This is a presentation on Mandibular Deformities & their Management from the point of view of an Maxillo-Facial Surgeon

1. MANDIBULAR DEFORMITIES
MODERATOR : Dr. Sheron M
PRESENTED BY: Dr. Rayan M

2. Contents
INTRODUCTION
MANDIBULAR DEFORMITIES
PREOPERATIVE ASSESSMENT
RAMUS: SAGITTAL SPLIT OSTEOTOMY
VERTICAL RAMUS OSTEOTOMY
INVERTED L AND C OSTEOTOMY
BODY OSTEOTOMY AND OSTECTOMY
GENIOPLASTY
COMPLICATIONS
REFERENCES

3. INTRODUCTION
Mandibular hypoplasia is defined as retruded mandibular position resulting
in a Class II skeletal relationship with either a normal or a deficient
mandibular growth rate.
Mandibular hyperplasia is defined as a protrusive mandibular position
resulting in Class III skeletal and occlusal relationships. This condition may
be initially seen with normal or accelerated mandibular growth rates.
Retrogenia- is defined as a deficient chin in profile relating to a more
posterior position of the chin .
Progenia –coined by Meyer’s in 1868,is defined as anterior positioning or
over development of chin

4. Agnathia- is the most severe form of mandibular maldevelopment and is
defined as an absent or hypolplastic mandible; although partial absence is
more common.
Micognathia –is defined as an abnormal arrested development of mandible
and the malformation is characterized by congenital hypolplasia of the
mandible
Macrognathia – an enlargement of the jaw,is a developmental deformity of
the mandible,characterized by a marked class III dentofacial relationship
Retrognathia – is defined as posterior placement of lower jaw than the
upper jaw, characterized with severe overbite
Prognathism –marked protrusion of either the upper or lower jaw. Also
called as extended jaw or Hapsburg jaw

5. DEFICIENT GROWTH RATE
• Patients experiencing deficient mandibular growth are initially
seen with progressively worsening mandibular retrusion and
Class II malocclusion, as normal maxillary growth outpaces
the deficient mandibular growth.
• If the deformity is corrected surgically during growth, a Class
II skeletal and occlusal relationship can be expected to recur,
as the maxilla continues to grow normally and the mandible
maintains its deficient growth rate.

6. ETIOLOGY OF MANDIBULAR DEFORMITIES
• Congenital: Hemifacial Microsomia ,Plagiocephaly Pierre
robin syndrome
• Developmental: Intrinsic Jaw-Growth Deformities Facial
Hemiatrophy Hemimandibular Hyperplasia/Elongation
Secondary Growth Deformities (Sternocleido mastoid
torticollis )
• Acquired : Condylar Trauma, Degenerative Joint
Disease,Tongue Thrust habit, Trauma, Muscle Disturbances,
and Other External Factors

7. MANDIBULAR ANTERO- POSTERIOR
DEFICIENCY

10. PROGNATHIC MANDIBLE
Prominent chin is the dominant feature (prominent
lower third of the face)
A concave profile
Severe cases show lip incompetence
Steep mandibular plane which may be parallel to
high palatal plane (angle over 35°,-Normal 25°)
Obtuse gonial angle
Middle third of the face appears relatively
deficient
Labio-mental fold may be diminished or absent
Naso-labial angle may be acute
Anterior facial height may be increased

11. DENTAL FEATURES
• Angle's class III molar malocclusion will be
seen
• Reverse horizontal overjet in the incisor area
• Posterior cross bite
Mandibular anterior teeth may be inclined
lingually (Nature's dental compensation) or
they may be upright Maxillary teeth may be
protrusive An anterior open bite may be
seen.

12. Assessment of facial esthetics
• Ideal proportions
• Facial anthropometric measurements
• Facial symmetry
• Vertical proportions
• Tooth lip relationship

13. Ideal proportions
• M.Y. Mommaerts, B.A.M.M.L. Moerenhout / Journal of Cranio-Maxillo-Facial Surgery 39 (2011)
107e110
The average ideal contemporary female face is shorter than the male
face, given the fact that interpupillary distance is similar. The lower
third in the face has a 30% upper lip, 70% lower lip-chin proportion.

14. Frontal view
Vertically
• Face is divided into equal
thirds.
• The upper third is from the
hair line to glabella.
• The middle third is from
glabella to subnasale.
• The lower third is from
subnasale to soft tissue
menton.
• The lower third can be further
divided from subnasale to
upper lip stomion as one-third
and lower lip stomion to soft
tissue menton equaling two-
thirds.

15. Frontal view
Horizontally
“Rule of fifths”
• The Central Fifth:
Delineated by the inner canthus of the
eyes
Inner canthal distance= alar base of
nose
• The Medial Fifth:
Width of mouth= interpupillary
distance
Line from the outer canthus should
coincide with the gonial angles
• The Outer Fifth:
Measured from the outer canthus to
the ear helix

16. CEPHALOMETRIC EVALUATIONS
• ANALYSIS OF THE FACIAL SKELETON.
• ANALYSIS OF THE JAW BASES.
• ANALYSIS OF THE DENTOALVEOLAR RELATIONSHIPS.

