Class 3 malocclusion

ASSESSMENT AND TREATMENT OF
CLASS III
• BY DR. TASNEEM AL-RBAIHAT
• SUPERVISED BY:
DR.Anwar al-abbadi
DR.Rania al-smadi
DR.hanan habarneh

DEFINITION:
-Class III incisor : is when the lower
incisor edge lies anterior to the cingulum
plateau of the upper incisors.
-Psaudo-class III : it is where an anterior
displacement masking an underlying sk
class I base.

INCIDENCE:
-IN WHITE POPULATION: 3-5% UK
-IN ASIAN POPULATION : 4-14%
-ANTERIOR CROSSBITE: 10% IN CHILDREN

CLASSIFICATION
Lin (2007) divides it into 3 categories according to
the difinition:
1- TRUE CLASS III: anterior crossbite cases w.
bilateral buccal occ. In class III.
2- CLASS III SUBDIVISION: anterior crossbite cases
w. one of the bilateral buccal occ. In class I and the
other in class III.
3- PSAUDO CLASSS III: bilateral class I buccal occ.
And majority of teeth in ant. crossbite (often due
to collapse of the arch perimeter).

AETIOLOGY:
1-SKELETAL:
-ENVIRONMENTAL: e.g. airway problems, scaring
from CLP, hormonal as in acromegaly.
-GENETICS: 1/3 of patients with severe class III have
a parent with class III problems.
2- S.T: tend to reduce the severity of CLIII, by lower
incisor retroclination and ULS proclination.
3- Dental factors:
Rarely ULS retroclination and LLS proclination,
Hypodontia or microdontia in the upper arch ,Impacted
upper teeth.
4- Habits: tongue to lower lip seal and macroglosia

FEATURES
1- SKELETAL FEATUES:
-Short cranial base length.
-Decrease cranial base angle resulting in forwards
position of mandible.
-Mainly skeletal class 3 base relationships but it could be
Class I or even class II skeletal base.
-55% had maxillary deficiency as one of the components
of the malocclusion and Mandibular prognathsim in 45%
of cases.( Guyer, Ellis, Behrents and McNamara (1986) ).
-59% had reduced or neutral lower facial heights and
that 41% had increased lower facial heights.(Guyer, Ellis,
Behrents and McNamara (1986)).

-The maxillary skeletal base widths were (statistically)
significantly smaller in the class 3 than in the class 1group
(Chen et al 2008)
-Skeletal asymmetries, esp. in conjunction with mandibular
prognathsim (Severt and Proffit, 1997).
-Reduced cranial base angle
-Increased saddle angle
-Obtuse gonial angle
-Reduced ANB
-Normal or increase MMP angle and lower face height
-Increased mand length
-Reduced maxillary length

2- S.T FEATURES:
S.T is not involved in aetiology but
encourages dentoalveolar compensation.
•Orbital rim hypoplasia and Increased scleral show
•Reduced maxillary length
•Malar hypoplasia in midface deficiency
•Paranasal hallowing
•Obtuse NLA and LMA.
•Reduced incisor show at smile
•Increase buccal corridor dark space
•Upper lip looks thin with reduced vermilion border show
while lower lip may be full and pendulous
•Prominent chin
•Concave or straight profile.

3- DENTAL FEATURES:
•Class III incisor relationship
•Mostly CI III molar relationship could be I or even II.
•Tendency to or full reverse OJ.
•Reduced OB, AOB may exist
•Max probably crowded, mandible is usually spaced.
•Incisors compensate for Skeletal base, i.e. Proclined
maxillary, retroclined mandibular incisors
• Tendency to posterior cross bite. It could be
unilateral with or without displacement or could be
bilateral mainly without displacement.

4- DISPLACEMENT:
-in an anterior or lateral direction or combination.
-It is due to: Unsatisfactory edge-to-edge incisor or Unsatisfactory
transverse buccal segment relationship.
5- FACIAL GROWTH:
Tends to be unfavourable i.e. backwards growth rotation.

