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ABO’S OBJECTIVE GRADING SYSTEM APPLIED
TO THE ANDREWS CAST SAMPLE
Cristiana Vieira de Araújo, D.D.S.
An Abstract Presented to the Faculty of the Graduate School
of Saint Louis University in Partial Fulfillment
of the Requirements for the Degree of
Master of Science in Dentistry
2009
Abstract
Purpose: This study investigated the scores obtained according to the ABO’s Objective
Grading System from a sample of casts of untreated individuals who would not benefit
from orthodontic treatment, to verify if “Board quality” occlusions are spontaneously
achievable or not, as well as in which of the categories measured the most points were
deducted to indicate where most discrepancies take place naturally. Materials and
Methods: The ABO’s OGS was used to measure 106 cast sets of study models
(panoramic radiographs were not used) from the Andrews Education and Research
Foundation, by the investigator calibrated by an ABO examiner. No panoramic
radiographs were measured. The total number of deducted points determined whether a
case is said to have “passed” or not the certification exam. The total deducted points
dictated the grouping of cases. According to the OGS, case reports from which 19 or
fewer points are deducted usually “pass”, case reports from which 30 or more point are
deducted usually “fail”, and cases from which 20 to 29 points are deducted are generally
“undetermined” to pass. The descriptive statistics tests showed abnormal distribution of
the scores, indicating the need of nonparametric tests and correlation tests to assess each
component’s weight towards the total deductions. Mann-Whitney and Spearman’s tests
were respectively used. Results: The total deductions ranged from 6 to 39 points, with a
total mean deduction of 17.2 points (SD 5.5). Seventy seven cases “passed” with a mean
deduction of 14.7 (SD 3.2); two cases failed [mean deduction of 37.0 (SD 2.0)] and 27
cases fell into the “undetermined” category, with a mean deduction of 23.0 (SD 2.78).
‘Overjet’ contributed the most to the overall total deductions. In the “passed” group,
occlusal relationships weighted the most towards the total deductions and in the
“undetermined” group, mandibular buccolingual inclinations had significant weight.
Conclusions: “Board quality” occlusions may be observed naturally. There are
significant differences in the frequencies of the spontaneously occurring discrepancies,
most of which do not display a normal distribution. The total of deducted points,
however, may not reflect the true severity of the discrepancies in a given case, since the
data used with this system is of ordinal nature, and the discrepancies are not translated
into values, but categories.
ABO’S OBJECTIVE GRADING SYSTEM APPLIED
TO THE ANDREWS CASTS SAMPLE
Cristiana Vieira de Araújo, D.D.S.
A Thesis Presented to the Faculty of the Graduate School
of Saint Louis University in Partial Fulfillment
of the Requirements for the Degree of
Master of Science in Dentistry
2009
COMMITTEE IN CHARGE OF CANDIDACY:
Assistant Professor Donald R. Oliver,
Chairperson and Advisor
Assistant Clinical Professor Patrick F. Foley
Adjunct Associate Professor Kirk D. Satrom
i
To my parents.
ii
ACKNOWLEDGEMENTS
The following individuals need to be acknowledged, for without their help, this project
would not have been possible:
Dr. Oliver for his guidance, infinite support and thoughfulness,
Dr. Behrents for his insight,
Dr. Foley for his guidance, kindness and expertise,
Dr. Satrom for his time and comments,
Dr. Andrews for his imense generosity and hospitality,
Dr. Buschang for his statistic assistance and comments,
Dr. Tako Araújo for his comments, suggestions and support,
Drs. Sara Wolfe and Yi-Ping Liu for their friendship, support and endless
patience.
iii
TABLE OF CONTENTS
List of Tables …………………...….……………………………………………….…… v
List of Figures ..…………………………………………….……………….……….…viii
CHAPTER 1: INTRODUCTION ……………………………………………………….. 1
CHAPTER 2: REVIEW OF THE LITERATURE
Normocclusion …..………….………………………… ………… 3
Malocclusions
Angle’s Classification .…………………………………….… 7
Severity of malocclusions …………….……………….…..… 9
The PAR Index ……………………………………………. 12
ABO’s Discrepancy Index ………………………….……... 13
Evaluation of Treatment of Malocclusions …….………….….… 14
ABO’s Objective Grading System ………………………... 16
References ……………………………...….………………………… 26
CHAPTER 3: JOURNAL ARTICLE
Abstract ……………………………………………………………… 28
Introduction ……………………………….…………………….…… 30
Materials and Methods ………………………………………...….…. 32
Results ……………………………………………………………..… 36
Discussion …………………………………………………………… 46
Conclusions ………………………………………………………..… 50
Literature Cited ……………………………………………………… 52
Appendix A: Figures ………………………………………………………..………..… 53
Appendix B: Tables ………………………………...………………………………..… 67
Vita Auctoris …………………...…………….…………………………………..…. . 107
iv
LIST OF TABLES
Table 2.1: Qualitative methods of recording malocclusion …………………………... 10
Table 2.2: Quantitative methods for recording malocclusion ……………………….. 11
Table 3.1: Descriptive statistics and distribution of the “passed” group …………… . 40
Table 3.2: Descriptive statistics and distribution of the “undetermined” group .......… 42
Table 3.3:
Nonparametric statistics test results between the “passed” and “undetermined”
groups ……………………………………………………………………….. 43
Table 3.4:
Mann-Whitney’s Ranks for the “Passed” and “Undetermined” Groups … 44
Table 3.5:
Descriptive statistics and distribution of entire sample ………………...... 45
Table B1:
Intra-examiner Pearson’s correlation ……………………………………… 67
Table B.2: Spearman’s correlations between the Alignment and Rotations (maxillary)
and the other components for the entire sample ……………….…….… 68
Table B.3: Spearman’s correlations between the Alignment and Rotations (mandibular)
and the other components for the entire sample ….…………………..… 69
Table B.4: Spearman’s correlations between the Marginal Ridges (maxillary) and the
other components for the entire sample ……………………..….……… 70
Table B.5: Spearman’s correlations between the Marginal Ridges (mandibular) and the
other components for the entire sample ……………….……………..… 71
Table B.6: Spearman’s correlations between the Buccolingual Inclinations (maxillary)
and the other components for the entire sample ………….…….……… 72
Table B.7: Spearman’s correlations between the Buccolingual Inclinations (mandibular)
and the other components for the entire sample ….………………..…… 73
Table B.8: Spearman’s correlations between the Overjet and the other components for
the entire sample ………………………………………………...……… 74
Table B.9: Spearman’s correlations between the Occlusal Contacts (maxillary) and the
other components for the entire sample …………..…………….……… 75
Table B.10: Spearman’s correlations between the Occlusal Contacts (mandibular) and
the other components for the entire sample ……………….…………… 76
v
Table B.11: Spearman’s correlations between the Occlusal Relationships and the other
components for the entire sample ……………….…………………...… 77
Table B.12: Spearman’s correlations between the Interproximal Contacts (maxillary)
and the other components for the entire sample ……………….…… … 78
Table B.13: Spearman’s correlations between the Interproximal Contacts (mandibular)
and the other components for the entire sample ….…………………..… 79
Table B.14: Spearman’s correlations between the Total Points Deducted and the other
components for the entire sample ………………………...…….……… 80
Table B.15: Spearman’s correlations between the Alignment and Rotations (maxillary)
and the other components for the “passed” group …..………….……… 81
Table B.16: Spearman’s correlations between the Alignment and Rotations
(mandibular) and the other components for the “passed” group ….….… 82
Table B.17: Spearman’s correlations between the Marginal Ridges (maxillary) and the
other components for the “passed” group …………………..…..……… 83
Table B.18: Spearman’s correlations between the Marginal Ridges (mandibular) and
the other components for the “passed” group …………….…….……… 84
Table B.19: Spearman’s correlations between the Buccolingual Inclinations (maxillary)
and the other components for the “passed” group ……….……..……… 85
Table B.20: Spearman’s correlations between the Buccolingual Inclinations
(mandibular) and the other components for the “passed” group …..…… 86
Table B.21:
Spearman’s correlations between the Overjet and the other components for
the “passed” group ……………………………………………...…….… 87
Table B.22: Spearman’s correlations between the Occlusal Contacts (maxillary) and the
other components for the “passed” group ….……..…………….……… 88
Table B.23: Spearman’s correlations between the Occlusal Contacts (mandibular) and
the other components for the “passed” group …………….………….… 89
Table B.24: Spearman’s correlations between the Occlusal Relationships and the other
components for the “passed” group ……..……….…………………...… 90
Table B.25: Spearman’s correlations between the Interproximal Contacts (maxillary)
and the other components for the “passed” group ……………….…….. 91
Table B.26: Spearman’s correlations between the Interproximal Contacts (mandibular)
and the other components for the “passed” group ……………………… 92
vi
Table B.27: Spearman’s correlations between the Total Points Deducted and the other
components for the “passed” group ……………………...…….….….… 93
Table B.28: Spearman’s correlations between the Alignment and Rotations (maxillary)
and the other components for the “undetermined” group ……….……… 94
Table B.29: Spearman’s correlations between the Alignment and Rotations
(mandibular) and the other components for the “undetermined” group .. 95
Table B.30: Spearman’s correlations between the Marginal Ridges (maxillary) and the
other components for the “undetermined” group …..………..….……… 96
Table B.31: Spearman’s correlations between the Marginal Ridges (mandibular) and
the other components for the “undetermined” group …...….…………… 97
Table B.32: Spearman’s correlations between the Buccolingual Inclinations (maxillary)
and the other components for the “undetermined” group …...….……… 98
Table B.33: Spearman’s correlations between the Buccolingual Inclinations
(mandibular) and the other components
for the “undetermined” group ………………………………………….. 99
Table B.34: Spearman’s correlations between the Overjet and the other components for
the “undetermined” group ………………………..………….............… 100
Table B.35: Spearman’s correlations between the Occlusal Contacts (maxillary) and the
other components for the “undetermined” group …………….….….… 101
Table B.36: Spearman’s correlations between the Occlusal Contacts (mandibular) and
the other components for the “undetermined” group …….……...….… 102
Table B.37: Spearman’s correlations between the Occlusal Relationships and the other
components for the “undetermined” group ..…….…………………..... 103
Table B.38: Spearman’s correlations between the Interproximal Contacts (maxillary)
and the other components for the “undetermined” group ……….……. 104
Table B.39: Spearman’s correlations between the Interproximal Contacts (mandibular)
and the other components for the “undetermined” group …………….. 105
Table B.40: Spearman’s correlations between the Total Points Deducted and the other
components for the “passed” group ……………………...…………… 106
vii
LIST OF FIGURES
Figure 2.1: The American Board measuring gauge ……………………………..,…… 17
Figure 2.2:
Updated summary of the Objective Grading System’s criteria and
pertinent deductions ……………………………………………….……. 24
Figure 3.1: ABO cast-radiograph evaluation form …………………………………… 34
Figure 3.2: Grouping according to scores for entire sample
……………….……… 35
Figure 3.3: Mean deductions from each component for both groups .. ..…………….. 37
Figure A.1: Frequency of total points deducted ……………………………………… 53
Figure A.2:
Frequencies of points deducted from maxillary
“alignment and rotations” …………………………….………….…..… 54
Figure A. 3:
Frequencies of points deducted from mandibular
“alignment and rotations” …..……………………………………..…..… 55
Figure A.4:
Frequencies of points deducted from maxillary
“marginal ridges” ……………………………………………………..… 56
Figure A.5:
Frequencies of points deducted from mandibular
“marginal ridges” ……………………….……………………………… 57
Figure A.6:
Frequencies of points deducted from maxillary
“buccolingual inclinations” ……………………………………….….… 58
Figure A.7:
Frequencies of points deducted from mandibular
“buccolingual inclinations” ……………………………………….….… 59
Figure A.8: Frequencies of points deducted from “overjet”………..………………… 60
Figure A.9: Frequencies of points deducted from
“occlusal relationship”………………………………………..………… 61
Figure A.10: Frequencies of points deducted from maxillary
“occlusal contacts” ……………………………………………………… 62
Figure A.11: Frequencies of points deducted from mandibular
“occlusal contacts” …..……………………………………….…..……… 63
viii
Figure A.12: Frequencies of points deducted from maxillary
“interproximal contacts” ………..…………………………….…….....… 64
Figure A.13: Frequencies of points deducted from mandibular
“interproximal contacts” ……….………………………..…….………… 65
Figure A.14: Mean deduction per component grouped according to their final score:
“passed” vs. “undetermined” ………………………….………………... 66
ix
CHAPTER 1: INTRODUCTION
An understanding of normality assists one to recognize abnormalities and quantify
the degree of their severity, indicating what goals are to be attained in order to achieve
the result most approximate to normal standards.
An original sample of 120 sets of casts from untreated individuals was gathered
and described by Andrews1 as “nonorthodontic normal models”. They all displayed
straight teeth (in spite of not having had orthodontic treatment), pleasant looks,
“generally correct” bites and, in the author’s judgment, “would not benefit from
orthodontic treatment.” All of these casts also displayed six common features that the
author described as “the keys to normal occlusion”. The sample was further referred to in
the study as “the best in nature”.
Excellence in treatment finishing constitutes one of the fundamental goals of
orthodontics, which is to establish or reproduce a normal, healthy occlusion. During all
stages of treatment one should keep these goals in mind, providing a protected occlusion,
better aesthetics (both dental and facial), good periodontal health and long-term stability,
which are correlated to proper finishing.2
Proper finishing of orthodontic cases can be evaluated by a number of systems
developed for that purpose, and if done routinely in practice, may provide the
orthodontist with the chance to conduct self-assessment of his or her own work and,
hopefully, with it, opportunities to improve constantly. If one does not implement
systematic clinical protocols, one risks providing patients with incomplete or even
unsatisfactory treatment outcomes.3
1
The American Board of Orthodontics (ABO) has set standards that serve as
guidelines for adequate treatment finishing. Since 1999, it has implemented its Objective
Grading System (OGS) in Part III of the examination of orthodontists applying for
certification or re-certification. This system targets final panoramic radiographs and casts
utilizing calibrated examiners and a specially developed gauge for evaluating alignment,
marginal ridges, buccolingual inclination, occlusal relationship, occlusal contacts, overjet
and interproximal contacts (on the casts) and root parallelism (on the panoramic x-ray).
These criteria are used to determine if the candidate possesses adequate clinical skills to
be certified.2
If the above mentioned criteria for “Board-quality” treated cases are applied to
patients who do not need treatment, one would assume the scores to be satisfactory for
“passing”.
Would untreated normal occlusions, evaluated under the ABO’s OGS, obtain
“passing” scores? What criteria would hold the greatest range in results? What criteria
would weight the most towards the total?
