Diagnosis & early treatment of class 3 /certified fixed orthodontic courses by Indian dental academy

DIAGNOSIS & EARLY
TREATMENT OF CLASS III
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Evidence based treatment
• What we know
• What we do not know
• What we know that’s just not so
Profitt
• Treatment of Class III malocclusion is like
opening a Pandora's box

• Growth in 3 planes of space declines to
adult levels at different times
• Transverse - preadolescent
• A-P - adolescent
• Vertical - post adolescent
Makes sense to time procedures at
different times for different space
problems

• Determine best time for orthodontic
treatment
• Cost
• Principles related to timing

PLAN TREATMENT LATER?
- after adolescent growth spurt?
Prolonged growth in an unfavorable
pattern
- Class III, excessive mand. growth
- Orthodontic control of excessive
growth difficult
- Successful orthodontic camouflage
requires growth prediction
- Early surgery often unstable

Using Cervical Vertebral Maturation
System – CVMS
• Start early treatment
• CS 1 – 2 years before peak
• CS 2 – 1 year before peak
• CS 3 & CS 4 – pubertal spurt peak
• CS 5 & CS 6
• Franchi, Bacetti, McNamara 2005

Can you predict long term response
from pretreatment cephalometric
readings ?
• AJO/DO 2004 JULY– FRANCHI , BACETTI
• Discriminating analysis based on ---
ramus height
cranial base angle
mandibular plane angle
80% identified correctlywww.indiandentalacademy.com

Range of Class III malocclusion
Class I Psuedo Class III True Class III
Prognosis better

Diagnostic Criteria for Pseudo &
True Class III patients
• Family history
• Incisal relationship
• CO/CR discrepancy
• Molar relationship
• Difference in the WITS Analysis
• Gonial angle
• Growth rate & direction with time

PSEUDO CLASS III –
FEATURES
1. Positional malrelationship
2. Reflex functional mandibular
protraction
3. Retroclined maxillary incisors & / or
proclined mandibular incisors
4. Acquired muscular reflex

Diagnostic Criteria
Clinical Profile
a. Profile may / may
not be concave
b. Profile improves as
mandible drops from
occlusal contact
relationship to
postural position
c. Translation of
mandible forward
can be confirmed by
gently placing the
finger tips over TMJ
during opening &
closing.
Cephalometric
Profile
a. Wit’s appraisal
shows BO-AO 0 to
- 4 mm ( functional
occl. plane)
b. SNA,SNB angles
normal range. ANB
normal.
c. Maxillary incisors
may /may not be
more upright than
normal.

Differential Diagnosis of Class III
• Dental assessment
• Functional assessment
• Clinical assessment
• Cephalometric assessment

Dental Assessment
Molar relationship & Overjet
• Class III molar Class III molar
Negative overjet Positive overjet
Functional assessment Retroclined lower
CO/CR shift incisors
no shift shift
correct it
Clinical & Cephalometric
assessment
True Class III Psuedo Class III Compensated Class
III
DIFFICULT

Functional Relationships Of CLASS III
• Relationship between rest position & full
occlusion in sagittal plane –
• Rotational movement without sliding
• Closing movement with anterior sliding
• Closing movement with posterior sliding
• Pure rotational movement from postural
rest to occlusal position

• Rotational movement without slide –
• Non-functional, true CLASS III –
unfavorable prognosis

• Rotational movement with anterior slide –
• During articular phase – mandible shifts
forward into prognathic forced bite –
functional non-skeletal – psuedo CLASSIII
– favorable prognosis

• Rotational movement with posterior slide –
• Pronounced mandibular prognathism,
mandible may slide posteriorly into
maximum intercuspation – masks true
sagittal dysplasia – unfavorable prognosis

TRUE FORCED BITE – PSEUDO
FORCED BITE
• Anterior slide in both
• True forced bite = pseudo Class III =
favorable prognosis
• Pseudo forced bite = true Class III =
unfavorable prognosis
• Differentiation by cephalometrics
• Partially dentoalveolar – compensated
skeletal Class III

TRUE FORCED BITE – PSEUDO
FORCED BITE
• Upper incisors
tipped labially &
lower incisors
lingually
• Mandible guided
toward anterior
while closing
• Placing incisors in
correct axial
position reveals a
negative overjet –
eliminates anterior
slide

PROFILE / CLINICAL ASSESSMENT
• Check proportionate
positions of maxilla &
mandible in A-P plane
• Place patient in
natural head position
• Drop line from bridge
of nose to base of
upper lip & second
line from base of
upper lip to chin
• Straight or concave
profile in young
patients indicates
skeletal Class III

CEPHALOMETRIC ASSESSMENT
• Best analysis – relate maxilla to mandible
• Discriminant analysis found WIT’S
appraisal most decisive in distinguishing
camouflage from surgical treatment ( AJO
2002)
• Wit’s > - 5 = malocclusion might not be
resolved by camouflage with facemask or
chin cup.