17. • Drop a perpendicular line to HP from
Glabella.( G – Pg)
• Measure the position of the pogonion
from this line parallel to HP.
• Mean value: 0 +/- 4
Inference
Increased –ve value indicated mandibular
deficiency is severe.
Uses
Indicates mandibular prognathism or
retrognathism
MANDIBULAR PROGNATHISM

18. Disadvantages
This measurement should be evaluated in conjunction with other
values to distinguish between microgenia ,macrogenia /
retognathia ie, if Pg is positioned posteriorly further examination is
necessary to determine if the defect is a small hard tissue chin, small
mandible, average sized mandible positioned posteriorly thin soft-
tissue chin or a combination of these .

19. Vertical height ratio
• Drop a perpendicular
line to HP from
Glabella, to this line
drop a perpendicular
line from Sn. Transfer
the HP through
Menton.
• Mean value: 1 +/- 1
1:1

20. INFERENCE
• The ratio of middle 3rd to lower 3rd facial height measured
perpendicular to HP.
• Ratio less than 1 = denotes disproportionality and there is large
lower 3rd of face and vice versa.
• Disadvantages
• Further evaluation of lower 3rd of face is needed.
Uses
Anterior face proportionality is assessed by taking the ratio of
middle 3rd facial height to lower 3rd facial height measured
perpendicular to HP.

21. SADDLE ANGLE (N-S-Ar)
•Normal value:123± 5o
•A large saddle angle usually signifies a
posterior condylar position and a
mandible that is posteriorly positioned
with respect to the cranial base and the
maxilla

22. ARTICULAR ANGLE(S-Ar-Go)
•It is constructed between the upper
and the lower parts of the posterior
contours of the facial skeleton.
•Normal value:143± 6o
•It is large when the mandible is
retrognathic & small when the
mandible is prognathic.

23. GONIAL ANGLE
•It expresses the form of the
mandible, but also gives
information on the mandibular
growth direction.
•Normal value:128± 7o
•A small or acute Gonial angle is
suggestive of a horizontal growth
pattern.

24. Treatment Soft tissue changes
Antero –posterior movement of
incisors
60-70% of incisor movement
Vertical movements of incisors Minimal ,unless jaw rotates
Mandibular advancement Chin 1:1 with bone
Lower lip 60-70% with incisor
Mandibular setback Chin 1:1
Lip 60%
Mandibular advancement with
maxillary superior positioning
Chin 1:1 with bone
Lower lip 70% of incisors
Nose elevation
Shortening of upper lip
Mandibular inferior border
repositioning
Soft tissue forward 60-70%
Chin up 1:1

25. Planning in Orthognathic Surgery
• Patient Concerns or Chief
Complaints
• Clinical Examination
– General physical
examination
– Facial evaluation
• Frontal
• Lateral
– Oral Examination
– TMJ
• Radiographic Evaluation
– Cephalometric Analysis
• Model analysis
• Dental model surgery
• STO (Surgical Treatment
Objective)
• Definitive Treatment Plan

26. Mandibular deformities
• Excess
– Concave profile
– Midface appears
deficient
– Lower third broad
– Lower lip thin
• Deficiency
– Convex profile
– Lower lip everted
– Deep labiomental
crease
– Mentalis strain with
lip closure

27. • Class II div 1 with
normal overbite
(maxillary excess and
mandibular deficiency)
• Class I with deep bite
• Class II division 2
• Modified sagittal ramus
osteotomies and
augmentation
genioplasty

28. Class II deformity with open bite
• Asymmetric class II
dentofacial deformity
• Class III dentofacial deformity
• Segmental total subapical
superior maxillary
repositioning
• Surgical control of nasal
and upper lip aesthetics
• Augmentation Genioplasty
• Modified sagittal ramus
osteotomies with optional
genioplasty

29. HISTORY
Body osteotomy 1849 Hullihen anterior subapical osteotomy
Horizontal osteotomy of vertical ramus – Blair in 1897
Osteotomy of ramus of mandible – Caldwell and Letterman.
(1954)
The intraoral approach to the subcondylar osteotomy Moose
1964
Winstanley 1968; Lateral approach for ramus osteotomy

30. • Subsigmoid Oblique subcondylar osteotomy – Robinson and
Hinds in 1955
• In 1957 Obwegeser and Trauner – Sagittal Split Osteotomy
• 1942 – Hofer was the first to describe genioplasty- extraoral
approach.
• 1957 – Trauner and Obwegeser described intraoral approach.

