ANGLE ORTHODONTIST(

1. ANGLE ORTHODONTIST
1975 April
Volume 45(2)
PRESENTED BY
PRIYA SHARMA
PG IST YEAR

2. HISTORY
First formed in 1930
First Editor-in-Chief- Mrs. Angle and Dr. Frank A. Gough was the
 First Business Manager- Dr. Frank A. Gough
The society was formed by the members of the
Edward H. Angle Society of Orthodontia at a meeting in Chicago in
1930.
Dr. Allan G. Brodie presented the first scientific paper of this
journal.
 For the first 17 years, this was the only journal devoted strictly to
orthodontics because
American Journal of Orthodontics and Dentofacial Orthopedics

3. THE ANGLE ORTHODONTIST
Bimonthly peer-reviewed medical journal covering orthodontics
 Published by the E. H. Angle Education and Research Foundation
 Official journal of the Edward H. Angle Society of Orthodontia.
The editor-in-chief is Steven J. Lindauer (
Virginia Commonwealth University).
 The journal has a 2014 impact factor of 1.225.

4. IMPACT FACTOR
The impact factor (IF) is a measure of the frequency with which the
average article in a journal has been cited in a particular year.
2014 -1.225.
JUNE 2024 - 3

5. Journal Title: Angle Orthodontist
Publisher: Allen Press Inc.
ISSN: 33219
Type: journal
Journal Scope: Dentistry; Medicine
Country: United States
SJR: 1.167
Quartile: Medicine (miscellaneous) (Q1); Orthodontics (Q1)

6. DIAGNOSIS & TREATMENT
PLANNING OF UNILATERALCLASS II
MALOCCLUSIONS
AUTHOR
ROBERT A WERTZ
401 South Dearborn Kankakee, Illinois 60901

7.  Unilateral Class II malocclusion is a common orthodontic
condition that involves an asymmetric relationship between the
maxillary and mandibular arches, often caused by skeletal or
dental discrepancies.
 Unilateral Class II cases can result from various factors such as
tooth drift, missing teeth, or developmental anomalies. Identifying
the underlying cause of the asymmetry is essential for successful
treatment, as it can guide clinicians in choosing the most effective
therapeutic approach.
INTRODUCTION

8.  Orthodontists must utilize appropriate diagnostic tools
and carefully assess both skeletal and dental components
to formulate an individualized treatment plan.
 Among these tools, the Symmetropost—a device used to
study the symmetry of dental arches—is highlighted as an
invaluable diagnostic aid.
 By understanding the factors contributing to unilateral
Class II malocclusions, orthodontists can implement
effective treatment strategies, either through extraction or
non-extraction methods, to achieve both functional and
aesthetic goals.

9. Fig. 1 Symmetropost in
analysis of a relatively
symmetrical maxillary arch.
Fig 2
Fig 3
Fig. 2 Symmetropost
demonstrating forward
position of maxillary
right buccal segment.
Fig. 3 Study of
mandibular arch sym-
metry with aid of
symmetropost.

10. AIM
 Discuss the diagnostic role of the Symmetropost in identifying
asymmetries in the dental arches.
 Present various case studies demonstrating different treatment
strategies for unilateral Class II malocclusions.
 Provide a framework for developing individualized treatment
plans that address both dental and skeletal components of
unilateral Class II.
 The aim of this article is to explore the diagnostic process,
treatment planning, and management of unilateral Class II
malocclusions. Specifically, it intends to:

11. MATERIALAND METHODS
◦ Diagnostic Tools
The key diagnostic tool discussed in this study is the Symmetropost.
Constructed from a T-shaped wire structure,
 Used to assess the symmetry of the dental arches, particularly in cases of
Class II malocclusions.
Allows clinicians to visualize and measure the alignment of the maxillary and
mandibular arches, aiding in the identification of asymmetries that contribute to
unilateral Class II issues.
The use of facial photographs, dental casts, and radiographs further
complements the diagnostic process.
These tools help clinicians assess the position of the maxillary and mandibular
arches, as well as any skeletal discrepancies.

