UNIVERSITY OF GLASGOW
Management of facial & dental asymmetry
Personal note
Mohammed Almuzian
1/1/2014
.
Table of Contents
Definition ................................................................................................
Features ....................................................................................................................
Facial & dental asymmetry
Definition
Symmetry defined as equality in form of parts distributed around a centre or an axis
...
was mandibular midline deviation from the facial midline. This occurred in
62% of patients, followed, in descending order ...
1. Skeletal
2. Dental
3. Muscular
4. Functional
5. Combination
Another classification from Bishara 1994 et al and Chai et ...
1. Genetic & epigenetic factors
I. Torticollis
II. CLP
III. Progressive hemifacial atrophy (Parry-Romberg syndrome) the ca...
III. Postnatal
• Tumour e.g osteochondroma – asymmetry and open bite on the involved side
and mandibular deviation occurs....
1. Torticollis
2. Decreased muscle tone after CVA or cerebral palsy
3. Massetric hypertrophy
D. Local dental factors
(Holm...
6. Iatrogenic due to uncontrolled space closure in orthodontic treatment
The local factors of asymmetry can also be divide...
• Functional assessment
iii. Supplemental records
1. Lateral Ceph
2. OPG
3. PA Ceph
• Anatomic approach,
• Bisection appro...
In details
I. History (trauma, family history, syndrome, previous radiation therapy)
II. Clinical examination
1. Extraoral...
• Occlusal cant
2. Intraoral features
a) Vertical occlusal evaluation
• Canted occlusal plane (tongue blade/interpupillary...
• Overall arch shape (max/mand). Lundstrom, 1961 used the maxillary raphe
as a reference line.
e) Functional assessment
• ...
a) Anatomic approach, by Harvold 1964
• Horizontal line through ZF suture
• Vertical line perpendicular to this from crist...
5) SPECT (single photo emission computer tomography) is a nuclear
medicine tomographic[1] imaging technique using gamma ra...
3. Patient concern
4. Compliance
5. Severity
6. Aetiology (skeletal, dental, st, functionl),
7. Location
8. Progressivity....
2. Treatment of asymmetry
i. Mild cases
ii. Moderate to severe
• Camouflage treatment
• Orthopaedic management
• Orthognat...
4. Space opening in one side and composite build ups of the microdontic teeth.
5. IPS of the macrodontic teeth.
III. Asymm...
3) Space closure stage:
• Push-pull mechanics
• Asymmetric torque that allow the space closure of the side with less torqu...
• class III elastics to the non-shift side early in treatment, supported by upper
headgear
III. Lower incorrect, without m...
Functional asymmetry
1. Habit breaker if the functional displacement is due to cross bite caused by habit.
2. Mild deviati...
Treatment of skeletal asymmetry
A. Mild cases, accept or orthodontic camouflage after monitoring the
progressivity of the ...
Advantages
I. To avoid consequence of disturbed or secondary unfavourable growth in the
craniofacial structure
II. Psychol...
• Lower mandibular border plasty (e.g Hemimandibualr hypertrophy)
• Distraction osteogenesis appears to offer the possibil...
• Autosomal dominant
• Affect male than female m:f = 3:2
• A condition that affects aural, oral and mandibular development...
• Unilateral microtia
• Pre-auricular tags
• Vertical dystopia
• Facial asymmetry
• Agenesis of the ramus
3. Oral & dental...
• Surgery
• Then Functional appliance
c. Late intervention
• Orthodontic
• Surgery
2. Second way of treatment distraction ...
Advantages
More stable because of the gradual distraction of the soft tissue
Indication of DO
1. HFM
2. Treacher Collins s...
5. ID canal NOT bowed on affected side,
6. Normal height of ramus of mandible
7. Obtuse angle of mandibular at side effect...
11.Treatment involves ramus osteotomy, condylectomy or condylar shave.
Condylar ankylosis
True condylar ankylosis
• I caus...
• Infection in the joint.
• Tumour of the joint structures.
2. Extra-articular (extracapsular)
• Muscle trismus.
• Disuse ...
• This produces an occlusal cant down to the normal side.
• In rare bilateral cases the mandible is short but symmetrical....