31. SURGICAL

32. MANDIBULAR SURGERY
Ramus Procedures
– Bilateral sagittal split Osteotomy
– Vertical ramus Osteotomy
– Inverted – L Osteotomy
– ‘C’ or arcing Osteotomy
Body procedures
– Anterior body Osteotomy
– Posterior body Osteotomy
– Midsymphyseal Osteotomy
Sub apical body procedures
– Anterior mandibular subapical osteotomy
– Posterior mandibular subapical osteotomy
– Total alveolar osteotomy

33. Management of the growing patient with mandibular dentofacial
deformities presents a unique and challenging problem for
orthodontists and surgeons.
The surgical procedures required for correction of the deformity
may affect postsurgical growth and dentofacial development.
Further, facial growth may continue postoperatively and negate the
benefits of surgery performed, resulting in treatment outcomes that
are less than ideal.
From individual patient characteristics, the type of deformity, and
the indications for early surgical intervention, it is possible to
effectively treat many cases during growth.
Larry M.Wolford et al , Considerations for orthognathic surgery during growth,
Part 1: Mandibular deformities; Am J Orthod Dentofacial Orthop 2001;119:95-101

34. 36
Saggital Split
Osteotomy
Historical development of orthognathic surgery; Journal of Cranio-Maxillofacial
Surgery, Volume 24, Issue 4, August 1996, Pages 195-204, E.W. Steinhäuser

35. A. Trauner & Obwegeser, 1957
B. Dal pont,1961
C. Hunshuck,1968
D. Epcker,1977

36. Trauner & Obwegeser, 1957

37. Modifications in Sagittal Split Osteotomy
• Dalpont in 1961: Advocated extending facial osteotomy
anterior to the antegonial notch to include a greater segment of
the body of the mandible
• The oblique cut is advanced to molar
region & vertical cut through lateral
cortex
The lower horizontal cut to vertical
cut on the buccal cortex between
the 1st and 2nd molar.

38. • Hunsuck in 1968: Advocated carrying the
medial cut only to the retrolingular fovea,
not all the way to the posterior border
The placement of the medial cut is important
not only to minimize inferior alveolar
nerve trauma, but also to prevent potential
unfavorable splits
His anterior vertical cut was similar to Dal
Pont’s
Evaluation of Mandibular Setback After Bilateral Sagittal Split Osteotomy With the Hunsuck Modification
and Miniplate Fixation .Journal of Oral and Maxillofacial Surgery, Volume 65, Issue 11, November
2007, Pages 2176-2180 Xue-Wen Yang, Xing Long, San-Jie Yeweng, Chia-Tze Kao

39. In 1977, Epker proposed several refinements. These
included
1. Less stripping of the masseter muscle
2. Limited medial dissection
3. All of which led to decreased postoperative swelling,
hemorrhage, and manipulation of the neurovascular
bundle.
The decreased stripping of the masticatory muscles
increased the vascular pedicle to the proximal segment,
which diminished bone resorption and loss of the gonial
angle.

40. 1974 – Spiessel advocated rigid internal
fixation of BSSO to promote healing,
restore early functioning and attenuate
relapse.
In 1977, Epker suggested modifications:
Minimal stripping of masseter muscle
Limited medial dissection (the extent of
soft tissue dissection of the
pterygomasseteric sling)
These modifications decrease post
operative swelling, hemorrhage and
manipulation of neurovascular bundle

41. • Wolford: Used inferior border saw to facilitate controlled
inferior border split
• Bell, Schendel and Epker 1977 extended the vertical cut to
the lower border of the mandible reducing the incidence of
wrong splits

42. INDICATIONS - BSSO
• Mandibular advancement or set back
• Correction of asymmetries
• Severe decreased posterior mandibular height
• Extremely thin medio-lateral width of ramus
• Severe ramus hypoplasia
• Severe asymmetry
Contra-Indications
Peter Ward Booth; Maxillofacial surgery Second Edition;
2007

43. Surgical technique
• Incision is placed over the anterior
aspect of the ramus to the mid
ramus, running down over the
external oblique ridge to the first
molar region and curving down to
the buccal vestibule.
• Initially only mucosa is incised.
Sharp dissection at the ramus is
continued to periosteum

44. • Periosteal elevation of the lateral
aspect of the mandible at the
molar region is done down to the
inferior border
• On ramus lateral dissection is
kept minimal
• Medial dissection is done very
carefully at the medial aspect of
the ramus
Profitt and White; Contemporary treatment of Dentofacial deformity. 2003

45. • Level of lingula is assessed
• Dissection above the level
of mandibular foramen is done
• Osteotomy (the cut should extend
behind the mandibular foramen but
need not be upto the posterior border
of the ramus)
Reyneke; Essentials of Orthognathic Surgery; 2003

46. B. Spiessl was the first to apply rigid internal fixation in
orthognathic surgery in 1974
Historical development of orthognathic surgery; Journal of Cranio-Maxillofacial
Surgery, Volume 24, Issue 4, August 1996, Pages 195-204, E.W. Steinhäuser

