Long-term skeletal effects of high-pull headgear plus fixed appliances: a cephalometric study

123 Pages·2016·3.86 MB·English

by  Eve Erin Bilbo

University of Iowa
Iowa Research Online
Theses and Dissertations
Spring 2014
Long-term skeletal effects of high-pull headgear
plus fixed appliances: a cephalometric study
Eve Erin Bilbo
University of Iowa
Copyright 2014 Eve Erin Bilbo
This thesis is available at Iowa Research Online: https://ir.uiowa.edu/etd/4578
Recommended Citation
Bilbo, Eve Erin. "Long-term skeletal effects of high-pull headgear plus fixed appliances: a cephalometric study." MS (Master of Science)
thesis, University of Iowa, 2014.
https://doi.org/10.17077/etd.7sp3222b
Follow this and additional works at:https://ir.uiowa.edu/etd
Part of theOrthodontics and Orthodontology Commons
LONG-TERM SKELETAL EFFECTS OF HIGH-PULL
HEADGEAR PLUS FIXED APPLIANCES:
A CEPHALOMETRIC STUDY

by
Eve Erin Bilbo

A thesis submitted in partial fulfillment
of the requirements for the Master of
Science degree in Orthodontics
in the Graduate College of
The University of Iowa

May 2014

Thesis Supervisor: Professor Thomas E. Southard
Graduate College
The University of Iowa
Iowa City, Iowa

CERTIFICATE OF APPROVAL

MASTER’S THESIS

This is to certify that the Master’s thesis of
Eve Erin Bilbo
has been approved by the Examining Committee
for the thesis requirement for the Master of Science
degree in Orthodontics at the May 2014 graduation.

Thesis Committee: ____________________________________
Thomas E. Southard, Thesis Supervisor

____________________________________
Steven Marshall

____________________________________
Nathan Holton
ACKNOWLEDGMENTS

I would like to thank Dr. Southard for being my mentor on this project. Your
investment in my education will never be forgotten. Thank you for always having an
open door to answer my questions and to provide help. You have an incredible teaching
ability, and I owe you a debt of gratitude for admitting me to this orthodontic program
where I have learned to love this field.
Thank you also to Dr. Marshall, for your willingness to share your vast
knowledge and for the kind way with which you do it. I also want to thank Dr. Holton,
who was essential to me being able to work through this project. Thank you for your
endless patience and kindness toward me.
I also want to thank Dr. Karin Southard, Dr. Allyn Thames, and Dr. Marlene
Sanabria, who laid the groundwork for this project, long before I became involved. Your
hard work was invaluable. Thank you, in addition, for allowing me to use your materials
for my thesis.
Finally, I want to thank my family, and especially, my wonderful husband,
Jonathan. Thank you for always being there for me and for being my “#1 fan” and my
support.

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TABLE OF CONTENTS

LIST OF TABLES……..……………………………………………..…………............. iv
LIST OF FIGURES……………………………………………………………………….v
INTRODUCTION………………………………………………………………………...1
LITERATURE REVIEW…………………………………………………………………4

Class II Malocclusion: What is it? ……………………………………………….4
Incidence of Class II Malocclusion………………………………………………..4
Etiology of Class II Malocclusion….……………………………………………...5
Class II Growth Compared to Normal Growth……………………………………6
Class II Treatment Options……..…………………………….…………………...8
Growth Modification……………………………………………………….……..9
Headgear……..…………………………………………………………………..10
Cervical-Pull Headgear…………………………………………………11
High-Pull Headgear………………………………………...…………..12
Functional Appliances…………………………………………………….……..17
Removable Functional Appliances………………………………………18
Herbst Appliance………………………………………………………...19
Summary…………………………………………………………………………21

MATERIALS AND METHODS………………………………………………...………23

Sample………………………………………………………………………....... 23
Cephalometric Landmarks………………………………….……………………27
Construction of X-Y Axis………………………………………………………..29
Landmark Assessment…………………………………………………………...29
Correction for Magnification of Cephalometric Measurements…………………34
Measurement Reliability…………………………………………………………35
Statistical Analysis……………………………………………………………….35

RESULTS………………………………………………………………………………..37

Initial Comparisons Between Control and Headgear Groups…………………....55
Angular Data Findings…………………………………………………………...55
Horizontal Data Findings………………………………………………………...75
Vertical Data Findings…………………………………………………………...80

DISCUSSION…………………………………………………………….......………... 82

CONCLUSIONS…………………………………………………………………....…..87

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REFERENCES……………………………………………………………………….. 89

APPENDIX…………………………………………………………………………… 94

Overview of Statistical Methods.....................................................................97