2
CHAPTER 2: REVIEW OF THE LITERATURE
Normocclusion
Angle,4 the first to create a systematic classification for malocclusions, stated that
it was essential for one who intended to correctly diagnose malocclusion to be educated
regarding normocclusion. The familiarity with “normal or ideal occlusion of teeth” (along
with “normal facial lines”) should be such that one has these concepts “so fixed in the
mind as to form the basis from which to reason, and to intelligently note all deviations
from the normal”, otherwise taking the risk of conducting treatment as “the merest
empiricism”.4
In his description of “ideal” occlusion, Angle4 presented figures from which the
reader should observe the “graceful curve” described by the teeth in the arches, as those
teeth are “arranged as to be in the greatest harmony with their fellows in the same arch, as
well as with those in the opposite”.4 The author perceived the relative position of first
molars as being the “key” to occlusion. For normal occlusion to occur, the first molars
had to be arranged so that “the mesio-buccal cusp of the upper first molars received in the
sulcus between the mesial and distal buccal cusps of the lower, with the slight
overhanging of the upper teeth bringing the buccal cusps of the bicuspids and molars of
the lower jaw into mesio-distal sulci of their antagonists, while the upper centrals,
laterals, and cuspids overlap the lower about one-third the length of their crowns”. Angle4
also believed that each individual tooth’s structural morphologies was developed in order
to make “occlusion the one grand object, (…) that they may best serve the purpose for
which they were designed, – namely, the cutting and gridding of the food.” It was his
3
perception that any “irregularities” would disturb the function and aesthetics of this
mechanism.4
Haeger et al.5 developed an index for morphologic evaluation of dental
relationships. The Ideal Tooth Relationship Index (ITRI) was based on the visual
inspection for occlusal analysis according to the inclined planes, interproximal contacts,
occlusal contacts and the cusp to marginal ridges relationships, of 92 sets of casts of
orthodontic patients, at different times. The authors then presented a percentile
quantification of the ideal dental relationships found in the population studied: the initial
ITRI mean was 26%, improving to 52% at the end of treatment and continuing to
improve up to a mean of 59% during and after the observed retention period.
Additionally, they acknowledged the ITRI as a useful tool for analysis of assessment of
treated occlusions, closer to normal, and not the most adequate one for assessing the
severity of initial malocclusions, even suggesting indices such as the Occlusal Feature
Index, Treatment Priority Index, Handicapping Malocclusion Assessment Record as
“better” alternatives for the latter purpose. According to this study, treated cases present a
higher percentile of ITRI than naturally occurring good occlusions.5
In the classic article “The six keys to normal occlusion,” Andrews1 acknowledges
Angle’s “key” first molars occlusion concept as a guideline for orthodontic diagnosis, not
as “sine qua non of proper occlusion”. From observations in the clinical environment and
orthodontic meetings, Andrews1 noted that even occlusions displaying the mesiobuccal
cusp of the upper first permanent molars occluding with the mesiobuccal groove of the
lower permanent first molars, hence displaying the “vital cusp-embrasure relationship”
still exhibited other “inadequacies” after orthodontic treatment.
4
Over a period of four years, Andrews1 gathered a sample of 120 sets of models of
untreated individuals, which he considered to be “nonorthodontic normal models”. The
entire sample displayed straight teeth in spite of not having had orthodontic treatment,
was pleasant looking and had “generally correct” bites. In his judgment, the occlusions in
the sample “would not benefit from orthodontic treatment”, and he further referred to
those cases as “the best in nature”. More detailed observations, led the author to the
conclusion that the sample shared six common features. These features were:
1) Molar relationship - not only Angle’s “key” relationship had to be present, but
the distal surface of the distobuccal cusp of the upper first permanent molar had
“to contact and occlude with the mesial surface of mesiobuccal cusp of the lower
second molar. The mesiodistal cusp of the upper first permanent molar fell within
the groove between the mesial and middle cusps of the lower first permanent
molar”, while the canines and premolars should present buccal cusp-embrasure
and lingual cusp-fossa relationships. According to Andrews,1 even with Angle’s
buccal molar relationship present it is possible for abnormal occlusion to occur.
2) Crown angulation - the term ‘angulation’ was used to describe the desired
mesiodistal “tip” the crowns displayed along their long axis – not the teeth’s,
crowns’ only – so their occlusal portions were mesial to their gingival ones, and it
is suggested the degree of crown tipping displayed, especially in the maxillary
anterior teeth – due to the longer crowns, which dictates the amount of space teeth
take up, therefore, influencing the posterior occlusion.
5
3) Crown inclination – the term designated the buccolingual or labiolingual
inclinations – or crown “torque”. They vary according to the functional
morphology of particular groups of teeth.
4) Rotations – they were absent.
5) Spacing – no spacing was observed.
6) Curve of Spee - all the casts to display a flat or mild Curve of Spee.
Later, Andrews1 compared the untreated sample to another, referred to as “the
best in treatment results”— 1150 sets of final models from orthodontically treated
patients, displayed in orthodontic meetings and conferences. The above mentioned
features found in all the untreated cases from the sample were then validated: the
presence of all six of them constituted normal occlusions and the absence of even one of
them constituted a “defect predictive of an incomplete end result” in the treated sample.
Again, in his view, the sample designated as “best in nature” would not have any benefits
from orthodontic treatment.1 His observations later led him to the development of the
Straight Wire Appliance, in which the brackets were “preprogrammed” to position the
teeth closer to the ideal values previously obtained from his “naturally excellent
occlusion” sample, rather than the bends made in the wire determining their position.
Some of the advantages of this approach, in his view, included greater consistency and
exactness in the results, “optimizing” the later, bringing the end of an orthodontic case
closer (and faster) to ideal occlusion.6
Tahir et al.7 using the ITRI, in a retrospective study, evaluated the treatment
outcome of 90 ABO cases and compared, among other aspects, their occlusal changes to
147 naturally occurring good-to-excellent occlusions from the Andrews Foundation for
6
Education and Research. The treated sample displayed a marked increase in the
percentage of ideal tooth relationships, surpassing the Andrews sample “group scores in
all areas, except for anterior interarch relationships”, even though their study’s prediction
was that the treated sample scores “would approach but fall short” of the “best in nature
sample”. The Andrews sample mean total score was 47% (SD 9.98) and the ABO’s
sample, 64.5% (SD 8.58). The authors, however, stated the probability of a selection on
cases for the ABO, which could have influenced their higher scores, since the pattern of
distribution of the scores was very similar: anterior relationships scored higher than
posterior, buccal relationships higher than lingual relationships on the posterior segments
and anterior intraarch relations scored the highest. In theory, the 100% “perfect” ITRI
occlusion is possible, but rarely observed, neither as treatment result nor spontaneously.7
Malocclusions
Angle’s classification of malocclusions
Once Angle suggested the relationships present in a normal occlusion, he saw the
necessity in a “definite nomenclature” in orthodontics, stating it to be just as necessary as
in anatomy. The development of a classification system for malocclusions came to him as
a response to what he conceived as being “totally inadequate”, since they were indefinite,
not accurately indicating what needed to be addressed in order to correct the
malpositioning of teeth. Angle then suggested the classification of the seven possible
“malpositionings” (buccal, labial or lingual occlusion, mesial or distal occlusion, infra or
supra-occlusion and torso occlusion – teeth rotated on along their axis) and their
combinations to be as follows:
7
1) Class I: the relative sagittal positioning of the arches is correct (first
molars may display transverse malpositioning, though) and the irregularities are
usually displayed in the anterior segments of the arches, with great variation,
involving from a single tooth up to both whole arches.
2) Class II: abnormal relative sagittal positioning of the arches, in which
all mandibular teeth are distally placed compared to normal, resulting in
disharmony of the anterior region of the arches. This malocclusion can be
classified into two distinct divisions, and these have yet a subdivision each:
. Class II First division – Elongated and tapered upper arch with
protrusive incisors (…). Its subdivision presents itself with the
same, but less severe features of the First division, since only one
of the sides is in distal occlusion.
. Class II Second division – Upper incisors retruded, with crowding
(“bunching”) in a “slightly narrowed” upper arch. Its subdivision is
just as the described for the First division subdivision.
3) Class III: abnormal sagittal positioning of the jaws, in which “all the
lower teeth” occlude mesially to normal by “the width of one bicuspid, or even
more in extreme cases”. The teeth can be relatively aligned to displaying
“considerable bunching and overlapping, especially in the upper arch”, the lower
anterior segment is often retroclined. If the mesial occlusion to normal is only
observed in one of the sides of the arches, it is considered a subdivision case and,
therefore, less severe.4
8
The author briefly describes the possibility of yet another category, which
displays one side in mesial and the other in distal occlusion to the normal, but he
acknowledges its extreme rarity, and therefore, being unnecessary to describe it into
greater detail.4
Severity of malocclusions
Even with Angle’s own remarks about room for improvement of his classification
system, along with innumerous critiques, due to its simple objectivity and its aim –
prescribing treatment – it is, to date, since its first publication in 1899, the “standard”
orthodontic classification, being widely used and accepted system worldwide.8
Tang and Wei8 reviewed the pertinent literature regarding methods of recording
and measuring malocclusions, divided into either qualitative or quantitative ones. Their
summaries for the divisions and comparisons among the methods are displayed on Tables
2.1 and 2.2.
The authors compare and indicate the shortcomings of the various methods from
both types, pointing out the Occlusal Index (OI) as the least biased one and with the
highest correlations with clinical standards and with validity over time. The Grade Index
Scale for Assessment of Treatment is also described: a Swedish grading system based on
a deduction point system which can allocate the patients from very urgent need to little
need, but according to them, the criteria used was vague. At the time of this comparison,
few studies had been conducted using the Index of Orthodontic Treatment Need (IOTN),
in which a combination of dental health components (traits to which are attributed
“longevity and satisfactory functioning of the dentition”) with five grades and a aesthetic
9
scale (in which 10 points are associated with the series of attractiveness-ratedphotographs that illustrate it). They found that this index had satisfactory validity and
reproducibility, but had not been applied to diverse populations.7
Table 2.1: Qualitative methods of recording malocclusion (modified from Tang and Wei7)
Author
Year
Features
Angle
1899
Stallard
1932
McCall
1944
Sclare
1945
Fisk
1960
Björk, Krebs
and Solow
1964
Proffit and
Ackerman
1973
WHO/FDI
1979
Kinaan and
Bruke
1981
Classification of molar relationship interpreted guideline and as a prescription for
treatment.
General dental status, including some malocclusion symptoms, but without
specific definitions of the later items
Recorded malocclusion “symptoms”: molar relationship, post. cross-bite, ant.
crowding, rotated incisors, excessive overbite, open bite, labial or lingual version,
tooth displacement, constriction of arches, but no definition of the symptoms were
specified, and the recording was gradually undiscerning, being entered in an “allor-none” fashion
Specific malocclusion “symptoms” recorded: Angle’s molar classification, arch
constriction with or without incisor crowding, upper protrusion with or without
incisor crowding, upper constriction without incisor crowding, labial prominence
of canines, lingually placed incisors, rotated incisors, crossbite, open bite and close
bite.
Classification into the four dimensions of malocclusions, since dental age was
used for grouping patients (time) and the three planes of space were observed:
1) Sagittal relationship: Angle’s classification, ant. Crossbite and overjet;
2) Transverse relationship: post. cross-bite (max. teeth occluding either lingually
or buccally to mand.); 3) Vertical relationship: overbite (+ or -)
Objective registration of malocclusion symptoms based on detailed definitions.
Computerized analysis of data. Possessed 3 parts: 1) Anomalies in the dentition:
tooth anomalies, abnormal eruption, malalignment of individual teeth; 2) Occlusal
anomalies: deviations in the positional relationship between upper and lower dental
arches in all three planes; 3) Deviations in space conditions: spacing or crowding
Five-step protocol for assessing malocclusions (no definite criteria was given):
1) Alignment: Ideal, crowding, spacing, mutilated; 2) Profile: mandibular
prominence or recession, lip profile to nose and chin (convex, straight, concave);
3) Crossbite: inter-arch relationship in the transverse plane; 4) Angle’s sagittal
plane classification; 5) Bite depth: inter-arch vertical relationships
Five major groups of items were recorded, under well defined recording criteria:
1) Gross anomalies; 2) Dentition: agenesis, supranumerary, malformed incisor,
ectopic eruption; 3) Space conditions: diastema, crowding, spacing
4) Occlusion: a. incisal segment: max. overjet, mand. overjet, cross-bite, overbite,
midlines OR b. lateral segment: sagittal relations, open bite, post. cross-bite;
5) Orthodontic treatment need judged subjectively: not necessary, doubtful,
necessary, urgent.
Five characteristics measured: 1) Overjet; 2) Overbite; 3) Post. cross-bite (# of
teeth in cross-bite, uni or bilateral); 4) Buccal segment crowding or spacing;
5) Incisal segment alignment (acceptable, crowed, spaced, displaced, or rotated,
following defined criteria)
10
Table 2.2: Quantitative methods for recording malocclusion (modified from Tang and
Wei7)
Author
Year
Features
Massler and Frankel
1951
Malalignment index
by Vankirk and
Pennell
Handicapping
labiolingual deviation
index by Draker
1959
Occlusal feature index
by Poulton and
Aaronson
Malocclusion severity
estimate (MSE) by
Grainger
1961
Occlusal index (OI)
by Summers
1966
Treatment priority
index (TPI) by
Grainger
1967
Handicapping
malocclusion
assessment record
(HMAR) by
Salzmann
1968
Count the number of teeth displaced or rotated. Assessment of tooth
displacement and rotation is qualitative – all or none.
Tooth displacement and rotation were measured, then defined
quantitatively: <1.5mm or > 1.5 mm. Tooth rotation defined quantitatively:
<45o or >45o.
Measurements include cleft palate (all or none), traumatic deviations (all or
none), overjet (mm), overbite (mm), mand. protrusion (mm), ant. open bite
(mm), and labiolingual spread (a measurement of tooth displacement in
mm).
Measurements include lower ant. crowding, cuspal interdigitation, vertical
overbite, and horizontal overjet. Occlusal features measured and scored
according to defined criteria.
Seven weighted and defined measurements: 1- Overjet, 2- Overbite, 3- ant.
open bite, 4- agenesis of max. incisors, 5- first permanent molar
relationship, 6- pot. Crossbite, 7- tooth displacement (actual and potential).
Six malocclusion syndromes were defined: 1)positive overjet and anterior
open bite. 2) Positive overjet, positive overbite, distal molar relationship,
and post. crossbite w/ max. teeth buccal to mand. teeth. 3) Negative overjet,
mesial molar relationship, and post. crossbite w/ max. teeth lingual to mand.
teeth. 4) Congenitally missing max. incisors. 5) Tooth displacement.
6) Potential tooth displacement.
Nine weighted and defined measurements: 1- Molar relation, 2-overbite,
3-overjet, 4-post. crossbite, 5- post. open bite, 6- tooth displacement, 7midline relation, 8- max. median diastema, 9-agenesis of max. incisors.
Seven malocclusion syndromes defined: 1)Overjet and open bite. 2)Distal
molar relation, overjet, overbite, post. crossbite, midline diastema, and
midline deviation. 3) Agenesis max. incisors. 4) Tooth displacement (actual
and potential). 5) Posterior open bite. 6) Mesial molar relation, overjet,
overbite, post. crossbite, midline diastema, and midline deviation 7) Mesial
molar relation, mixed dentition analysis (potential tooth displacement), and
tooth displacement.