47. Advantages of plate and screw application
for orthognathic surgery
• The application of plates and screws is more rapid and
easier.
• The stabilization of the bone segments is better and
much more reliable.
• The convenience for the patient is greater, because
intermaxillary fixation is no longer necessary
• There is less danger for the patient, because in the
critical postoperative phase after extubation the mouth
can be opened and cleaned and the airway can be easily
controlled
Historical development of orthognathic surgery; Journal of Cranio-Maxillofacial
Surgery, Volume 24, Issue 4, August 1996, Pages 195-204, E.W. Steinhäuser

48. Advantages
• Healing is quick
• Rigid fixation can be used
• Modifications can maintain position of angle
of mandible
• Major muscles of mastication remain in
original spatial position

49. Orthognathic Positioning System: Intraoperative System to Transfer Virtual
Surgical Plan to Operating Field During Orthognathic Surgery John W.
Polley and Alvaro A. Figueroa, J Oral Maxillofac Surg -:1-10, 2012
Use of an occlusal-based ‘‘orthognathic
positioning system’’ (OPS) for
Orthognathic Surgery
• During surgery, the occlusal splint is
either Permanently or Temporarily
secured to the maxillary dentition

50. Advantage
• Great flexibility in repositioning the distal tooth bearing area
• Minimal alteration in the position of muscles of mastication & the
TMJ
• Easier application of RF
• Enhanced healing because of the larger bony interface
• Immediate postsurgical jaw mobilization;
• More accurate control of condylar position;
• Better speech during the healing phase

51. Disadvantages
1) Procedure Takes Longer;
2) The Surgery Must Be Very Accurate;
3) An immediate shift in occlusion postsurgery if the condyle is not
properly seated in the fossa;
4) An increased risk of inferior alveolar nerve injury,
5) Technically greater difficulty in correcting moderate to severe
asymmetries;
6) Greater blood loss, although rarely consequential.

52. INVERTED “L” OSTEOTOMY
• The inverted “L” osteotomy (ILO) can be used to advance the
mandible and vertically lengthen the ramus, but it may require
bone or synthetic bone grafting to control the positional orientation
of the proximal segment and to fill the bony voids between
segments. The use of rigid fixation is recommended.
By Winstanley in 1968
For mandibular set back in
mandibular excess patients

53. Indications
• For treating mandibular
retrusion
• For mandibular set backs
• Mandibular asymmetry
• Ramus lengthening
• Severe decrease in posterior
mandibular body width.
Contraindication
• Abnormal posterior location
of mandibular foramen.
• Mandibular advancement
without grafting
• Condylar fractures (relative)

54. TECHNIQUE
Vertical bone cut is
made from a point just
a few millimetres
above and behind
lingula.
Horizontal cut can be
made through extraoral
or intraoral technique
with saw or bur.
Bone graft used to fill the
defect in case of
advancements.

56. “C” osteotomy
• Modification of inverted “L”
technique.
• The vertical cut is brought forwards
just below the level of inferior dental
nerve in a horizontal direction
towards 3rd molar.
• Completed by making a short
vertical anterior cut through lower
border.
• Bone grafts should be tailored to fit
the defect following the application
of IMF.
• Stabilized with circumferential or
intraosseous wire.

57. Precaution :
• Neuro vascular bundle
• When it is used for set back
proximal fragment should
be carefully trimmed to
allow close approximation
of fragments

58. Advantages
• Can correct mandibular
prognathism
• Coronoid and temporalis and
medial pterygoid muscle
need not be stripped retained
- proximal fragment
• Can setback the mandible to
a great distance
• Can lengthen or advance
mandible when used with
bone grafting
• Rigid skeletal fixation may
be used
Disadvantages
• Usually requires bone or
synthetic bone grafting for
mandibular advancement.
• Healing time may be
increased compared to other
techniques because of poor
approximation of segments
when grafts are not used.

59. VERTICAL RAMUS OSTEOTOMY
The vertical ramus osteotomy (VRO) can be used to advance the
mandible and vertically lengthen the ramus with appropriate bone or
synthetic bone grafting as indicated to control the positional
orientation of the proximal segment and fill bony voids.
The amount of mandibular advancement and vertical lengthening
possible with this technique is limited by the temporalis muscle
attachment and interference of the coronoid processes on the
zygomatic arch.
Thus, for larger movements a coronoidectomy may be needed, or the
clinician may need to revert to other surgical options

60. The ILO and VRO can be performed on patients of virtually any
age because the design of the osteotomies avoids developing
teeth.
However, care must be taken to avoid damage to developing
teeth during application of rigid fixation.
By Caldwell-letterman in 1954
Modified by Robinson and Hinds in
1955

61. Indication :
1) Correction of mandibular setbacks.
2) Correction of mild open bites.
3) Asymmetry of mandible requiring setback

62. TECHNIQUE
Segment may be wired in place with transverse wire.IMF for 2 weeks
- strong or heavy elastics used to guide occlusion.
After completion of osteotomy bilaterally the mandible is placed into
occlusal splint and put on IMF.
When major repositioning of mandible is required consider
coronoidectomy.
Posterior to mandibular foramen upto sigmoid notch,inferiorly to
lower border in the region of antegonial notch.
Vertical cut from sigmoid notch to the inferior aspect of angle of
mandible.Modified by Hall et al (1975) : curved fashion osteotomy
cut.