1. Excision of the condyle
2. Insertion of an interpositional temporalis myofascial peninsular flap
3. Bilateral coronoide...
Surgical Approach and preparation
The preoperative preparation differs from the standard orthognathic workup in
several re...
8. Pneumothorax.
Summary of the evidences
• Vig & Hewitt (1975) showed an overall asymmetry present in most of the
36% of ...
• Stability after orthognathic surgery, Proffit and Severt 1997
• Hemifacial microsomia
1. Prevalence
2. 1/5000 births but...
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Facial and dental asymmetry by almuzian

  1. 1. UNIVERSITY OF GLASGOW Management of facial & dental asymmetry Personal note Mohammed Almuzian 1/1/2014 .
  2. 2. Table of Contents Definition .....................................................................................................................................................4 Prevalence ...................................................................................................................................................4 Aetiology and classification..........................................................................................................................5 The local factors of asymmetry can also be divided into............................................................................10 Diagnosis....................................................................................................................................................10 Treatment...................................................................................................................................................16 Treatment of asymmetry............................................................................................................................17 Treatment of dental asymmetries..............................................................................................................18 Treatment mechanics.................................................................................................................................20 I.Upper incorrect to facial midline......................................................................................................20 II.Lower incorrect, without mandibular shift and without skeletal asymmetry..................................20 III.Lower incorrect, without mandibular shift but with skeletal asymmetry.......................................21 IV.Lower incorrect, with mandibular shift. ........................................................................................21 V.Bimaxillary to the same side............................................................................................................21 VI.Bimaxillary to opposite sides..........................................................................................................21 Functional asymmetry................................................................................................................................22 Skeletal asymmetry....................................................................................................................................22 Indication..............................................................................................................................................23 Advantages...........................................................................................................................................24 Soft tissue asymmetry................................................................................................................................25 Hemifacial microsomia...............................................................................................................................25 Prevalence .................................................................................................................................................25 Classification of HFM according to Przansky .............................................................................................26 Aetiology....................................................................................................................................................26 Mohammed Almuzian, University of Glasgow, 2013 Page 2
