Orthognathic surgery

Orthognathic surgery
Supervised by
Dr.Ahmad Altarawneh
Prepared by
Dr.Ali Mohammed alsayani

Outlines
• Introduction
• Diagnosis and assessment
• Initial Planning
• The Borderline Patient Camouflage Versus Surgery
• Indications and contraindications
• Special Considerations in Planning Surgical Treatment
• Presurgical orthodontics
• Orthodontic appliance
• Stabilizing arch wire
• Procedure of cast prediction (Model Surgery)
• Splints and Stabilization
• Surgical techniques
• Post surgery Care
• Retention
• Stability
• Adjunctive facial procedure
• Problems
• Distraction Osteogenesis
• References

Introduction
• Orthognathic surgery is surgery aimed to correction
of functional and aesthetic of severe dentofacial
deformity through combination of orthodontic ,
surgical and possibly restorative dentistry.

• However, the most common reason for
patients seeking combined orthodontic and
surgical treatment is dental and/or facial
aesthetic problems.

Diagnosis and assessment
1) History :
 Patient age.
 Patient concern.
 Patient motivation& expectation.
 Psychological status.
 Medical and dental history.

2) Clinical Examination:
Assess skeletal , soft tissue and dental features.
1. Extra oral features:-
A) Frontal analysis
Symmetry

Vertical proportions
In normal proportions the
face can be divided into three
equal thirds.
The lower third can be
divided so that the
commisures of the lips is one
third of the way from the base
of nose to chin.

Lip line
 At rest 2-4 mm of incisor show.
During smiling, whole length of incisor
is showing.
If there is excess of gingiva is showing,
it may referred as a gummy smile.

B) Profile analysis
 The patient should be assessed in the natural head
position.
 The middle and lower thirds are assessed in relation to the
forehead.
 In normal profile, the base of the nose lies approximately
vertically below the anterior part of the forehead.

It is a line joining the soft tissue chin and
tip of nose.
Normal value; 0- 2mm(+/-2mm).
In normal face, lower lip lie on or
anterior to this line and upper lip little
further posterior.
Rickett’s E-line

zero meridian line
It is a line perpendicular to FH –line passing through the
soft tissue nasion to measure the position of the chin.
Ideally passes through the soft tissue Pogonion
( 0 +/-2mm).

Harmony line & angle
It is a line from soft tissue pogonion
through upper lip bisecting the nose.
H-line angle formed between H-line
and line joining N to Pog.
The Average value 7-15 degree.
Measures upper lip prominence
and/or retrognathic soft tissue chin.

Nasolabial angle
Angle formed by joining tip of nose,
sub nasal and labrial Superioris.
The normal value 90-99 degree.
The Nasolabial angle should be noted,
as it can be affected by excessive
retraction or proclination of the upper
incisors.

2. Intra oral features
 A full assessment of the dentition and occlusion needs to be
undertaken.
Any dental disease needs to be identified , treated and
stabilized before combined orthodontics and orthognathic
surgery can begin.

3) Temporomandibular Joint ( TMJ )
The presence of any signs or symptoms of TMJ dysfunction
such as limitation of opening , noises , pain should be noted.
 Any symptoms should be treated conservatively prior to
treatment.

4) Radiographic Examination
This usually includes radiographs taken as part of the routine
orthodontic assessment of a patient with a skeletal discrepancy.
A panoramic dental view (OPT) , a lateral cephalometric
radiograph.
 Additional views may be needed depending on the case. For
example; PA skull radiograph may be taken to assess asymmetry.

 Planning for orthodontic/orthognathic surgary
• A team approach composed of an orthodontist , surgeon ,
restorative dentist and psychologist if needed.
• Using the information taken from the history , clinical
examination and diagnostic records, it should be possible to
create a problem list.
• Establish where the problem maxilla , mandible or both.

The Borderline Patient Camouflage Versus Surgery
• The envelope of discrepancy shows the
amount of change that could be
produced by orthodontic tooth
movement alone (the inner envelope ),
orthodontic tooth movement combined
with growth modification (the middle
envelope) and orthognathic surgery (the
outer envelope).
• Soft tissue limitations not reflected in the
envelope of discrepancy often are a
major factor in the decision for
orthodontic or surgical–orthodontic
treatment.