For all the above criteria, dental development stage was taken under
consideration (deciduous, mixed and permanent).
Eleven weighted and defined measurements: 1- upper ant. segment
overjet, 2- lower ant. segment overjet, 3- overbite of upper ant. over lower
ant., 4- ant. open bite, 5- agenesis of incisors, 6- distal molar relationship,
7- mesial molar relation, 8- buccal post. crossbite, 9-lingual post. crossbite,
10- tooth displacement, 11-gross anomalies.
Seven malocclusion syndromes were defined: 1- max. expansion
syndrome, 2- overbite, 3- retrognathism, 4- open bite, 5- prognathism,
6- max. collapse syndrome, 7- agenesis of incisors.
Weighted measurements consist of three parts:
1) Intraarch deviation – agenesis, rotation, spacing, crowding.
2) Interarch deviation – overjet, overbite, crossbite, open bite,
mesiodistal deviation.
3) Six handicapping dentofacial deformities: 1- Facial and oral clefts,
2-lower lip palatal to maxillary incisors, 3-occlusal interference,
4-functional jaw limitation, 5- facial asymmetry, 6- speech
impairment. (This part can only be assessed on life patients.)
1960
1960
1961
11
The PAR Index
Even though a number of indices had been developed and used to assess the type
and the severity of malocclusions as well as treatment outcomes, no “universal”
consensus had been reached, not one enabling reliability and reproducibility of the
assessments by either the same or different examiners, since they lacked “uniform
interpretation and application of the criteria”.9
The British Orthodontic Standards Working Party composed of ten experienced
orthodontists analyzed more than 200 dental casts in different stages of development as
well as pre-treatment and post-treatment ones, projected on screens, allowing the party to
view and discuss the cases at the same time, until they agreed upon the characterization
of the presented features of the cases in form of estimations of occlusal alignment. In this
way, the Peer Assessment Rating Index (PAR Index) was developed, providing “a single
summary score for all the occlusal anomalies which may be found in a malocclusion.”
The PAR Index indicates estimations of how much of a deviation from normal alignment
and occlusion a case displays, these being defined “as all anatomical contact points being
adjacent, with a good intercuspal mesh between upper and lower buccal teeth, nonexcessive overjet and overbite,” observed on its eleven component: upper right segment,
upper anterior segment, upper left segment, lower right segment, lower anterior segment,
lower left segment, right buccal occlusion, overjet, overbite, centerline and left buccal
occlusion. Subtracting pre treatment scores from post ones indicate the “degree of
improvement” or “success of treatment,” in a uniform standardized fashion.9
12
ABO’s Discrepancy Index
Orthodontists interested in obtaining ABO certification must take its exams. The
ABO’s main goal-clinical excellence-since Ketcham founded it in 1929, along with a few
colleagues who shared this vision clinical excellence, because few programs were
associated with university education but rather most training took the form of
preceptorships or took place in proprietary schools. Those men saw the need for
establishment of “national standards for orthodontists through a testing process.” Their
ideals of standardization aimed at the delivery of higher quality orthodontics. These
ideals were presented as part of the Board objectives for certification in the very the first
application form: “to elevate the standards of the practice of orthodontia; to familiarize
the public with its aims and ideals; to protect the public against irresponsible and
unqualified practitioners.” The ABO has been associated with high standards in clinical
orthodontics since its beginning, and has kept this association, more recently, by means
of re-certification throughout a practitioner’s career.10 Board certification does not
provide legal standing, nor may it be used as a promotional tool for the orthodontist
bearing it. The perceived benefits of being certified vary from individual to individual,
but they seem “couched in the ethical fiber of our specialty,” additionally, it is thought
one would become a better clinician than he or she was before pursuing Board
certification.11
As one becomes more familiar with what is involved in the certification process,
one begins to understand the reasoning for the development of an ABO Discrepancy
Index (DI), as a way of measuring case complexity, which is a determinant feature for
cases presented for Phase III examination. Even though the difficulty in treating a case is
13
subjective, the complexity of a case, if measured by number and severity of the elements
varying from normal, is quantifiable. In the attempt to test the applicant’s clinical skills as
well as to standardize the types of cases presented, the ABO’ DI is made of “clinical
entities that are measurable and have generally accepted norms” as overjet, overbite,
anterior open bite, lateral open bite, crowding, occlusion, lingual posterior crossbite,
buccal posterior crossbite, ANB angle, IMPA and SN-GoGn angle. These elements and
their combination can objectively describe a malocclusion. And the greater number of
elements present in a case, along with the greater their absolute values are, the more
complex the case is, implying in a more difficult or “challenging” treatment.12 An
applicant for Initial Board Certification must submit, for Case Report Examination,
besides 6 other specified cases, 3 cases with DI equal or greater than 10 and 3 cases with
DI equal or greater than 20.13
Evaluation of treatment of malocclusions
While the PAR Index is useful for assessment of pre- and post- orthodontic casts,
Eismann14 developed a method to analyze the efficiency of treatment, evaluating fifteen
criteria:
a) crowding or spacing of incisors (per jaw)
b) crowding or spacing of posterior teeth (per side and jaw)
c) vestibular eruption of canine (per side and jaw)
d) rotation of incisors
e) axial inclination of teeth
f) overbite
14
g) frontal open bite (including canines; per 1-2 pairs of opposite teeth)
h) open bite of posterior teeth (per pair of opposite teeth)
i) overjet
j) crossbite of two opposite teeth in the frontal region (including canines)
k) anteroposterior occlusion of posterior teeth (per side and jaw)
l) deviation between the midline of the dental arch and the raphe palatine
mediana
m) deviation between the midlines of the upper and lower jaws
n) deviations in the transverse occlusion of posterior teeth (per jaw).
Each criterion after being measured is compared to tables of values the
investigators considered to be normal, and then a score in points is given to it. The final
score is obtained by adding the individual scores and the total represents the “extent of
the morphological abnormality.”14
Gottlieb3 attempted to develop a grading system for the orthodontist to use
routinely in practice, being a tool for self-assessment. He suggested a “specific and
simple grading system” to encourage its use. The treatment features selected were a
variation of the list of used by the Eastern Association of Strang Tweed Study Groups,
consisting of characteristics commonly used to assess orthodontic correction, which are:
Class I molar and cuspid relationships, cusp interdigitation, overbite, overjet, midline,
rotation, crowding or spacing, arch form, and torque and parallelism.
For each of the above mentioned features, the following grades were assigned: 5
points were attributed if the condition was corrected, 3 if almost corrected, 1 if half way
corrected, zero if not corrected and -1 point was given if the condition worsened as result
15
of treatment. The scoring is then recorded in a chart, comparing side-by-side pre- and
post-orthodontic values for the casts. Five is given to the initial characteristic in need of
correction, and zero if no correction is required. The next column holds the values as
described above for the treated casts.3
The total values are added in each column. The pre-treatment values are the
maximum possible score from which the added post-treatment values can reach, so that if
every issue was corrected, the correction would be of 100%. The quantified correction
percentile is then classified: if 85% or better is of the correction needed is achieved, the
result is good. Between 75% and 85%, the result is satisfactory, between 65% and 75%,
mediocre, 50% and 65% is a poor result and if less than 50% of the needed correction
was obtained, the result is unsatisfactory.3
Widely based on Eismann’s and Gottlieb’s methods, even if for the ABO these
methods lacked the precision and their reliability and validity had yet to be tested, hence
not meeting its needs, the institution developed the Objective Grading System (OGS) for
dental casts and panoramic radiographs for the Part III of the certification (or recertification) exam process. The OGS is similar to the ITRI, since both strict analyses are
“based on the number of ideal tooth relationships,” but the latter method accounts solely
for the presence or absence the relationship and the former takes under consideration
some degree of its severity.
The ABO, since 1999, has applied its OGS to evaluate treatment outcomes of the
applicants, in order to attest the quality standard of the treatment provided, and therefore,
the standard of the candidate to receive its certification.2 The ABO examiners evaluate
seven criteria in each set of the final casts of the case reports turned in, with the aid of a
16
specifically designed gauge (Figure 2.1), and root parallelism on the panoramic
radiographs. The criteria analyzed by the Board committee provide specific guidelines for
what the orthodontist should be striving for in a treatment, and their achievements
indicate the completion of treatment or not.2
2
1
4
3
4
Figure 2.1: The American Board of Orthodontics measuring gauge.
Fig. 2.1: ABO measuring gauge. 1: Used to measure alignment, overjet, occlusal contacts, interproximal
2
the
criteria
bewide.
evaluated
and
Casko et al.,the
contacts According
and occlusaltorelationships,
‘1’ following
portion of the
gaugeshould
is 1 mm
2: Used
to scored
measure
mandibular posterior buccolingual inclination, the ‘2’ portion displays 1 mm high “steps”. 3: Used to
measure
discrepancies
in marginal
ridges, the ‘3’ portion has 1mm high “steps”. 4: Used to measure
on the OGS
(see Table
2.3 for summary):
discrepancies in maxillary posterior buccolingual inclination, the ‘4’ portion has 1 mm high “steps”.
(Extracted and modified from the ABO website: www.americanboardortho.com)
The alignment, according to the ABO, should be of the incisal edges along with
the lingual surfaces for the upper, and labial surfaces for the lower serving as guidelines
for anterior segments alignment; posteriorly, the upper arch alignment is dictated by the
proper arrangement of the mesiodistal central groove of the premolars and molars, and
the lower arch alignment is indicated by the correct position of the premolars and molars
buccal cusps. The mandibular posterior quadrants are aligned if “the mesiobuccal and
distobuccal cusps of the molars and premolars” are in the same mesiodistal alignment;
17
the posterior segments of the maxillary arch are aligned if mesiodistal central grooves are
contained in the same plane.
Marginal ridges should all be at the same level in the posterior segments, provided
the patient has no “restorations, minimal attrition and no periodontal bone loss”,
indicating that the cementoenemal junctions are also leveled and bone levels are at the
same height. Besides having them leveled provides easier establishment of occlusal
contacts, since some are the actual “contact for the opposing cusps.”
Buccolingual inclination is measured to assess the applicant’s capacity to control
“torque” of the posterior teeth, assuring proper occlusion in maximum intercuspation,
with little difference in projection of buccal and lingual cusps, avoiding interferences in
excursion.
Occlusal relationship is used to assess the relationship of posterior upper and
lower dentitions in the sagittal plane, and it is measured according to Angle’s system,
along with occlusal contacts, they indicate the establishment of proper maximum
intercuspation of opposing teeth. Overjet is measured to assess the sagittal relationship in
the anterior teeth, and transverse on the posterior, and interproximal contacts must be
present and tight, indicating that all spaces within the arches are closed.2
The actual grading or scoring deducts 1 point for each contact point out of
alignment by 0.5 and 1 mm, if the misalignment is greater than 1 mm, then 2 points are
subtracted for it. “No more than 2 points shall be subtracted for any tooth,” and their
sum is then subtracted from the 64 points of the alignment score. The marginal ridges
should be at the same level or within 0.5 mm of irregularity without any penalization, if
the ridges are unleveled by 0.5 to 1 mm, 1 point is subtracted for that interproximal
18
contact. If the discrepancy is greater than 1 mm, 2 points are subtracted. Again, “no
more than 2 points will be subtracted for any contact point” and the sum of the
deductions is then subtracted from 32, the marginal ridges score. The buccolingual
inclinations of upper and lower posterior teeth are measured with the flat surface of the
gauge extended between the occlusal surfaces of both sides, so that its straight edge
should contact the buccal cusps of the lower molars and their lingual cusps should be
within 1 mm gingivaly located, and the opposite should take place in the upper arch, so
that the lingual cusps of molars and premolars are in the same level and their buccal
cusps are within 1 mm gingivaly positioned. If the discrepancies among the cusps
projections are between 1 to 2 mm, 1 point is deducted for that tooth, if greater than 2
mm, 2 points are deducted, but “no more than 2 points shall be subtracted for any
tooth”. The sum of deducted points is then subtracted from 40 – the score for posterior
torque. The anteroposterior occlusal relationship should fall with or within 1 mm of
Angle’s Class I. If there is a deviation between 1 and 2 mm in the previously described
relationships, 1 point is subtracted per tooth; if the deviation is greater than 2 mm, 2
points, the maximum deductable per tooth, are deductable. Their sum is then subtracted
from 24 – the occlusal relationship score. For the occlusal contacts, if a functioning
posterior cusp is not contacting the opposing arch by a distance lesser than 1 mm, 1
point is deducted, if the distance is greater than 1 mm, 2 points (the maximum of
deductable points per tooth) are deductable. The sum of these deducted points is then
subtracted from 64 points – the total score for occlusal points. For scoring the overjet, if
there is a distance between the buccal lower cusps and the center of the occlusal surface
and it is lesser than 1 mm, 1 point is deducted per tooth, if greater than 1 mm, then 2
19
points are deducted; the same score takes place for the anterior overjet: if there is a
distance lesser than 1 mm between lower canines and incisors in relation to the lingual
surface of the upper canines and incisors, 1 point is also deducted per tooth; if the
distance is greater than 1 mm, then 2 points are deducted per tooth, and the maximum
deduction is also 2 points per tooth. The sum of the deductions is then subtracted from
32, giving the overjet score. The assessment of interproximal contacts is made from an
occlusal view of the models, if no interproximal contact is observed between two teeth
and the space is up to 1 mm, 1 point is deducted for that contact, if greater than 1 mm,
than 2 points are deducted, but no more then 2 points are deducted from a contact. The
sum of the deducted points is then subtracted from 60, providing the interproximal
contacts score. Panoramic radiographs are to evaluate the final position of the roots,
which should be parallel to one another. One point is deducted if a tooth displays its root
out of parallelism and 2 points if roots are converging to the point of being “touching”.4
Similarly to the PAR index, the OGS presents for each criterion, graduating
degrees of deviation from a normal value and also consists of independent scoring for
each tooth or contact within the dentition, which accumulate for each criterion and
further for a final score. No tooth or contact may lose more than two points per criterion.