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LIST OF TABLES

Table 1: Total Control Group (n=21)…………..……………………………………… 24
Table 2: Total Headgear Group (n=21)…………...…………………………………… 25
Table 3: Initial Model Measurements for the Control Group……………………...…… 25
Table 4: Initial Model Measurements for the Headgear Group………………..………. 26

Table 5: Mean Cephlometric Angular Measures and Changes between Time
Points for the Control Group…………………………………………………... 37

Table 6: Mean Cephalometric Angular Measures and Changes between Time
Points for the Headgear Group……...………………………….……………... 40

Table 7: Mean Cephalometric Horizontal Linear Measures and Changes between
Time Points for the Control Group…………………………………………… 43

Table 8: Mean Cephalometric Horizontal Linear Measures and Changes between
Time Points for the Headgear Group…………………………………………. 46

Table 9: Mean Cephalometric Vertical Linear Measures and Changes between Time
Points for the Control Group………………………………………………… 49

Table 10: Mean Cephalometric Vertical Linear Measures and Changes between Time
Points for the Headgear Group…………………………………………….... 52

Table A1: Control Subjects Ages…………………………………………………….... 94

Table A2: Headgear Subjects Ages……………………………………………..……... 95

Table A3: Time Period Headgear Worn………...……………………………………... 96

Table A4: Time Period Elastics Worn………………………………………………..... 97

Table A5: Control Paired T-test Results…………………………………………….......99

Table A6: Headgear Paired T-test Results…………………………………………..... 103

Table A7: Two-Sample T-test Results...........................................................................107

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LIST OF FIGURES

Figure 1: Cephalometric Landmarks…………………………………………………... 28
Figure 2: X-Y Axis ...………………………………………………………………….. 31
Figure 3: Horizontal Measurements ……...……………………………………………. 32
Figure 4: Vertical Measurements …………………………………………………….... 33

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LIST OF GRAPHS

Graph 1: SNA Control ……………………………………………………………….... 56
Graph 2: SNA Headgear ………………………………………………………………. 56
Graph 3: SNA Control versus Headgear .…………………………………………….... 57
Graph 4: SNA Changes .……………………………………………………………….. 57
Graph 5: SNB Control …………….....………………………………………………… 58
Graph 6: SNB Headgear ….…………....………………………………………………. 59
Graph 7: SNB Control versus Headgear ....……………….……………………………. 59
Graph 8: SNB Changes………………………………………………………………… 60
Graph 9: ANB Control…………………………………………………………………. 61
Graph 10: ANB Headgear……………………………………………………………… 61
Graph 11: ANB Control versus Headgear……………………………………………... 62
Graph 12: ANB Changes………………………………………………………………. 62
Graph 13: U1 to SN Control…………………………………………………………… 63
Graph 14: U1 to SN Headgear…………………………………………………………. 64
Graph 15: U1 to SN Control versus Headgear…………………………………………. 64
Graph 16: U1 to SN Changes…………………………………………………………... 65
Graph 17: FMIA Control………………………………………………………………. 66
Graph 18: FMIA Headgear…………………………………………………………….. 66
Graph 19: FMIA Control versus Headgear…………………………………………….. 67
Graph 20: FMIA Changes……………………………………………………………… 67
Graph 21: FH to NA Control…………………………………………………………... 68
Graph 22: FH to NA Headgear………………………………………………………… 69
Graph 23: FH to NA Control versus Headgear………………………………………… 69
Graph 24: FH to NA Changes………………………………………………………….. 70
Graph 25: FMA Control………………………………………………………………... 71
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Graph 26: FMA Headgear..……………………………………………………………. 71
Graph 27: FMA Control versus Headgear……………………………………………... 72
Graph 28: FMA Changes………………………………………………………………. 72
Graph 29: SN-MP Control..……………………………………………………………. 73
Graph 30: SN-MP Headgear…………………………………………………………… 74
Graph 31: SN-MP Control versus Headgear…………………………………………... 74
Graph 32: SN-MP Changes……………………………………………………………. 75
Graph 33: Y-axis to A-pt Control……………………………………………………… 76
Graph 34: Y-axis to A-pt Headgear……………………………………………………. 76
Graph 35: Y-axis to A-pt Control versus Headgear……………………………………. 77
Graph 36: Y-axis to A-pt Changes……………………………………………………... 77
Graph 37: Y-axis to MxH Control……………………………………………………... 78
Graph 38: Y-axis to MxH Headgear…………………………………………………… 79
Graph 39: Y-axis to MxH Control versus Headgear…………………………………... 79
Graph 40: Y-axis to MxH Changes……………………………………………………. 80

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