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 cingulumplateau of the upper incisors.

-Psaudo-class III : it is where an anterior displacement masking an underlying skclass I base.

INCIDENCE:

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

CLASSIFICATIONLin (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

FEATURES1- 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 mandibularprognathsim (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-Accept2-Interceptive treatment 3-Growth modification4-Orthodontic camouflage5-Orthodontic decompensation and orthognathicsurgery6-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 relationshipD- 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 mandprognathism .

**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 hypodivergentgrowth 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 unfavourable2- 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 sagittalsplit 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 history4- Severity of the underlying skeletal problem5- Presence or absence of functional displacement

6- Degree dentoalveolar compensation7- Amount of crowding, OJ, OB8- Vertical height9- 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-assisstedapproach 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.