  3. 3. Features .....................................................................................................................................................26 Treatment Hemifacial microsomia.............................................................................................................27 Advantages.................................................................................................................................................29 Indication of DO.........................................................................................................................................29 Complications.............................................................................................................................................29 Hemimandibualr elongation.......................................................................................................................29 Hemimandibualr hypertrophy ...................................................................................................................30 Condylar ankylosis......................................................................................................................................31 Limited mouth opening (Trismus) ..............................................................................................................31 Presentation of Ankylosis...........................................................................................................................32 Diagnosis of for ankylosed TMJ .................................................................................................................33 Treatment Choices ....................................................................................................................................33 Surgical Approach and preparation ...........................................................................................................35 Complications ............................................................................................................................................35 Summary of the evidences.........................................................................................................................36 Mohammed Almuzian, University of Glasgow, 2013 Page 3
  4. 4. Facial & dental asymmetry Definition Symmetry defined as equality in form of parts distributed around a centre or an axis (Stedman’s medical Dictionary) while asymmetry defined as dissimilarity of parts on either side of a straight line or plane, or about a centre or axis. Prevalence In general population • Most people have an asymmetry in the face and dentition, but it is usually mild. (Shah and Joshi, 1978) • Vig & Hewitt (1975) showed an overall asymmetry present in most of the 36% of children in their study, with the left side being larger. • No significant gender difference found (Melnik, 1991). • Here was a 90% chance that the deviation was to the left • The mandible and the dentoalveolar region exhibited the greatest degree of symmetry this is because the growth of the mandible takes the longest period of growth. • History of trauma was found in only 14% of patients with asymmetry. • Sheats 1998 (US) 12% facial asymmetry and 21 % noncoincidence of dental midlines. Among orthodontic patients, the most common asymmetry trait Mohammed Almuzian, University of Glasgow, 2013 Page 4
  5. 5. was mandibular midline deviation from the facial midline. This occurred in 62% of patients, followed, in descending order of frequency, by lack of dental midline coincidence (46%, maxillary midline deviation from the facial midline (39%), molar classification asymmetry (22%), maxillary occlusal asymmetry (20%), mandibular occlusal asymmetry (18%), facial asymmetry (6%), chin deviation (4%), and nose deviation (3%). In orthognathic patients: (server and Proffit 1996) • 25% of class II have asymmetry • 40% of class III have asymmetry. • 26% of orthognathic cases have facial asymmetry (Proffit, 1996) and 60% of them with asymmetry in the lower face and 80% of them have chin deviation. The midface (primarily the nose) also was affected in about 30% of the asymmetric patients • Burden 1999 showed that 56% of the lay person and 83% of the orthodontist can recognize 2mm ML discrepancy. Aetiology and classification It can be classified according to the structures involved: Mohammed Almuzian, University of Glasgow, 2013 Page 5
  6. 6. 1. Skeletal 2. Dental 3. Muscular 4. Functional 5. Combination Another classification from Bishara 1994 et al and Chai et al 2008 I. Skeletal factors 1. Genetic & epigenetic factors 2. Environmental II. Functional mandibular deviations 3. In occlusion 4. In opening III. Muscular factors IV. Local dental factors V. Combinations In details A. Skeletal factors Mohammed Almuzian, University of Glasgow, 2013 Page 6
  7. 7. 1. Genetic & epigenetic factors I. Torticollis II. CLP III. Progressive hemifacial atrophy (Parry-Romberg syndrome) the cause either autoimmune disease or genetic causes as autosomal dominance factors. IV. Hemimandibualr atrophy V. Hemifacial hypertrophy VI. Condylar hyperplasia which is subdivided by Obowegeser and Mekek 1986 into: a) Hemimandibualr elongation b) Hemimandibualr hypertrophy c) Hybrid forms 2. Environmental I. Prenatal • Intra-uterine pressure like Pier Robin syndrome • FAS • CLP II. Neonatal • Condylar fracture during birth Mohammed Almuzian, University of Glasgow, 2013 Page 7