Indications of orthognathic surgery
• Severe CI 3
• Severe CI 2
• Long face syndrome/AOB
• Facial asymmetries
• Chin abnormalities
• Craniofacial anomalies e.g. CLP

For class II according to Proffit 1992
• OJ > 10mm
• ANB > 9°
• Pog posterior to N perpendicular > 18mm
• Mandibular length > 70 mm
• Anterior facial height > 125mm

For class III according to Kerr et al 1992
• ANB = - 4°.
• maxillary mandibular ratio = 0.84.
• lower incisor inclination (LI/MP = 83°).
• Soft tissue profile (Holdaway angle = 3.5°).
*vertical dimension had little effect on treatment
decision.

Contraindications &/or limitations
• Growing patient
• Minor cases
• Medical condition
• Psychologically unstable patient

Special Considerations in Planning Surgical Treatmen
• Orthognathic surgery should be delayed until growth is
completed in patients who have problems of excessive
growth (mandibular prognathism)
• patients who have problems of growth deficiencies,
surgery can be considered earlier but rarely before the
adolescent growth spurt.

• The major indication for orthognathic surgery before
puberty is:-
• a progressive deformity.
• severe psychosocial problems caused by restriction of
growth due to ankylosis of the mandible after a
condylar injury or severe infection.

Other Considerations
Special Points in Planning Orthognathic Surgery
• If the attached gingiva is inadequate, gingival grafting
should be completed before genioplasty to prevent
recession of the gingiva in the lower incisors.
• Remove the lower third molars at least 6 months before
orthognathic procedure.

Correction of combined vertical and
anteroposterior Problems
• Short face Class II patients ( Increasing AFH ) :
Mandibular ramus surgery is preferred to increase face
height with downward movement of the posterior maxilla,
so that the mandible is forced to rotate down and back.

• Long face Class II patients ( Decreasing AFH ):
A LeFort I osteotomy to elevate the posterior maxilla is
preferred to reduce face height but If the mandible is
still deficient after it rotates up and forward ,
mandibular advancement should be done.
• For Class III patients, the same guidelines for
vertical change are applicable.

 Presurgical orthodontics
 Alignment and leveling
 Decompensation.
 Arch coordination
 Presurgical orthodontics objectives in the transverse plane
 Presurgical orthodontics objectives in the vertical plane

Alignment and leveling
• Dental crowding, spacing, and rotations should be
corrected before orthognathic surgery.
• If segmental osteotomy is planned we should provide
spaces between the roots, so we can tip the bracket

• Curve of spee should be flat (according to ideal
occlusion)
• A better result may be achieved by completing
leveling post surgically .

• In short face , when an increase in face height is
desired, lower incisors should not be depressed before
surgery. Maintenance of curve of spee is needed(3-
point landing).
• In normal or excessive face height, leveling by
intruding the incisors should be done before surgery.

Decompensation
• Compensations can be dental or skeletal, vertical,
transverse and/or sagittal.
• Presurgical orthodontic decompensation is
essential to enable the surgeon to make a
considerable amount of surgical correction

Decompensation in class II
• Procline upper incisors.
• Retrocline lower incisors.
• Use class III elastic.
Decompensation in class III
• Retrocline upper incisors.
• Procline lower incisors.
• Use class II elastic.

Decompensation in deep bite
 Extrusion mechanics to molars.
 Incisors also need to be extruded.
 clockwise rotation of mandible occurs.
 L.F.H increases & chin prominence reduces.

Decompensation in open bite
 The presurgical orthodontics should accentuate
the open bite through intrusion of the labial
segments and extrusion of the buccal segments.

 Dental extrusion of skeletal open bite will be
unstable in the long run.
 It may also create an excessive display of gingiva.
 Reversed curve of spee should be levelled.

Arch coordination
• Arch coordination refers to coordinating the widths of
the dental arches.
• Coordination involves:-
– Arch expansion.
– Arch contraction.
– Occlusal plane leveling and alignment.

