MANAGEMENT OF FACIAL ASYMMETRY

PRESENTED BY:

Dr. SHAZEENA QAISER

INTRODUCTION

• Facial esthetics evaluation is the most important part of the orthodontictreatment-planning procedure.

• The attainment of the best facial esthetic appearance for a given patient is aprimary goal of orthodontic treatment.

• The evaluation of a patient’s frontal symmetry is the most critical aspect ofdiagnosis because this is the most appreciated view for any individual. Eventhe most esthetic faces are associated with mild forms of facial asymmetry.

• The individuals who report for an orthodontic treatment are oftenassociated with facial asymmetry that may be greater than the acceptablenorms.

DEFINITIONS ‘DORLAND’• Symmetry:

The similar arrangement in form & relationship of parts around a common axis or on each side of a plane of a body.

• Asymmetry

Variations in the size & relationships of the two sides of a body

Woo (1931)-

• Bones of cranium show asymmetry- rt. side being larger

• Bones of facial complex – contralateral asymmetry.

Vig & Hewitt (AO 1975)-

• Dentoalveolar region exhibit greatest symmetry.

• Allows symmetric functions even with asymmetric jaws.

CLASSIFICATION OF FACIAL ASYMMETRIES

1. Skeletal asymmetries

2. Soft tissue asymmetries

3. Functional asymmetries

ETIOLOGY

AJO PIRTTINIEMI 1994

A. PRENATAL CAUSES

• 1. Facial clefting syndromes - unilateral CLCP - craniofacial clefts

I. GENETIC

• 1. Hemi facial microsomia

• 2. Neurofibromatosis

• 3. Birth trauma

• 4. Intra uterine pressure during preg.

II . CONGENITAL

B. Postnatal causes

• 1. Trauma & infection

• 2. Muscle dysfunction

• 3. Functional deviations

• 4. TMJ derangements

• 5. Hemi mandibular hypertrophy

• 6.Pathologies

ENVIRONMENTAL

A. Malformations with abnormal developmental

processes in embryonic stage ( 1%)

1.Hemifacial microsomia

2.Congenital hemifacial hypertrophy

3.Cleft lip & palate

COHEN 1982

B. Deformations caused by non disruptive

mechanical forces during fetal period:(2%)

1.Congenital muscular torticollis

2.Postural scoliosis

3.Plagiocephaly

C. Disruptions caused by breakdown of normal

developmental processes with onset later in life

1.Unilateral condylar hyperplasia

2.Hemifacial atrophy

3.Infections & inflammations

4.Fracture & trauma

5.Lateral malocclusion

6.Muscular dysfunction

DIAGNOSIS

1.History

2. Clinical examination

3.Radiographic examination

4.Photographic analysis

5.Digital videography

6.Articulated study models

HISTORY:

• -Can reveal aetiology

• -Severity of deformity

CLINICAL EXAMINATION

• Reveals asymmetry in the

vertical, antero-posterior , lateral dimension.

EXTRAORAL EVALUATION

• Frontal

-Mid pupillary distance aligned with commissures

1. Inter ocular dimensions-

interpupillary-65mm

inter canthal- 35mm

2.Midfacial bony support-

lower third of iris of the eye to be covered

with lower eyelid

VERTICAL

Vertical reference plane- nasion to subnasale

•upper horizontal plane – bipupillary line

• lower horizontal line - through the stomion

Arnett and Bergman AJO1993

• The pupils are assessed for level with the horizon.

If in level - used as horizontal reference line

• (1) upper canine level

• (2) lower canine level

• (3) chin and jaw level.

The pupils are not level to the horizon:

A constructed frontal horizontal reference line is visualized as follows:

• 1. Frontal natural head posture.

• 2. Horizontal line parallel to the horizon through the pupil area

• 3. Assess other structures relative to this line

SUBMENTO VERTEX VIEW

INTRA ORAL EXAMINATION

1. Evaluation of the dental midlines

2. Vertical occlusal evaluation

-Transverse cant of maxilla

3. Transverse and antero-posterior occlusal evaluations

• Unilateral cross bites

• B-L inclination of teeth

FUNCTIONAL EXAMINATION

1. Maximal opening

2. TMJ evaluation

• postural rest position

• -CR-CO discrepancy

• -laterocclusion/ laterognathia

3. Motor & sensory evaluation

RADIOGRAPHIC EXAMINATION

Importance of head position

1. The lateral cephalogram

2. The panoramic radiograph

3. Postero-anterior projection

4. Submento vertex view

5. 3-D cephalograms

LATERAL CEPHALOGRAM

Only little useful information

In CR ,CO and initial contact permits visualization of mand.position

OPG:Gross pathologies -Size &shape of condyle, ramus &body of mandible

PA CEPHALOGRAM

• Important adjunct for qualitative & quantitative evaluation of dentofacial region

• Extent of deformity( orbital/ upper facial symmetry),

• Skeletal /dental involvement.