But, unlike the PAR index, weighting between the eight criteria is only based the total
number the designated elements for a criterion, in the permanent dentition. So, “it could
be argued that by having criteria with different maximum scores, the several criteria
with lower possible deduction scores such as occlusal relationship (with a maximum
score of 24) are inherently weighted in the total compared to others such as alignment
(with maximum score of 64).” No reference was made as to this trait being intentional
20
or not during the design of the OGS. However, the ABO defined the OGS as a pass/fail
treatment outcome evaluation.15
A perfect case, with no deductions, would score a total of 380 points. The ABO
reports that a total score of 350 or lower (≤ 92.1%) on a case report is a failure – “that
loses more than 30 points will fail”. Case reports with a total score of 361 or greater (≥
94.7%) will usually pass this particular portion of the certification process, with a
deduction up to 19 points. And total scores between and including 351 (92.3%) to 360
(94.5%), from which 20 to 29 points were deducted, are considered acceptable if the
quality of the records and treatment plan are acceptable: other aspects evaluated on the
Phase III of the examination are the quality of the presented records, the assertiveness of
the treatment plan as well as the planned positioning of the maxillae, upper and lower
dentitions and soft tissue alterations, which are all “carefully scrutinized”.2
Waters15 hypothesized a correlation between subjective evaluation and the ABO
grading system, but then rejected it. In testing the validity of the OGS utilizing a visual
analogue scale (VAS) from poor to excellent for each criterion and then the OGS itself,
three groups (Board certified orthodontists, non-Board certified orthodontists and
second-year graduate orthodontic residents from Saint Louis University) were asked to
measure a blinded sample of consecutively finished cases from the program, previously
measured by the primary investigator. Even though a number of significant correlations
between the groups’ scores and the investigator’s were encountered, “the reliability was
poor for all the observed criteria.” Therefore, the study was unable to validate the OGS
due to “a general lack of concordance between judges’ perceptions of grading scales” or
21
the VAS scales. However the author found the OGS to be “reliable, objective, and
relatively easy to learn”.15
The ABO’s Objective Grading System criteria were developed to evaluate
orthodontic treatment outcomes, and were based on a number of works which describe
classifications systems of malocclusions and how to evaluate their correction after
orthodontic treatment is performed. The most recent update in these took place in June,
2008, according to the ABO’s website, and they are summarized in Figure 2.2.
When analyzing the obtained data from cases to be scored by the Objective
Grading System, one must: 1) acknowledge the nature of the data related to each of
criterion observed, 2) each criterion has a specific number of possible points to be
deducted, depending on the number of possible discrepant elements present at their
maximum severity level, leading to a maximum 2 point deduction, regardless of the
magnitude of the discrepancy. As explained by Cook16 “for example, marginal ridges at
the same level or within 0.5 mm would not receive a deduction, marginal ridges that
deviate from 0.5 mm to 1 mm receive a one-point deduction, and marginal ridges that
deviate greater than 1 mm receive a two-point deduction.” In this fashion the obtained
data is of ordinal nature: since there are only three categories for scoring a given
relationship, no points deducted if discrepancy is absence or within the first established
deviation, 1 point is deducted if the discrepancy is within the second established
deviation and 2 points are deducted is the discrepancy is within or over the third
deviation, so that the severity of a discrepancy is not translated into the points deducted
on the third deviation, as it would have to be, had their nature been interval or ratio. The
deducted points from each category are added up for towards the final score: summing
22
ordinal data is inappropriate, and “the ABO treats this data as interval/ratio for
convenience of scoring”. When utilizing the OGS to evaluate the overall quality of a
case or to compare cases, one must understand that the total final score may not
accurately indicate the true severity present in a case, requiring careful interpretation of
the results.16
One of the objectives of an investigation conducted by Yang-Powers et al.17 was
“to assess the contribution of each of the 8 components of the OGS to the total OGS
score” from a sample of 92 cases finished at the University of Illinois at Chicago and 32
cases previously presented to the ABO from five Board-certified orthodontists (14 had
been evaluated with the OGS, having the ABO cases later divided into pre and postOGS) from the Chicago area. In the university group, the highest mean deduction was
on the buccolingual inclination criterion at 9.42 (SD 5.03) and the lowest mean
deduction, the interproximal contacts at 0.64 (SD 1.22). For the ABO group, the highest
mean deduction was on the buccolingual inclination criterion as well at 7.91 (SD 4.79),
and the lowest mean, at 0.38 (SD 0.66), on the interproximal contact criterion also. The
mean for alignment was 7.31 (SD 4.34), for occlusal contact was 2.47 (SD 3.30), for
overjet, 5.06 (SD 3.37), and for marginal ridges, 3.16 (SD 3.25). Significant differences
(P < .05) between the groups were observed for the occlusal contact, overjet, panoramic
radiograph and total score components. The total mean deduction for the university
group was 45.54 points, and 33.88 was the mean for the ABO group. Only 18 out of the
92 university cases, 19.6%, scored 30 or less points, and only 15 (46.9%) of the 32 ABO
cases scored alike. The pre-OGS ABO group, 18 cases, only 7 (38.9%) would have
achieved similar score, while among the 14 post-OGS cases, 11 (78.6%) did so. The
23
authors observed an improvement of about 40% in the total scores, comparing the postOGS cases to the pre-OGS ones.17
Cast/Radiograph Evaluation
June/2008
ALIGNMENT/ROTATIONS
0.5 – 1 mm = 1 for each tooth
> 1 mm = 2 for each tooth
BUCCOLINGUAL INCLINATION**
0 - 1 mm = satisfactory
1 - 2 mm = 1 ( for each posterior tooth)
> 2 mm = 2
** Do not score the mandibular 1st premolars
OCCLUSAL CONTACTS***
Contact = satisfactory
< 1 mm = 1 ( for each posterior
> 1 mm = 2 tooth out of contact)
INTERPROXIMAL CONTACTS
0.5 - 1 mm = 1 ( for each interproximal contact)
> 1 mm = 2
MARGINAL RIDGES*
0.5 - 1 mm = 1 ( for each interproximal contact
> 1 mm = 2 between posterior teeth)
OVERJET
< 1 mm = 1 ( for each maxillary tooth)
> 1 mm = 2
* The canine-premolar contact is not to be
considered
The distal of lower 1st premolar is not to be
included
OCCLUSAL RELATIONSHIP
< 1 mm = satisfactory
1 - 2 mm = 1 (for each maxillary tooth from the
> 2 mm = 2 the canines to the 2nd molars)
ROOT ANGULATION
Parallel = 0
Not parallel = 1
Root contacting
adjacent root = 2 ( for each occurrence )
Maxillary and mandibular canines are not to be scored.
NOTE: Gauge Width is 0.5 mm; Gauge Height is 1 mm
Third molars are not scored unless they substitute for the second molars.
Figure 2.2: Updated Summary of the Objective Grading System’s Criteria and Pertinent
Deductions (extracted and modified from the ABO website: www.americanboardortho.com)
Having in mind that the primary objective of an orthodontic treatment is to
provide the patient with a functional occlusion and esthetic harmony by emulating the
24
normal features (or assumed normal features) one should be aware that the primary
emphasis of the Board examination is to evaluate the end result, and thus, the
candidate’s clinical competency. Questions to be asked are: would an individual with
naturally normal occlusion have the passing OGS score as if he or she were treated
patients? Are the criteria considered to be orthodontic treatment goals applicable to
evaluate the occlusion of an individual who does not require orthodontic treatment? Is
the ABO’s OGS is a tool for assessment of good occlusions in general or just for the
ones which result from orthodontic treatment and hence had the ABO standards as
guidelines?
25
References
1. Andrews, LF. The six keys to normal occlusion. Am J Orthod 1972;62:271-309.
2. Casko, JS, Vaden JL, Kokich VG, Damone J, James RD, Cangialosi TJ, Riolo ML,
Owens SE, Bills ED. Objective grading system for dental casts and panoramic
radiographs. Am J Orthod Dentofacial Orthop 1998;114:589-99.
3. Gottlieb EL. Grading your orthodontic treatment results. J Clin Orthod 1975;9:155-61.
4. Angle, EH. Classification of Malocclusion. Dental Cosmos 1899; 248-64, 350-57.
5. Haeger, RS, Schneider BJ, BeGole EA. A static occlusal analysis based on ideal
interarch and intraarch relationships. Am J Orthod Dentofacial Orthop 1992;101:459-64.
6. Andrews, LF. The straight wire appliance. Br J Orthod 1979;6:125-43.
7. Tahir E, Sadowsky C, Schneider BJ. An assessment of treatment outcome in American
Board of Orthodontics cases. Am J Orthod Dentofacial Orthop 1997;111:335-42.
8. Tang, ELK, Wei, SHY. Recording and measuring malocclusion: a review of the
literature. Am J Orthod Dentofacial Orthop 1993;103:344-51.
9. Richmond S, Shaw WC, O’Brien KD, Buchanan IB, Jones R, Stephens CD, Roberts
CT, Andrews M. The development of the PAR index (Peer Assessment Rating):
reliability and validity. Eur J Orthod 1992;14:125-39.
10. Riolo ML, Owens SE, Dykhouse VJ, Moffitt AH, Grubb JE, Greco PM, English JD,
Briss BS, Cangialosi TJ. A change in the certification process by the American Board of
Orthodontics. Am J Orthod Dentofacial Orthop 2005;127:278-81.
11. American Journal of Orthodontics. The benefits of certification by the American
Board of Orthodontics. Am J Orthod Dentofacial Orthop 1999;116:110.
12. Cangialosi TJ, Riolo ML, Owens SE Jr., Dykhouse VJ, Moffitt AH, Grubb JE, Greco
PM, English JD, James RD. The ABO discrepancy index: A measure of case complexity.
Am J Orthod Dentofacial Orthop 2004;125:270-78.
13. Dykhouse VJ, Moffitt AH, Grubb JE, Greco PM, English JD, Briss BS, Jamieson SA,
Kastrop MC, Owens SE. ABO initial examination: official announcement of criteria. Am
J Orthod Dentofacial Ortho 2006;130:662-65.
14. Eismann D. A method of evaluating the efficiency of orthodontic treatment.
Transactions of the European Orthodontic Society 1974;223-32.
26
15. Waters, J. Evaluation of orthodontically treated patients from the SLU graduate
orthodontic program: the ABO objective grading system compared with subjective
evaluation [Thesis]. St. Louis, MO: Saint Louis University:p47.
16. Cook, MK. Evaluation of Board-Certified Orthodontist’s Sequential Finished Cases
with the ABO Objective Grading System [Thesis]. St. Louis, MO: Saint Louis
University:p7.
17. Yang-Powers LC, Sadowsky C, Rosenstein S, BeGole E. Treatment outcome in a
graduate orthodontic clinic using the American Board of Orthodontics grading system.
Am J Orthod Dentofacial Orthop 2002;122:451-55.
27
28
CHAPTER 3: JOURNAL ARTICLE
Abstract
Purpose: This study investigated the scores obtained according to the ABO’s Objective
Grading System from a sample of casts of untreated individuals who would not benefit
from orthodontic treatment, to verify if “Board quality” occlusions are spontaneously
achievable or not, as well as in which of the categories measured the most points were
deducted to indicate where most discrepancies take place naturally. Materials and
Methods: The ABO’s OGS was used to measure 106 sets of study models from the
Andrews Education and Research Foundation, by the investigator calibrated by an ABO
examiner. No panoramic radiographs were evaluated. The total number of deducted
points determined whether a case is said to have “passed” or not the certification exam.
The total deducted points dictated the grouping of cases. According to the OGS, case
reports from which 19 or fewer points are deducted usually “pass”, case reports from
which 30 or more point are deducted usually “fail”, and cases from which 20 to 29 points
are deducted are generally considered borderline cases which may or may not pass in a
given year. These cases have been labeled “undetermined” for the purposes of this study.
The descriptive statistics tests showed abnormal distribution of the scores, indicating the
need of nonparametric tests and correlation tests to assess each component’s weight
towards the total deductions. Mann-Whitney and Spearman’s tests were respectively
used. Results: The total deductions ranged from 6 to 39 points, with a total mean
deduction of 17.2 points (SD 5.5). Seventy seven cases “passed” with a mean deduction
of 14.7 (SD 3.2); two cases failed [mean deduction of 37.0 (SD 2.0)] and 27 cases fell
29
into the “undetermined” category, with a mean deduction of 23.0 (SD 2.78). ‘Overjet’
contributed the most to the overall total deductions. In the “passed” group, occlusal
relationships weighted the most towards the total deductions and in the “undetermined”
group, mandibular buccolingual inclinations had significant weight. Conclusions:
“Board quality” occlusions may be observed naturally. There are significant differences
in the frequencies of the spontaneously occurring discrepancies, most of which do not
display a normal distribution. The total of deducted points, however, may not reflect the
true severity of the discrepancies in a given case, since the data used with this system is
of ordinal nature, and the discrepancies are not translated into values, but categories.
30
Introduction
The knowledge of normality enables one to recognize abnormalities and quantify
the degree of their severity, indicating what goals to be attained in order to achieve the
result most approximate to normal standards.
According to Andrews, who gathered a sample of 120 sets of casts of untreated
individuals, which he designated as “nonorthodontic normal models” because they all
displayed straight teeth in spite of not having had orthodontic treatment, they were
pleasant looking, they had “generally correct” bites and, in the author’s judgment, “would
not benefit from orthodontic treatment”. Those shared six features that the author
advocated to be “the keys to normal occlusion”, further referring to this sample as “the
best in nature”.1
The excellence in finishing and the quality displayed at the end of an orthodontic
treatment constitutes a fundamental goal of the orthodontic specialty, which is to
establish or reproduce a normal, healthy occlusion. During all stages of treatment one
should keep the end of treatment in mind, providing a protected occlusion, better
aesthetics (both dental and facial), good periodontal health and long-term stability, which
is correlated to proper finishing.
Proper finishing of orthodontic cases can be evaluated by a number of systems
developed for that purpose, and if done routinely in practice, may provide the
orthodontist with the chance the conduct self-assessment and critique his or her own
work and, hopefully, with it, opportunities to improve oneself constantly. If one does not
implement clear cut systematic clinical protocols, one risks providing patients with
incomplete or even unsatisfactory treatment outcomes.
31
The American Board of Orthodontics (ABO) has set standards that serve as
guidelines for adequate treatment finishing. Since 1999, it has implemented its Objective
Grading System (OGS) in Part III of the examination to orthodontists applying for
certification or re-certification. This system targets final panoramic radiographs and casts
utilizing calibrated examiners and a specially developed gauge for evaluating alignment,
marginal ridges, buccolingual inclination, occlusal relationship, occlusal contacts, overjet
and interproximal contacts (on the casts) and root parallelism (on the panoramic x-ray).
These criteria are evaluated to determine if the candidate possesses adequate clinical
skills to be certified.2
If the above mentioned criteria for “Board-quality” treated cases are applied to
patients who do not need treatment, one assumes the latter scores to be more than
satisfactory for “passing”.
Would untreated normal occlusions, if evaluated under the ABO’s OGS, obtain
“passing” scores? What criteria would hold the greatest range in results? Are they the
same ones as treated patients display the greatest range as well? The purpose of this
investigation is to determine if the criteria evaluated by the ABO’s OGS are applicable to
naturally good occlusions.
32
Materials and Methods
After the training of the primary investigator with the ABO, October 2000 CDROM Board examination preparatory disc and online tutorial from the ABO website, 5
sets of final models of non-extraction cases treated at SLU-CADE were repeatedly
blinded graded using the ABO gauge. It was repeated eight times for intra-examiner
reliability and efficiency development. The results from these measuring sessions were
then compared to the results obtained from the same 5 cases measured by an official
ABO examiner. The results were compared and the mean value obtained from the main
investigator was significantly higher than the ABO examiner, who then provided a
tutorial session to the primary investigator until agreement on the deduction values was
achieved and calibration was confirmed.