  8. 8. III. Postnatal • Tumour e.g osteochondroma – asymmetry and open bite on the involved side and mandibular deviation occurs. • Trauma e.g. fractures ( 25% of fracture go undiagnosed and cause later an ankylosis while 75% grow normally, • Infection • Cyst • Post radiation • Nerve damage, • Idiopathic condylar resorption B. Functional mandibular deviations 1. In occlusion: Constricted maxillary arch or malposed tooth causes premature contact in CR leading to deviation into CO 2. In opening • Due to anterior disc derangement that result in mandibular deviation when the condyle translate from hinge to translation movement • Eagle mouth syndrome (long styloid process) C. Muscular Mohammed Almuzian, University of Glasgow, 2013 Page 8
  9. 9. 1. Torticollis 2. Decreased muscle tone after CVA or cerebral palsy 3. Massetric hypertrophy D. Local dental factors (Holmes 1989) 1. Number of teeth: • Premature loss of primary teeth like C or D but not the E • Traumatic loss of permenant teeth • Hypodontia • Supernumerary teeth 2. Size of teeth • Macrodontia • Microdontia 3. Position of teeth • Ectopic eruption of teeth causing asymmetric crowding • Localization of crowding 4. Habit like digit sucking habit 5. Pathology like caries and loss of tooth contact Mohammed Almuzian, University of Glasgow, 2013 Page 9
  10. 10. 6. Iatrogenic due to uncontrolled space closure in orthodontic treatment The local factors of asymmetry can also be divided into (Lunstrom, 1961) 1. Qualitative – different size teeth/location in the arch/position of arch in head 2. Quantitative – differences in no. of teeth/presence of CLP Diagnosis i. History (trauma, family history, syndrome, previous radiation therapy) ii. Clinical examination A. Extraoral examination • Profile • Frontal • Transverse B. Intraoral features • Vertical • Transverse • Anteroposterior • Intraarch feature Mohammed Almuzian, University of Glasgow, 2013 Page 10
  11. 11. • Functional assessment iii. Supplemental records 1. Lateral Ceph 2. OPG 3. PA Ceph • Anatomic approach, • Bisection approach • Triangulation approach 4. Technesium isotope scan 5. SPECT (single photo emission computer tomography) 6. Medical CT Scan 7. CBCT 8. MRI Scans 9. Study models 10.Facebow record 11.Photograph 12.Sterophotogrammetry 13.Laser scanning 14.Combinations Mohammed Almuzian, University of Glasgow, 2013 Page 11
  12. 12. In details I. History (trauma, family history, syndrome, previous radiation therapy) II. Clinical examination 1. Extraoral examination Profile assessment • Class III skeletal pattern which is the first sign of Hemimandibualr hypertrophy problem • Class II skeletal pattern indicates Hemimandibualr atrophy Frontal assessment To assess the symmetry of the face a midline need to be constructed I. Dropping a perpendicular line from glabella • to supraorbital bridge • to interpupilliary line • to inter-auricular line II. Dropping a line pass through nasion and philitrum and tip of the nose III. By using the rule of fifths Bird and warm view Transverse assessment • Chin cant Mohammed Almuzian, University of Glasgow, 2013 Page 12
  13. 13. • Occlusal cant 2. Intraoral features a) Vertical occlusal evaluation • Canted occlusal plane (tongue blade/interpupillary line). b) Transverse A. X-bites (skeletal, dental or functional), may need to de-programme with occlusal splint for definitive diagnosis. B. Evaluation of dental midlines, when the mouth • Open, • Initial contact • CR, • CO c) Anteroposterior occlusal evaluations • Molar and canine relationship in both sides • Overjet • Overbite d) Intraarch feature • Local dental factors (early loss etc.) Mohammed Almuzian, University of Glasgow, 2013 Page 13
  14. 14. • Overall arch shape (max/mand). Lundstrom, 1961 used the maxillary raphe as a reference line. e) Functional assessment • Displacements. 3. Supplemental records 1) Lateral Ceph Sometime a rough idea can be extracted when the right and left sides are superimposed 2) OPG • Useful to survey dental and bony structures of the maxilla and mandible. • Shape of condyles and ramus But geometric distortions exist due to focal tough, positional problem, magnification problem. 3) PA Ceph • Valuable to compare right and left sides as located at relatively equal distances form the film and X-ray source. • It provides qualitative and quantitative evaluation. • Taken in occlusion and mouth open. • Bishara 1993 describe the methods of using PA radiograph Mohammed Almuzian, University of Glasgow, 2013 Page 14