Various P.A Analysis:

• Rickett’s Analysis

• Svanholt and Solow Analysis

• Grummon’s Analysis

• Grayson’s Analysis

• Hewitt analysis

• Chierici method

• COMPUTED TOMOGRAPHY

3-D evaluation of osseous & soft tissues Complex diagnosis

•3-DIMENSIONAL CT

-Reproduces detailed skeletal pathology

- Assess post treatment changes

•MRI SCAN

-Also provide 3-D representation of deformity

-For better visualization of soft tissue

PHOTOGRAPHIC ANALYSIS

• Head position, patient position, flash

• Extra oral Photographs –

Frontal - lips relaxed , smile

Oblique ( rt & lt) ,

Profile ( rt & lt),

Submental

• Intra oral photographs

• Impossible to assess dynamic asymmetries

Photographic montage/ composite photographs

• -reveal altered facial form and disclose difference in configuration of both sides of the face

TREATMENT MODALITIES

SKELETAL ASYMMETRIES:

• In growing Individuals, orthopedic appliances in conjunction with orthodontics are used to help improve or correct the developing imbalance.

• Severe discrepancies may require a combination of surgery and orthodontics.

• Abnormalities of the coronoid and condylar processes as well as in the position and shape of the articular disks should be considered when limited opening, acute mal- occlusions, or mandibular deviations are found.

FUNCTIONAL ASYMMETRIES

• Mild deviations caused by functional shifts -minor occlusaladjustments

• More severe deviations -orthodontic treatment to align the teeth

• Occlusal splints may be necessary to properly evaluate the presence and extent of the functional shift by eliminating the habitual posturing and de- programming the musculature.

• Because functional shift can also be the result of a skeletal asymmetry, rapid maxillary expansion, orthognathic surgery, and orthodontic treatment may be indicated in the management of these cases.

SOFT TISSUE ASYMMETRIES

• Deformities caused by soft tissue imbalance can be treated by either augmentation or reduction surgery.

• Augmentations include the use of bone grafts and silicone implants to re-contour the desired areas of the face.

• With the mild dental, skeletal, and soft tissue deviations the advisability of treatment should be carefully considered.

Asymmetry Treatment

Growing Children

Hybrid Functional

Appliances

Distraction

Osteogenesis

Adults

Surgical

OSTEOTOMYOrthodontic camouflage

Functional asymmetry

OcclusalCallibration

Splints

TREATMENT POSSIBILITIES

1. MAXILLARY ARCH EXPANSION

2. ORTHODONTIC ARCH COORDINATION

3. SPLINTS

4.OCCLUSAL THERAPY

MAXILLARY EXPANSION

• 1. Slow expansion

• 2. Orthopedic rapid palatal expansion

• 3. SARPE

• 4. Segmental osteotomy

To achieve desired expansion with stability,it should be accomplished by sutural adjustments & not by alveolar bending dental tipping

SLOW EXPANSION:

• Can bring about skeletal expansion in primary dentition

• Lingual arch /quad helix- 50% sk. exp.

• Jack screw

• FR functional regulator - indirect effect

RAPID PALATAL EXPANSION

• Very successful in children prior to sutural closure.

• 0.5mm day- 10 mm exp. in 20 days- 75- 80% of sutural

expansion

Haas type

Hyrax type

Minn expander

• 3:2 ratio of widening in canines & molars

SARPE:

• Brown(1938)-described SARPE with midpalatal split

• Shetty(1994)-main areas of resistance to expansion are midpalatal suture followed by pterygomaxillarybuttress

• Subtotal Lefort I osteotomy –except posterior and superior articulations

• Should be done after mand Decompensation

• During surgery – activated by 1- 1.5mm – 5 days of rest –0.5mm day

• Spacing between central incisors

• Expansion completed within 4 weeks of surgery

Segmental Lefort I osteotomy

• Indicated in open bite cases, where SARPE is contraindicated

• Total down fracture of maxilla followed by anterior segmenting.