One hundred and six study models displaying naturally good-to-excellent
occlusions collected by Lawrence Andrews, and kept at the Andrews Foundation for
Education Research, were measured, along with randomly chosen 18 cases that were remeasured, for intra-examiner reliability assessment (see table B1 in Appendix B for
details). The Andrews sample is continuously amplified, since study models are still
being collected. An effort was made to measure models from the original sample alone.
That was not possible, but the majority of the casts (86 cases, 81.13%) did belong to the
original. The mean age for the Andrews sample was 24 years old, approximately.3All of
the model sets displayed full permanent dentition, except for third molars, not found in
the entire sample. Casts displaying characteristics which made the OGS assessment not
possible or inaccurate were excluded, such as casts with broken teeth, casts trimmed
differently than that prescribed by the ABO or articulated mounted casts, and models
33
with destroyed anatomy. The measurements were recorded on copies of the official
grading form used at Phase III of the ABO examination (Figure 3.1). The deductions
from each of the seven observed categories were individually recorded for investigation
of possible variance among them, and with this, investigation of each criterion’s
contribution to the total score.
Initially, three groups were obtained according to the total score or points
deducted from each cast, as Casko et al.2 suggested that generally deductions of 19 or less
points indicate “pass”, deductions of 30 and above generally indicate “fail” and that total
deduction between 20 and 29 points usually point towards “undetermined” cases, that are
then evaluated by other examiners to determine whether it would pass or not.
The 106 casts were then divided and they fell into the categories as follows: 77
into the “passed” category (approx. 72.6%), 27 cases fell into the “undetermined”
category (approx. 25.5%) and 2 cases score 30 or greater, falling into the “failed”
category (approx. 1.9%). See Figure 3.2.
For statistical purposes, since the size of the “failed” category was too small to be
significant, it was not used for the analysis. Hence, a total of 104 case scores were
analyzed and placed into one of the two following categories: 1st) ‘Passed’: those that
scored 19 and below, and 2nd) ‘Undetermined’: those that scored between or equal to 20
and 29.
It is important to stress the choice of names for the categories was based only on
the measurement of casts, and for that purpose, it was assumed that no points were
deducted at all due to discrepancies in root parallelism, since panoramic radiographs were
unavailable for analysis.
34
XXX
XXX
XXX
Figure 3.1: ABO cast-radiograph evaluation form (extracted and modified from the
ABO’s website: www.americanboardortho.com)
35
To increase the level of detailing in the descriptive statistics of this investigation,
whenever possible, the criteria having maxillary and mandibular distinct components
were separated as the collected data was entered into the Statistical Package for Social
Sciences (SPSS). Then, descriptive statistics analysis took place for final total scores and
individual ones: the mean, median, mode, standard deviation, skeweness, standard error
of skewness and range, as well as the minimum and maximum scores were obtained for
each of the seven criteria and their total. The frequencies of deductions per criteria for the
whole sample were also assessed. With the first descriptive analysis results, it was
observed that the skeweness and the kurtosis indicated an abnormal distribution of the
data. Then, nonparametric statistic testing and correlations took place, Mann-Whitney
and Spearman, respectively.
25.5%
27 casts
1.9%
2 casts
Pass.
Undet.
Fail.
72.6%
77 casts
Figure 3.2: Grouping according to scores for entire sample (≤ 19 points = “passe”, 20 ≥
points ≤ 29 = “undetermined” and ≥ 30 points = “fail”).
36
Results
The objective of this study was to determine whether or not a Board-quality
standard of occlusion could be achieved without orthodontic intervention, or if the
deducted points from naturally good-to-excellent occlusion cases would still allow them
to “pass” according to the ABO’s OGS criteria.
The mean deduction for the 106 cases was 17.2 (SD 5.5). The 77 cases which
“passed” had a mean deduction of 14.7 (SD 3.21) points and the 2 that failed, 37 (SD 2.0)
points, and the 27 undetermined ones, 23.0 (SD 2.78) points (Figure 3.2). Since the size
of the “failed” group was not significant, for statistical purposes, the 2 “failed” cases
were not considered. The two groups “passed” and “undetermined” were analyzed (see
Figures A1 in Appendix A, for their frequencies.) Their deductions means per component
are represented in Figure 3.3.
37
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
passed
undeter.
1
2
3
4
5
6
7
8
9
10
11
12
13
Figure 3.3: Mean deducted points in each component for the “passed” and
“undetermined” groups.
Fig. 3.3: X-axis – components/categories of possible deductions – 1) maxillary alignment and
rotations; 2) mandibular alignment and rotations; 3) maxillary marginal ridges; 4) mandibular
marginal ridges; 5) maxillary buccolingual inclinations; 6) mandibular buccolingual inclinations;
7) overjet; 8) maxillary occlusal contacts; 9) mandibular occlusal contacts; 10) occlusal
relationships; 11) maxillary interproximal contacts; 12) mandibular interproximal contacts; 13)
total deductions. Y-axis: number of deductable points.
According to the descriptive analysis, the mean deduction value for the maxillary
alignment and rotations in the “passed” group was approximately 2.8 (SD 1.4) and 3.5
(SD 1.53) for the same mandibular measurement. These measurements in the
“undetermined” group had their mean deduction of approximately 3.4 (SD 1.3) for the
maxilla and 3.4 (SD 0.98) for the mandible (see Figures A.2 and A.3, respectively,
Appendix A, for their frequencies.)
In the “passed” group, the mean deduction for marginal ridges in the maxilla was
of approximately 0.7 (SD 0.97) and 0.7 (SD 1.02), approximately, in the mandible. The
38
same measurements in the “undetermined” group was of 1.0 (SD 0.98) in the maxilla and
1.1 (SD 1.17) in the mandible (see Figures A.4 and A.5, respectively, for their
frequencies.)
The mean value of points deducted from maxillary buccolingual inclinations in
the “passed” group was 0.50 (SD 0.93) and 0.75 (SD 1.11) for the same mandibular
measurement. In the “undetermined” group, the mean deducted points for the maxillary
buccolingual inclination was 0.5 (SD 0.98) and 1.7 (SD 2.52) for the mandibular one (see
Figures A.6 and A.7, respectively, for their frequencies.)
The overjet category showed a mean deduction of 2.5 (SD 2.07) points in the
“passed” group and 5.3 (SD 3.50) in the “undetermined” group. Occlusal relationship had
a mean deduction of 1.7 (SD 1.76) in the “passed” group and 3.5 (SD 2.06) in the
“undetermined” group (see Figures A.8 and A.9, respectively, for their frequencies.)
The “passed” group had a mean deduction of 0.69 (SD 1.27) for the maxilla and
0.22 (SD 0.60) for the mandible; the “undetermined” group had a mean deduction of 1.31
(SD 2.5) points in the maxilla and 0.62 (SD 1.3) points in the mandible. For maxillary
occlusal contacts, 0.25 (SD 0.75) was the mean of deducted points for the “passed” group
and 0.33 (SD 0.62) for the “undetermined” group; for mandibular occlusal contacts, 0.39
(SD 0.69) was the mean deduction for the “passed” group and 1.1 (SD 1.41) was the
mean for the “undetermined” group (see Figures A.10 and A.11, respectively, for their
frequencies.)
The “passed” group in the interproximal contacts criteria showed a mean
deduction of 0.69 (SD 1.27) points in the maxilla and 0.22 (SD 0.60), in the mandible.
The latter deduction mean was 0.5 (SD 1.16) points and the former, 0.9 (SD 1.86) points
39
in the “undetermined” group (see Figures A.12 and A.13, respectively, for their
frequencies.)
The values observed for skeweness and kurtosis obtained from the descriptive
statistical analysis indicated abnormal distribution of the data (Tables 3.1 and 3.2),
indicating that the median and quartiles found for each criterion should be used to
provide a more accurate description of the results, instead of the means and standard
deviations. The association of the nature of the data analyzed (ordinal) combined with its
abnormal distribution suggested the use of nonparametric tests (Mann-Whitney) and
correlations (Spearman).
The median of the total deducted points was 17.0, range from 6 to 39 points.
Comparing the two groups, the median of the “passed” group was 15 (ranging from 6 to
19) and 22 of the “undetermined” group (ranging from 20 to 29).
The median of deducted points on the maxillary alignment and rotations criterion
was 3 points (ranging from 0 to 8) for the “passed” group and 4 points (ranging from 1 to
6) for the “undetermined” group. The mandibular alignment and rotations displayed a
deduction median of 4 points (ranging from 0 to 9) for the “passed” group and 4 (ranging
from 2 to 5) in the “undetermined” group.
40
Table 3.1: Descriptive statistics and distribution of the “passed” group, according to the measured
categories (Population, N= 77).
P e r c e n t i l e
C
Mea
Med
SD
Skw
SES
Kur
SEK
Rng
Mn
Mx
25%
50%
75%
1
2
3
4
5
6
7
8
9
10
11
12
13
2.80
3.54
0.68
0.74
0.51
0.75
2.55
0.25
0.39
1.66
0.69
0.22
14.69
3.0
4.0
0.0
0.0
0.0
0.0
2.0
0.0
0.0
1.0
0.0
0.0
15.0
1.38
1.53
0.97
1.02
0.93
1.11
2.07
0.75
0.69
1.76
1.27
0.60
3.21
0.82
0.36
1.42
1.24
2.48
1.56
1.28
4.24
1.51
0.95
2.04
2.90
-0.58
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
0.27
1.60
1.78
1.40
0.64
7.47
1.82
2.11
22.16
0.84
0.37
3.78
8.19
-0.40
0.54
0.54
0.54
0.54
0.54
0.54
0.54
0.54
0.54
0.54
0.54
0.54
0.54
8.0
9.0
4.0
4.0
5.0
4.0
10.0
5.0
2.0
7.0
5.0
3.0
13.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
6.0
8.0
9.0
4.0
4.0
5.0
4.0
10.0
5.0
2.0
7.0
5.0
3.0
19.0
2
3
0
0
0
0
1
0
0
0
0
0
1
3
4
0
0
0
0
2
0
0
1
0
0
1
4.0
4.0
1.0
1.0
1.0
1.0
3.0
0.0
1.0
3.0
1.0
0.0
17.0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
3.0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
. 0
5.0
Legend:
1 – Maxillary Alignment and Rotations
C - Components
2 – Mandibular Alignment and Rotations
Mea. – Mean
3 – Maxillary Marginal Ridges
Med. - Median
4 – Mandibular Marginal Ridges
SD – Standard Deviation
5 – Maxillary Buccolingual Inclinations
Skw.- Skewness
6 – Mandibular Buccolingual Inclinations
SES. – Standard Error of Skewness
7 – Overjet
Kur - Kurtosis
8 – Maxillary Occlusal Contacts
SEK – Standard Error of Kurtosis
9 – Mandibular Occlusal Contacts
Rng - Range
10 – Occlusal Relationships
Mn - Minimum
11 – Maxillary Interproximal Contacts
Mx - Maximum
12 – Mandibular Interproximal Contacts
13 –The
Totalmedian
Scores Deducted
of deducted points on the maxillary marginal ridges criterion was 0
point (ranging from 0 to 4) for the “passed” group and 1 point (ranging from 0 to 3) for
the “undetermined” group. The mandibular marginal ridges displayed a deduction median
of 0 point (ranging from 0 to 4) for the “passed” group and 1 point (ranging from 0 to 4)
in the “undetermined” group.
The median of deducted points on the maxillary buccolingual inclination criterion
was 0 point (ranging from 0 to 5) for the “passed” group and 0 point (ranging from 0 to
3) for the “undetermined” group. The mandibular buccolingual inclinations displayed a
41
The median deduction on the overjet criterion was 5 points (ranging from 0 to13) for the
“undetermined” group and 2 point (ranging from 0 to 10) for the “passed” group.
The median of deducted points on the maxillary occlusal contacts criterion was 0
point (ranging from 0 to 5) for the “passed” group and 0 point (ranging from 0 to 2) for
the “undetermined” group. The mandibular occlusal contacts displayed a deduction
median of 0 point (ranging from 0 to 2) for the “passed” group and 1 point (ranging from
0 to 5) for the “undetermined” group.
The median deduction on the occlusal relationship criterion was 1 point (ranging
from 0 to 7) for the “passed” group and 3 points (ranging from 0 to 8) for the
“undetermined” group.
The median of deducted points on the maxillary interproximal contacts criterion
was 0 point (ranging from 0 to 5) for the “passed” group and 0 point (ranging from 0 to
8) for the “undetermined” group. The mandibular interproximal contacts displayed a
deduction median of 0 point (ranging from 0 to 3) for the “passed” group and the
“undetermined” group had a median deduction of 0 point (ranging from 0 to 4).
42
Table 3.2: Descriptive statistics and distribution of “undetermined” group, according to the
measured categories (Population, N=27).
Percentile
C
Mea
Med
SD
Skw
SES
Kur
SEK
Rng
Mn
Mx
25%
50%
75%
1
2
3
4
5
6
7
8
9
3.44
3.41
1.04
1.15
0.55
1.70
5.30
0.33
1.07
3.48
0.92
0.52
23.04
4 . 0
4 . 0
1 . 0
1 . 0
0 . 0
0 . 0
5 . 0
0 . 0
1 . 0
3 . 0
0 . 0
0 . 0
22.0
1.28
0.97
0.98
1.17
0.97
2.52
3.49
0.62
1.41
2.06
1.86
1.16
2.78
-0.10
-0.13
0.45
0.63
1.59
2.02
0.70
1.74
1.45
0.20
2.71
2.05
0.76
0.45
0.45
0.45
0.45
0.45
0.45
0.45
0.45
0.45
0.45
0.45
0.45
0.45
-0.04
-0.96
-0.89
-0.43
1.27
4.37
-0.31
2.08
1.56
-0.43
8.04
2.97
-0.59
0.87
0.87
0.87
0.87
0.87
0.87
0.87
0.87
0.87
0.87
0.87
0.87
0.87
5.0
3.0
3.0
4.0
3.0
10.0
13.0
2.0
5.0
8.0
8.0
4.0
9.0
1.0
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
20.0
6.0
5.0
3.0
4.0
3.0
10.0
13.0
2.0
5.0
8.0
8.0
4.0
29.0
2.0
3.0
0.0
0.0
0.0
0.0
3.0
0.0
0.0
2.0
0.0
0.0
21.0
4.0
4.0
1.0
1.0
0.0
0.0
5.0
0.0
1.0
3.0
0.0
0.0
22.0
4.0
4.0
2.0
2.0
1.0
3.0
8.0
1.0
2.0
5.0
1.0
0.0
25.0
1 0
1 1
1 2
1 3
Legend:
1 – Maxillary Alignment and Rotations
2 – Mandibular Alignment and Rotations
3 – Maxillary Marginal Ridges
4 – Mandibular Marginal Ridges
5 – Maxillary Buccolingual Inclinations
6 – Mandibular Buccolingual Inclinations
7 – Overjet
8 – Maxillary Occlusal Contacts
9 – Mandibular Occlusal Contacts
10 – Occlusal Relationships
11 – Maxillary Interproximal Contacts
12 – Mandibular Interproximal Contacts
13 – Total Scores Deducted
C - Components
Mea. – Mean
Med. - Median
SD – Standard Deviation
Skw.- Skewness
SES. – Standard Error of Skewness
Kur - Kurtosis
SEK – Standard Error of Kurtosis
Rng - Range
Mn - Minimum
Mx - Maximum
In order to test the differences in the medians, the Mann-Whitney test was used,
since the distribution of the sample, in most parameters did not display central tendency,
but when comparing the two groups, the distributions were similar. The results are
summarized in Table 3.3 and Table 3.4.