  15. 15. a) Anatomic approach, by Harvold 1964 • Horizontal line through ZF suture • Vertical line perpendicular to this from crista galli. • Nasion and ANS tend to fall on or very near ~ 90% of the time b) Bisection approach • Bilateral landmarks are located and bisected • Reference line through as many of their midpoints as possible c) Triangulation approach • Vig and Hewitt,1979 • Identification of bilateral structures and midline • Triangles are constructed that divide the face into various components • Right and left triangles compared for symmetry 4) Technesium isotope scan, Proffit 2005 • Bone seeking Tc99m can be used to distinguish an active growing condyle • It is injected and then it can be detected in the body by medical equipment (gamma cameras). • False +ve is very common. • Dose equivalent = 20 chest X-rays. Mohammed Almuzian, University of Glasgow, 2013 Page 15
  16. 16. 5) SPECT (single photo emission computer tomography) is a nuclear medicine tomographic[1] imaging technique using gamma rays 6) Medical CT Scan Accurate but high radiation 7) CBCT 8) MRI Scans Useful for soft tissue asymmetries. 9) Study models Demonstrate arch asymmetries 10) Facebow record Using study casts, demonstrates the relationship of the jaws in all three planes 11) Photograph 12) Sterophotogrammetry Hajeer et al 2004 13) Laser scanning of the face by Toma 2011, Alqattan 2013 14) Combinations Treatment Treatment depends on: 1. Age 2. Growth remains Mohammed Almuzian, University of Glasgow, 2013 Page 16
  17. 17. 3. Patient concern 4. Compliance 5. Severity 6. Aetiology (skeletal, dental, st, functionl), 7. Location 8. Progressivity. 9. Is there a cant to the maxillary plane Treatment of asymmetry A. Treatment of dental asymmetries 1. Stop habits and eliminate mandibular displacements (early in Tx) 2. Space management to correct asymmetry 3. Asymmetric differential mechanics • Extraoral mechanics • Inter-arch mechanics • Intra-arch mechanics B. Functional asymmetry C. Skeletal asymmetry 1. Preventive treatment Mohammed Almuzian, University of Glasgow, 2013 Page 17
  18. 18. 2. Treatment of asymmetry i. Mild cases ii. Moderate to severe • Camouflage treatment • Orthopaedic management • Orthognathic surgery, Early intervention or Late intervention D. Soft tissue asymmetry In details Treatment of dental asymmetries Treatment is often orthodontically. I. Stop habits and eliminate mandibular displacements (early in Tx) II. Space management to correct asymmetry (space maintainer or balanced extraction) 1. Asymmetric and or Unilateral extraction (Rebellato, 1998) 2. Unilateral distalization by (URA with finger spring on one side supported by HG, asymmetric HG, non-compliance molar distalizer like Jone Jigs or pendulum appliance, sliding jigs supported by HG) 3. Asymmetric HG to correct UML Mohammed Almuzian, University of Glasgow, 2013 Page 18
  19. 19. 4. Space opening in one side and composite build ups of the microdontic teeth. 5. IPS of the macrodontic teeth. III. Asymmetric differential mechanics Holmes 1989 divided them into: 1. Extraoral mechanics • J hook (either on J hook or even two J hook cab be applied to the U and L simultaneously to correct ML deviation in opposite direction). • Asymmetric HG with Class III elastic to correct U & L ML that deviated to one side. 2. Inter-arch mechanics • Differential II/III elastics, • Oblique or diagonal elastic anteriorly (if too long can cant the occlusal plane). 3. Intra-arch mechanics 1) Bracket set up: Reverse the lower canine brackets on one side (the side at which the LML shifted) or using tip edge bracket on one side allowing less tipping to correct the ML. 2) Alignment stage • Unilateral LB, • Unilateral cinch back Mohammed Almuzian, University of Glasgow, 2013 Page 19
  20. 20. 3) Space closure stage: • Push-pull mechanics • Asymmetric torque that allow the space closure of the side with less torque of the posterior teeth to happen thus aims in correcting the ML. • Unilateral thinning of the AW • Differential force during space closure • Unilateral closing loop, • Elastomeric modules to increase the friction at one side to allow asymmetric space closure 4) Anchorage • Differential anchorage or increasing the number of anchor teeth • TADs Treatment mechanics I. Upper incorrect to facial midline. • asymmetric extraction • lace-back canine or cinch back on non-shift side only • open coil spring on shift side II. Lower incorrect, without mandibular shift and without skeletal asymmetry. • apply measures described above Mohammed Almuzian, University of Glasgow, 2013 Page 20