Growth status assessment for class III patients:
Mandibular skeletal maturity can be assessed by means
of a series of biologic indicators:
1-History (is the patient changing shoes)
2-Growth chart like an increase in body height.
3-Biological parameters like:
-Skeletal maturation of the hand and wrist (Bjork, 1967)
or cervical vertebral maturation (CVM).
-Dental development and eruption (Bjork, 1967)
-Chronological age
-Secondary sexual features.

TREATMENT OPTIONS FOR CLASS III
1-Accept
2-Interceptive treatment
3-Growth modification
4-Orthodontic camouflage
5-Orthodontic decompensation and orthognathic
surgery
6-Compromised orthodontic treatment

FACTORS INFLUENCING TTT OPTIONS:
1.Patient concern (dental or facial concern)
2.Patient age
3.Growth
4.Medical condition
5.Patient compliance
6.Family history of class III
7.Severity of skeletal problem.
8.Clinical condition of the teeth and oral tissues.
9.Amount of the OJ & OB
10.Degree of crowding
11.Degree of compensation
12.Presence of displacement

TREATMENT SCENARIOS ACCORDING TO
DENTAL AGE:
1- IN PRIMARY DENTITION:
There is no evidence to suggest that this will avoids, or reduces,
the complexity of later orthodontic treatment.
** we may grind the primary canine that interfere with the occ.

2- IN EARLY MIXED DENTITION:
-Incisor crossbites due to retained primary incisors: Treatment
extract retained primary teeth

- Premature contact and mandibular displacement or incisors
erupted in cross bite relationship, then
*Extract or grind cusp tips (usually primary canines)
*Posterior onlay to overcome the posterior crossbite that
caused displacement.
*Procline maxillary permanent incisor(s) using an upper
removable appliance (URA) or a fixed appliance (4 x 2 appliance
which is well tolerated less dependent on compliance and Offers
three-dimensional control)
*Anterior cross elastics.
*Expand by URA or Q helix .

3- MID-LATE MIXED DENTITION:
- Class III incisors with deep overbite and
mild/moderate skeletal Class III: Protraction headgear
and rapid maxillary expansion.
- Proclined lower incisors: URA incorporating inverted
labial bow or URA to procline ULS.

4- ADULT TREATMENT:
A- Mild/moderate skeletal discrepancy:
- no concern about facial appearance : Camouflage skeletal
pattern using fixed appliances.
- WITH concern about facial appearance: will require Combined
orthodontic treatment/orthognathic surgery decided later.
B- Severe skeletal discrepancy with no concern about facial
appearance :
Compromised treatment.
C- Severe skeletal discrepancy with a concern about facial
appearance :
Combined orthodontic treatment/orthognathic surgery

REASONS for early ttt of class III:
A. To eliminate CR-CO discrepancies which may cause:
periodontal damage , occlusal wear ,and TMJ problems.
B- To provide a more favourable environment for growth and
development of the maxilla and mandible with a reduction in
dental compensation because remodelling may occur in the
joint as the postured position which will act as functional
appliance and making correction of the crossbite more difficult
at a later date.
C- To provide space for the eruption of the buccal segments
as a result of proclination of the upper incisor so the canines
and premolars can be guided into a class 1 relationship
D- Psychological benefits resulting from improved dental and
facial appearance.

ORTHOPAEDIC TTT OPTION
Effect of orthopaedic appliance in class III:
**In general orthopaedic appliances are more
effective if C.III is due to maxilla retrusion than mand
prognathism .
**However, most of the effects are dentoalveolar in
nature with maxillary incisor proclination and
mandibular retroclination .

Positive factors for orthopaedic treatment:
• good co-operation
• No familial prognathism
• Young growing patient
• Acceptable facial aesthetics
• Mild skeletal discrepancy (ANB < -20 )
• Normal MMPA
• No asymmetries (Symmetrical condylar growth)
• -2mm reverse OJ or edge to edge relationship
• Minimal dental compensation
• Functional shift

TYPES OF ORTHOPAEDIC TTT
IN CLASS III
1- Protraction HG
• Means of applying anterior directed
forces to teeth and/or skeletal structures
from an extra-oral source.
• It is appropriate to refer to this type of
treatment as facemask therapy.

