This document summarizes a study comparing the outcomes of symmetric vs asymmetric extraction protocols for treating Class II subdivision malocclusions. The study examined pre-treatment and post-treatment models of 51 patients, with 28 patients receiving symmetric 4-premolar extractions and 23 receiving asymmetric 3-premolar extractions. The asymmetric approach showed a tendency for better correction of dental midline deviation and posterior discrepancies. However, there were no statistically significant differences in final occlusion or changes between the two protocols.

1. GOOD AFTERNOON
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SAND ART

2. Under the guidance of :
Dr. Mohammad Mushtaq,
PROFESSOR & Head
By:
Sneh Kalgotra,
2nd Year P.G.
Department of Orthodontics & Dentofacial
Orthopaedics, GDC & H, Srinagar.
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3. Class II subdivision treatment success rate with
symmetric and asymmetric extraction protocols.
 Guilherme Janson,
 Eduardo Alvares Dainesi,
 Jose Fernando
 Karina Jeronimo
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4. About the present article
 Year : 2003
 Volume : 124
 Page number : 257-64
 Received for publication : September 2002
 Accepted for publication : December 2002
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5. prologue
Patients with Class II subdivision malocclusions have Class
I characteristics on one side and Class II characteristics
on the other, primarily because of the distal positioning
of the mandibular first molar in relation to the maxillary
first molar on the Class II side.
 In most patients with Class II subdivision malocclusion,
the maxillary dental midline is coincident to
the mid-sagittal plane, or has a minimal deviation, whereas
the mandibular dental midline is usually displaced toward
the Class II side.
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6.  The possible treatment approaches include
symmetric extraction of 4 premolars and
asymmetric extraction of 3 premolars.The 4-
premolar-extraction approach will produce a
final occlusion with bilateral Class I molar and
canine relationships.
 On the other hand, asymmetric extraction
of 3 premolars (2 maxillary premolars and 1 mandibular
premolar on the Class I side) will produce Class I
canine and molar relationships on the Class I side and
Class II molar and Class I canine relationships on the
Class II side, along with coincidence of the maxillary
and mandibular dental midlines.
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7. Proposed alternative title
Class II subdivision treatment success rate with
symmetric and asymmetric extraction protocols in vitro study :
pre- and post treatment study models comparison using
Grainger’s treatment priority index.
21 words
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8. Material and methods
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9. Material and methods
 The sample was selected retrospectively from the
files of the Orthodontic Department at Bauru Dental
School.
Initial and final study models of 51 patients who initially
had Class II subdivision malocclusions and were treated
with fixed edgewise appliances were collected.
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Group 1 included 28 patients
(11 males, 17 females)
treated with 4 symmetric
extractions, at an
initial mean age of 13.55
years (range, 10.25 to 19.75).
Group 2 included 23 patients
(10 males, 13 females) treated
with 3 asymmetric
extractions, at an initial mean
age of 14.87 years (range,
11.66 to 17.83).

10. Selection criteria
A full Class II molar relationship on one side and a
Class I molar relationship on the other and all
permanent teeth up to the first molars.
 Sample selection was based exclusively on the initial
anteroposterior dental relationship, regardless of any
other dentoalveolar or skeletal characteristic.
 Forty nine patients had Class II Division 1 subdivision
malocclusions (27 in group 1 and 22 in group 2), and 2
had Class II Division 2 subdivision malocclusions (1 in
each group).
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11. Material and methods
A form (Fig) was used
to calculate the TPIon
the pretreatment and
posttreatment study
models of each patient.
The items measured
were restricted to
those describing an
occlusal anomaly.
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12. Two copies of the form (Fig) were required to calculate
the TPIs of each patient.

13. Development of PTI
 A storehouse of invaluable records,
particularly for a developmental study, is
available at the Burlington Orthodontic
Research Centre. Sets of dental casts are on
file from across-sectional sample of patients
was taken.
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14. CLASS II SUBDIVISION

15. Material and methods
Maxillary-to-mandibular dental midline deviation,
overbite, and overjet were measured before and after
treatment with Mitutoyo calipers (Mitutoyo America, Aurora,
Ill).
● Dental midline deviation: transversal distance between
the maxillary and mandibular dental midlines;
● Overbite: vertical distance from the incisal edge of
the mandibular incisor to the perpendicular projection
of the incisal edge of the maxillary incisor on the
labial surface of the mandibular incisor;
● Overjet: horizontal distance between the labial surface
of the mandibular incisor and the incisal edge of the
maxillary incisor.