  21. 21. • class III elastics to the non-shift side early in treatment, supported by upper headgear III. Lower incorrect, without mandibular shift but with skeletal asymmetry. • in mild cases, apply measures described above • unilateral extraction in moderate cases where dento-alveolar compensation is to be maximised • orthognathic surgery in severe cases, or acceptance of the condition IV. Lower incorrect, with mandibular shift. Where the centreline shift is due entirely to a mandibular displacement, the discrepancy will correct once the displacement has been eliminated. Where other causes are also present, apply the measures described above for types 1 and 2 V. Bimaxillary to the same side. • The choice of extractions is most important. Removal of first premolars on the non- shift side and second premolars on the shift side gives the most favourable anchorage balance for correction, provided extractions are warranted. • In uncrowded (skeletal asymmetry) cases, unilateral extractions may be considered if dentition is generally protrusive, or accept the condition. VI. Bimaxillary to opposite sides • Early in treatment, apply measures described as for type 1. • Later in treatment, diagonal anterior elastic will provide the ideal vector without any demand on anchorage. • Class II & class III elastics also gives reciprocal anchorage. • for resistant shifts in the later stages, "J" hook headgear applied to the canines in the non-shift sides (eg upper left and lower right quadrants) Mohammed Almuzian, University of Glasgow, 2013 Page 21
  22. 22. Functional asymmetry 1. Habit breaker if the functional displacement is due to cross bite caused by habit. 2. Mild deviations due to functional shifts can be done with minor occlusal adjustments (grinding C’s, or extraction). 3. Occlusal splints may be needed for deprogramming 4. Expansion of the constricted arch (RME, Q helix, URA, AW or SARPE) Skeletal asymmetry Preventive treatment Fortunately, most jaw fractures in preadolescent children can be treated with little or no surgical manipulation of the segments and little immobilization of the jaws because the bony segments are self-retentive and the healing process is rapid. Treatment should involve • Open reduction of the fracture should be avoided. • Short fixation times (usually maintained with intraoral intermaxillary elastics) and rapid return to function. • A functional appliance during the post-injury period can be used to minimize any growth restriction. The appliance is a conventional activator or bionator-type appliance that symmetrically advances the mandible to nearly an edge-to-edge incisor position. Using this appliance, the patient is forced to translate the mandible, and any remodelling can occur with the mandible in the unloaded and forward position. Mohammed Almuzian, University of Glasgow, 2013 Page 22
  23. 23. Treatment of skeletal asymmetry A. Mild cases, accept or orthodontic camouflage after monitoring the progressivity of the case. B. Moderate to severe: after monitoring the progressivity of the case 1. Camouflage treatment by orthodontic alone 2. Orthopaedic management of occlusal canting in growing patients using hybrid functional by Vig and Vig 1986. It consists of acrylic block at the side of overgrowth and no block at the undergrowth site to allow eruption of the teeth at the underdeveloped site. There is a buccal shield same like the one use in Frankle appliance to allow arch expansion. 3. Orthognathic surgery A. Early intervention It is better to avoid early maxillary surgery to avoid scar interference with maxillary growth. Sometime high condylar shaving or condylotomy is prescribed. Indication I. Ankylosis: treated by growth centre transplant using costrocondal rib in sever class II II. HFM usually treated early 5 years by inverted L osteotomies or distraction (Davis and Sandy1998) III. Sever class III or class II with social impact Mohammed Almuzian, University of Glasgow, 2013 Page 23
  24. 24. Advantages I. To avoid consequence of disturbed or secondary unfavourable growth in the craniofacial structure II. Psychological benefit. B. Late intervention The surgeries might be: 1. Lefort I osteotomy to reposition the maxilla 2. Sometime, mandibular asymmetry can cause some secondary maxillary asymmetry which might be treated by: • Maxillary segmental surgery, • Surgically assisted RME. 3. Sagittal split osteotomies of the mandibular ramus to advance or shorten one side more than the other 4. Other mandibular surgery are: • Genioplasty • VSS • Inverted L • Condylar excision, • Condylar shave Mohammed Almuzian, University of Glasgow, 2013 Page 24
  25. 25. • Lower mandibular border plasty (e.g Hemimandibualr hypertrophy) • Distraction osteogenesis appears to offer the possibility of augmenting the amount of both bone and soft tissue in the mandibular anterior area. Stability after orthognathic surgery Proffit and Severt 1997 found that 1. Genioplasty to correct asymmetry was stable 2. Maxillary surgery to correct cant was stable 3. Ramus surgery 1/3 of the result is lost 4. Bimax is more stable than mandibular surgery alone Soft tissue asymmetry It can be treated either by: • Augmentations include the use of bone grafts, collagen filler, Botox and implants to recontour the desired areas of the face • Soft tissue reduction surgery. Hemifacial microsomia Prevalence • 1/5000 births but varies Mohammed Almuzian, University of Glasgow, 2013 Page 25