Indications
A- Treatment of maxillary retrusion: An ideal case would be;
• good co-operation
• No familial prognathism
• Young growing patient
• Acceptable facial aesthetics
• Mild skeletal discrepancy (ANB < -20 )
• Normal MMPA
• No asymmetries (Symmetrical condylar growth)
• -2mm reverse OJ or edge to edge relationship
• Retroclined ULS
• Proclined LLS
• Functional shift
B- Reinforcement of anterior anchorage and dental protraction allowing
closure of space from behind in patients suffering from hypodontia
C- Stabilization following maxillary osteotomy/distraction osteogenisis
D- Rotate arch segments in cleft palate patients
E- Remove hyper-anterior contact in TMJ internal derangement cases.

•TIMING:
• Dental age: the optimal time for treatment is in the early late
mixed dentition, coincident with the eruption of the upper
permanent incisors.
• Skeletal age: early treatment at CVM2 showes effective
forward displacement of the maxillary structures whereas the late
treatment at CVM3 showes no change.
• Chronological age: for optimal orthopaedic effects,
treatment should be initiated before the patient is 9 years
old (Proffit, 2000).

EFFECTS :
• Correction of a centric occlusion-centric relation discrepancy.
This happens rapidly in patients with an edge to edge relationship
and associated displacement
• Maxillary skeletal protraction, with up to 3mm of forward
movement of the maxilla possible , these effects are stable after 3
years follow-up.
• Proclination and forward movement of the maxillary dentition
• Lingual tipping of the lower incisors
• Redirection of mandibular growth in a downward and backward
direction, resulting in an increase in lower anterior facial height.

•ADVANTAGES :
•Sutural loosening
•Correct transverse discrepancy that commonly
associated with class III malocclusion
•Displace the maxillary complex anteriorly. This is
due to butterfly effect of expansion at the Midpalatal
suture and because of the anterior sloping of the facial
sutures

PROTRACTION FACE MASK SYSTEM :
A- EXTRAORAL PART:
*TYPES:
1- protraction headgear
( HICKHAM )
2- Facial mask ( Delaire)

3- suborbital protraction app.
(GRUMMONS)
•Advantages: frame more rigid,
no force on TMJ, no LLS retroclination,
easy to adjust and wear during sleep
•Disadvantages: not esthetic
4- Nola Protraction app.

5- petit style face mask :
• Has a single central vertical bar
• well tolerated
• economically much more
attractive.

B- INTRAORAL PART :
1- In order to maximize the amount of skeletal change in young
children, a removable full coverage acrylic splint is used with a
protraction headgear (Proffit 1986).
2- McNamara (1987) has described the use of a Biocryl and wire splint
that is bonded in the mouth. The splint material should be at least 3 mm
thick with a 0.045" stainless steel wire framework. The two halves of
the splint are joined by an expansion screw. Traction hooks to receive
the elastics from the headgear are placed in the first premolar region.
3- RME with hook can be used
4- Fixed appliance
5- Some recommend using an intraoral bone plate to support the PHG
force.
**Systematic review to compare the dentally anchored face mask with
skeletally anchored one by Major (2012) in Canada, he found
Approximately 3 mm of horizontal A-point movement is predictably
attainable with the skeletal one in comparison to dental one.

C- Rapid maxillary expansion
** ADVANTAGES :
1- Sutural loosening
2- Correct transverse discrepancy that commonly associated
with class III malocclusion
3- Displace the maxillary complex anteriorly. This is due to
butterfly effect of expansion at the Midpalatal suture and because
of the anterior sloping of the facial sutures

** EVIDENCE :
- some evidence suggests that the expansion
makes antero-posterior skeletal change more
likely. Kim et al (1999)
-There is other evidence that the expansion is
optional and should be dictated by the
maxillary arch width related to the lower arch
width.