64. Disadvantages
• Unless segments are wired it is difficult to control the position
of condyle.
• Healing time may be increased because of poor bony interface
between segments.
• Difficult to use rigid internal fixation.
• May require long term interarch elastics.
• Open bite usually recurs early in post operative phase.

66. BODY OSTEOTOMY AND OSTECTOMY
Extraction of 2nd premolar
Vestibular incision placed
from one cuspid area to
opposite area
Subperiosteal dissection
carried out inferiorly
approximately below the
apices of the teeth
Identification of mental
neurovascular bundles and
extension of incision
posteriorly

67. Indications
• Mandibular set back
• •Mandibular prognathism with
ramus procedure.
•Anterior open bite closure
•Curve of spee reduction
•Progenia correction
•In class III-anterior body
osteotomy –wedge of bone
removed and setback
Contraindications
Anatomic discrepancies leading to
reduction in bone to bone contact
•Torquing of the proximal segments
is the classic problem
•Root anatomy is variable (Difficult
to perform osteotomy in the
premolar region)

68. ANTERIOR MANDIBULAR SUB APICAL SURGERY
Anterior mandibular dentoalveolar deformities have been defined
as excessive, deficient, or asymmetric growth of the
dentoalveolar structures.
The condition may be due to overdevelopment or
underdevelopment of alveolar bone, dental ankylosis, anodontia,
premature tooth loss, macroglossia, microglossia, habitual
factors, or genetics.

69. This is a commonly used procedure. Basic indications for its use
are :
• To correct mandibular dentoalveolar protrusion.
• To close open bites.
• To level an excessive curve of spee.
• To correct mandibular dental arch asymmetry.

70. The horizontal sub apical Osteotomy is
made 5mm below the teeth apices.
Level of mental foramen can be used as
a guide.
Horizontal cut is completed through
lingual cortex.
Interdental ostectomy is performed.
Excessive interdental bone should not
be remove, especially in crestal area, as
this can create periodontal problem.

71. • Midsymphysis osteotomy is sometimes necessary to narrow or
widen the intercuspid distance.
• After cuts are completed bilaterally the segments are mobilized
and teeth are placed into preformed occlusal splints.

72. POSTERIOR SUBAPICAL MANDIBULAR
SURGERY
Indications :
• To upright posterior mandibular teeth in severe lingoversion or
buccoversion.
• To upright posterior teeth in severe mesioversion.
• To close a premolar or molar space.
• To level supra erupted posterior teeth.
Access : Intra - oral vestibular incision.
Technique : Care should be exercised to avoid unnecessary
elevation of both buccal and lingual mucoperiosteum from the
segment to be mobilized.

73. • The portion of lateral cortex overlying the Inferior Alveolar
bundle is removed and preserved.
• Lingual cortex is carefully osteotomized.
• The horizontal osteotomy is extended at least 5mm.Posterior to
second molar
• The vertical cut should be made 4-5mm distal to last molar to
avoid periodontal problems
• The segment is mobilized, and wired to the splint.

74. TOTAL SUBAPICAL OSTEOTOMY OF
MANDIBLE
• Has limited use and
needs to be combined
with a Hunsuck
sagittal split of
Ramus
Total subapical mandibular osteotomy to correct class 2 division 1 dento-facial deformity;
JCMS : vol 40, issue 3, 2012

75. Indications
• Advancement of whole of lower dental arch which is retro
posed but the mandible is in normal shape.
• To increase the vertical height of lower jaw.
• For leveling procedures anteriorly or posteriorly

76. TECHNIQUE
A horizontal sub apical cut is made below the
teeth and below the inferior dental nerve from
the third molar on one side to opposite side.
Vertical cut through the lateral cortex which
extends superiorly to the crest of alveolus upto
ramus of mandible as in sagittal split osteotomy
Medial cut is finished on medial side just
beyond mandibular foramen.
It is important to ensure that the horizontal
division through the main body of mandible is
complete.
Fragments can be stabilized using
circumferential or interosseous wires can be
used.

77. Contraindications :
• Decreased anterior / post mandibular height.
• When dentoalveolar needs to be advanced
beyond stable chin point.