Cephalometric Analysis for Class III
• Intermaxillary 6 - 18 years
• Wits 0 mm
• Maxillo.-Mand. Diff 23 mm (12 y)
(Class III - 28mm)
• ANB 2°
(Class III 0° to -1°)
• Zero Meridian
(maxilla) + 2.3 mm
(pogonion) 0 mm
Mild to moderate Class III – WITS = - 4 to - 5 mm
Face mask therapy

Cephalometric Characteristics
ClassI,PseudoClassIII,True Class III
SNA SNB
CLASS I 83.3 ± 3.3 80.6 ± 3.1
PSEUDO
CLASS III
81.4 ± 4.0 81.2 ± 3.6
TRUE CLASS III 80.3 ± 3.6 81.8 ± 3.3
Lin JJ 1994www.indiandentalacademy.com

U 1 - SN L 1 - MP
CLASS I 107.3 ± 6.1 94.4 ± 5.6
PSUEDO
CLASS III
109.4 ± 5.9 91.7 ± 6.9
TRUE CLASS III 111.0 ± 5.5 87.7 ± 6.8

SN - MP Gonial Angle
CLASS I 30.7 ± 4.3 121.7 ± 5.5
PSUEDO
CLASS III
33.0 ± 4.9 120.5 ± 5.7
TRUE CLASS III 36.1 ± 4.3 124.3 ± 14.3

7 Structural Signs 0f Extreme
Mandibular Growth Rotation
• Inclination of the condylar head
• Curvature of the mandibular canal
• Shape of the lower border of the mandible
• Inclination of the symphysis
• Inter incisal angle
• Inter molar angle
• Anterior lower face height
Bjork A. 1969www.indiandentalacademy.com

DETERMINATION OF INDIVIDUAL
GROWTH RATE & DIRECTION
• Growth treatment response vector –
GTRV ANALYSIS – PETER NGAN
• Serial cephalometric radiographs used to
predict excessive mandibular growth
• GTRV ratio = hori. growth changes of max
hori. growth changes of man

GTRV RATIO
• Mild to moderate Class III skeletal patterns
with GTRV ratio between 0.33 & 0.88 can
be successfully camouflaged by facemask
therapy
• Class III patients with excessive mand.
growth & GTRV ratio below 0.38 – future
orthognathic surgery needed

• Long term outcome ?
• What happens during adolescent growth ?
• Maxilla forward, maxillary tooth
movement, mandible rotates down & back
• Will he / she make it without surgery?
depends totally on mandibular growth at
adolescence

• Treating pseudo Class III early – better
prognosis — to start with they were
Class I therefore NO SURPRISE

Early Timely Class III Treatment
• Advantages –
• Eliminate CO/CR discrepancies
• Improve smile & self esteem of patient
• Maximize the growth potential of the
maxilla ?
• Predict excessive mandibular growth ?

Goals of Early Timely Class III
Treatment
• Prevent progressive,
irreversible soft tissue
or bony changes
• Eliminate CO/CR
discrepancies
• Avoid abnormal
incisal wear
• Improve skeletal
discrepancies –
minimize excessive
dental compensations
• Improve lip posture &
facial appearance
• Improve self concept,
self esteem &
psychosocial well
being
O’Brien et. al. AJO 2003www.indiandentalacademy.com

Questionable Goals Of Early
Treatment
• To simplify Phase 2 comprehensive
orthodontic treatment
• To alleviate / reduce surgery ?
• Still not enough literature to know

When to intercept Class III developing
malocclusion? - Turpin’81
POSITIVE FACTORS –
• Good facial esthetics
• A-P functional shift
• Mild skeletal disharmony
• Convergent facial type
• Young patient with growth remaining
• Symmetrical condyle
• No familial prognathism
• Good cooperationwww.indiandentalacademy.com