43
Table 3.3: Nonparametric statistic tests results between groups “passed” and “undetermined”.
Comp.
Mann-Whitney U
Wilcoxon
Z
Asymp. Sig.
(2-tailed)
1
723.50
3726.50
-2.403
0.016
2
977.50
1355.50
-0.479
0.632
3
801.50
3832.50
-1.934
0.053
4
829.50
3832.50
-1.701
0.089
5
1037.50
1415.00
-0.018
0.986
6
861.00
3864.00
-1.471
0.141
7
508.50
3511.50
-3.983
0.000
8
926.00
3929.00
-1.279
0.201
9
749.50
3752.50
-2.569
0.010
10
515.00
3518.00
-3.969
0.000
11
1001.00
4004.00
-0.350
0.726
12
975.00
3978.00
-0.762
-7.728
13
0.00
3003.00
-7.728
0.000
Legend:
1 – Maxillary Alignment and Rotations
2 – Mandibular Alignment and Rotations
3 – Maxillary Marginal Ridges
4 – Mandibular Marginal Ridges
5 – Maxillary Buccolingual Inclinations
6 – Mandibular Buccolingual Inclinations
7 – Overjet
8 – Maxillary Occlusal Contacts
9 – Mandibular Occlusal Contacts
10 – Occlusal Relationships
11 – Maxillary Interproximal Contacts
12 – Mandibular Interproximal Contacts
13 – Total Scores Deducted
44
Table 3.4: Mann-Whitney’s ranks for the “passed” and “undetermined” groups.
Comp.
1
2
3
4
5
6
7
8
9
10
11
12
13
passed
yes
und.
yes
und.
yes
und.
yes
und.
yes
und.
yes
no
yes
und.
yes
und.
yes
und.
yes
und.
yes
und.
yes
und.
yes
und.
Total
N
77
27
77
27
77
27
77
27
77
27
77
27
77
27
77
27
77
27
77
27
77
27
77
27
77
27
104
Mean Rank
48.40
64.20
53.31
50.20
49.41
61.31
49.77
60.28
52.53
52.43
50.18
59.11
45.60
72.17
51.03
56.70
48.73
63.24
45.69
71.93
52.00
53.93
51.66
54.89
39.00
91.00
Sum of Ranks
3726.50
1733.50
4104.50
1355.50
3804.50
1655.50
3832.50
1627.50
4044.50
1415.50
3864.00
1596.00
3511.50
1948.50
3929.00
1531.00
3752.50
1707.50
3518.00
1942.00
4004.00
1456.00
3978.00
1482.00
3003.00
2457.00
Legend:
1 – Maxillary Alignment and Rotations
2 – Mandibular Alignment and Rotations
3 – Maxillary Marginal Ridges
4 – Mandibular Marginal Ridges
5 – Maxillary Buccolingual Inclinations
6 – Mandibular Buccolingual Inclinations
7 – Overjet
8 – Maxillary Occlusal Contacts
9 – Mandibular Occlusal Contacts
10 – Occlusal Relationships
11 – Maxillary Interproximal Contacts
12 – Mandibular Interproximal Contacts
13- Total Scores Deducted
Another aspect investigated in this study was the contribution each of the OGS’s
criteria had towards each total score and, therefore, how much each accounted for the
“passed” or “undetermined” distinction.
45
As previously mentioned, the data was not distributed normally, indicating that
the need for nonparametric correlations. The descriptions above may not truly
characterize the samples and its two groupings. A description closer to reality and more
detailed is given on Table 3.5, in which the median and quartiles of distribution are
indicated for each criterion.
Table 3.5: Descriptive statistics and distribution of entire sample, according to the measured
categories (Population, N=104).
Percentile
1
1
1
1
C
Mea
Med
SD
Skw
SES
Kur
SEK
Rng
Mn
Mx
25%
50%
75%
1
2
3
4
5
6
7
8
9
2.96
3.50
0.77
0.85
0.52
1.00
3.26
0.27
0.57
2.13
0.75
0.30
16.85
3.0
4.0
0.0
0.0
0.0
0.0
3.0
0.0
0.0
2.0
0.0
0.0
17.0
1.37
1.40
0.98
1.07
0.93
1.64
2.78
0.71
0.97
2.00
1.44
0.79
4.80
0.54
0.37
1.12
1.04
2.20
2.75
1.40
3.80
2.13
0.74
2.50
2.83
0.28
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.24
0.77
2.08
0.44
0.15
5.44
10.48
1.92
19.06
5.30
-0.15
7.24
7.66
-0.10
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
0.47
8 . 0
9 . 0
4 . 0
4 . 0
5 . 0
10.0
13.0
5 . 0
5 . 0
8 . 0
8 . 0
4 . 0
23.0
0
0
0
0
0
0
0
0
0
0
0
0
6
8.0
9.0
4.0
4.0
5.0
10.0
13.0
5.0
5.0
8.0
8.0
4.0
29.0
2.0
3.0
0.0
0.0
0.0
0.0
1.0
0.0
0.0
0.0
0.0
0.0
13.0
3.0
4.0
0.0
0.0
0.0
0.0
3.0
0.0
0.0
2.0
0.0
0.0
17.0
4.0
4.0
1.0
2.0
1.0
2.0
4.0
0.0
1.0
3.0
1.0
0.0
20.0
0
1
2
3
Legend:
1 – Maxillary Alignment and Rotations
2 – Mandibular Alignment and Rotations
3 – Maxillary Marginal Ridges
4 – Mandibular Marginal Ridges
5 – Maxillary Buccolingual Inclinations
6 – Mandibular Buccolingual Inclinations
7 – Overjet
8 – Maxillary Occlusal Contacts
9 – Mandibular Occlusal Contacts
10 – Occlusal Relationships
11 – Maxillary Interproximal Contacts
12 – Mandibular Interproximal Contacts
13 – Total Scores Deducted
.
.
.
.
.
.
.
.
.
.
.
.
.
0
0
0
0
0
0
0
0
0
0
0
0
0
C - Components
Mea. – Mean
Med. - Median
SD – Standard Deviation
Skw.- Skewness
SES. – Standard Error of Skewness
Kur - Kurtosis
SEK – Standard Error of Kurtosis
Rng - Range
Mn - Minimum
Mx - Maximum
46
Analyzing the sample as a whole, Spearman’s correlations were significant in the
following criteria, from strongest to weakest (two asterix indicating a correlation at the
0.01 level, and one asterix, correlation at the 0.05 level): overjet (ρ= 0.50**), occlusal
relationship (ρ= 0.49**), maxillary alignment and rotations (ρ= 0.29**), mandibular
marginal ridges (ρ= 0.28**), maxillary marginal ridges (ρ= 0.22*), maxillary and
mandibular occlusal contacts (ρ= 0.21*). See Tables B.2 – B.14 in Appendix B, for
details.
The “passed” group’s Spearman’s correlations were significant in the following
criteria, from strongest to weakest: occlusal relationship (ρ= 0.37**), overjet (ρ= 36**),
mandibular alignment and rotations (ρ= 0.35**) and mandibular marginal ridges (ρ=
0.29*). See Tables B.15 – B.27, in Appendix B, for details.
Analyzing the “undetermined” group, Spearman’s correlations was significant in
the mandibular buccolingual inclination criterion (ρ= 0.49*). See Tables B.28 – B.40 for
details.
Discussion
The sample utilized in this study was originally gathered by Andrews for analysis
of what those occlusions, which had not had, nor would benefit from orthodontics, shared
47
in a significant fashion. The common traits were narrowed to six, which were then
validated by comparison to treated cases. And not all treated cases displayed the traits.
With the present study, the purpose was to investigate whether the untreated
sample would “pass” if observed under the same criteria used by the ABO for the treated
cases, and could also be said to display “Board-quality”.
A significant 77 cases (72.6%) out of the 106 had 19 or fewer points deducted and
were then considered to have “passed”, in general terms. Two cases scored 30 or above,
scores that suggest, usually, immediate failures. The remaining 27 cases had from 20 to
29 points deducted, scores considered to be generally “undetermined” for passing or not a
given case. This group then may contribute to the passing group, providing even greater
significance to it, since 98.1% or 104 cases would have then passed. The “undetermined”
group, however, was individually considered for statistical analysis purposes.
Cases selected to be presented at Part III examination, in a way of “leveling” all
applicants, must meet certain pre-treatment discrepancy scores. It seems is the
investigators opinion that a thorough process should take place for validating both
scoring systems as well as the quality of the treatment outcome: all cases submitted
should be scored under the ABO’s DI and OGS for both pre and post-treatment. In this
fashion, a quantifiable improvement may be attested. As of now, they are unrelated: the
measurements take place at different times during the exam, and before and after records
are not seating side-by-side. The DI components are, among others, overjet, overbite,
anterior open bite, lateral open bite, crowding, occlusion, lingual posterior crossbite,
buccal posterior crossbite. Not all of these entities may be measured with the OGS, so
objectively quantifying the improvement or outcome of a given case becomes unlikely.
48
Overbite, for instance, is not a criterion of the OGS, even though it is measured three
times with the DI. There are differences between the criteria observed and scored towards
the Discrepancy Index and the Objective Grading System. Overbite, for example, is a
criterion of the DI, but is not addressed in the OGS evaluation.
The sample investigated in this study was selected based on its appropriateness to
what Andrews1 was originally investigating, that being the components of good-toexcellent occlusions. Therefore, the abnormal distribution of the data from the sample
observed in the present study was expected: central tendencies were not observed for the
present components. Having cases with naturally occurring good occlusions measured
with the OGS and having their significant majority pass displays validity in this grading
system.
The investigator observed that the subjective evaluation of the study models was
misleading, since a number of casts had noticeable discrepancies but still obtained
“passing” scores according to the OGS. These observations are in accordance with the
negative correlation between subjective grading and the OGS applied to a sample of
treated cases described by Waters,4 who suggests, as does Cook,5 that the OGS is less
critical on the evaluation of final treatment models and ultimately, on the scoring, which
favors the applicants’ attempts to pass Part III and to become certified. The true severity
of some discrepancies was not represented by this scoring system.
Overjet contributed significantly towards the total deduction in the entire sample
and in the “passed” group. Overall, overjet and occlusal relationship had significant
“weight” towards the total deductions. In the “passed” group, occlusal relationship then
overjet, and mandibular alignment and rotations weighted significantly towards this
49
group total deductions. The role overbite plays in lower anterior crowding may explain
this significance and their correlation. And in the “undetermined” group, mandibular
buccolingual inclinations weighted significantly towards the total deducted scores.
The components which were significant not only were present among the total
deductions, but also displayed significant deductions in the total, suggesting their
validity. The strengths of the correlations, however, were not overall high. This may be
due to nature of the sample: its cases were chosen according to pre-established criteria by
Andrews1, and should display good-to-excellent occlusions, therefore, should not have
particular criteria significantly contributing towards their total deductions.
A higher percentile of ITRI was observed in the treated group, as Tahir et al.6
described after its comparison to natural good occlusions, the Andrews sample mean total
score was lower than the ABO’s sample. This fact, as the author stated, occurred
probably due to the selection of cases for the ABO, for the candidates purposefully
choose cases that would have better scores. This suggestion is supported by the
distribution patterns of the scores, which were very similar: anterior relationships scored
higher than posterior, buccal relationships higher than lingual relationships on the
posterior segments and anterior intraarch relations scored the highest. The ITRI criteria
evaluated differs from the OGS criteria, so that objective comparison between those
results and the results from this study would not be valid or significant.
Yang-Powers et al.,3 comparing the scores obtained from two different treated
samples, indicated buccolingual inclination as the criterion with the highest mean
deduction for both groups and interproximal contacts, the criterion with the lowest mean
deducted points . Such findings partially support the results from this study, that is the
50
criterion with highest correlation towards the total in the “undetermined” group was
mandibular buccolingual inclinations. But deductions from maxillary interproximal
contacts also displayed a significant correlation towards the total (however weaker than
buccolingual inclination’s) in the “undetermined” group. A closer comparison between
the mean deductions for each category for the “passed” and “undetermined” groups can
be observed in Figure A.14.
Conclusions
With this investigation it was concluded that a significant number of untreated
cases with “good-to-excellent” occlusions would have scored well enough to pass the
objective grading portion of the ABO’s Part III certification process, designed to evaluate
treatment outcomes. According to the OGS general prescription, 72.6% of the sample (77
cases) had 19 or fewer points deducted, therefore “passed”, 1.9% of the sample (2 cases)
had 30 or more points deducted, indicating immediate failures and 25.5% had between 20
and 29 points deducted, so their passing was “undetermined”. The two groups formed for
statistical analysis, “passed” and “undetermined”, displayed a mean of 17.2 and 24.0
points deducted, respectively. The descriptive analysis indicated abnormal data
distribution, hence nonparametric tests were conducted from then on, and the medians
and quartiles were used to describe the distribution of the scores. Spearman’s correlation
indicated ‘overjet’ as the significant contributing criterion towards deducted points on the
entire sample (ρ>0.01). Overall, overjet and occlusal relationship had significant
51
“weight” towards the total deductions. In the “passed” group, occlusal relationship then
overjet, and mandibular alignment and rotations weighted significantly towards the total.
In the “undetermined” group, mandibular buccolingual inclinations contributed
significantly to this group’s total deductions.
“Board quality” occlusions are observed naturally, however, there is a significant
difference in the frequency of the spontaneously occurring discrepancies. The total of
deducted points, however, may not reflect the true severity of the discrepancies in a given
case, since the data used with the ABO system is of ordinal nature. The discrepancies
have limited severity deduction, which may not have been truly reflected in the total
scores in this study.
The abnormal distribution of sample and relative strength of the correlations
observed in this study (overall, weak) are due to the previous selection of the cases, done
by Andrews according to his components of good occlusions.
52
Literature Cited
1. Andrews, LF. The six keys to normal occlusion. Am J Orthod 1972;62:271-309.
2. Casko, JS, Vaden JL, Kokich VG, Damone J, James RD, Cangialosi TJ, Riolo ML,
Owens SE, Bills ED. Objective grading system for dental casts and panoramic
radiographs. Am J Orthod Dentofacial Orthop 1998;114:589-99.
3. Yang-Powers LC, Sadowsky C, Rosenstein S, BeGole E. Treatment outcome in a
graduate orthodontic clinic using the American Board of Orthodontics grading system.
Am J Orthod Dentofacial Orthop 2002;122:451-55.