12. CASE STUDIES
Three clinical cases are presented in this
article to demonstrate different approaches
to managing unilateral Class II
malocclusions:
Case 1: A unilateral Class II on the left
side due to forward positioning of the
maxillary left buccal segment.
Case 2: A unilateral Class II on the right
side due to the loss of the mandibular right
first molar, causing posterior drifting of
the mandibular arch.
Case 3: A skeletal-based unilateral Class
II with retrusion of the mandibular right
CASE 1
CASE 2
CASE 3

13. TREATMENT APPROACHES
Each case is managed using a combination of diagnostic tools and
treatment strategies:
Extraction Therapy: In certain cases, the extraction of teeth (e.g.,
first bicuspids) is considered to create space and correct the asymmetric
occlusion.
Non-Extraction Therapy: Functional appliances and headgear may
be used to guide the growth of the arches and correct the molar
relationship.
Retention Protocols: Post-treatment retention strategies are employed
to maintain the achieved occlusion.

14. RESULTS
Unilateral Class II on the Left Side

Pre-treatment: The maxillary left buccal
segment was forward, resulting in a Class II
molar relationship and a lack of space for
cuspid eruption.

Post-treatment: Extraction of the first
bicuspid on the Class II side of the maxillary
arch created sufficient space to correct the
molar relationship and improve arch
symmetry (Fig. 7).
Fig. 7 Pretreatment maxillary cast depicting forward
position of maxillary left buccal segment creating a
unilateral Class II molar relation and lack of arch length.
Posttreatment cast following uni-lateral extraction to
create arch length, maintain anterior symmetry and allow
finishing of molar in Class II relation.

15. Unilateral Class II on the Right Side
Pre-treatment: The mandibular right first
molar was lost, leading to drifting of the
second molar and posterior teeth.
Post-treatment: Extraction of the
maxillary first bicuspids and mandibular
first bicuspid, along with the use of Class II
elastics, corrected the molar relationship
and restored dental arch symmetry (Fig. 8).
Fig. 8 Pretreatment and posttreatment
maxillary casts where first bicuspids
were extracted to create arch length and
left first molar was extracted to effect
Class II correction. Note the symmetry
of arch form in the treatment result.

16. Case 3: Skeletal-Based Unilateral Class
II
Pre-treatment: The mandibular right
side was retruded, with the mandibular
midline shifted to the right.
Post-treatment: Extraction of maxillary
first bicuspids and mandibular second
bicuspids, along with alignment of the
arches in a Class I relationship, achieved
successful correction (Fig 9)
Fig. 9 Loss of mandibular right first molar
resulting in a Class II buccal seg-ment
relationship as forward drifting of the second
molar was accompanied by posterior drifting
of the bicuspids and cuspid. Note that the
incisors remained symmetrically placed as
they occupy part of the left cuspid space.

17. DISCUSSION

Unilateral Class II malocclusions

Complex cases

Require careful diagnosis and personalized treatment
planning.

The diagnostic use of the Symmetropost is valuable in
identifying and addressing asymmetries in the dental arches.

Its ability to detect deviations in the position of the maxillary
and mandibular arches helps clinicians pinpoint the root
causes of the malocclusion.

18. 
Treatment planning for unilateral Class II cases
Highly individualized

Clinician must consider both skeletal and dental factors, the patient's
growth potential, and the desired esthetic outcomes.

The case studies presented illustrate the flexibility of treatment options
available, both extraction and non-extraction methods are effective
depending on the specific characteristics of the malocclusion.

In growing patients, functional appliances can be used to modify the
position of the dental arches,

In adult patients may require surgical intervention in severe skeletal
cases.

The retention phase is crucial for ensuring the stability of the achieved
results, particularly when dealing with asymmetries.