Treatment of Class III
• FR III
• Reverse twin block
• Chin Cup therapy
• Protraction Face Mask
• Tandem appliance
• Camouflage therapy
• Surgery

WHEN IS THE BEST TIME TO START
FACEMASK TREATMENT
• Midpalatal suture broad & smooth during
infantile stage – 8 -10 yrs.
• Suture more squamous & overlapping in
juvenile stage – 10 -13 yrs. ( Melsen &
Melsen - AJO 1982)
• Maxillary protraction effective in
deciduous, mixed & early permanent
dentitions. – clinical studies ( AJO
1997,1998; EJO 2001)

WHEN IS THE BEST TIME TO START
FACEMASK TREATMENT
• More anterior maxillary displacement when
treatment started in deci. or early perm. dentition
– (Angle Orthod 1998 ; AJO 1998 )
• Optimal time to intervene in Class III seems to
be when maxillary incisors erupt
• Long term study AJO 2004 – end of phase 2
fixed appliance therapy - greater forward
movement of maxilla & less mandibular
projection found only in early treatment group –
deciduous & early mixed dentitionwww.indiandentalacademy.com

• Maxillary growth completed in females by
15 yrs.– Bjork 1966 ; Bjork & Skieller -
BJO 1977
• Maxillary growth in females completed by
18 yrs. – Iseri & Solow - EJO 1990
• Adolescent boys maxilla stopped growing
by 18 yrs. – Savara & Singh – Angle
Orthod. 1968 ; Broadbent et. al 1975

• Reyes et. al – Angle Orthod. 2006 –
• 1091 untreated Class III subjects
studied –
• No significant increase in maxillary
length at various chronological ages
in either sex
• ANB & WIT’s – no skeletal
improvement during growth

• Early mixed dentition treatment –
improves maxillary sagittal growth when
compared to treatment in late mixed
dentition – Chong Y H et. al - Angle
Orthod. 1996 ; Franchi et. al - AJO 2000
• Treatment in late mixed dentition –
increases in vertical dimensions due to
backward positional rotation of the
mandible – Franchi , Baccetti , McNamara
AJO 2000

Basic Principles of Early
Treatment
•Midfacial Vulnerability
•Earlier the Treatment Greater the Stability
•Disarticulation of teeth and TMJ
•Orthopedic Sutural Expansion of the Maxilla
•Overtreatment
•Laboratory Comprehension
•Early Detection of Deviation of Growth

• 20 % to 30 % adult Class III – maxillary
retrusion & no mandibular prognathism –
Ellis, McNamara – J. Oral Maxillofacial
Surg. 1984
• 62 % had component of maxillary
retrusion Sue G. et al. – J Dent Res. 1987
• Developing Class III malocclusion – A-P
& vertical maxillary deficiencies – normal
to slightly protruded mandibles & average
to deep overbites – Hopkin et al. – Angle
Orthod 1968 ; Mouakeh M – AJO 2001www.indiandentalacademy.com

• Current trend-- TREAT MAXILLA NOT
MANDIBLE
• Early face mask therapy– demonstrates
effectiveness
• How early to treat ?
--- Delaire -- 8 years
--- recent papers – skeletal changes up to
onset of adolescence
--- at all ages dental changes occur & 10 %
mandibular changes likely
CLASS III

Intraoral Appliances used with Face
Mask therapy
• Banded or soldered palatal expansion
appliance
• Bonded palatal expansion appliance
• Fixed plate or lingual arches
• Quad helix

• Is expansion necessary for maxillary
protraction? -- 6-8 years - yes – helps
forward protraction of maxilla.
( Melsen AJO 1982 )
• Bonded palatal expansion appliance – 400
gms elastic on each side 12 hrs. per day –
8-12 months of protraction-- correction
normally seen after 8 months
• Frontomaxillary, Zygomaticotemporal,
Zygomaticomaxillary & Pterygopalatine
sutures are affectedwww.indiandentalacademy.com

Factors influencing A point
movement
Author Year Exp. Force Tx time A pt.mo
Nanda ‘80 Haas 500 gm 4 mths. 1.5mm
Ischii ‘87 No exp. 250 gm 11-24 m 2.7mm
Tindlund ‘89 Quad he 700 gm 12 mths. 3.0mm
Mervin ‘97 Hyrax 400 gm 6 mths. 2.0mm
Da silva ‘98 Haas 350 gm 12 mths. 1.5mm
Gallagher ‘98 Slow exp 600-800
gm
8-9 mths 1.6mm/
yr
Nartallo-
Turley
‘97 Hyrax 200-450
gm
11 mths. 3.3mm