78. Mandibular Basal Osteotomy: New Designs and Fixation Techniques; Patricia E.
Lopez, Cesar A. Guerrero and Elena V. Mujica; J Oral Maxillofac Surg 69:786-797,
2011

79. Genioplasty
• Also known as Mentoplasty
• 15% of all dentofacial deformity involve chin
INTRODUCTION

80. HISTORY
Hinds and Kent in 1969 were the first to realize and discuss the importance of
maintaining the soft tissue attachment along the inferior segment
In 1965 Reichenbach and colleagues proposed wedge osteotomy and vertical
shortening of the chin.
Trauner and Obwegeser, in 1957, used the horizontal osteotomy through an
intraoral incision with degloving of the anterior mandible.
Converse in 1950, discussed the feasibility of bone grafts introduced through
intraoral approaches.
The horizontal sliding osteotomy was first described by Hofer in 1942. He
used an extra oral incision
1st surgical correction was with metals and ivory

81. Genioplasty
Genioplasty
Augmentation
– Horizontal Osteotomy
– Alloplastic augmentation
– Vertical lengthening
Reduction
– Anteroposterior
– Vertical
Straightening
– Leveling
– Rotation
Advancement

82. • Chin deformities can manifest in
three dimensions, majority are in the
horizontal plane
• Harmony is more important than
absolute proportionality.

83. • Evaluation of lip position, shape and depth of
the labiomental fold, and the soft tissue
envelope covering the mandibular symphysis.
• Mentalis muscle activity must be closely
evaluated and hyperactivity diagnosed.

84. • Chin contour is influenced by soft tissue thickness,
as well as by the underlying bony contour.
• The labiomental fold is influenced by the relative
position of the maxilla, it is deepened in the
presence of a deep bite or skeletal class II
malocclusion
• Flattened in a class III malocclusion.

85. Treatment planning for chin surgery requires a
detailed three dimensional analysis that
includes soft tissue, dental, and skeletal
aspects
Incision

87. Advancement Genioplasty

89. Double Sliding Genioplasty

90. Horizontal reduction…

91. Vertical Augmentation with
Advancement Genioplasty

92. Vertical Augmentation Genioplasty

93. Vertical Reduction Genioplasty

94. Asymmetric Genioplasty

95. CHIN SHIELD OSTEOTOMY – A NEW GENIOPLASTY
TECHNIQUE AVOIDING A DEEP MENTO-LABIAL FOLD IN
ORDER TO INCREASE THE LABIAL COMPETENCE
• A genioplasty technique in which
the advancement of an anterior
mandibular segment is executed
with a specific osteotomy form
that helps to avoid a deep
mentolabial fold and improves
labial competence.
International Journal of Oral and Maxillofacial Surgery, Volume 38, Issue 11, November
2009, Pages 1201-1205; A. Triaca, T. Furrer, R. Minoretti

96. zigzag osteotomy for genioplasty that will permit the surgeon to
decrease the vertical or transverse dimensions of the chin, or
both, and simultaneously advance or set back the chin, if
necessary
Seied Omid Keyhan,et al; Zigzag genioplasty: a new technique for 3-dimensional
reduction genioplasty; British Journal of Oral and Maxillofacial Surgery, Volume 51, Issue
8, December 2013, Pages e317-e318

97. Advantages of the zigzag technique:
It preserves the bone structure of the midsymphyseal area as far as
possible
There is the possibility of combined vertical and transverse reduction
The possibility of a minimal mistake in symmetrical repositioning of the
chin is minimal
There is the possibility of combined advancement and setback
There is a minimal change in the position of the mentolabial fold
There is the possibility of a combined reduction of the height of the
mandibular body
It is possible to correct an asymmetrical chin

98. • The suprahyoid muscular attachments can be preserved
• There is minimal neurovascular disturbance
• There is minimal injury to the apices of the root
• The chin was reduced transversely by dividing the total
amount reduced on both sides without compromise of
the midsymphyseal area
• Bony fragments may be repositioned quickly by
preservation of the bony strut in the middle of the
osteotomy

99. Recent modifications in mandibular
procedures
• Chin wing osteotomy
• Indications:
hyperdivergent
Mandible
Triaca. A, et al. Chin Wing Osteotomy for the correction of hyperdivergent skeletal class
III deformity: technical modification. Br. J. Maxillofac Surg (2015)

100. RECENT MODIFICATIONS IN
MANDIBULAR PROCEDURES
• Verical ramus elongation and
mandibular advancement by
endobuccal approach
• Indications: Posterior vertical
insufficiency and short
mandibular body.
F. Grimaud, et al. Vertical ramus elongation and mandibular advancement by endobuccal approach:
Presentation of a new osteotomy technique. J Stomatol Oral Maxillofac Surg.2017 Feb;118(1):66-69

101. • Lingual short split for
BSSO
• Indications: For
patients with thick
cortical bone and
thin medullary bone,
with potential risk of
undesirable splits.
Sant’Ana ,et al. Lingual Short Split: A Bilateral Sagittal Split Osteotomy Technique Modification.
J Craniofac Surg 2017 Oct;28(7):1852-1854