  26. 26. • Autosomal dominant • Affect male than female m:f = 3:2 • A condition that affects aural, oral and mandibular development. It caused by disturbance in the number, activity and migration of NCC (especially in the lower face area, the NCC migrate for long distance) • Varies from mild to severe • Can be bilateral, and one side can be more severe than the other Classification of HFM according to Przansky 1. Grade 1 condyle only 2. Grade 2 condyle and mild ramus involvement 3. Grade 3 condyle, ramus and coronoid severely involved Aetiology 1. Autosomal dominance inheritances 2. Stapaedial artery bleeding Features The facial phenotype 1. General features: cardiac, renal and skeletal abnormalities 2. Facial features: Mohammed Almuzian, University of Glasgow, 2013 Page 26
  27. 27. • Unilateral microtia • Pre-auricular tags • Vertical dystopia • Facial asymmetry • Agenesis of the ramus 3. Oral & dental features: • CLP • Delayed teeth eruption, • Hypodontia • Hypoplastic teeth Treatment Hemifacial microsomia 1. One way of treatment involves a costo-chondral graft, and a hybrid functional appliance in different phases. a. Very Early intervention at age of 5-6 years • Functional appliance • Then Surgery • Then functional appliance b. Early intervention at age of 8-9 years Mohammed Almuzian, University of Glasgow, 2013 Page 27
  28. 28. • Surgery • Then Functional appliance c. Late intervention • Orthodontic • Surgery 2. Second way of treatment distraction osteogenesis (DO). It is a method of increasing bone length & originally described by Ilizarov (1988). The technique involves: 1. Corticotomy – circumferential sectioning of compact bone and maintenance of medullary complex. 2. Screw device holding bone pins rigidly and then the two pieces are separated in a controlled and gradual process, which induces bony proliferation between them. 3. Screw turned after 5 days • 1mm/day – adults • 2mm/day – children • Insufficient speed = bony union • Undue haste = fibrous non-union Mohammed Almuzian, University of Glasgow, 2013 Page 28
  29. 29. Advantages More stable because of the gradual distraction of the soft tissue Indication of DO 1. HFM 2. Treacher Collins syndrome 3. Ankylosis 4. Sever class III with maxillary hypoplasia 5. Sever class II with mandibular hypoplasia 6. Calvarial expansion in craniosynstosis 7. Missing bone due to trauma or pathology Complications 1. Extra-oral scarring 2. Small and fiddly intra-orally Hemimandibualr elongation 1. Mechanism not understood, 2. Appears early teens (most frequent in girls) 3. Transverse displacement of the chin point 4. Lower dental ML deviation in relation to UML but correct to midpoint of the chin Mohammed Almuzian, University of Glasgow, 2013 Page 29
  30. 30. 5. ID canal NOT bowed on affected side, 6. Normal height of ramus of mandible 7. Obtuse angle of mandibular at side effected 8. Long mandibular body at side effected 9. No open bite or occlusal cant 10.Cross bite at the non-affected side and scissor bite on the contralateral. Hemimandibualr hypertrophy 1. Mechanism not understood 2. Appears late teens (may be earlier, most frequent in girls) 3. Three dimensional enlargement of one side of the mandible including condyle, condylar neck, ramus and body of the mandible 4. Big condyle 5. ID canal bowed on affected side, 6. Body of mandible bows downwards on affected side, 7. Angle of mandible rounded 8. Increase mandibular ramus height 9. Cant of occlusion at effected side 10.Lower dental ML deviation in relation to midpoint of the chin in order to compensate by increase in the incisor angulation. Mohammed Almuzian, University of Glasgow, 2013 Page 30
  31. 31. 11.Treatment involves ramus osteotomy, condylectomy or condylar shave. Condylar ankylosis True condylar ankylosis • I caused by pathology or trauma or infection • X ray reveals pure bony union • Very sever restricted mouth opening • The best treatment of condylar fracture is early mobilization to avoid ankylosis False condylar ankylosis • Transient Limited mouth opening (Trismus) • Due to extra-articular abnormality, the result is limited mouth opening Limited mouth opening (Trismus) There are many causes of limited mouth opening which may be classified as follows. 1. Intra-articular (intracapsular) • Functional: Anterior displacement of the meniscus without reduction. • Trauma: Osseous or fibro-osseous ankylosis, secondary to trauma • Inflammatory: Ankylosing spondylitis, juvenile rheumatoid arthritis. Mohammed Almuzian, University of Glasgow, 2013 Page 31
  32. 32. • Infection in the joint. • Tumour of the joint structures. 2. Extra-articular (extracapsular) • Muscle trismus. • Disuse muscle atrophy, contractures secondary to intra-articular ankylosis or psychogenic trismus. • Post-radiotherapy and thermal scarring. • Post-traumatic scarring. • Oral submucous fibrosis. • Infection or inflammation of the masticatory muscle • Anatomical like Eagle syndrome. Presentation of Ankylosis If developed at early age: • Ankylosis in children produces impaired mandibular growth with bilateral deformity in all dimensions. • This deformity is asymmetrical in unilateral cases with a straight small hemi- mandible on the ankylosed side, and a marked contralateral bowing deformity. • Retrognathia and retrogenia become more apparent with age. Mohammed Almuzian, University of Glasgow, 2013 Page 32