Presurgical orthodontics objectives in
the transverse plane
• The problem is the skeletal or dental
• Dental discrepancies are usually treated by means
of buccal tipping of the posterior teeth while
skeletal discrepancies are corrected by bodily
movement of the posterior teeth.
• the tipping should not exceed 4 to 6 mm total.
• Bodily movement of the posterior teeth should be
done by means of segmental osteotomy.

• Is the problem relative or absolute
• Articulation of the casts into a class I occlusion
allows the clinician to easily distinguish between
relative and absolute maxillary constriction.
• If the occlusion is proper when the casts are
brought into class I canine relationship the
discrepancy is relative; otherwise, if a crossbite
still exists, then the discrepancy is absolute.

• Absolute skeletal transverse discrepancy requires
planning for segmental osteotomy or surgically
assisted rapid palatal expansion (SARPE).
• SARPE technique is used in cases with a severe
discrepancy or when the transverse defect of the
maxillary bone is an isolated skeletal anomaly.
• Segmental maxillary osteotomy is used for more
modest defects (up to 7 mm).

Orthodontic appliance
• Use metal bracket is the best.
• Use 0.022 slot to allow use rigid wire for more
stability.
• Second molar should be banded.

Stabilizing arch wire
 As the patient is approaching the end of orthodontic
preparation for surgery.
 The stabilizing wires are full-dimension edgewise wires (i.e.,
17 × 25 steel in the 18-slot appliance, 21 × 25 TMA or steel
in the 22-slot appliance).
 Hooks as attachments to tie the jaws together while rigid
fixation is placed.

 Stabilizing archwires should be placed at least 4
weeks before surgery so that they are passive when
the impressions are taken for the surgical splint
(usually 1 to 2 weeks before surgery).
 Minor interferences that can be corrected easily
with archwire adjustments can significantly limit
surgical movement.

Procedure of cast prediction (Model Surgery)
 The selection of articulator is the first step in
preparation for effective model surgery.
 Face Bow Selection.

 The maxillary dental cast is mounted on a semi
adjustable articulator with the aid of a facebow
transfer from the patient.
 The mandibular dental cast is mounted with the aid
of a bite registration taken with the patient's jaws in
centric relation.

 Model simulation for surgical movement .
 The sequence of movements are:
• The maxillary cast is repositioned and fixed in the new position on
the articulator.
• intermediate occlusal wafer splint is generated.
• The mandibular cast then is repositioned to oppose the maxillary
cast, simulating the final position of the jaws at surgery.
• This final position generates the final occlusal wafer splint for use at
surgery and during the period of jaw rehabilitation following surgery.

Splints and Stabilization
 The splint should be thin 2mm thickness with adequate strength.
 Splint stays in place during initial healing ( 3 to 4 weeks).
 It should be trimmed to allow good access to the teeth for hygiene
and permit lateral movements during jaw function.
 It should remain in place until the stabilizing wires also are replaced
with lighter and more flexible archwires

in general can achieve+ 1cm movement, mainly used to correct maxillary
excesses and AOB.
 Procedures
 Segmental ;-
Wassmund/Wunderer (anterior).
Schuchardt (posterior).
 Le Fort I osteotomy
 Le Fort II osteotomy
 Le Fort Ill osteotomy ± Kufner modification, does not
 alter position of nose
Maxillary Surgical procedures

 Total maxillary osteotomy
 Le Fort I. Osteotomy
The surgical cut goes through the wall of the maxillary sinuses ,
lateral nasal walls and the nasal septum at the level just superior to
the apices of the maxillary teeth.
 Le Fort II osteotomy
It is a pyramidal osteotomy, it differs from Le Fort I that it passes
anteriorly toward the orbit. It is used mainly with CLP.
 Le Fort III osteotomy
It is used for the correction of symmetrical mid-face recession
affecting zygomatico-maxillary and orbital regions.

• Le Fort III modified Kufner (does not alter position of nose)
Used when the nasal bridge and projection are both good, but the
infra orbital region and the dentoalveolus are retruded, with mild
zygomatic flattening.

 Segmental alveolar maxillary osteotomy:
• Anterior segmental osteotomy:
Mobilize the anterior segment of the maxilla and
allows the reposition in an upward, downward and a
rotational manner.
• Posterior segmental osteotomy.
• Anterior and posterior segmental osteotomy.

