Treatment of Class 2 malocclusion

TREATMENT OF
CLASS 2
MALOCCLUSION
www.indiandentalacademy.com

CONTENTS
• INTRODUCTION
• ETIOLOGY
• CLASSIFICATION
• FEATURES
• TREATMENT
• CONCLUSION

INTRODUCTION
Orthodontic specialty deals with various
malocclusions . Malocclusion is the study
of its cause or causes. Development of
normal dentition and occlusion depends on
number of interrelated factors that include
the dentoalveolar, skeletal and
neuromuscular factor.

etiology
1. HERIDITY
2. TRAUMA
• Prenatal
• Postnatal
1. HABITS
• Finger sucking habit
• Tongue thrusting habit.
• Mouth breathing habit.
• Lip biting habit.

4. DISEASE
A. Systemic disease
B. Endocrine disease
C. Local disease
 Gingival or periodontal disease
 Tumors
 Caries
4. MALNUTRITION
5. UNKNOWN ETIOLOGY

SYNDROMES OCCURRING COMMONLY WITH
MALOCCLUSIONS ARE CLASSIFIED AS:
(COHEN,PROFFIT,BELL,WHITE )
1.Malformation syndromes associated
with mandibular deficiency.
with mandibular prognathism.
with problems of facial height.
with facial asymmetry.www.indiandentalacademy.com

Malformation syndromes associated with
mandibular deficiency:

Pierre Robin syndrome

Treacher Collins syndrome: ( Mandibulo facial
dysostosis; Franceschetti syndrome )

•Nager acrofacial dysostosis:
•Wilder vanck Smith syndrome:
•Mobius syndrome:
•Hallermann – Streiff syndrome

CLASSIFICATION

ANGLE’S CLASS I
• Distal marginal ridge of the upper first
permanent molar contacts and occludes with
the mesial surface of the mesial marginal
ridge of the lower second molar.
• The mesio-buccal cusp of the upper first
permanent molar falls within the groove
between the mesial and middle cusps of the
lower first permanent molar.
• The mesio-lingual cusp of the upper first
molar seats in the central fossa of the lower
first molar.

ANGLE’S CLASS II
• Mesial marginal ridge of the upper second
permanent molar contacts and occludes with the
distal surface of the distal marginal ridge of the lower
first molar
• The distobuccal cusp of the upper 1st permanent
molar occludes in the buccal groove of the lower 1st
permanent molar.
• Angle has sub divided class II malocclusions into
two divisions
Div. I
Div. II

Class II sub division
When a class II molar relations exists on
one side and a class I relation on the
other, it is referred to as Class II
subdivision.
Based on whether it is a Div. 1 or Divi. 2
it can be called Class II Div. 1
subdivision or Class II Div. II Subdivision.

BALLARD’S CLASSIFICATION
Class I : the lower incisal edges occlude with
or lie immediately below the cingulum of the
upper incisors.
Class II : The lower incisal edges lie part to the
cingulum platean of the upper incisors.

BALLARD’S CLASSIFICATION various skeletal
relationship.
SKELETAL CLASS I : The projection of the axis of
the lower incisors would pass through the crowns of
the upper incisors.
SKELETAL CLASS II : The lower apical base is
relatively too far back.
The lower incisors axis would pass palatal to the upper
incisal crown.

CANINE CLASSIFICATION
CLASS I - Mesial slope of upper canine
Coincides with the distal slope of lower
canine
CLASS II - Distal slope of upper canine
coincides with the mesial slope of the lower
canine.

Classification
According to Moyers class II can be divided into Six Horizontal
types and Five vertical types (AJO-DO 1980 Nov (477-494): Differential
diagnosis of Class II malocclusions – Moyers)
Horizontal class II Types
NORMAL SKELETAL PATTERN:Displays normal relationship
of maxilla and mandible to the cranial base and to each other.
Upper and lower dentition are within their normal positions over their
basal bones

TYPE A or DENTAL CLASS II :A Normal skeletal profile
and normal A-P position of jaws. Mandibular dentition is placed
normally on its base but Maxillary dentition is protracted,
resulting in class II molar relationship and increased incisal
overjet and overbite than normal.