4. Waters, J. Evaluation of orthodontically treated patients from the SLU graduate
orthodontic program: the ABO objective grading system compared with subjective
evaluation [Thesis]. St. Louis, MO: Saint Louis University:p47.
5. Cook, MK. Evaluation of Board-Certified Orthodontist’s Sequential Finished Cases
with the ABO Objective Grading System [Thesis]. St. Louis, MO: Saint Louis
University:p7.
6. Tahir E, Sadowsky C, Schneider BJ. An assessment of treatment outcome in American
Board of Orthodontics cases. Am J Orthod Dentofacial Orthop 1997;111:335-42.
53
54
APPENDIX A
Bar Chart
Number of cases
passed
12
passed
Passed
undetermined
Undetermined
10
8
6
4
2
0
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
21.
22.
23.
24.
25.
26.
27.
28.
29.
00 11
00 12
00 13
00 14
00 15
00 16
00 17
00
00
00
002000 21
00 22
00 23
00 24
00 25
00 26
00 27
00 28
00 29
6006. 8008. 9009. 10
18
19 20.
TT
Total Deductions
Figure A1: Frequency of total points deducted.
53
Bar Chart
Number of cases
passed
passed
Passed
undetermined
25
Undetermined
20
15
10
5
0
0.00
1
1.00
2
2.00
3
3.00
4
4.00
5
5.00
6
6.00
8
8.00
Deductions due AetRmx
to Alignment and Rotations (maxillary)
Figure A.2: Frequency of points deducted from maxillary “alignment and rotations”.
54
Bar Chart
Number of cases
30
Passed
Undetermined
25
20
15
10
5
0
0
1
2
3
4
5
6
7
9
Deductions due to Alignment and Rotations (mandibular)
Figure A.3: Frequency of points deducted from mandibular “alignment and rotations”.
55
Bar Chart
Number of cases
passed
passed
Passed
undetermined
50
Undetermined
40
30
20
10
0
.00
0
1.00
1
2.00
2
3.00
3
4.00
4
MRmx due to Marginal Ridges (maxillary)
Deductions
Figure A.4: Frequency of points deducted due to maxillary “marginal ridges”.
56
Bar Chart
Number of cases
passed
passed
Passed
undetermined
Undetermined
50
40
30
20
10
0
.00
0
1.00
1
2.00
2
3.00
3
4.00
4
Deductions due to Marginal MRmd
Ridges (mandibular)
Figure A.5: Frequency of points deducted due to mandibular “marginal ridges”.
57
Bar Chart
Number of cases
passed
Passed
passed
Undetermined
undetermined
60
50
40
30
20
10
0
0
.00
1
1.00
2
2.00
3
3.00
5
5.00
DeductionsBImx
due to Buccolingual Inclinations (maxillary)
Figure A.6: Frequency of points deducted due to maxillary “buccolingual inclinations”.
58
Bar Chart
Number of cases
passed
passed
Passed
undetermined
Undetermined
50
40
30
20
10
0
0.00
1.00
1
2.00
2
3.00
3
4.00
4
8.00
8
10.00
10
BImd
Deductions due to Buccolingual Inclinations (mandibular)
Figure A.7: Frequency of points deducted due to mandibular “buccolingual inclinations”.
59
Bar Chart
Number of cases
passed
Passed
passed
Passed
Undetermined
undetermined
20
Undetermined
15
10
5
0
.00
0
1.00
1
2.00
2
3.00
3
4.00
4
5.00
5
6.00
6
7.00
7
8.00
8
9.00
9
10.00
10
11.00
11
12.00
12
13.00
13
OJ
Deductions due to Overjet
Figure A.8: frequency of points deducted due to “overjet”.
60
Bar Chart
Number of cases
passed
passed
Passed
undetermined
Undetermined
60
40
20
0
.00
0
1.00
1
2.00
2
5.00
5
Deductions
OCmx due to Occlusal Contacts (maxillary)
Figure A.9: Frequency of points deducted due to maxillary “occlusal contacts”.
61
Bar Chart
Number of cases
passed
passed
Passed
undetermined
60
Undetermined
50
40
30
20
10
0
0
.00
1
1.00
2
2.00
4
4.00
5
5.00
Deductions
due to Occlusal Contacts (mandibular)
OCmd
Figure A.10: Frequency of points deducted due to mandibular “occlusal contacts”.
62
Bar Chart
Number of cases
passed
passed
Passed
undetermined
30
Undetermined
25
20
15
10
5
0
.00
0
1.00
1
2.00
2
3.00
3
4.00
4
5.00
5
6.00
6
7.00
7
8.00
8
Deductions
RO due to Occlusal Relationships
Figure A.11: Frequency of points deducted due to “occlusal relationship”.
63
Bar Chart
Number of cases
passed
passed
Passed
undetermined
Undetermined
60
50
40
30
20
10
0
.00
0
1.00
1
2.00
2
3.00
3
4.00
4
5.00
5
8.00
8
DeductionsICmx
due to Interproximal Contacts (maxillary)
Figure A.12: Frequency of points deducted due to maxillary “interproximal contacts”.
64
Bar Chart
Number of cases
passed
Passed
passed
Undetermined
undetermined
60
40
20
0
.00
0
1.00
1
2.00
2
3.00
3
4.00
4
Deductions due to Interproximal
Contacts (mandibular)
ICmd
Figure A.13: Frequency of points deducted due to mandibular “interproximal contacts”.
.
65
Mean deducted points per component
AetRmx
25
AetRmd
MRmx
MRmd
BImx
BImd
OJ
OCmx
OCmd
RO
ICmx
ICmd
TT
20
15
10
5
0
Passed
Undetermined
Legend: AetRmx) maxillary alignment and rotations; AetRmd) mandibular alignment and rotations; MRmx)
maxillary marginal ridges; MRmd) mandibular marginal ridges; BImx) maxillary buccolingual inclinations;
BImd) mandibular buccolingual inclinations; OJ) overjet; OCmx) maxillary occlusal contacts; OCmd)
mandibular occlusal contacts; RO) occlusal relationships; ICmx) maxillary interproximal contacts; ICmd)
mandibular interproximal contacts; TT) total deductions.
Figure A.14: Mean deduction per component grouped according to their final score:
“passed” vs. “undetermined”.
66
APPENDIX B
Table B.1: Intra-examiner Pearson’s correlation.
Component Mean SD
r
1o
3.27 1.17 0.963**
1r
3.38 1.19
2o
2.94 1.25 0.805**
2r
3.05 0.80
3o
0.83 0.92 0.932**
3r
0.83 0.92
4o
0.88 1.23 0.942**
4r
0.94 1.10
5o
0.50 0.85 0.946**
5r
0.61 0.97
6o
1.00 1.32 0.881**
6r
0.94 1.05
7o
3.27 2.71 0.997**
7r
3.27 2.49
8o
0.27 0.66
-0.345
8r
0.88 1.13
9o
1.16 1.61 0.564*
9r
0.55 0.98
10o
2.50 2.22 0.990**
10r
2.61 2.25
11o
0.16 0.51 0.682**
11r
0.38 0.97
12o
0.22 0.73
0.265
12r
0.05 0.23
13o
17.38 5.47 0.985**
13r
17.72 5.21
Legend:
1. Maxillary Alignment and Rotations
2. Mandibular Alignment and Rotations
3. Maxillary Marginal Ridges
4. Mandibular Marginal Ridges
5. Maxillary Buccolingual Inclinations
6. Mandibular Buccolingual Inclinations
7. Overjet
8. Maxillary Occlusal Contacts
9. Mandibular Occlusal Contacts
10. Occlusal Relationships
11. Maxillary Interproximal Contacts
12. Mandibular Interproximal Contacts
13. Total of Deducted Points
“o”. Original Measurement
“r”. Re-Measurement
67
Table B.2: Spearman’s correlations between the Alignment and Rotations
(maxillary) and the other components for the entire sample.
Component under investigation: 1
N
ρ
S
(Sample)
1
1.00 0.00
104
2
0.15 0.14
104
3
-0.04 0.68
104
4
-0.04 0.69
104
5
-0.10 0.33
104
6
-0.07 0.50
104
7
0.08 0.40
104
8
0.14 0.17
104
9
0.13 0.18
104
10
0.09 0.35
104
11
-0.27** 0.00
104
12
-0.14 0.17
104
13
0.29** 0.00
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
68
Table B.3: Spearman’s correlations between the Alignment and Rotations
(mandibular) and the other components for the entire sample.
Component under investigation: 2
ρ
S
N
(Sign. 2-tailed) (Pop.)
1
0.15
0.14
104
2
1.00
0.00
104
3
-0.10
0.30
104
4
0.26**
0.01
104
5
-0.02
0.87
104
6
-0.21*
0.03
104
7
0.01
0.95
104
8
-0.01
0.89
104
9
-0.14
0.16
104
10
-0.12
0.21
104
11
0.13
0.17
104
12
-0.09
0.39
104
13
0.16
0.11
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
69
Table B.4: Spearman’s correlations between the Marginal Ridges (maxillary) and
the other components for the entire sample.
Component under investigation: 3
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.04
0.68
104
2
-0.10
0.30
104
3
1.00
0.00
104
4
0.15
0.12
104
5
-0.10
0.30
104
6
-0.01
0.89
104
7
0.02
0.84
104
8
-0.15
0.12
104
9
-0.07
0.50
104
10
0.02
0.82
104
11
-0.00
0.99
104
12
0.20*
0.04
104
13
0.22*
0.03
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
70
Table B.5: Spearman’s correlations between the Marginal Ridges (mandibular)
and the other components for the entire sample.
Component under investigation: 4
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.04
0.69
104
2
0.26**
0.01
104
3
0.15
0.12
104
4
1.00
0.00
104
5
0.08
0.43
104
6
-0.21*
0.03
104
7
-0.04
0.71
104
8
0.06
0.53
104
9
-0.08
0.41
104
10
0.09
0.37
104
11
0.14
0.16
104
12
-0.03
0.79
104
13
0.28**
0.00
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
71
Table B.6: Spearman’s correlations between the Buccolingual Inclinations
(maxillary) and the other components for the entire sample.
Component under investigation: 5
ρ
S
N
(Sig. 2 tailed) (Pop.)
1
-0.10
0.33
104
2
-0.02
0.87
104
3
-0.10
0.30
104
4
0.08
0.43
104
5
1.00
0.00
104
6
0.07
0.48
104
7
-0.17
0.09
104
8
-0.09
0.38
104
9
-0.03
0.75
104
10
-0.09
0.38
104
11
0.01
0.90
104
12
-0.09
0.37
104
13
-0.01
0.90
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
72
Table B.7: Spearman’s correlations between the Buccolingual Inclinations
(mandibular) and the other components for the entire sample.
Component under investigation: 6
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.07
0.50
104
2
-0.21*
0.03
104
3
-0.01
0.89
104
4
-0.21*
0.03
104
5
0.07
0.48
104
6
1.00
0.00
104
7
-0.12
0.25
104
8
0.11
0.25
104
9
0.03
0.78
104
10
0.10
0.29
104
11
-0.03
0.77
104
12
-0.18
0.07
104
13
0.11
0.25
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
73
Table B.8: Spearman’s correlations between the Overjet and the other
components for the entire sample.
Component under investigation: 7
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.08
0.40
104
2
0.01
0.95
104
3
0.02
0.84
104
4
-0.04
0.71
104
5
-0.17
0.09
104
6
-0.11
0.25
104
7
1.00
0.00
104
8
0.04
0.66
104
9
0.13
0.19
104
10
0.00
0.97
104
11
-0.08
0.43
104
12
0.01
0.90
104
13
0.50**
0.00
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
74
Table B.9: Spearman’s correlations between the Occlusal Contacts (maxillary)
and the other components for the entire sample.
Component under investigation: 8
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.14
0.17
104
2
-0.01
0.90
104
3
-0.16
0.12
104
4
0.06
0.52
104
5
-0.09
0.38
104
6
0.11
0.25
104
7
0.04
0.66
104
8
1.00
0.00
104
9
0.13
0.18
104
10
0.07
0.50
104
11
-0.06
0.55
104
12
-0.06
0.58
104
13
0.21*
0.04
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
75
Table B.10: Spearman’s correlations between the Occlusal Contacts (mandibular)
and the other components for the entire sample.
Component under investigation: 9
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.13
0.18
104
2
-0.14
0.15
104
3
-0.07
0.50
104
4
-0.08
0.42
104
5
-0.03
0.75
104
6
0.03
0.80
104
7
0.13
0.19
104
8
0.13
0.18
104
9
1.00
0.00
104
10
-0.06
0.54
104
11
-0.15
0.13
104
12
-0.10
0.30
104
13
0.21*
0.03
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
76
Table B.11: Spearman’s correlations between the Occlusal Relationships and the
other components for the entire sample.
Component under investigation: 10
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.09
0.35
104
2
-0.12
0.21
104
3
0.02
0.82
104
4
0.09
0.37
104
5
-0.09
0.38
104
6
0.10
0.29
104
7
0.00
0.97
104
8
0.07
0.50
104
9
-0.06
0.54
104
10
1.00
0.00
104
11
0.02
0.86
104
12
0.13
0.20
104
13
0.49**
0.00
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
77
Table B.12: Spearman’s correlations between the Interproximal Contacts
(maxillary) and the other components for the entire sample.
Component under investigation: 11
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.27**
0.01
104
2
0.13
0.17
104
3
-0.00
0.99
104
4
0.14
0.16
104
5
0.01
0.90
104
6
-0.03
0.77
104
7
-0.08
0.43
104
8
-0.06
0.55
104
9
-0.15
0.13
104
10
0.02
0.86
104
11
1.00
0.00
104
12
0.07
0.51
104
13
0.14
0.15
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
78
Table B.13: Spearman’s correlations between the Interproximal Contacts
(mandibular) and the other components for the entire sample.
Component under investigation: 12
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.14
0.17
104
2
-0.09
0.40
104
3
0.20*
0.04
104
4
-0.03
0.80
104
5
-0.09
0.37
104
6
-0.18
0.07
104
7
0.01
0.90
104
8
-0.06
0.58
104
9
-0.10
0.30
104
10
0.13
0.20
104
11
0.07
0.51
104
12
1.00
0.00
104
13
0.15
0.14
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
79
Table B.14: Spearman’s correlations between the Total Points Deducted and the
other components for the entire sample.
Component under investigation: 13
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.29**
0.00
104
2
0.16
0.11
104
3
0.22**
0.03
104
4
0.30**
0.00
104
5
-0.01
0.90
104
6
0.11
0.25
104
7
0.50**
0.00
104
8
0.21*
0.04
104
9
0.21*
0.03
104
10
0.49**
0.00
104
11
0.14
0.15
104
12
0.15
0.14
104
13
1.00
0.00
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
80
Table B.15: Spearman’s correlations between the Alignment and Rotations
(maxillary) and the other components for the “passed” group.