Anterior segmental osteotomy:
• Typical sites for interdental osteotomies are
between laterals and canines, premolars and
canines, or between incisors.

Segmental osteotomy between maxillary
laterals and canines.

Indications:-
• Poor transverse relationship of the maxilla and
control of intercanine width.
• Correcting Bolton discrepancy.
• Controlling incisor buccolingual angulation.
• An easier technique.

Advantages:-
• Single-stage surgery.
• Intraarch asymmetry correction.
• Controlling the Curve of Spee.
• Controlling the Curve of Wilson.

Disadvantages :-
• When there are already 2 occlusion planes between
canines and premolars.
• When there is maxillary anteroposterior skeletal
excess and premolar extractions are planned.

Maxillary osteotomies for transverse problems
 LeFort I down fracture surgery with parasagittal osteotomies
It consist of parasagittal osteotomies in the floor of the nose or floor
of the sinus that are connected by a transverse cut anteriorly.
 LeFort I down fracture surgery with midsagittal osteotomies.
 Surgically-assisted palatal expansion:
Using bone cuts to reduce the resistance without totally freeing the
maxillary segments, followed by rapid expansion of the jackscrew.

Soft tissue effects of Le Fort I advancement
• Nasal tip is advanced by one sixth of the maxillary
advancement (Henderson et al 1984).
• AP advancement of the lip 60-80% and the tip of nose 20%.
• NLA decreased.
• Upper lip flattens.
• Vermilion exposure increased.
• Increase in the width of the alar base.
• Tip of nose move superiorly.
• Lower lip rolled and advanced.

in general can achieve± 1cm movement, mainly used to correct Cl 2/3
problems.
 Procedures
• Condyle.
• Segmental - Kole osteotomy.
• Body osteotomy (rarely used).
• Ramus - bilateral sagittal split osteotomy (BSSO).
• Vertical subsigmoid osteotomy (VSS).
• C-shaped and inverted L osteotomy (rarely used) ± grafts.
• Genioplasty -augmentation, reduction, asymmetries.
Mandibular Surgical procedures

Bilateral Sagittal Split Osteotomy
(BSSO)
Mandibular Surgery

Bilateral Sagittal Split Osteotomy (BSSO)
Indication:-
• Mandibular advancement(less than 10 -12 mm).
• Mandibular set back (less than 7-8 mm).
• Correction of asymmetry (Minor).
• Anterior open bite patient with maxillary
operation to reduce the posterior facial height.

Vertical Subsegmoid Osteotomy (VSO)
Indication:
• Large mandibular set back.
• Restricted mouth opening.
• Thin ramus.

Inverted L osteotomy
Indications:-
• Big advancement where the mandibular rami
are deficient both vertically and horizontally.
• Big set back.
• Big asymmetry.

Body osteotomy (rarely used)
• The objective is to remove a pre-planned segment
of mandibular body allowing the anterior segment
of the jaw to be set back.

Lower labial segmental osteotomy
(Subapical osteotomy)
Indications:
• 1- An exaggerated curve of Spee.
• 2- Correction of bimaxillary protrusion.
Anterior mandibuloplasty
• It combines lower labial segment surgery with
simultaneous genioplasty, all the cuts being
continuous.

Genioplasty in Orthognathic Treatment
A. Reduction genioplasty:
• 1- Vertical reduction genioplaty.
• 2- Horizontal reduction genioplasty.
B. Augmentation genioplasty:
• 1- Vertical augmentation.
• 2- Horizontal augmentation. (sliding or double
sliding genioplasty)

Post surgery Care
• Mandibular osteotomies almost never requires an overnight
stay , maxillary osteotomies typically require overnight
hospitalization and two-jaw surgery almost always requires 1 to
2 days hospital stay.
• Patients require surprisingly little pain medication, particularly
following maxillary surgery.

• The first week after surgery, Patients are advised to
maintain a soft diet and advised to open and close
gently within comfortable limits.
• The next 2 weeks, patients advice to progress to
foods that require some chewing and three (10-
15minute) sessions of opening and closing exercises
as well as lateral movements are indicated, with the
patient closing into the splint.

• From the third to the eighth week, the range of motion is
increased.
• By 6 to 8 weeks after surgery, they should be back on a
normal diet.
• This coincides with the time when the orthodontist can
allow the patient to eat without the use of elastics.