HORIZONTAL TYPE B: Displays mid face prominence with a
mandible of normal length. Size of maxilla is increased but
mandible is normal Antero posteriorly

HORIZONTAL TYPE C: Displays class II profile though the
maxilla and mandible are further back beneath the anterior
cranial base than normal the lower incisors are tipped labially,
the upper incisors are either upright or tipped off the base
labially according to the vertical category.

HORIZONTAL TYPE D: Displays a skeletal profile which is
retrognathic because there is a smaller than normal mandible. The mid
face is normal or slightly diminished. The mandibular incisors are
either upright or lingually inclined, where as maxillary incisors are
typically labially positioned. Lip trap can be seen in most of the cases.

HORIZONTAL TYPE E: severe "Class II" profile due
to a prominent midface and a normal or even prominent
mandible. Bimaxillary protrusion Class II malocclusions are
more likely to be horizontal Type E. Both dentitions, in Type E,
have a tendency to be forward on their bases and the incisors
are often in strong labioversion

HORIZONTAL TYPE F: Combination of maxillary
protrusion and Mandibular retrusion with upper and
lower anteriors Upright over their basal bones

Vertical class II types:
1.Vertical type 1or High angle case:
Features:
1. Anterior facial height >Posterior facial height.
2. Mandibular and functional occlusal planes are steeper than normal.
3. Palatal plane may be tipped downwards while the anterior cranial
base tends to be upward.
4. Orthodontists call a "steep mandibular plane" or a "high angle"
case and may be what oral surgeons call the "long face syndrome''

Vertical type 2:
features:
1.Square face.
2.Mandibular plane, functional occlusal plane and palatal planes
are more horizontal and often seem parallel.
3.Gonial angle is smaller than normal
4.Anterior cranial base appears horizontal.
5.Skeletal deep bite

Vertical type 3
Features:
1. Palatal plane tipped upward
2. Decreased upper anterior
facial height
3. Predisposition to open bite.
4. Mandibular plane is steeper
than normal

Vertical type 4:
Features:
1. Mandibular plane, functional occlusal
plane and palatal planes are tipped
downward.
2. Gonial angle is relatively obtuse.
3. Lip line high in the maxillary alveolar
process.
4. Upper incisors are tipped labially and
lower incisors are tipped lingually.
5. Most rare, severe, and anomalous of the
vertical types

Vertical type 5:
Features:
1.Mandibular and functional occlusal planes
are placed normally
2.palatal plane is tipped downward
3.Gonial angle is smaller than normal.
4.Skeletal deep bite may be present
5.lower incisors are labially tipped and
upper incisors are lingually tipped.

IDENTIFYING HORIZONTAL TYPES
• Dental Class II – Type A
• Midface prognathic --- Type B and E
• Mandibular retrognathic --- Type C and D
• Combination of Mandible And Maxillary
extreme skeletal features – Type F

IDENTIFYING VERTICAL TYPES
• Type I – shows large values for angles of PM vertical line
with Mand. Occl. and palatal plane.
• Type II – smaller values for same angles
• Type III – Small Pal Plane angle with PM vertical
• Type IV – found in association with horizontal
Type B
• Type V - Large Pal. Plane angles with Pm vertical, normal
occlusal and mand plane angles, smaller gonial angles

CLASS II DIVISION 2

ClassII Division 2 malocclusions are
frequently present in brachyfacial patterns
with resulting strong musculature. They
generally have moderate to minimum
convexity, but occasionally do have a higher
convexity with resulting orthopedic problems.
The lower facial height and mandibular arc
are below normal range.