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16. Material and methods
To determine the error, 30 pairs of study models
were randomly remeasured by the same examiner.
The t test for independent samples was used for
normal distributions and verified by the
Kolmogorov-Smirnov test (for initial and final
values, as well as for the changes).
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17. Critical appraisal of material and
methods
Authors have not considered the skeletal
parameters underlying the problem as they
form significant part of the treatment
planning and cannot be generalized for the
patients.
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18. Results
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19. Results
There were significant differences between the
groups only for initial mean age and final midline
deviation and its change during treatment.
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20. Discussion
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21. Discussion
 Compatibility of the groups
Because both groups were similarly chosen, it could be
expected that these characteristics would be evenly
distributed among them.
 Extractions of either the first or second premolar
was not a concern for several reasons.
a)The probability of extraction of the second
premolars would be similar in both groups.
B) Previous studies have shown that resistance to
mesial movement of the posterior segments is similar
after extracting the first or second premolar.
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22. Discussion
 Another selection criterion was all permanent
teeth up to the first molars before treatment.
 The absence of any tooth might, in some
instances, either simplify or complicate correction
of the malocclusion, and this could interfere with
the results.
 The 2 patients with Class II Division 2 subdivision
 malocclusion were included in the sample because
 there was 1 for each group and also because
correction of the dentoalveolar anteroposterior
discrepancy is similar in both types of Class II
malocclusion
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23. Discussion
Study design
 The best way to evaluate initial malocclusion severity
and final occlusal outcome is a direct clinical
evaluation of each patient.
 However, this would be almost impossible in a
retrospective study.
 The first would be tracking the patients for years
after treatment; many might have changed their
addresses or moved to other cities.
 Even if many of the patients could be found, their
treatment results could be affected by relapses or
dental losses.
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24. Discussion
 The TPI, as developed by Grainger,was selected
among other indexes:
Because it allows for dental cast evaluation.
The most commonly used indexes are valid for
determining treatment priorities.
The TPI is particularly applicable for comparing
orthodontic treatment results.
It is also a good epidemiologic indicator.
 TPI was applied because its reliability has already
been demonstrated.
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25. Discussion
 TREATMENT CHANGES:
 The greater change in overjet is probably due to
the smaller amount of retraction of the
mandibular incisors required in patients with
asymmetric extractions.
There is also a greater difficulty in controlling
the overbite when 4 first premolars are
extracted; this might explain why the 3-premolar-
extraction approach showed a tendency for a
better correction of this vertical irregularity.
There was a better success rate of correcting
the interdental midline deviation with asymmetric
extractions.
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26. Discussion
 It would be more difficult to correct the anteroposterior
discrepancy of the posterior segments on the Class II
side when 4 premolars are extracted. That is because the
Class II molar relationship must be corrected by means
of Class II inter maxillary elastics with extra-oral
headgear, which requires intense patient compliance.
 Correcting the midline deviation in this treatment is
easier, because it will be achieved simultaneously with
closing the extraction space in the mandibular arch, with
little or no need for intermaxillary elastics for midline
correction and patient compliance.
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27. Discussion
Correcting an interdental midline deviation is also more
arduous because the mandibular midline will tend to
displace even more toward the Class II side during
closure of the mandibular premolar extraction space.
In this situation, Class II elastics on the Class II side
and diagonal anterior elastics must be used to help
correct the interdental midline deviation. This creates a
greater dependence on patient compliance for a
satisfactory result and therefore a greater risk for
failure.
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28. Discussion
 Treatment time of these extraction protocols
should also be considered. The number of
extracted premolars has a direct relationship to
treatment time, according to Fink and Smith.
Treatment time is increased by 0.9 months for
each extracted premolar.
 In adult patients with Class II subdivision
malocclusion, extractions would also help to
 decrease these unfavorable consequences.
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29. Critical appraisal of discussion
 Strengths of this study
- It is a simple study.
-The sample was randomly selected to avoid biasing.
-There is also minimal need for Class II and anterior
diagonal intermaxillary elastics, because the molars on
the Class II side will remain in their initial positions and
the correction of the interdental midline deviation will
be consequent to closing the mandibular extraction
space.
-Less trauma to the patient.
- Saving a sound tooth .
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30.  Weakness of the study:
 Authors have not mentioned anything about the
clinical finding in the patient pre-treatment and
post treatment.
 Authors have not considered cephalomertic values
for treatment planning.