 Postsurgical Orthodontics (6 - 8 weeks)
• Once a range of motion is achieved and the surgeon is
satisfied with the initial healing, the finishing stage of
orthodontics can be started.
• With rigid fixation, this now is at 2 to 4 weeks post surgery.
• The splint is removed, the stabilizing arch wires are also
removed and replaced by working wires to bring the teeth
to their final position.

• Light vertical elastics are needed initially with these
working arch wires .
• The typical settling of teeth into full occlusion can
be achieved rapidly using light round wires (16 mil
steel) and posterior box elastics with an anterior
vector.

•A flexible rectangular wire in the upper arch to maintain
torque control of the maxillary incisors (in 18-slot, 17 × 25
TMA & in 22-slot, 21 × 25 M-Niti often is a good choice, with
a round wire in the lower arch.
•Patients wear the light elastics full time, including while they
are eating for 4 weeks , then for the first 4 weeks full time
except for eating followed by another 4 third weeks night
time wearing.

Retention
• Retention after surgical orthodontics is no different than for other
adult patients.
• One important exception; if the maxilla was expanded transversely, it
is important to maintain the expansion during the finishing
orthodontics with full-time retainer wearing in the maxilla for at least
6 months.
• If a transpalatal lingual arch was placed following surgery, it should
not be removed during the first postsurgical year.

Stability
Profitt produce a hierarchy of stability:-
Maxillary superior movement – very stable.
Mandibular Advancement – stable.
Two jaws surgery – stable with rigid fixation.
Mandibular Setback – unstable.
Maxillary inferior movement – unstable.
Maxillary transverse expansion – very unstable.

Adjunctive facial procedure
• A variety of adjunctive facial procedures can be
used as adjuncts to orthognathic surgery to
improve the soft tissue contours beyond what is
available from repositioning the jaws.

Adjunctive facial procedure
• Chin procedure (Augmentation or Reduction)
• Rhinoplasty
• Lip Procedures (Augmentation or Reduction)
• Sub mental Procedures

Problems
Surgical:-
• Morbidity of surgical procedure.
• 20-25% Risk of permanent altered sensation with BSSO.
• Increase alae width with fullness of upper lip with maxillary
impaction.
• Double chin with mandibular set back.
• Lip sag following augmentation genioplasty.

Orthodontic:-
• All associated risks of orthodontic treatment.
• Problems with closure of old Xtn spaces, root resorption,
inadequate expansion.
• Risk of periodontal recession especially around lower
incisors in Class III cases.

Relapse:-
• Variable depending on procedure.
• Increase risk when mandibular procedures are
used to close AOB due to stretching of pterygo-
massetric sling.

Distraction Osteogenesis
 It is an inducing a callus of bone by osteotomy or
corticotomy followed by distraction of proximal
and distal ends resulting in increase of bone
length.
 llizarov first to define practical use in limb
lengthening by corticotomy.

Indications:-
• Correction of severe congenital craniofacial defects;
(Micrognathia, Midface retrusion, Craniofacial anomalies).
• Maxillary hypoplasia due to previous cleft palate surgery.
• Palatal and mandibular expansion.
• Dentoalveolar hypoplasia for implant insertion.
• Tumour/trauma reconstruction.
• TMJ ankylosis.

Technique:-
•Corticotomy or osteotomy.
•7 day latency period, until intact vascular supply established.
•Prolonged, progressive and gradual distraction, correct rate
and rhythm of distraction which should be 1mm/day:
below 0.5mm / day ---- premature union
above 1.5mm / day ---- non-union
•Consolidation period of 8-10 weeks.

References
• Contemporary Orthodontic 5th edition – William R. Proffit.
• Postgraduate Notes in Orthodontics 7th edition
• Excellence in orthodontic 2010 – David Birnie, Nigel Harradine.
• Why segment the maxilla between laterals and canines?
Lucas Senhorinho Esteves1, Jean Nunes dos Santos2, Steven M.
Sullivan3,
• Orthodontic Preparation for Orthognathic Surgery
Abdolreza Jamilian, Alireza Darnahal and
Letizia Perillo

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