CLASSIFICATION OF CLASS II DIV-2
Type A Maxillary four permanent incisors can
tip palatally without occurrence of crowding
 High lip line position
 The lips attain a more dorsal position and a
“dished in” appearance.
BY-VAN DER LINDENwww.indiandentalacademy.com

Type B- The maxillary permanent central
incisor will move palatally gradually.
The available space in maxillary dental arch
is limited.Thus lateral incisors are placed
labially.
The lower lip will become positioned
inferiorly to maxillary lateral incisors and will
contribute to the increase of their labial
inclination.

Type C- There is a marked shortage of
available space in the maxillary dental
arch.
Centals and Laterals are palatally tipped,
and canines, emerges buccally and
labially tipped position.

TYPE A
TYPE B
TYPE C

THERAPEUTIC CLASSIFICATION.
Class II malocclusions can be classified
Therapeutically as:
1.Skeletal class II.
2.Dentoalveolar class II.
3.Functional class II

Skeletal class II
Antero posterior disproportion of jaws in size and position
result in skeletal class II.
Skeletal class II Pattern can result due to:
1. Increased size of Maxilla.
2. Decreased size of Mandible
3.Combination of Increased Maxilla and Decreased
Mandible size

CEPHALOMETRIC FINDINGS INDICATING
CLASS II DUE TO
MANDIBULAR DEFICIENCY: Variant 1:
1. Downward and back ward
rotation of mandible
caused by small size of
ramus and body of
mandible.
2. Decreased posterior facial
height.
3. Steep mandibular plane
angle.
4. Increased ANB angle.
5. Increased angle of
convexity. www.indiandentalacademy.com

6. Increased over jet.
7. Greater positive value of wits appraisal.
8. Posterior position of point B in relation to Na
perpendicular.
9. Normal position of point A in relation to Na
perpendicular.
10.Dental compensation of protruded mandibular
incisors

features:
1. Convex profile.
2. Normal or an increased ramus
length.
3. Flat mandibular plane angle.
4. Normal or increased posterior
facial height.
5. Excessive bony chin masking
the mandibular deficiency but
still have lack of support for
lower lip.
Variant 2:

6. Short anterior facial height.
7. Hyperactive mentalis muscle.
8. Deep anterior overbite
9. Maxillary incisors are lingually inclined masking
the anteroposterior dental discrepancy..
10.Accentuated curve of spee.

MANDIBULAR DEFICIENCY:
Variant 3:Due to retruded position:
Features:
1. Normal or decreased size of mandible.
2. Cranial base angle is more obtuse.
3. Glenoid fossa is more posteriorly positioned.

FUNCTIONAL CLASS II :(FORCED BITE MALOCCLUSION)
Based on different types of movement of mandible from
rest position to occlusion class II malocclusions can be
divided into 3 functional types.
1.Functional True class II malocclusion.
2.Functional class II with posterior sliding
movement
3.Functional class II with anterior sliding movement

CLASS II DIV.1: A MALOCCLUSION IS
CHARACTERIZED BY
•PROCLINED : Upper incisors with resultant
increase in overjet
• A deep incisor OVER BITE can occur in the ant
region.
•A characteristic feature of this malocclusions is
the presence of abnormal muscle activity.
•The upper lip is usually hypotonic, short and
fails to form a lip seal.
•The lower lip cushions the palatal aspect of the
upper teeth, a feature typical of a class II Div 1
referred to as “lip trap”.www.indiandentalacademy.com

• The Tongue occupies a lower position
thereby failing to counter act the buccinator
activity.
• The unrestrained Buccinator activity results in
narrowing of the upper arch at the premolar
and canine regions thereby producing a “V”
shaped upper arch.
• hyper active mentalis activity.
The "three M's": Muscles,
Malformation and
Malocclusion - Graber:
AJO-DO 1963 Jun (418-
450) www.indiandentalacademy.com