TECHNIQUES :
• Appliance is activated TWICE PER day until the desired
increase in maxillary width has been obtained.
• If patients do not need an increase in maxillary width, the
appliance is still activated for 7-10 days to disrupt the
maxillary sutural system and promote maxillary protraction .
• After the patient activated the maxillary appliance for 7-10
days protraction headgear is fitted.

FORCE LEVEL :
• Moving maxillary anterior teeth forward: 400g per side, 12-
14h/day
• Maxillary protraction : 800g per side, 14h/day
• Overcorrect to compensate for mandibular growth
• Active treatment should be limited to 9-12 months because of
the risk of decalcification of the dentition

FORCE DIRECTION :
• To avoid bite opening, place
protraction elastics near maxillary
bicuspids.
• Force vector should be 15-30
degree below the horizontal
• To avoid irritation to the lip, use
crossed elastic,
• Pay special attention to airway
and tongue posture

Ngan et al (1996) showed the significant dentoskeletal changes
and improvement s in dentofacial profile could be obtained from 6
monthes ttt with max. expantion and protraction.
Ngan et al (1997) suggested that :
-Correction of class III was aeivable in 6-9 monthes and was stable
2 years after removal.
- max. expantion in conjunction with protraction produced greater
forward movement of the max.
- significant and beneficial S.T profile change can be expected
during ttt
- ttt works best in pts with retrusive maxilla and hypodivergent
growth pattern.

Ngan et al (1998) looked at max. expantion and
protraction in Chinese population treated at 8.5 years of age
.
-RME was only carried out for 7 days before protraction ,
compared with the more usual 10-14 days.
- changes of 1.6 degree were found in SNA and 3.0 degree
in ANB during ttt although some relapse occurred in the 2-
year period after ttt
- substantial amount of relapse were found in the
maxillary expantion but not in the mand.; RME did
not result in a net increase in arch perimeter .

TRANSITIONAL PERIOD :
After treatment objectives have been achieved, the patient can be
retained with a number of appliances:
•The facemask, FR-3 appliance, Acrylic maxillary retainer with
reverse lower labial bow , or Chin cup (seldom used).
Post protraction ttt consideration:
1-As mandibular growth exceeds maxillary growth during
adolescence, early Class III correction may be lost during the
teenage period. The patients and parents should again be warned
of the possibility of orthognathic treatment if growth is
unfavourable
2- Upper labial root torque during fixed appliance stage: Most class
III patients demonstrate considerable proclination of the upper
labial segment at the end of treatment.

SHORT TERM EFFECTIVENESS OF PH :
- Early Class III orthopaedic treatment with protraction face
mask in patients less than 10 years of age is skeletally and
dentally effective in the short term (15 months.).
-70% of patients had successful treatment, defined as
achieving a positive overjet.
-Early treatment does not seem to confer a clinically
significant psychosocial benefit.
- No TMJ problem

LONG TERM EFFECTIVENESS :
-RME/FM therapy led to successful outcomes in about 73%
of the patients.
-Signiﬁcantly improved sagittal dentoskeletal relationships.
-
-These favourable changes were mainly due to
improvements in the sagittal position of the mandible, but
the maxillary changes reverted completely in the long term.

2- TANDEM TRACTION
BOW APPLIANCE:
attachments are fixed to the top
and bottom teeth. In the top
attachment there is a hook on
each side. A metal bar is placed
in the lower attachment, which
sits in front of the lower teeth.
An elastic band can then be
placed on each side to pull the
top jaw forward and bottom
jaw backwards, to correct the
prominent lower teeth

3- CHIN CUPS:
•The idea is that because the condyle is a growth site, the growth
impeded by extra-oral force (Graber, 1977).
•most human studies have found little difference in mandibular
dimensions between treated and untreated subjects .
•Chincup appliances greatly improve the skeletal profile in the
short term such changes are however rarely maintained during the
pubertal growth spurt
•Force 500g per side 12-14 h/day for 4-5 years. Once the anterior
crossbite was corrected, the patient was instructed to wear the chin
cup at least 10 hours per day until slight Class II canine and molar
relationships were established.
•The best age is before canine and premolar erupt (CS2-CS3
maturity) this is the first growth spurt of mandible

Requirement for the usage of Chin
Cup :
• Mild Skeletal III, ability to achieve edge to
edge incisors.
• Short vertical facial height ( Chincup cause
clockwise rotation of the mandible.
• Proclined or upright LLS (Chincup cause
lingual tipping of the lower incisors.
• Absence of severe facial and dental asymmetry.