19. CONCLUSION
Unilateral Class II malocclusions present a significant challenge in
orthodontics, but with careful diagnosis and an individualized treatment
plan, optimal results can be achieved.
The Symmetropost is a valuable tool in identifying dental
asymmetries, allowing for precise treatment planning. The cases
discussed highlight the importance of considering both dental and
skeletal factors when selecting an appropriate treatment strategy.
 Whether through extraction or non-extraction methods, the ultimate
goal is to achieve a functional, stable, and aesthetically pleasing
occlusion for the patient.

20. THE LONGITUDINAL STUDY OF REST
POSITIONAND CENTRIC OCCLUSION
E. H. WILLIAMSON, J. B. WOELFEL, B.H. WILLIAMS
Department of Orthodontics College of Dentistry The Ohio State University
Columbus, Ohio 43210

21. INTRODUCTION
The physiologic rest position (PRP) and centric occlusion (CO) are
important parameters in dental occlusion, and their stability has been
questioned. Studies have examined these positions and results vary
regarding their consistency over time.
Boucher defined PRP as the habitual, postural position of the mandible
when the patient is at rest in an upright position, with the condyles in a
neutral, unstrained position in the glenoid fossa.
Rest position and centric occlusion are considered fundamental in
understanding mandibular function.
 It is important to assess whether these positions exhibit stability over
time.

22. AIM
To determine the degree of stability or instability of PRP and CO in
dentulous individuals with random occlusions over a 15-year period.
Focusing on lateral cephalometric radiographs, electromyography, and
clinical observation.
The study seeks to determine whether these positions remain stable or
undergo significant changes with age, occlusal adjustments, or dental
treatment.

23. MATERIAL & METHODS
Sixteen dentulous subjects with random occlusions were
selected for this study. Cephalometric radiographs taken in
1958-1960 were compared with similar radiographs taken
in 1973.
These radiographs were analyzed using identical
techniques and equipment, including cephalometric x-rays,
and electromyography for determining rest position.

24. SUBJECT 1958-60 (SIX REST POSITION) 1973
1 135-138 135-137
2 147.5-151 150-151
3 145.5-147 146.5-147
4 132-136 134.5-136
5 144.5-145 143.5-145
6 139-141 137.5-139
7 136.5-139 138-139
8 137-137.5 137-137.5
9 129-129.5 129-129
10 133-134 132-132.5
11 131-134 133.5-134
12 143-144 144-145
13 140,5-143 142-142
14 141-144.5 140-141
15 137-139 134-136
16 133.134 134.5-136
RANGES OF NASION MENTON MEASUREMENTS IN MM AT REST

25. SUBJECT SNM NASION MENTON AT
REST
NSM MAND. PL.-SN
1 .2 .9 .4 .3
2 .1 1,6 .6 .3
3 0 .7 0 .6
4 .1 .6 .1 1.0
5 0 .4 0 .2
6 .2 1.7 .2 .6
7 .7 1.0 .7 .3
8 .3 .1 .7 0
9 .2 .3 0 .6
10 ..2 1.3 .1 1.5
11 .4 1.0 1.1 .8
12 0 1.1 .4 .1
13 .8 .3 .1 1.3
14 .5 1.5 1 .8
15 1.4 4.1 1.4 .9
16 .4 1.3 .6 1.0

26. PROCEDURE
Lateral cephalometric radiographs were taken for each subject in rest position
and centric occlusion.
Electromyography was used to measure electrical activity from the anterior
belly of the digastric and temporal muscles to determine the minimal activity
associated with rest position.
Measurements included both linear (such as nasion to menton) and angular
(such as Sella-Nasion-Menton) dimensions.
Control measurements were also recorded to eliminate potential distortions or
errors.
A total of three radiographs were taken: one in rest position, one in centric
occlusion, and one with the mouth completely open to visualize the condyle
position.