Features:
1.Mandibular molars assume a
posterior position with respect to maxillary
1st molars and maxillary arch.
2.Mandibular arch may or may not show
any individual irregularities but usually has
exaggerated curve of spee.
3.Supraversion of mandibular incisors.
4.Mandibular labial gingival tissue is often
traumatized
FEATURES OF CLASS II DIVISION-2

5.Maxillary arch is wider than normal in
inter canine region.
6.Remarkable and constant distinguishing
feature is lingual inclination of maxillary
centrals and labial inclination of lateral incisors.
7.Excess overbite (closed bite)

8.Abnormal path of closure due to combination of
lingual inclination of maxillary incisors and
infraocclusion of posteriors result in mandible
to be forced into retruded tooth guidance with
condylar movement posteriorly and superiorly
in articular fossa creating a displacement.
9.Electromyographic research shows with
dominance of the posterior fibers of both
temporalis and masseter muscleswww.indiandentalacademy.com

Features Class II division 1 Class II division 2
Profile Convex Straight to mild
convexity
Lips
• upper
• lower
• competency
Short
everted
incompetent
Normal
Normal
Competent
Mentalis muscle Hyperactive -
Lower facial
height
Normal or increased Decreased
Arch form “V” shaped Square, “U” shaped
Mentolabial
sulcus
Deep Deep or normal

Palate Deep Normal
Incisors Proclined Centrals are
retroclined
Overjet Increased Decreased
Overbite Deep overbite Closed bite
Crown root Normal angulation Axis of crown and
root are bent and is
referred to as collum
angle
Path of closure Normal Backward
Interocclusal
clearance
Normal/increased/
decreased
increased

Why to correct class II?
1.Esthetics.
2. Function.
3.Trauma.
4.TMJ problems.
5.Periodontal problems.

TREATMENT PLANNING OF CLASS II:
Treatment planning of class II depends mainly on 3
criteria:
1. Nature of malocclusion.
1.Skeletal.
2.Dentoalveolar.
3.Functional.
4.Combination.
2.Severity of malocclusion.
1.Mild.
2.Moderate.
3.Severe.
3.Age.
2.After growthwww.indiandentalacademy.com

General strategies for class II correction
1.Differential restraint and control of skeletal
growth
1.Extra oral traction.
2.Differential promotion of skeletal Growth:
1.Functional appliances.
3.Guidance of eruption and alveolar
development:

4.Movement of teeth and alveolar process
(Camouflage treatment).
1.Extraction treatment.
2.Non Extraction treatment.
5.Training of muscles:
1. Functional appliances.
6.Surgical Translation of parts after growth in severe
cases:
1.Orthognathic surgerywww.indiandentalacademy.com

TREATMENT

ORTHPAEDIC DEVICES USED IN
TREATMENT OF CLASS II

Types of Head gears
1. High pull H.G(parietal)
2. Medium pull H.G(occipital)
3. Low pull H.G(cervical)
4. Combee pull H.G
5. Reverse pull H.G

Center of resistance (CR)
Maxillary first molar
Entire maxilla
Entire maxillary teeth

Clinical location of the Cres:
(Stanley Braun angle 1999;69: 81
- 84)
• An amalgam plugger or similar
instrument in the maxillary vestibule
when the teeth are in occlusion and
the soft tissues and lips are relaxed.
The amalgam plugger is positioned
half the distance from the functional
occlusal plane to the lower border of
the orbit corresponding to the distal
contact of the maxillary first molar.
The instrument is then palpated
externally and a mark is made on the
skin surface corresponding to it.