•Maximum expansion occurs in molar area

• Advantage: minimal relapse

•Disadv: exp. more than 6mm

Repositioning splints AJO 1991. Schmid et.al.

• Used mainly in TMJ dysfunctions

• Indicated only when it is impossible to identify functional interferences due to neuromuscular adaptation

• Superior repositioning splints are preferred

• Regular wear for 2-3 mths enables compensatory changes in TMJ.

Orthopaedic Hybrid Functional Appliances

• Hybrid /blend of several components designed to address specific problems

These components produce basal and dentoalveolar changes by acting on the following:

• 1. Eruption (biteplanes)

• 2. Linguofacial muscle balance (shields or screens)

• 3. Mandibular repositioning

• Functional appliances used either alone or in conjunction with surgery for the following purposes:

• (1) to improve symmetry of the mandible and maxillary deficiency,

• (2) to restore the dental occlusion,

• (3) to expand soft tissues

• (4) to lengthen the mandibular ramus

Herbst appliance:

• Works as an artificial joint between the maxilla and the mandible. The appliance is fixed to the teeth -orthodontic bands.

• The appliance is constructed to displace the mandible anteriorly and to the unaffected side for correction of the mandibular retrusion and asymmetry.

• The construction bite - incisors in an edge-to-edge position , midline overcorrected by 3.5 mm.

Twin block AJO 1988 Clark

•When activated unilaterally - correct postur mand. displacement (mid line displacement an asymmetric buccal segment relationships).

DISTRACTION OSTEOGENESIS

•The regeneration of bone between vascularised bone surfaces that are separated by gradual distraction.

Surgical Osteotomy

•Maxillary hypoplasia:

Le-forte 1 osteotomy With max.advancement.•Maxillary hyperplasia:

maxillary segmental setback.•Maxillary vertical excess:

leforte-1 osteotomy with maxillary impaction.

mandibular hyperplasia: 1)sagital split osteotomy.2)sub-sigmoid osteotomy.

•Mandibular hypoplasia:1)sagital split osteotomy with mandibular

advancement.

Orthodontic camouflage-When skeletal deformity is very mild and any further change is

not expected, camouflage should be considered.1. Transverse cant correction

• 2 occlusal planes : upper &lower Connects incisal edge of C.I to M-B cusp tip of I molars –important for normal intercuspation .

• Natural plane of occlusion: axial inclinations of premolars to be perpendicular & that of molars mesially inclined

•Normal –transverse occlusal plane – esthetic&- parallel to the transcommisural line & a line tangent to lower lip

• Asymmetry cases – transcommisural lines’ll not be parallel to other facial planes – treatment occlusal plane should not be parallel to facial planes

2. Midline coordination

• Translate midline (asymmetric extractions)

• Tipping of the teeth to midline

• Altering the occlusal cant

Occlusal therapy

• Selective grinding /Occlusal adjustment

-Reshaping the occlusal surfaces of the teeth to achieve a desired occlusal contact pattern

-Removal of the tooth structure limited to enamel.

• Restorations of teeth –

crowns & FPDs

Rule of thirds

Each inner incline of posterior teeth is divided into 3 equal parts:

• If opposing centric cusp tip contacts the third closest to the central fossa – selective grinding

• If opposing centric cusp tip touches the middle third – crowns FPDs

• If opposing centric cusp tip contacts the cusp tip –orthodontic arch coordination

DENTAL COMPENSATIONS

• Midline shifts- dental compensation to make the dental midline shift

• Axial inclination of molars

– to compensate for the developing cross bite in the contralateral side

• Canting of maxillary occlusal plane

Surgical

•Conditions with severe skeletal asymmetries are not able to be corrected by orthodontic camouflage and growth modification so surgical procedures are used to correct the deformities or asymmetries.

1. Distraction osteogenesis

2.Maxillary surgeries - Lefort I

3. Mandibular surgeries

- BSSO

- Inferior body osteotomy

- genioplasty

4. TMJ surgeries

5. Autogenous/alloplastic augmentation

1)Rhinoplasty.

2)Genioplasty.

3)Cheiloraphy.

COSMETIC SURGERIES

CONCLUSION

•A team approach in the management ofasymmetries always produces a high degree ofsuccess which influences the social & personalwell being of these patients.

•Joining hands together enlightens the futureof such patients.