 Nor have the authors made any comparions of the
cephalometric values pre and post treatment to
give us a clear picture of the results achieved and
the conclusions made.
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31.  Nor have the authors mentioned any model analysis
they used to decide for the first or second pre molar
extraction.
 Infact authors have failed to mention which pre molar
did they extract.
 Autos have failed to mention any soft tissue
evaluation pre and post treatment.
 Authors have also not mentioned about the direction
of future research in this area.
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32. Conclusion
 Treatment of Class II subdivision malocclusions with
extraction of 3 premolars showed a tendency to a slightly
better treatment success rate in correcting the maxillary-
to-mandibular dental
midline deviation and consequently a tendency for a
slightly better correction of the anteroposterior discrepancy
of the posterior segments, compared with 4-premolar-
extraction treatment.
 There were no statistically significant differences in the
final values of TPI, overbite, overjet, or treatment
changes in these variables between the Class II subdivision
groups treated with either protocol.
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33. Review of literature
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34. Nance , K.N. The removal of second pre-
molars in orthodontic treatment. A.J.O
35:685-695,1949.
 Another early refernce tosecond pre-molar
extraction was by Nance in 1949.
 He spoke of removing second pre-molar in an
effort to keep the incisors over basal bone.
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35. Dewel, B. F, Second premolar extraction in
Orthodontics : Principles, procedures and
case analysis, A.J.O. 41:107,1995
 In 1955 treated and reported a borderline
extraction case I shich extraction of
secondpremolars was utilized. He found relapse of
rotations , but felt that this was less severe than
would have occurred with extraction of first
premolars or no extarctions.
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36. Schoppe, R.J. An analysis of second pre-
molar extraction rocedures, Angle Orthod,
34:292-302,1964
In 1964,Schoppee wrote that since there is
variation in the type and severity of orthodontic
cases, there must be a variety of tretament plans
and appliances . He concluded that when arch –
length discrepancy is seven and a half mms or lss
and thre is no need o retract the incisors, it amy
be advisable to remove second rather than first
pre molars
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37. Logan, Lee R, Second premolar extraction
in class II and Class II, A.J.O 63:114-
147,1973
 That mandibular molars can be moved far too mesially
in Class II cases with extraction of second premolars.
He also stated that such extraction facilitaties
closure of an open bite by reducing posterior vertical
dimension
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38. deCastro,Newton, Second premolar
extraction, A,J,O 65:115-137,1974.
 He wrote that when the arch – tooth discrepancy
is five milimeters or les s ina aptient with good
profile, extraction of second premolars is
indicated.
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39. Joondeph, Donald R. and Ridel, Richard A,
Second premolar serial extraction A.J.O
69:169-189,1976.
 The drift pattern in cases where the second
premolar are absent is more favourable than the
first premolar.
 When lingual movement of incisors is indicated
they advise extraction of first premolars.
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40. Williams, Raleigh and Hosila, Fred J, The
effect of different extraction sites upon incisor
retraction. A.J.O 69:338-410,1968
 Whether diagnosis is based on the Apo line, the
Steiner’s analysis, or the Tweed triangle, the
position of the lower incisor is prime importance
and each clinician has a concept of where he wants
to put the teeth for maximum stability, esthetics
and function. The amount of retarction is
determined by varying the extraction site.
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41. Posen, A, Perioral assesment, Angle
Orthod, 446:118-143,1976
 In 1976 Posen, in his evaluation of the tonicity of
the perioral musculature, advices extraction of
second pre molars when extraction is necessary in
patients with hypertonic lip muscles. His work and
interest is a “pommeter”, an instrument he
designed to measure lip activity, is also a typical
of the swing towards soft tissue evaluation.
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42. Ketterhagen D.H. ,First premolar or second
pre molar extraction ;Angle Orthod,49: 190-
198,1979.
 The combination of lips to E line and lower left
central to Apo was helpful in classifying second
pre molar cases.
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43. Extraction Choice: In the Era of Evidence Based
Orthodontics
 However, the superiority of first premolar over
second premolar extraction is not supported by
recent evidence. Second premolar extraction is in
harmony with Mother Nature’s Rules. Mother
Nature ruled in many instances to eliminate
second premolars from the dentition
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44. Asymmetric extractions in orthodontics
Camilo Aquino MelgaçoI; Mônica Tirre de Souza Araújo
 Asymmetric extractions could simplify and facilitate
orthodontic treatment and mechanics in some specific
cases. As a result, first molars relationship could
differ for right or left sides and this asymmetry
would not bring functional or esthetics problems. In
cases of Bolton discrepancy, a lower incisor extraction
option should be considered. However, the
orthodontist must have total control of the mechanics
used to achieve the best final results at the end of
the treatment.