SELECTION OF HEADGEAR

CERVICAL H.GCERVICAL H.G
• Extrusion of teeth and
steepening of O.P-
Cervical H.G with outerCervical H.G with outer
bow lowbow low
• Extrusion of teeth and
flatenning of O.P-O.P-
Cervical H.G with outerCervical H.G with outer
bow very highbow very high

OCCIPITAL H.GOCCIPITAL H.G
• Intrusion of teeth and
steepening of O.P-
Occipital H.G with outerOccipital H.G with outer
bow post to C.O.Rbow post to C.O.R
• Intrusion of teeth and
flatenning of O.P-
Occipital H.G with outerOccipital H.G with outer
bow ant to C.O.Rbow ant to C.O.R

• Distal force and flatenning of
O.P Combee pull H.G withCombee pull H.G with
outerbow above C.Routerbow above C.R
• Distal force and steepening of
O.P- Combeepull H.G withCombeepull H.G with
outer bow below C.Router bow below C.R
• Distal force with no change in
O.P- Combeepull H.G withCombeepull H.G with
outer bow through C.Router bow through C.R
COMBEE PULL H.GCOMBEE PULL H.G

The most optimum treatment time is between
maturational stages SMI 4 to 7, a very high velocity
period of growth.
The next most desirable time to treat is during
the accelerating velocity period between stages SMI
1 to 3, and
The least desirable time is during the
decelerating velocity period between maturational
stages SMI 8 to 11.
Timing of cervical headgear treatment -
Kopecky and Fishman : AJO-DO 1993 Aug
(162-169)

CLASS II ELASTICSCLASS II ELASTICS

CLASS II
ELASTICS
INCREASED
ACTIVITY OF L.P.M
NEW MANDIBULAR
POSITION
FORWARD MOVEMENT
OF LOWER DENTAL
ARCH
Increased activity
of the retrodiscal
pads
Increased growth
activity of the
condylar cartilage
and lengthening of
the mandible
GPR page 45www.indiandentalacademy.com

FUNCTIONALFUNCTIONAL
APPLIANCESAPPLIANCES

Functional appliances are designed to change the
patients
•Pattern of function,
•Alter the jaw relationships,
•Reprogram the neuromusculature,
thus altering the functional matrix of the face.

Criteria for functional appliances selection
Indications for functional appliances:
•Patient in growth phase.
•Skeletal Class II malocclusions due decreased size of
mandible are good indicators for functional appliances
•Horizontal growth pattern.

Contraindications:
1.Patient in post growth phase.
2.Skeletal Class II malocclusions due to prognathic
maxilla.
3.Skeletal class II due to normal sized and retrusive
positioned mandible(unfavorable prognosis).
4.Gross irregularities in individual tooth
positions(crowding and rotations).
5.Proclined lower anterior teeth.
6.Vertical growth pattern.

Activator:
Indication: Mild to moderate class II
malocclusions with deep bite and
horizontal growth pattern.
Contraindication:
1.Crowding cases.
2.Proclined lower anteriors.
3.In vertical growers.

EFFECTS:
Antero-posterior effects:
1) A forward displacement of the lower arch.
2) A distal movement of maxillary arch.
3). An inhibition of the forward growth of the maxilla.
4) A stimulation of condylar growth.
5) A remodelling of the mandibular fossa.
6) An elimination of interferences which guide the mandible
distally during closure.

The vertical effects:
Successful overbite reduction found to be accompanied by:
1) Inhibition of lower incisor eruption.
2) Facilitation of molar eruption.
3) Encouragement of forward mandibular rotation.
4) An increase in lower face height.

AFFECTS OF BIONATOR:
• Change in tongue position.
• Keeps away buccal musculature.
• Lip seal.
• Mandibular protrusion.
Bionator (Balters appliance):

Effects of Bionator : (AO, 1995:423 - 430:
Changes in soft tissue profile following treatment with the bionator: D.
William Lange, Varun Kalra, B.)
1) Decreased skeletal convexity.
2) reduced overjet and overbite.
3) Decreased facial convexity.
4) Increase in mentolabial angle.

Frankel functional regulator
Indications :
Class II cases with abnormal perioral
muscle function
FR-2
Mechanism of action:
This appliance is used as oral
gymnastic appliance to help in
overcoming abnormal perioral muscle
activity and rehabilitates the muscles
and to establish proper lip seal.