•THE EFFECT OF CHIN CUP
THERAPY :
• Retardation of mandibular growth : before
puberty but this is then lost with continual
growth.
• Remodelling of the condyle and glenoid
fossa .
• Backward rotation of the mandible.
• Closure of the gonial angle.
• Result in lingual tipping of LLS.

4- REVERSE CHIN CUP THERAPY
• Developed in Germany in 2012 by
Rahman 2012.
• shows similar result when compared to
FM in RCT involving 42 samples at age
of 8-9 years.
• it is able to produce forward movement
of the maxilla associated with lingual
tipping for LLS and labial tipping for ULS.
• All patients received the same
protraction force of 500 g per side with a
30 degree downwards pull using
elastics.
• The proposed advantages were that it
was smaller and less bulky , therefore
encouraging children to wear it.

5- Bone anchored orthopaedic appliance (Bollard
miniplates, PFH supported with miniplates)
• Plate comes in different size and form.
• It should be adapted to the bone surface
• and fixed with 2.5*5mm screw.
• Heavy Class 3 elastic used.
• Age of 9-13
• Force about 150gm 24h/day, Loading start 3 weeks after insertion.
• The major problem is the low rigidity of bone for young pt which
affects stability of the plate and the presence of teeth follicle
which might cause problem with implant insertion. Also plate
removal is problematic bec it needs surgery and sometime the
bone grow over the screw.
• Success rate 92% with 3mm improvement of maxilla position and
zygoma.

ADVANTAGES OF THIS APPROACH :
• it is clearly more effective than a facemask to a
maxillary splint and also appears to produce more
skeletal change than has been reported with
facemasks to anterior miniplates
• wearing an Extraoral appliance is not necessary
and nearly full-time application of the force can be
obtained.

6- Shapiro and Kokich 1984 used
the same idea by inducing artificial
ankylosis and use the ankylosed
teeth as anchor.

7- FUNCTIONAL APPILANCES :
** REVESE TWIN BLOCK :
Its design :
- Cantilever springs behind the upper incisors,
- A midline expansion screw,
- A lower labial bow
- Intersecting blocks at 70 degrees with a vertical height
of 7 mm.
- Block on U4s,5s and L5s,6s .
*The patient is instructed to wear the appliance on a
full-time basis initially, activating the midline expansion
screw twice a week.

EFFECT :
-There is no sustained effect on growth of either the
maxilla or mandible.
- the backwards and downwards rotation of the
mandible and an increase in lower face height.
Therefore, this type of treatment is inappropriate for
high angle cases with an already increased FMPA.
- Primarily as a result of dentoalveolar effects and by
clockwise rotation of the mandible.

** FR 3 :
•They are designed to rotate the mandible downward and
backward, and to guide the eruption of the teeth so that
the upper posterior teeth erupt down and forward whilst
eruption of the lower teeth is restrained. This rotates the
occlusal plane in the direction that favours correction of a
class III molar relationship.
•They also tip the mandibular incisors lingually and the
maxillary incisors labially, introducing an element of
dental camouflage for the skeletal discrepancy.
In theory, the lip pads stretch the periosteum in a
way that stimulates forward growth of the maxilla

Camouflage (dental compensation for mild
cases)
Indications :
• Patient past peak growth
• Non-progressive worsening of the Class III.
• Class I or mild class III skeletal base relationship;
• Average or reduced lower face height;
• Average or increased overbite;
• Minimal reverse OJ or edge-edge relationship
• Proclined lower incisors;
• Upright or retroclined upper incisors;
• Molar relationship less than half unit Cl Ill
• Patient not concern about the profile
• Favourable soft tissue features
• Anterior displacement on closing from RCP into ICP.