102. Morris DE, Lo LJ, Margulis A. Pitfalls in orthognathic surgery: avoidance and management of complications. Clinics in
plastic surgery. 2007 Jul 31;34(3):e17-29.
COMPLICATIONS
OCCURRING WITH
MAXILLARY OR
MANDIBULAR OSTEOTOMY
GENIOPLASTY
•Infection
•Instrumentation
exposure
•Unanticipated fracture
•Malunion/non union
•Malocclusion‘
•Skeletal relapse
•Avascular necrosis
•Gingival recession
•Devitalization of teeth
•IAN injury
•Hemorrhage
•Condylar resorption
•Malpositioned
segments
•Unfavourable split
UNIQUE TO
MANDIBULAR
OSTEOTOMY
•Mental nerve
injury
•Contour
irregularity
•Ptosis of mentalis

103. Complications
• Undesirable Splits
• Injury to the neurovascular bundle
• TMJ problems
• Excessive Bleeding
• Condylar malpositioning

104. Undesirable Splits
• Most commonly at buccal cortex of the proximal
segment
or
• Vertically through the third molar area of the
distal segment.

105. Prevention of bad splits
Proper corticotomy technique
The bur or saw blade must be angled parallel to the
mandibular occlusal plane for the medial ramus cut.
Removal of internal oblique ridge facilitates visualization
of medial cut
The corticotomy that connects medial ramus and the
lateral body corticotomies should be as lateral as possible

106. Access bevel is placed on the anterior lip of vertical
corticotomy to allow the chisel to slide
The medial cut is enhanced with sharp chisel under
direct vision so that any subsequent stress placed upon it
will result in split along the desired lines.
No heavy prying forces are placed on segments

107. • If a bad split occurs – to proceed with
the operation or to abort the procedure
(in large advancements this decision is
crucial)
The management: the most proximal
stable segment containing the condyle
should be rigidly fixed to the intact
distal segment
A rigid device, such as a reconstruction
plate.
Aggressive rigid fixation of the fragments
and early mobilization are
recommended

108. • Postoperative follow up in bad splits:
– Fragment displacement
– Poor healing
– Counterclockwise rotation of proximal segment
– If occlusion has been affected; reoperating has to
be considered with bone grafting
– Non union or osteomyelitis (rare)

109. • In most instances where third molars were present
during the time of surgery an effort was made to
retain these teeth
• The authors anticipated that other factors such as
the height and the width of the corpus of the
mandible and the width and thickness of the
ramus would influence the difficulty level
• This study showed that no single measurement
influenced the difficulty of the sagittal split
Variations in the anatomical dimensions of the mandibular ramus and the presence of third molars:
its effect on the sagittal split ramus osteotomy; J. Beukes, J.P. Reyneke, P.J. Becker: Int. J. Oral
Maxillofac. Surg. 2013; 42: 303–307.

110. Third molars involved at the osteotomy
site
Extrusion of teeth complicate ramus
surgery.
This is fairly common when
intraosseous wiring and MMF are
used for stabilisation of mandibular
segment.
Extrusion can also occur with post
surgical elastics particularly when
there is associated post surgical
malocclusion.

111. Presence of mandibular third molars during bilateral sagittal split
osteotomy increases the possibility of bad split but not the risk of
other post-operative complications
• Bad splits occurred at five of the 169
sites with mandibular third molars
(3.0%) and five of the 333 sites (1.5%)
without mandibular third molars
• Presence of third molars during surgery
increases the surgical difficulty and third
molar removal concomitant with BSSO
it is challenging even for experienced
surgeon

112. Injury to the neurovascular bundle
Neuropraxia
Axonotomesis
Neurotmesis
Sensory nerve injuries are more common
The best way to minimize is to prevent a bad split
Facial nerve injury can be prevented by staying within the periosteal
envelop of mandible
Incidence ranges from 0%-14%
Can occur in 2phases
•If osteotomy is close to mandibular f oramen
•Medial displacement of the proximal segment compressing and tearing the
nerve

113. • A short split is recommended for large setbacks because
posterior movement of the distal segment may be obstructed
by the styloid, the mastoid process or the transverse process of
the cervical vertebra
• If visibly damaged or transected completely; inferior alveolar
nerve
– Re approximation without tension

114. • If the nerve has been abraded or shreded but is partially intact
– To leave it
– Excise the entire damaged portion, and graft the defect
– To attempt to free both ends, freshen the edges and perform
a direct repair
Release enough nerve to accomplish direct repair, the
proximal nerve segment has to be removed posteriorly
from the bony canal to the mandibular foramen

115. TMJ problems
• Internal derangements
• Perforation of the articular disc
• Degenerative joint disease
• Muscle dysfunction
• Hypomobility
• Hypermobility
• Pain

116. All patients experience some limitation in mouth opening after
surgery
– Condylar displacement during surgery
– Postsurgical condylar adaptation
Remodelling of the condyle in the postsurgical period is very
likely, and patients usually regain their presurgical level of
function several months after surgery is performed
Hypomobility: lateral or medial condylar displacement

117. • Malposition of the condyle in an anterior-posterior or vertical
direction leads to occlusal changes postoperatively
• Failure to seat the proximal segments properly into the fossa
during surgery may result in condylar displacement
– Resorption of the condyle has been observed

118. Excessive Bleeding
• Common vessels involved
– Inferior alveolar
– Facial
– Retromandibular vein
– Masseteric
– Lingual
If bleeding continuous, the inferior alveolar artery
should be dissected free from the nerve and
ligated.

