
of torque, all five attachment sets displayed similar resistances with the exception of the In-Ovation R set at +10 degrees. At ±15 degrees of torque, the In-Ovation R and the SmartClip sets produced significantly larger frictional resistances than the other three sets. The data suggest that the presence of third-order torque can influence the kinetic frictional resistances in posterior dental segments during anterior retraction using sliding mechanics with self-ligating brackets and that frictional resistance will increase at a greater rate when the torque exceeds ±10 degrees with the present combination of sizes of slots and wire. Furthermore, whether a self- ligated bracket is active or passive may not be clinically significant regarding friction in the presence of torque approaching and exceeding 15 degrees.
Page 1: THE EFFECTS OF THIRD-ORDER TORQUE A
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 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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