TECHNIQUES OF CAMOUGLAGE TTT :
1- NON-EXTRACTION :
•Expansion in upper arch to relieve crowding, eliminate crossbites
and mandibular displacements
•Procline upper incisors, retrocline lower incisors (it is unwise to
procline the upper incisors beyond 120 degrees to the maxillary
plane or retrocline the lower incisors beyond 80 degrees to the
mandibular plane.)
2- EXTRACTION :
aims of extractions:
• To relieve crowding or ML,
• Correct incisor inclination
• Correction of class III
• To achieving a positive overjet
• To achieving a positive overbite
• To constrict the lower arch in order to correct any transverse
problems.

•Option of extraction :
• Extraction upper 5`s to maintain U lip support+ lower 4`s to allow LLS
retroclination.
• Extraction of 4x4.
• Extraction of a single lower incisor: If the upper arch is well-aligned but space
is required to align and retrocline the lower incisors, extraction of a single lower
incisor can be an option (Zachrisson 1999) but it may leave some black triangle
and gingival recession. This decision depend on the presence of (large IC
distance, minor crowding , square shape L incisors not triangular).
• A better approach to camouflage in patients of European descent with a
moderately severe Class III problem is extraction of one lower incisor, which
prevents major retraction of the lower teeth, while the maxillary incisors are
moved facially with some tipping allowed.
• The combination of upright mandibular incisors and proclined maxillary
incisors often leads to good dental occlusion rather than the expected tooth-size
problem, but a wax setup always should be done when one lower incisor
extraction is considered to verify the probably occlusal outcome.

• For Asian (or rarely, other) Class III patients with
major protrusion of the lower incisors, using skeletal
anchorage to move the whole lower arch posteriorly
can be quite helpful in correcting the problem.
•Extraction of third molars usually is needed in
order to move the mandibular dental arch back. If
second molars are extracted to facilitate distal
movement, third molars may erupt as satisfactory
replacements, but this is not as likely as in the
maxillary arch and therefore is not recommended as
a routine procedure.

•Bracket setups :
• To get further proclination of ULS, use MBT in the ULS
• Lingual crown torque on LLS
• Contra-lateral canine brackets (to avoid LLS proclination)
Mechanics :
• Lacebacks in LA (to avoid LLS proclination)
• Cinch back in LA (to avoid LLS proclination)
• Banding 7`s to increase posterior anchorage to retract lower
dentition
• Closing space on a round wire in the lower arch will facilitate
retroclination of the lower incisors.
• CIII elastics (better to use short class III elastic to avoid posterior
teeth overeruption)
• Avoid distal headgear forces on maxilla in C3 patients
• NB: do not extract in lower arch if surgery is anticipated

transverse problems can be addressed
by :
• URA
• Q helix
• RME
• If more than 8mm, Surgically assisted RME
• Constriction of the LA
• AW expansion of the UA
• Auxillary AW in the UA

Orthognathic surgery options
1- Sagittal split ramus osteotomy (SSRO) or bilateral sagittal
split osteotomy (BSSO) to set the mandible backward.
2- Intraoral vertical ramus osteotomy (IVRO) or vertical
subsigmoid osteotomy (VSSO) or vertical or oblique
subcondylar osteotomy (VSO) is different names for the same
technique using an intraoral approach. This is used to reduce
the size of the mandible .

3- mandiular step osteotomy .
4- Surgically assisted rapid palatal expansion (SARPE) to
correct the combined transverse problems
5- Le Fort I (total maxillary osteotomy), the combination
of Le Fort I and Le Fort III, or Le Fort II in one operation
or different operations.

What Factors need to be taken into Account
When Planning a surgical treatment for class III
cases ??
1- planning the type of surgery :
The required surgery is planned around the
aetiology of the skeletal discrepancy taking into
account facial aesthetics, stability of the result, TMJ
and airway, little morbidity.
Allows the decision to make regarding whether the
maxilla is to be advanced or the mandible set back,
or a combination of these.