Component under investigation: 1
N
ρ
S
(Sample)
1
1.00 0.00
77
2
0.20 0.08
77
3
-0.09 0.45
77
4
-0.02 0.87
77
5
-0.04 0.73
77
6
-0.19 0.09
77
7
-0.02 0.84
77
8
0.04 0.76
77
9
0.09 0.46
77
10
-.0.05 0.68
77
11
-0.024* 0.04
77
12
-0.016 0.18
77
13
0.21 0.07
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
81
Table B.16: Spearman’s correlations between the Alignment and Rotations
(mandibular) and the other components for the “passed” group.
Component under investigation: 2
ρ
S
N
(Sign. 2-tailed) (Pop.)
1
0.20
0.08
77
2
1.00
0.00
77
3
-0.12
0.28
77
4
0.27*
0.02
77
5
-0.01
0.92
77
6
-0.20
0.08
77
7
0.07
0.56
77
8
-0.04
0.73
77
9
-0.03
0.80
77
10
-0.13
0.24
77
11
0.09
0.46
77
12
-0.15
0.20
77
13
0.35**
0.20
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
82
Table B.17: Spearman’s correlations between the Marginal Ridges (maxillary)
and the other components for the “passed” group.
Component under investigation: 3
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.09
0.45
77
2
-0.12
0.28
104
3
1.00
0.00
77
4
0.00
0.98
77
5
-0.18
0.12
77
6
-0.00
0.96
77
7
-0.01
0.95
77
8
-0.06
0.60
77
9
-0.08
0.48
77
10
-0.06
0.60
77
11
-0.13
0.25
77
12
0.13
0.27
77
13
0.13
0.27
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
83
Table B.18: Spearman’s correlations between the Marginal Ridges (mandibular)
and the other components for the “passed” group.
Component under investigation: 4
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.02
0.87
77
2
0.27*
0.02
77
3
0.00
0.98
77
4
1.00
0.00
77
5
-0.02
0.86
77
6
-0.21
0.07
77
7
-0.02
0.84
77
8
0.12
0.30
77
9
-0.09
0.44
77
10
-0.05
0.68
77
11
0.05
0.66
77
12
-0.05
0.67
77
13
0.29*
0.01
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
84
Table B.19: Spearman’s correlations between the Buccolingual Inclinations
(maxillary) and the other components for the “passed group”.
Component under investigation: 5
ρ
S
N
(Sig. 2 tailed) (Pop.)
1
-0.04
0.73
77
2
-0.01
0.92
77
3
-0.18
0.12
77
4
-0.02
0.86
77
5
1.00
0.00
77
6
0.11
0.36
77
7
-0.06
0.61
77
8
-0.04
0.72
77
9
0.04
0.74
77
10
-0.13
0.28
77
11
-0.07
0.55
77
12
-0.06
0.59
77
13
0.00
0.99
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
85
Table B.20: Spearman’s correlations between the Buccolingual Inclinations
(mandibular) and the other components for the “passed group”.
Component under investigation: 6
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.19
0.09
77
2
-0.20
0.08
77
3
-0.01
0.96
77
4
-0.21
0.07
77
5
0.11
0.35
77
6
1.00
0.00
77
7
-0.30**
0.01
77
8
0.09
0.46
77
9
0.01
0.93
77
10
-0.01
0.95
77
11
0.00
0.97
77
12
-0.14
0.24
77
13
-0.06
0.58
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
86
Table B.21: Spearman’s correlations between the Overjet and the other
components for the “passed” group.
Component under investigation: 7
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.02
0.84
77
2
0.07
0.56
77
3
-0.01
0.95
77
4
-0.02
0.84
77
5
-0.06
0.61
77
6
-0.30**
0.01
77
7
1.00
0.00
77
8
-0.10
0.40
77
9
-0.06
0.60
77
10
-0.08
0.50
77
11
-0.11
0.34
77
12
-0.03
0.79
77
13
0.36**
0.00
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
87
Table B.22: Spearman’s correlations between the Occlusal Contacts (maxillary)
and the other components for the “passed group”.
Component under investigation: 8
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.04
0.76
77
2
-0.04
0.72
77
3
-0.06
0.06
77
4
0.12
0.30
77
5
-0.04
0.72
77
6
0.09
0.46
77
7
-0.10
0.40
77
8
1.00
0.00
77
9
0.13
0.27
77
10
-0.02
0.89
77
11
0.09
0.44
77
12
-0.06
0.60
77
13
0.20
0.09
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
88
Table B.23: Spearman’s correlations between the Occlusal Contacts (mandibular)
and the other components for the “passed group”.
Component under investigation: 9
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.09
0.46
77
2
-0.03
0.80
77
3
-0.08
0.48
77
4
-0.09
0.44
77
5
0.04
0.74
77
6
0.01
0.93
77
7
-0.06
0.60
77
8
0.13
0.27
77
9
1.00
0.00
77
10
-0.17
0.13
77
11
-0.08
0.52
77
12
-0.06
0.63
77
13
0.02
0.86
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
89
Table B.24: Spearman’s correlations between the Occlusal Relationships and the
other components for the “passed group”.
Component under investigation: 10
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.05
0.70
77
2
-0.13
0.24
77
3
-0.06
0.60
77
4
-0.05
0.68
77
5
-0.13
0.28
77
6
-0.01
0.95
77
7
-0.08
0.50
77
8
-0.02
0.90
77
9
-0.17
0.13
77
10
1.00
0.00
77
11
0.06
0.58
77
12
0.18
0.12
77
13
0.37**
0.00
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
90
Table B.25: Spearman’s correlations between the Interproximal Contacts
(maxillary) and the other components for the “passed” group.
Component under investigation: 11
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.24*
0.09
77
2
0.09
0.46
77
3
-0.13
0.25
77
4
0.05
0.66
77
5
-0.07
0.55
77
6
0.00
0.97
77
7
-0.11
0.34
77
8
0.09
0.44
77
9
-0.08
0.52
77
10
0.06
0.58
77
11
1.00
0.00
77
12
0.08
0.48
77
13
0.18
0.12
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
91
Table B.26: Spearman’s correlations between the Interproximal Contacts
(mandibular) and the other components for the entire sample.
Component under investigation: 12
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.16
0.18
77
2
-0.15
0.20
77
3
0.13
0.27
77
4
-0.05
0.67
77
5
-0.06
0.59
77
6
-0.14
0.24
77
7
-0.03
0.79
77
8
-0.06
0.60
77
9
-0.06
0.63
77
10
0.18
0.12
77
11
0.08
0.47
77
12
1.00
0.00
77
13
0.18
0.12
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
92
Table B.27: Spearman’s correlations between the Total Points Deducted and the
other components for the “passed” group.
Component under investigation: 13
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.21
0.07
77
2
0.35**
0.00
77
3
0.13
0.27
77
4
0.29*
0.01
77
5
0.00
0.99
77
6
-0.06
0.58
77
7
0.36**
0.00
77
8
0.20
0.08
77
9
0.02
0.86
77
10
0.37**
0.00
77
11
0.18
0.12
77
12
0.18
0.12
77
13
1.00
0.00
77
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
93
Table B.28: Spearman’s correlations between the Alignment and Rotations
(maxillary) and the other components for the “undetermined” group.
Component under investigation: 1
N
ρ
S
(Sample)
1
1.00 0.00
27
2
-0.05 0.80
27
3
-0.10 0.63
27
4
-0.25 0.20
27
5
-0.27 0.17
27
6
0.06 0.78
27
7
-0.10 0.61
27
8
0.30 0.15
27
9
0.08 0.68
27
10
0.23 0.24
27
11
-0.45* 0.02
27
12
-0.14 0.50
27
13
-0.17 0.39
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
94
Table B.29: Spearman’s correlations between the Alignment and Rotations
(mandibular) and the other components for the “undetermined” group.
Component under investigation: 2
ρ
S
N
(Sign. 2-tailed) (Pop.)
1
-0.05
0.80
27
2
1.00
0.00
27
3
0.02
0.94
27
4
0.29
0.14
27
5
-0.01
0.97
27
6
-0.22
0.28
27
7
-0.12
0.56
27
8
0.07
0.73
27
9
-0.44**
0.02
27
10
-0.03
0.90
27
11
0.30
0.14
27
12
0.08
0.68
27
13
-0.08
0.69
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
95
Table B.30: Spearman’s correlations between the Marginal Ridges (maxillary)
and the other components for the “undetermined” group.
Component under investigation: 3
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.10
0.63
27
2
0.02
0.94
27
3
1.00
0.00
27
4
0.43*
0.02
27
5
0.12
0.56
27
6
-0.16
0.44
27
7
-0.21
0.30
27
8
-0.46*
0.02
27
9
-0.23
0.25
27
10
-0.06
0.77
27
11
0.34
0.09
27
12
0.34
0.08
27
13
0.10
0.60
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
96
Table B.31: Spearman’s correlations between the Marginal Ridges (mandibular)
and the other components for the “undetermined” group.
Component under investigation: 4
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.25
0.20
27
2
0.29
0.14
27
3
0.43*
0.02
27
4
1.00
0.00
27
5
0.37
0.06
27
6
-0.31
0.11
27
7
-0.34
0.08
27
8
-0.08
0.68
27
9
-0.25
0.20
27
10
0.17
0.40
27
11
0.31
0.12
27
12
-0.03
0.90
27
13
0.05
0.81
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
97
Table B.32: Spearman’s correlations between the Buccolingual Inclinations
(maxillary) and the other components for the “undetermined” group.
Component under investigation: 5
ρ
S
N
(Sig. 2 tailed) (Pop.)
1
-0.27
0.17
27
2
-0.01
0.97
27
3
0.12
0.56
27
4
0.36
0.06
27
5
1.00
0.00
27
6
-0.01
0.97
27
7
-0.42*
0.03
27
8
-0.20
0.32
27
9
-0.20
0.32
27
10
-0.08
0.70
27
11
0.23
0.25
27
12
-0.15
0.44
27
13
-0.17
0.41
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
98
Table B.33: Spearman’s correlations between the Buccolingual Inclinations
(mandibular) and the other components for the “undetermined” group.
Component under investigation: 6
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.06
0.78
27
2
-0.22
0.28
27
3
-0.16
0.44
27
4
-0.31
0.11
27
5
-0.01
0.98
27
6
1.00
0.00
27
7
0.09
0.66
27
8
0.10
0.63
27
9
-0.08
0.70
27
10
0.30
0.14
27
11
-0.11
0.59
27
12
-0.30
0.12
27
13
0.49**
0.01
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
99
Table B.34: Spearman’s correlations between the Overjet and the other
components for the “undetermined” group.
Component under investigation: 7
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.10
0.61
27
2
-0.12
0.56
27
3
-0.21
0.29
27
4
-0.34
0.08
27
5
-0.42*
0.03
27
6
0.09
0.66
27
7
1.00
0.00
27
8
0.15
0.45
27
9
0.34
0.08
27
10
-0.56**
0.00
27
11
-0.00
1.00
27
12
0.04
0.86
27
13
0.36
0.07
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
100
Table B.35: Spearman’s correlations between the Occlusal Contacts (maxillary)
and the other components for the “undetermined” group.
Component under investigation: 8
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.28
0.15
27
2
0.07
0.72
27
3
-0.46*
0.02
27
4
-0.08
0.70
27
5
-0.20
0.32
27
6
0.10
0.63
27
7
0.15
0.45
27
8
1.00
0.00
27
9
-0.03
0.88
27
10
0.11
0.58
27
11
-0.40*
0.04
27
12
-0.08
0.72
27
13
0.21*
0.04
104
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
101
Table B.36: Spearman’s correlations between the Occlusal Contacts (mandibular)
and the other components for the “undetermined” group.
Component under investigation: 9
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.08
0.68
27
2
-0.44*
0.02
27
3
-0.23
0.25
27
4
-0.25
0.20
27
5
-0.20
0.32
27
6
-0.08
0.70
27
7
0.34
0.08
27
8
-0.03
0.90
27
9
1.00
0.00
27
10
-0.15
0.46
27
11
-0.35
0.08
27
12
-0.23
0.24
27
13
0.06
0.79
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
102
Table B.37: Spearman’s correlations between the Occlusal Relationships and the
other components for the “undetermined group”.
Component under investigation: 10
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
0.23
0.24
27
2
-0.03
0.90
27
3
-0.06
0.77
27
4
0.17
0.40
27
5
-0.08
0.69
27
6
0.29
0.14
27
7
-0.56**
0.00
27
8
0.11
0.60
27
9
-0.15
0.46
27
10
1.00
0.00
27
11
-0.20
0.36
27
12
-0.15
0.46
27
13
0.10
0.61
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
103
Table B.38: Spearman’s correlations between the Interproximal Contacts
(maxillary) and the other components for the “undetermined” group.
Component under investigation: 11
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.45**
0.02
27
2
0.29
0.14
27
3
0.34
0.09
27
4
0.31
0.12
27
5
0.23
0.26
27
6
-0.11
0.59
27
7
0.00
1.00
27
8
-0.40*
0.04
27
9
-0.35
0.08
27
10
-0.18
0.36
27
11
1.00
0.00
27
12
0.02
0.91
27
13
0.27
0.17
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
104
Table B.39: Spearman’s correlations between the Interproximal Contacts
(mandibular) and the other components for the “undetermined” group.
Component under investigation: 12
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.14
0.50
27
2
0.08
0.68
27
3
0.34
0.08
27
4
-0.03
0.90
27
5
-0.15
0.44
27
6
-0.30
0.12
27
7
0.04
0.86
27
8
-0.07
0.72
27
9
-0.23
0.24
27
10
-0.15
0.46
27
11
0.02
0.91
27
12
1.00
0.00
27
13
-0.02
0.91
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
105
Table B.40: Spearman’s correlations between the Total Points Deducted and the
other components for the “undetermined” group.
Component under investigation: 13
ρ
S
N
(Sig. 2-tailed) (Pop.)
1
-0.17
0.39
27
2
-0.08
0.69
27
3
0.10
0.60
27
4
0.05
0.81
27
5
-0.17
0.41
27
6
0.49**
0.01
27
7
0.36
0.07
27
8
0.11
0.59
27
9
0.05
0.79
27
10
0.10
0.61
27
11
0.27
0.20
27
12
-0.02
0.91
27
13
1.00
0.00
27
* Correlation significant at the 0.05 level (2-tailed).
** Correlation significant at the 0.01 level (2-tailed).
106
VITA AUCTORIS
Cristiana Vieira de Araújo, the oldest child of Eustáquio and Terezinha, was born
on December 23, 1981 in Belo Horizonte, Brazil. She was raised in that city.
In 1999, after attending St. David Catholic Secondary School in Waterloo,
Ontario as an exchange student, Cristiana graduated from Colégio Santo Antônio. She
was then admitted into the Dental School of the Pontifícia Universidade Católica of
Minas Gerais. In 2001, her family moved to St. Louis, Missouri, and she took a sabbatical
from dental school to attend undergraduate classes at Saint Louis University and
Maryville University.
Back to Brazil in 2002, she pursued her Doctor of Dental Science degree,
obtaining it in 2005. That same year she was accepted into the orthodontic residency
program at Saint Louis University.
107