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45. Cephalometric evaluation of symmetric and
asymmetric extraction treatment for patients with
Class II subdivision malocclusions.
A JO D O July 2007
 It was concluded that the 3-premolar asymmetric
extraction protocol in Class
II subdivision malocclusions produces significantly
less mandibular incisor and soft-tissue retraction
than the 4-premolar extraction protocol.
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46. Smile attractiveness in patients with Class II
division 1 subdivision malocclusions treated
with different tooth extraction protocols
EJO; Eur J Orthod (2011)
 It was concluded that smile attractiveness is
similar in treatment protocols of three, and four
premolar extractions and that widths of buccal
and posterior corridors do not influence smile
attractiveness in these groups.
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47. Critical reflection
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48. There is probably no facet of orthodontic treatment
that has caused as much controversy as the decision
to extract or not to extract or what to extract.
Like a pendulum the popularity of premolar
extraction has swung back nad forth, between the
extremes of non-extraction at any cost and rountine
extractions to achieve arbitrary cephalometric
norms.
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49.  Orthodontists daily make decisions regarding the
plans of treatment to be followed for their
patients carefullyand exhaustingly conducting
cepahlometric studies in combination with clinical
evaluation and model and photographic analysis.
 In spite of the wealth of material available for
planing treatmnt, ulitmately decisions are related
to an entity which we call “clinical judgment”.
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50. Bottom line: Extractions are just at a tool, not good
or bad in themselves. Used right, they improve the
quality of treatment, used wrong they create a poor
result.
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51. Refrences
1. Alavi DG, Begole EA, Schneider BJ. Facial and dental arch
asymmetries in Class II subdivision malocclusion. Am J Orthod
Dentofacial Orthop 1988;93:38-46.
2. Rose JM, Sadowsky C, Begole EA, Moles R. Mandibular
skeletal and dental asymmetry in Class II subdivision malocclusions.
Am J Orthod Dentofacial Orthop 1994;105:489-95.
3. Janson GRP, Metaxas A, Woodside DG, Freitas MR, Pinzan AP.
Three-dimensional evaluation of skeletal and dental asymmetries
in Class II subdivision malocclusions. Am J Orthod Dentofacial
Orthop 2001;119:406-18.
4. Cheney EA. The influence of asymmetries upon treatment
procedures. Am J Orthod 1952;38:934-45.
5. Cheney EA. Dentofacial asymmetries and their clinical significance.
Am J Orthod 1961;47:814-29.
6. Janson GRP, Pereira ACJ, Dainesi EA, Freitas MR. Dental
asymmetry and its implications in orthodontic treatment: a case
report. Ortodontia 1995;28:68-73.
7. Todd M, Hosier M, Sheehan T, Kinser D. Asymmetric extraction
treatment of a Class II Division 1 subdivision left malocclusion
with anterior and posterior crossbites. Am J Orthod Dentofacial
Orthop 1999;115:410-7.
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52. 8. Burstone CJ. Diagnosis and treatment planning of patients with
asymmetries. Semin Orthod 1998;4:153-64.
9. Erdogan E, Erdogan E. Asymmetric application of the Jasper
jumper in the correction of midline discrepancies. J Clin Orthod
1998;32:170-80.
10. Gianelly AA, Paul IAA. A procedure for midline correction.
Am J Orthod 1970;58:264-7.
11. Herschcopf SA. Class II, division 2 malocclusion—nonextraction.
Am J Orthod Dentofacial Orthop 1990;97:374-80.
12. Lewis D. The deviated midline. Am J Orthod 1976;70:601-16.
13. Wertz RA. Diagnosis and treatment planning of unilateral Class
II malocclusion. Angle Orthod 1975;45:85-94.
14. Grainger RM. The orthodontic treatment priority index. Vital
health and statistics series 2, no. 25. Washington, DC: National
Center for Health Statistics; 1967.
15. Ghafari J, Locke SA, Bentley JM. Longitudinal evaluation of the
treatment priority index (TPI). Am J Orthod Dentofacial Orthop
1989;96:382-9. CLASS II SUBDIVISION

53. THANK YOU.
-SNEH KALGOTRA,
PG STUDENT
3-D ART
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