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

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Results The data were analyzed using SPSS software, version 14.0 (SPSS, Inc., Chicago, IL). The mean frictional resistances and standard deviations thereof, associated with five individual crown-attachment sets and each of the seven torque values, are shown in Table 3-1. Figure 3-11 displays the mean frictional resistances from each of the crown-attachment sets; the seven means (associated with torque-angles) for an individual set are connected in order by straight lines. Significant differences in mean frictional resistances across pairs of third-order torque values from each set were statistically analyzed with the Mann-Whitney U test (Table 3-2). Kruskal-Wallis one-way analyses of variance and post-hoc Tukey comparisons determined significant differences (p < 0.05) between frictional resistances across the five crown-attachment sets at each of the seven torque angles and are presented in Tables 3-3 and 3-4. Actual test-archwire dimensions were determined to be equal to their nominal sizes. The average width and height of the wires were 0.0190 and 0.0250 inches, respectively. Neither +5 nor -5 five degrees of third-order rotation resulted in significant changes in frictional force from 62
aseline values at 0 degrees of torque with the exception of the SmartClip set, significantly greater at both the positive and negative torques, and the Time2 set, but only at +5 degrees of torque (Table 3-1). Increasing torque from 0 to ±10 degrees produced significant increases in frictional resistance from all four sets of self-ligating attachments (Table 3-2). Among the self-ligating sets, the In-Ovation R and the SmartClip sets showed significantly more friction from a further increase from both +10 to +15 and -10 to -15 degrees of torque; the Time2 set displayed a significant increase only from -10 to -15 degrees. The elastomerically ligated Victory sets showed the smallest overall increase in friction when torque-angle was increased, ranging from 303 grams at 0 degrees to 551 grams at -15 degrees. The SmartClip sets displayed the smallest mean frictional force of 55 grams at 0 degrees, but also provided the greatest resistance increase, producing a force of 744 grams at +15 degrees (Table 3-1). At +5, 0 and -5 degrees of torque, the Victory crown- attachment set generally produced significantly more friction than the four self-ligating sets; the single exception was the Time2 set at +5 degrees (Table 3-4). The Damon 3MX and SmartClip sets produced the smallest mean frictional forces at 0 degrees of torque. 63
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THE EFFECTS OF THIRD-ORDER TORQUE A
Page 3 and 4:
of torque, all five attachment sets
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COMMITTEE IN CHARGE OF CANDIDACY: A
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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: test-archwire in place and ligated,
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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