Factors influencing A point
movement
Author Year Exp. Force g Tx time A pt.mo
Balk ‘98 Hyrax 300-400 6-8mth. 2.1mm
Pangrezio ‘98 Bonded
RME
400-600 7-8mth. 1.8mm
Kapust ‘98 Hyrax 300-400 9-10mth. 2.8mm
Bacetti ‘98 Bonded
RME
400 11mth. 2.1mm
Ngan ‘98 Hyrax 400 8 - 9mth. 2.1mm
Cha ‘03 Hyrax 500 2.8mm
Westwood ‘03 RME 300-500 10mth. 1.8mmwww.indiandentalacademy.com

Clinical Profile
a. Concave Profile.
b. Had an even
anteroposterior pattern
of closure.
c. Mild functional element
was present.
d. Low lying tongue
posture.
e. Full anterior crossbite.
Cephalometric Profile
a. Wit’s appraisal shows
BO-AO – 4.5mm.
b. SNA 76.5,SNB 77.5,
ANB -10
c. Size of maxilla normal.

a. Reverse Headgear-
Delaire Facemask +
BONDED Posterior
Bite Plate with hooks
at the canines +
expansion screw-RED
Elastics.
b. Screw turns ¼ per
week.Force levels of
elastics 350-400 gms.
3 Months.
c. FR III + Chin Cap
d. Fixed appliances.www.indiandentalacademy.com

• Cephalogram
shows marked
positional
advancement of
the maxilla. ANB +
1.750
Wit’s -1mm.
Profile more or
less straight.
Anterior crossbite
fully corrected.
Pre Rx

Clinical Profile
a. Concave Profile.
b. Longish face.
c. Skeletal asymmetry.
d. Deviation of the
mandible to the left
on closure.
e. Presence of
functional element.
f. Unilateral left side
crossbite.
Cephalometric
Profile
a. Wit’s appraisal
shows BO-AO
– 5.5mm.
b. SNA 78,SNB 81.5,
ANB -3.50
c. Size of maxilla &
mandible normal.
d. PA view shows
skeletal asymmetry.

Treatment Plan
a. Removal of premature
contacts at left lateral
& canine region.
b. Posterior Bite Plate
+ Z springs with
expansion screw(for
unilateral left side
crossbite). – ¼ turn
per week---2 months.
c. FR III + Chin Cap
d. Fixed appliances.

• Marked
improvement in
maxillo-
mandibular
relation.
Crossbite
corrected.Wit’s
– 2mm. ANB
+ 1.50
Facial
symmetry
improved.

Disadvantages of ANB & WIT’S –
• ANB – Nasion position not fixed ;
rotation of jaws by growth or orthodontic
treatment can change ANB.
• WIT’S – Accurate identification of functional
occlusal plane not easy or accurately
reproducible ;
angulation of functional occlusal plane
caused by normal devt. of dentition or
orthodontic intervention can influence
Wit’s appraisal.

Innovative Cephalometric
Measurments
• BETA ANGLE – Chong Yo Baik , Maria
Ververidou – AJO 2004
• Angle indicating severity & type of skeletal
dysplasia in sagittal dimension
C
A
B
Beta angle
- Centre of condyle
27°- 35° - Class I
< 27° - Class II
> 35° - Class III

Innovative Cephalometric
Measurments
• C AXIS – Growth vector for Maxilla –
Sella to M point
• G AXIS – Growth vector for mandible –
Sella to G point

CONCLUSIONS
• Class III treatment still remains the
bane of all orthodontists.
• Grey areas in treatment timing still
persist.
• One must not try to be a hero while
treating Class III malocclusions.
• One needs to know the limitations
of Class III treatment.www.indiandentalacademy.com

• Early detection of CLASS III
malocclusion is beneficial.
• Judicious use of the growth
predictors is indicated.
• Discerning clinical acumen has to
be the forte in treating Class III.
• Evidence based treatment is the
need of the hour.www.indiandentalacademy.com

Thank you
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Diagnosis & early treatment of class 3 /certified fixed orthodontic courses by Indian dental academy

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