FR 1 : Treatment of class I and class II div 1.
FR1a : Class I with minor to moderate crowding and in
deep bite cases.
FR1b : Class II div 1 where overjet does not exceed 5 mm.
FR1c : Class II div 1 where overjet is more than 7 mm.
FR2 : Treatment of class II div 1 and div 2.
FR3 : Treatment of class III.
FR4 : Open bite and bimaxillary protrusion.
FR5 : Can incorporate head gear, indicated in patient
with high mandibular plane angle and vertical maxillary
excess.
FUNCTIONAL REGULATOR

Twin block appliance:
Indications:
1.In class II malocclusion to modify occlusal
inclined plane in disto occlusion that have a
distal component of force that is unfavorable
for normal forward mandibular development.
2.In patients with poor tolerance to other
functional appliances
Mechanism of action:
Forces of occlusion are used as functional
mechanism to correct malocclusion.

Management of Class II / Div. 2
Malocclusion.
• using the sagittal twin block appliance.
screws are put in the palate for arch
development in antero posterior direction.
They act by 75-80% advancement of
anteriors and 20-25% distalization of
posteriors. In cases where transverse
expansion is required a third screw may be
put transversely in the midline.

90% of all growing patients can be treated
successfully in only one phase by starting
treatment in the late mixed dentition.
1. Utilizing leeway space for crowding
correction
2. 1 mm of intercanine expansion produces a
0.73 mm increase in arch perimeter,
whereas a 1 mm expansion of the molars
produces only a 0.27 mm increase. (Germane N,
et al. AM J ORTHOD DENTOFAC ORTHOP 1991;100: 421-7).
One-phase versus two-phase treatment:
GIANELLY: AJO-DO 1995 Nov (556-559)

3. Molar distalizing: molars can be moved
distally 1 to 2 mm per month during late
mixed dentition period. (Armstrong MM. AM J
ORTHOD 1971;59:217-43).
4. In patients with mandibular retrognathism,
use of functional appliances intent to
stimulate mandibular growth. Less than
10.5 years - 3.2 mm/year mandibular
growth and greater than 10.5 years - 4.0
mm/year (McNamara JA Jr, et al. AM J ORTHOD 1985;88:91-
109).

FIXED FUNCTIONAL APPLIANCES
Indications:
1. Indicated in correction of class II
malocclusions due to retrognathic
mandible in growing patients.
2. In preadolescent patients to utilize
residual growth left.
3. Uncooperative patients.

SAGITTAL CHANGES:
• Restraint of maxillary growth: headgear like
effect
• Stimulation of mandibular growth
• Proclination of lower incisors
• Posterior movement of upper molars:
headgear like effect.
VERTICAL CHANGES:
• Eruption of lower molars; intrusion of lower
incisors: reduction of overbite
• Proclination of lower incisors contributing
to overbite reductionwww.indiandentalacademy.com

A. Rigid
1. Herbst appliance
2. Mandibular anterior
repositioning appliance
(MARA)
3. Mandibular protraction
appliance (MPA)
4. Eureka spring
5. Universal bite jumper
6. Mandibular corrector
7. Biopedic
8. Mandibular Advancing
Repositioning
Splint(MARS)

B. Flexible
• Jasper Jumper
• Churro Jumper
• Adjustable bite
corrector
• Klapper Super
Spring Corrector
• Forsus

C-II CORRECTION :
a likely scenario (Graber & Vanarsdall - pg 481)
Skeletal effects:
•Condylar growth amount during treatment (1-3 mm).
•Fossa displacement, growth, & adaptation (3-5 mm).
(BUSCHANG P H et al AJO 113;437, 1998)
•Elimination of functional retrusion (0.5-1.5 mm)
(upward and backward path of closure reduced).

