Management of Facial asymmetry
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Transcript of Management of Facial asymmetry
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.