119. Condylar Sag
Central Condylar sag
a. Bilateral
b. Unilateral
Peripheral Condylar Sag
Type I
Type II
Defined as an immediate or late change in position of the condyle
in the glenoid fossa after surgical establishment of a pre-planned
occlusion and rigid fixation of the bone fragments, leading to a
change in the occlusion

120. Condylar Sag : Most common complication;
• Intra operative improper positioning of the
condyle by the surgeon, joint edema, or
hemarthrosis such that condyle is not fully
seated.
• If not corrected the mandible will shift
posteriorly following release of MMF, creating
class II open bite.

121. – Preventive measure is to overcompensate in the
presurgical work up by providing a posterior open
bite in the occlusion
– Sequentially reducing the splint while selectively
extruding the teeth is safest method for closure of
postoperative post open bite.
– Intraoperatively maintaining a measure of the
medial pterygoid muscle on the proximal segment
(to minimize condylar sag)

122. Complications of ramus osteotomy :
Extensive stripping of proximal fragment
sometimes resulted in necrosis of angle
Bleeding
Nerve injury
Anterior open bite

123. Bleeding
• Most likely source of bleeding in VRO is from
masseteric artery as it passes through the
sigmoid notch of the ramus
• Packing with gauze is first measure, gel-foam
can be used.
• If facial artery is injured, it should be isolated
and ligated.

124. Open bite
• Although open bite can occur with any
osteotomy, it is more common with the VRO
• The most common problem is that the condyle
is not seated
• Training elastics are recommended
• Condylar resorption can also cause open bite

125. COMPLICATIONS OF GENIOPLASTY
• Traction neuropraxia
• Avascular necrosis of mobilised segment
• Haemorrhage
• Devitalisation of tooth
• Chin ptosis: flattening of labio-mental fold
Excessive lower tooth display
Lip incompetence

126. References
• Oral and Maxillofacial Surgery; Fonseca, Second edition ;
2009
• Peter Ward Booth; Oral and Maxillofacial Surgery; second
edition 2007
• Oral and Maxillofacial Surgery; Peterson, second edition
• Profitt and White; Contemporary treatment of Dentofacial
deformity. 2003
• Concepts, goals and techniques for successful orthognathic
surgery cases; C.E. article ortho 1: Theodore D. Freeland,
DDS, MS
• Surgical Correction of Facial Deformities; Varghese Mani,
First Edition 2010

127. • Intraoperative diagnosis of condylar sag after bilateral sagittal
split ramus osteotomy; British Journal of Oral and
Maxillofacial Surgery (2002) 40, 285–292 Johan. P. Reyneke,
C. Ferretti
• AAOMS Parameters of Care: Clinical Practice Guidelines for
Oral and Maxillofacial Surgery (AAOMS ParCare '12)
• Facial and dental planning for orthodontists and oral surgeons;
Arnett W and Richard.
• Historical development of orthognathic surgery; Journal of
Cranio-Maxillofacial Surgery, Volume 24, Issue 4, August
1996, Pages 195-204, E.W. Steinhäuser

128. • Mandibular Basal Osteotomy: New Designs and Fixation
Techniques; Patricia E. Lopez, Cesar A. Guerrero and Elena V.
Mujica; J Oral Maxillofac Surg 69:786-797, 2011
• Total subapical mandibular osteotomy to correct class 2
division 1 dento-facial deformity; JCMS : vol 40, issue 3, 2012
• Change in Condylar Long Axis and Skeletal Stability
Following Sagittal Split Ramus Osteotomy and Intraoral
Vertical Ramus Osteotomy for Mandibular Prognathia ;
Koichiro Ueki, et al; J Oral Maxillofac Surg 63:1494-1499,
2005
• Presence of mandibular third molars during bilateral sagittal
split osteotomy increases the possibility of bad split but not the
risk of other post-operative complications;

129. • Complications in Oral and Maxillofacial surgery; Kaban,
Pogrel and Perott, 1997
• Variations in the anatomical dimensions of the mandibular
ramus and the presence of third molars: its effect on the
sagittal split ramus osteotomy; J. Beukes, J.P. Reyneke, P.J.
Becker: Int. J. Oral Maxillofac. Surg. 2013; 42: 303–307.
• Evaluation of mandibular set back after BSSO with the
hunsuck Modification. Journal of Oral and Maxillofacial
Surgery, Volume 65, Issue 11, November 2007, Pages 2176-
2180 Xue-Wen Yang, Xing Long, San-Jie Yeweng, Chia-
Tze Kao
• Condylar positioning devices for orthognathic surgery: a
literature review. Costa F1, Robiony M, Toro C, Sembronio
S, Polini F, Politi M. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod. 2008 Aug;106(2):179-90.