  33. 33. • This produces an occlusal cant down to the normal side. • In rare bilateral cases the mandible is short but symmetrical. • In all cases the inter-incisal opening can be up to 10 mm even with total bony fusion reflecting the bone elasticity within the masticatory system. Diagnosis of for ankylosed TMJ • History and clinical examination • Imaging techniques including: 1. OPG. 2. True lateral skull. 3. PA 4. CT scan with 3D reconstruction. 5. Standard orthognathic photographic series. Treatment Choices Resection of the ankylosis should be carried out as early as possible to enable normal growth and avoid secondary deformity. There are many treatment strategies depending on the age of the patient the duration of the deformity and degree of secondary deformity. A. Ankylosis presenting in childhood or Ankylosis presenting during or post adolescence Mohammed Almuzian, University of Glasgow, 2013 Page 33
  34. 34. 1. Excision of the condyle 2. Insertion of an interpositional temporalis myofascial peninsular flap 3. Bilateral coronoidectomies (coronoidotomies) to free temporalis contractures 4. Costochondral growth centre to restore function and ramus growth with or without Distraction osteogenesis. NB: The anteroposterior deficiency and asymmetry in childhood is usually self- corrected with catch-up growth. B. Ankylosis presenting after the completion of facial growth. 1. Excision of the condyle 2. Insertion of an interpositional temporalis myofascial peninsular flap 3. Bilateral coronoidectomies (coronoidotomies) to free temporalis contractures 4. Reconstruction of the condyle with or without distraction osteogenesis. 5. In addition to one of these: • Genioplasty • BSS or inverted L osteotomy. • The maxillary procedure can be done to correct secondary problems C. Very late ankylosis in adults with no interference with facial growth. Exactly as B but in addition to 7-day pre- and 2-month postoperative course of bisphosphonate, which is currently alendronic acid 10 mg a day in the morning to avoid the localised fibrodysplasia ossificans . Mohammed Almuzian, University of Glasgow, 2013 Page 34
  35. 35. Surgical Approach and preparation The preoperative preparation differs from the standard orthognathic workup in several respects. 1. The anaesthetist must be skilled in fibre optic intubation and tracheostomy or submental approach. 2. The temporal area must be shaved and cleaned before the patient is taken into theatre. Complications 1. Scar 2. Damage to the orbital and frontal branches of the facial nerve. 3. Frey’s syndrome 4. Damage to parotid salivary gland 5. Limited opening due to • Inadequate bone removal • Failure to do a bilateral coronoidectomies. • Postoperative fibrodysplasia ossificans • Fusion of the graft with re-ankylosis 6. Failure of the costochondral graft to grow. 7. Excess growth of the graft Mohammed Almuzian, University of Glasgow, 2013 Page 35
  36. 36. 8. Pneumothorax. Summary of the evidences • Vig & Hewitt (1975) showed an overall asymmetry present in most of the 36% of children in their study, with the left side being larger. • 26% of orthognathic cases have facial asymmetry (Proffit, 1996) and 60% of them with asymmetry in the lower face and 80% of them have chin deviation. The midface (primarily the nose) also was affected in about 30% of the asymmetric patients • Another classification from Bishara 1994 et al and Chai et al 2008 • Condylar hyperplasia which is subdivided by Obowegeser and Mekek 1986 into: • Local dental factors , (Holmes 1989) • Bishara 1993 describe the methods of using PA radiograph • Technesium isotope scan, Proffit 2005 • Sterophotogrammetry Hajeer et al 2004 • Laser scanning of the face by Toma 2011 • Treatment of dental asymmetries, Space management to correct asymmetry, Asymmetric XLA’s (Rebellato, 1998) • Asymmetric differential mechanics , Holmes 1989 Mohammed Almuzian, University of Glasgow, 2013 Page 36
  37. 37. • Stability after orthognathic surgery, Proffit and Severt 1997 • Hemifacial microsomia 1. Prevalence 2. 1/5000 births but varies 3. Autosomal dominant 4. Affect male than female m:f = 3:2 5. A condition that affects aural, oral and mandibular development. It caused by disturbance in the number, activity and migration of NCC (especially in the lower face area, the NCC migrate for long distance) • Second way of treatment distraction osteogenesis (DO).It is a method of increasing bone length & originally described by Ilizarov (1988). Mohammed Almuzian, University of Glasgow, 2013 Page 37

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