THE PRE-SURGICAL ORTHO. IN CLASS III :
The pre-surgical orthodontics is planned around the surgery
required to achieve optimal aesthetics with the best achievable
occlusion. Three important points need to be considered;
1- Expansion: Assessment of arch co-ordination using the pre-
treatment models in a class I position will identify the extent of
any required expansion of the maxillary arch. If minimal
expansion is required, this can be achieved using the orthodontic
archwires during pre-surgical orthodontics.
2- Reverse Target overjet: The planned surgical moves for
optimal aesthetics dictate the reverse overjet required pre-
surgically.
3- Inclination of the ULS which is determined by the degree of
maxillary impaction while the inclination of LLS would be
determined by the amount of autorotation.

•WHAT ARE THE AIMS OF THE PRE-SURGICAL
ORTHO.?
• Alignment
• Levelling and alignment of the arches.
• Arch co-ordination.
• Decompensation: In this case, decompensation of the
upper and lower arches was required to produce an
appropriate reverse overjet pre-surgically and allow the
desired surgical movements to be carried out to promote
the desired facial change.
• Maintenance of the centre line with the mid-point of
the chin in Lower teeth and philtrum in the upper teeth

Borderline Camouflage/ Orthognathic Surgery
Patients:
The decision will depend on
1- Growth where there is any doubt about further skeletal
growth (principally mandibular), orthodontic camouflage
should be deferred, possibly until the remaining skeletal
growth has been expressed. In class III cases with a significant
skeletal component, the mandible will tend to grow more and
later than in class I individuals (Baccetti et al, 2007).
2- Any concerns about facial appearance.
3- Medical and family history
4- Severity of the underlying skeletal problem
5- Presence or absence of functional displacement

6- Degree dentoalveolar compensation
7- Amount of crowding, OJ, OB
8- Vertical height
9- Cephalometric Yardsticks

RME-ASSISSTED FM compared to SURGECALLY-
ASSISSTED FM protraction :
-40-60% of class III sk. Are due to max. deficiency , which is possible
to treat if the pt is still growing , and so FM therapy has been
proposed and is the most frequently used ttt , and RME has often
been performed as part of the ttt protocol. ( RME+FM)
- HERE, ttt results were : forward movement of max., clockwise
rotation of the mand., and forward movement of the UI with
retrusion of the LI.
-BUT ,
* PROTRACTION WERE NOT MORE THAN 2 MM IN 6-12
MONTHS
* IT WAS DIFFICULT TO MOBILIZE THE MAX. IN CLEFT CASES DUE
TO SCARING .
*** SO, WHAT TO DO ? WAIT FOR THE COMPLETION OF GROWTH
AND THEN PERFORM SURGERY.

-In this study , they reported that the values related to the ttt effect
of surgically assissted protraction of the max. using FM range from
3-12 mm in the very short term, compared to conventional FM.
-TTT PROTOCOL:
• In RME-ASSISSTED FM:
They used acrylic covered hyrax with Hooks for the attachement of
elastics and a Lingual wire (0.9mm) to support UI, applied with 1000
g of total force following the occurance of median diastema. Pt wore
RME-ASSISSTED FM for 16 hrs/day.
• In SURGICALLY-ASSISSTED FM:
they performed an incomplete LEFORT 1 osteotomy ,involved the
lat. Surface of the max., the FM was applied on the 5th-7th day
postsurgery with a total force of 1700-2000g with a 30 degree-
oriented elastics , pts wore the FM for 24 hrs/day until achieving
class II, THEN nighttime wear for 3 months.

RESULTS AND CONCLUSION:
-surgery-assissted max. protraction is effective at ANY AGE , and
the improvement is achieved in a relatively short period of time .
- we found 4 mm of max. protraction with surgically-assissted
approach in 5 monthes compared to only 1.3mm with RME-
ASSISSTED FM.
- the improvement was significantly more rapid and larger
compered to RME-ASSISSTED FM.

Class 3 malocclusion

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Class 3 malocclusion