• More favorable growth direction- trabecular
orientation (0.5-1.5 mm).
• Withholding of downward & forward maxillary
growth (1-1.5 mm).
• Differential upward & forward eruption of buccal
segments. (1.5-2.5 mm).
• Headgear effect (0.5-0.0 mm).

Regardless of the type of functional appliance used
(1) optimizing mandibular growth,
(2) redirection of maxillary growth,
(3) lingual tipping of the maxillary incisors,
(4) labial tipping of the mandibular incisors,
(5) mesial and vertical eruption of mandibular molars, and
(6) inhibition of mesial movement of the maxillary molars.
A combination of orthodontic (60% to 70%) and orthopedic
(30% to 40%) movements provides the correction necessary for
successful treatment.
AJO-DO 1989 Mar (250-258): REVIEW ARTICLE - Bishara
and Ziaja

Indications for Molar distalization
• Lack of space for eruption of premolars due to mesial
migration of permanent first molars
• End on molar relationship with mild to moderate space
requirement
• Cases with less than a full cusp class II molar relationship
• Good soft tissue profile
• Borderline cases
• Mild to moderate space discrepancy with missing 3rd
molars/2nd
molars not yet erupted

 Headgears
 Wilson Bimetric arch
 Modified Nance Lingual appliance
 Molar distalization with magnets
 Use of Super elastic NiTi
 NiTi Double Loop system
 Jones Jig

 The Pendulum
appliance
 Fixed piston appliance
 The K-loop appliance
 The distal jet
 Lokar Molar Distalizing
Appliance
 Franzulum appliancewww.indiandentalacademy.com

Camouflag
e

Treatment of malocclusion with underlying
mild or moderate jaw discrepancies, which can
achieve a good dental occlusion, through
extraction of certain teeth, to mask skeletal
problem.

IDEAL CASE

oMild to moderate
skeletal Class II Jaw
oReasonably good
alignment ( so that Xn
spaces can be used
for retraction and not
to relieve crowding)
oGood vertical facial
proportions, neither
extreme short face
(skeletal deep bite)www.indiandentalacademy.com

NOOOO……..

oSevere class II,
oModerate or severe
Class III,
oVertical Skeletal
Discrepancies.
oPatients with
severe crowding or
protrusion of
incisors in whom
extraction spaces
would be required
to align remainingwww.indiandentalacademy.com

“ENVELOPE OF DISCREPANCY”

Outer envelope
Inner envelope Orthodontic tooth movement
alone
Middle envelope Orthodontic tooth movt.+
Growth modification
Orthognathic surgery

Envelope of discrepancy for Maxilla

Envelope of discrepancy for mandible

SURGICAL CORRECTION OF CLASS II
Surgical option should be choosen in following cases:
1.Severe skeletal discrepancy or extremely severe dento
alveolar problem.
2.Adult patients
3.Young patients with extremely severe or progressive
deformity.
4.Good general health status of patient.

Cephalometric Assessment
Useful ratios:
1) SN: Maxilla: Mandible = 20:14:21
2) Corpus:Ramus = 7:5
3) Middle face : Lower face = 45 % : 55%
4) Postr:Antr face height(Jarabak)=62– 64%
5) Nasal : Labial = 1:4( Nasolabial angle )

Cephalometric Assessment
Useful ratios:
20
21
14
1
4
5
7

Surgical & orthodontic phases of
treatment.
3 phase
1. pre surgical orthodontic phase.
2. surgical phase.
3. post surgical orthodontic phase.

Pre surgical orthodontics
• Main aim is to position the teeth in the arches ,so that
the dental arches become compatible,facilitating their
proper placement during surgery.
• Main tooth movements commonly required include
intrusion,levelling,derotation,closure of
spaces,correction of anterior / posterior crossbites
&co-ordination of the arches.