27. RESULTS
Rest Position remained stable for most subjects,
 10 of the 16 subjects showing minimal changes in measurements between
the initial and final cephalometric radiographs.
The control measurement (nasion to incisal edge) showed no significant
changes only one subject showed a vertical increase in occlusion.
Vertical dimensions of centric occlusion increased in 10 subjects, remained
same in 4 subjects, decreased in 2 subjects.
The angular measurements (Sella-Nasion-Menton and Nasion-Sella-Menton
angles) showed little variation, with differences of 0 to 1.5 degrees between
baseline and 1973.
Changes in centric occlusion attributed to dental restorations, crowns and
partial dentures, with no evidence of TMJ dysfunction or pain.

28. DISCUSSION
The results suggest rest position and centric occlusion remain r stable over a 15-year
period in most individuals. While some changes were noted in the vertical dimension
of centric occlusion which were not significant enough to disrupt the overall balance
of the occlusion.
Rest position is determined by a complex coordination of muscular and
proprioceptive forces, and this stability can be affected by factors like dental
interventions or age-related changes.
In majority of the subjects in this study, there was a small range of stability
observed, most individuals showed minimal deviation over time.
The findings aligned with earlier studies suggesting that rest position tends to remain
fairly stable throughout life, despite minor variations due to malocclusion or tooth
loss.
Additionally, while dental restorations may alter occlusion slightly, they did not lead
to any significant changes in the rest position.

29. CONCLUSION
This 15-year longitudinal study has demonstrated that physiologic rest
position and centric occlusion tends to exhibit stability over time, with only
minor variations observed in a few subjects.
Vertical changes in centric occlusion were linked to dental treatments, but
these did not result in significant changes in rest position or cause dysfunction.
The results support the idea that rest position and centric occlusion are
relatively stable for most individuals, and any changes over time can be
attributed to external factors such as dental procedures.
Further studies could explore the long-term effects of extensive dental
restorations or age-related changes in greater detail.
Nonetheless, this study contributes valuable insight into the understanding of
mandibular positions over an extended period.

30. ASYMMETRY OFTHE HUMAN
FACIALSKELETON
P.S. VIG, A.B. HEWITT.
Dental School, London Hospital, London, E.1 2A.D England

31. INTRODUCTION
Measurements of the craniofacial skeleton, whether directly from
living subjects, dry skulls, or cephalometric radiographs, are used in
the investigation of facial growth, jaw development, and dentition
Previous studies, such as those by Woo, found asymmetry in the
cranium, with the right side being larger, reflecting the development of
the right hemisphere of the brain, while the left side of the facial
complex (specifically the zygoma and maxilla) exhibited asymmetry.
These findings have contributed to a growing understanding of facial
asymmetry,
But much of the lower third of the facial skeleton has not been
extensively studied.

32.  Direct measurements of facial soft tissue form may be distorted, they have provided
valuable insights into facial growth.
 Indirect methods, like three-dimensional cephalometric radiographs allowed for
more accurate assessments of facial asymmetry. Clinicians in oral surgery and
orthodontics seek standardized objective guidelines to assess facial asymmetry,
especially in children, displaying varying degrees of asymmetry.
This study aims to evaluate facial asymmetry through standardized PA ceph..
 To investigate the relative asymmetry of facial components.
It provides a systematic diagnostic tool to analyze asymmetry and understand its
underlying causes and development.

33. AIM
The aim of this study was to investigate the extent of facial
asymmetry in normal children by analyzing the standardized
posteroanterior cephalometric radiographs.
To assess the variations in the right and left facial components.

34. MATERIALAND METHODS
63 randomly selected cephalometric radiographs of normal
children (aged 9–18 years, mean age 14) who were referred to an
orthodontic clinic were traced. These children did not have any
clinically noticeable facial asymmetry or gross dental deviations.
 The sex distribution was 20 males and 43 females. The
radiographs were traced by one of the authors, with the method's
error determined using double determination. The anatomical
landmarks used for measurement included the sella, anterior nasal
spine, zygomatic points, and mandibular regions.