Extraction patterns
Extraction of
upper second premolars and
lower first premolars
Basically – the desired final postthe desired final post
surgical position of the incisors shouldsurgical position of the incisors should
be achieved presurgicallybe achieved presurgically

Leveling the mandibular arch.
• Accentuated curve of spee can be corrected by two
methods
1. Intrusion of incisors.
2. Extrusion of premolars

• If the incisors are elongated & face height is
normal / excessive they must be intruded to
prevent problems in controlling face height
at surgery.
• Face is short & distance from lower incisal
edge of the chin is normal leveling by
extrusion of posterior teeth is indicated.

Le Fort I maxillary osteotomy
– Posterior repositioning
– Superior repositioning
Maxillary anterior segmental osteotomy:
– Dentoalveolar proclination.
– Bimaxillary protrusion.
Interdental corticotomy : In class II div I cases
with maxillary prognathism and anterior spacing
MIDFACE SURGERIES

Mandibular deficiency can be corrected
surgically by
 Bilateral Saggital split osteotomy (Treatment
of choice).
 C osteotomy.
 L osteotomy.
 Vertical ramus osteotomy
MANDIBULAR SURGERIES

DISTRACTION
OSTEOGENESIS

A process of new bone formationbetweenA process of new bone formationbetween
the surfaces of bone segments graduallythe surfaces of bone segments gradually
separated by incremental tractionseparated by incremental traction
It was introduced by Ilizarov in 1951.
In 1989, McCarthy was the first to clinically
apply an external fixation device for
mandibular lengthening.

Distraction appliances of the maxillofacial region
can be divided into:
•Extra-oral appliances
•Unidirectional devices
•Bi-directional devices
•Multidirectional devices
•Intra-oral devices
•Tooth-borne devices
•Tissue-borne devices
•Hybrid (tooth and tissue borne) devices

Uni-Directional Distractor
Bi-Directional Distractor
Multi-Directional Distractor

MERITS OF DISTRACTION
• Potential for greater movements
• Potential for less relapse
• No donor site morbidity

DISADVANTAGES
• Patient compliance
• Socially acceptability
• Intensive post-op monitoring
• Lengthy treatment time
• Mechanical failures
• Procedure to remove distractors

Retention and
Stability

Retention and stability: A review of the
literature - Blake and Bibby (Am J Orthod
Dentofacial Orthop 1998;114:299-306)
Expansion is thought to be better tolerated in
Class II Division 2 cases than Class I and Class
II Division 1.
Adequate interincisal contact angle may prevent
overbite relapse and good posterior
intercuspation prevents relapse of both crossbite
and AP correction.www.indiandentalacademy.com

Overbite relapse tends to occur in the first 2 years
posttreatment and maintenance of intercanine width is
thought to increase stability.(30% to 50% of the
correction is retained)
Growth may aid in the correction of orthodontic
problems but may also cause relapse of treated cases.
Improved occlusion in the mixed dentition provides
better long-term stability (Dugoni SA et al Angle Orthod
1995;65:311-20).

RELAPSE REVISITED (James L. Vaden et al AJO DO
1997; 111: 543-53)
• Expansion in maxilla is retained whereas expansion in
mandible is lost.
• 78% of incisor overbite correction is lost in 15 years of
treatment.
• 58 % of mandibular incisor irregularity correction
maintained.
• 96% of maxillary irregularity correction maintained.

Relapse and Stability

The choice of appliance should be based on the proper
diagnosis. Clinicians should be thoroughly familiar
with the appliances they are using, including their
potential benefits and limitations. Clinicians also
should be aware of the effects of these appliances on
the dentofacial structures when formulating a
treatment plan for each individual patient.
CONCLUSION

REFERENCES
• Proffit WR: Contemporary Orthodontics
Mosby
• Moyers RE: Handbook of Orthodontics
• Fonseca – Oral and Maxillofacial Surgery
• Graber, Vanarsdall : current principles and
technique.
• Graber , Rakosi, Petrovic : dentofacial
orthopedics with functional appliances.

Treatment of Class 2 malocclusion

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