35. 1. SELLA
6 ANT NASAL SPINE
2. MEDIAL EXTENT OF
ORBIT.
7 ZYGOMATIC POINT
3 INFERIOR EXTENT OF
ORBIT
8 UPPER MOLAR POINT
4 CONDYLAR POINT
9 INCISOR POINT
5. MASTOIDALE
10. GONION
11 MENTON

36. MIDLINE AXIS OF MAXILLARY
REGION
MIDLNE AXIS OF MANDIBLE
REGION
ROENTGENOGRAPHIC
LANDMARKS
BISECTOR OF LIME JONING
BILATERAL LANDMARKS
Fig. 2 ASYMMETRY OF THE
MIDDLE AND LOWER THIRD OF
THE FACE COMPARED.

37. X MIDLINE AXIS REPRESENTING
MAXILLARY REGION
O. BILATERAL LANDMARKS
BISECTOR OF LINE JOINING
BILATERAL LANDMARKS
MIDLINE AXIS REPRESENTING
MANDIBULAR REGION
AA, ANATOMICAL AXIS OF FACE
Fig. 3 METHOD OF CONSTRUCTION OF
THE ARBITRARY ANATOMICAL AXIS
AND LONGITU-DINAL AXES OF THE
MIDDLE AND LOWER THIRDS OF THE
FACE.

38. A CRANIAL BASE REGION
LATERAL MAXILLARY
REGION
C. UPPER MAXILLARY
REGION
D. MIDOLE MAXILLARY
REGION
E LOWER MAXILLARY
REGION
F DENTAL REGION
G. MANDIBULAR REGION
Fig. 4 TRIANGULATION OF
THE FACE.

39. Two longitudinal axes representing the midline of the maxillary and mandibular
regions were drawn. These axes were used to calculate the angle of divergence,
which indicated the degree of asymmetry between the upper and lower thirds of the
face.
Triangulation method was used to assess the relative asymmetry in different facial
components, including the cranial base, maxillary regions, and mandibular regions.
The sides of the triangles were measured to the nearest 0.5 mm, and the areas of
the respective triangles were calculated, with standard errors determined by
Dahlberg's method. Paired t-tests were used to analyze the data.

40. RESULTS
The middle third of the face (cranial base and maxillary regions) exhibited a
leftward asymmetry, with 67% of subjects showing a deviation in this region. The
mean angle of divergence between the upper and lower thirds of the face was
found to be 1.9 degrees (±0.25).
The maxillary regions were generally larger on the left side, consistent with
findings from previous studies by Burke and Mulick.
However, the mandibular and dento-alveolar regions showed a greater degree of
symmetry, suggesting that the lower third of the face is more symmetrical
compared to the upper third.

41. DISCUSSION
Facial asymmetry is a well-documented phenomenon, with certain
body asymmetries being more common on one side. For instance,
hypoplasia of the first branchial arch is often more frequent on the
right side, while cleft lip tends to occur more on the left.
This study found that the left side of the facial complex, particularly
the maxillary regions, was larger in most cases, which is in line with
prior studies.

42. The findings suggest that facial asymmetry may be a compensatory adaptation
during facial growth, where facial components adjust to achieve functional
integration.
 Scott's theory that the facial skeleton is a unit made up of semi-independent
regions could explain the observed variations in asymmetry, with some regions,
such as the orbits and nasal cavities, showing more independence in their growth
and shape.
Additionally, the functional adaptation during mastication may help compensate
for minor asymmetries, allowing for optimal dental occlusion even when
underlying facial asymmetries exist.
The role of lingual and labial musculature in molding the dento-alveolar
structures may also contribute to reducing asymmetry during tooth eruption,
ultimately minimizing the impact of basal asymmetries on facial appearance.

43. CONCLUSION
This study has provided insights into the extent of facial asymmetry
in normal children
It revealed that the left side of the maxillary regions tends to be
larger, contributing to the overall asymmetry of the face, particularly
in the upper third.
The mandibular and dento-alveolar regions were found to be more
symmetrical, suggesting that compensatory mechanisms operate
during facial growth to integrate the facial components. The findings
underscore the importance of considering both structural and
functional adaptations in understanding facial asymmetry.

44. THANK YOU