treatment plan cephalometric analysis maxillary osteotomy mandibular osteotomies distractor osteogenesis

1. ORTHOGNATHIC
SURGERY
DR. HAYDAR MUNIR SALIH ALNAMER
BDS, PHD (BOARD CERTIFIED)

2. Orthognathic surgery
 the orthognathic surgery may define as Surgery to treat facial
disproportion or surgery for correction of dentofacial deformities.
Orthognathic comes from the Greek orthos (straight) and
gnathos (Jaw).
 Malocclusion and associated abnormalities of the skeletal
components of the face can occur as a result of a variety of
factors, including inherited tendencies, prenatal problems,
systemic conditions that occur during growth, trauma, and
environmental influences

3. Treatment objectives
 Function:
 Aesthetics:
 Other possible benefits:
Temporomandibular joint dysfunction
Mouth opening
Sleep apnea
Traumatic occlusions and dental health

4. The management protocol for facial
deformity should comprise the:
 History
 Clinical examination
 Investigations
 Initial diagnosis
 Treatment plan
 Pre-surgical orthodontics
 Surgery
 Post-surgical orthodontics
 When appropriate, restorative dentistry, psychological intervention or
support and speech therapy will be required.

5. History
At the initial appointment a thorough interview
should be conducted with the patient to
discuss the patient's perception of the
problems and the goals of any possible
treatment. The patient's current health status
and any medical or psychological problems
that may affect treatment are also discussed at
this time.

6. Clinical examination
 The patient is best assessed sitting upright in good light
with head in the natural head position and the Frankfort
horizontal parallel to the floor.

7. Frontal view
 It is a critical point to remember that facial evaluation is
not the search for deviation from the norm of a single
facial unit but the search for proportion (e.g. a face that is
vertically excessive means that, in relation to the
transverse dimension, the face is excessively long and not
that it is longer than another face. By increasing only the
vertical dimension facial harmony is lost, but by increasing
both transverse and vertical dimensions harmony is
restored.

8. Facial proportions

9. The amount of gingival exposure (gummy smile)

10. Facial width analysis
• The normal inter-pupillary distance should be
65 ± 3 mm
• while the intercanthal distance should measure
32 ± 2 mm.
• Vertical lines drawn through the medial canthi
should coincide with the ala of the nose
• while vertical lines drawn through the medial
margins of the irides of the eyes should
coincide with the comers of the mouth.

11. Facial form
 The height-to-width
proportions are 1.3:1 for
females and 1.35:1 for males.
 The bigonial width should be
approximately 30% less than
the bizygomatic dimension

12. Keep in mind that no face is perfectly symmetric !

13. Profile view
 Nasolabial angle: is measured
between the columella of the
nose and the upper lip.
 The angle should be 90 ± 10°
and is a guide to the upper lip
support by the maxillary
incisors. It is, however, also
influenced by the decreased
vertical dimension due to
maxillary vertical deficiency.

14. Profile view
 The lip-chin-throat angle: is formed
between the lower border of the chin and a
line connecting the lower lip and soft tissue
pogonion (110 ± 10°)
 It is most commonly acute in flat or concave
profiles with class III dentoskeletal patterns.
 An obtuse angle is seen in class II
malocclusion

15. Profile view
 Upper lip length: The upper lip
length is measured from subnasale
to lower lip and should be 20 ± 2
mm for females and 22 ± 2
mm for males
 ensure when evaluating the lips that
they are in repose.

16. Profile view
 During treatment planning it
should be kept in mind that the
upper lip length will increase with
age.

17. Profile view
 Labiomental angle is formed
by the intersection of the
lower lip and the chin and is
measured at soft tissue B-
point.
 The angle should be gently
curved (mean= 120 ± 10°)

19. Hard tissue landmarks
 Sella (S): the center of the
sella turcica, as on the
lateral cephalogram, which
is located by inspection

20. Hard tissue landmarks
 Nasion (N): the most
anterior point on the
frontal nasal suture in
the midsagittal plane

21. Hard tissue landmarks
 Orbitale (OR): the
lowest point on the
inferior orbital rim.

22. Hard tissue landmarks
 Anterior nasal spine
(ANS): anterior tip of
the nasal spine.

23. Hard tissue landmarks
 A-point (A): the most
posterior midline point in
the concavity where the
lower anterior edge of the
anterior nasal spine meets
the alveolar bone overlying
the maxillary incisor teeth

24. Hard tissue landmarks
 B-point (B): the most
posterior midline point in
the concavity of the
mandible between the
alveolar bone overlying the
lower incisor teeth and the
pogonion

25. Hard tissue landmarks
 Gonion (Go): the point is defined
by using two lines, one tangent to
the posterior border of the
mandibular ramus and the other
tangent to the lower border of the
mandibular corpus; found by
bisecting the angle formed by the
two lines and extending the
bisector through the curvature of
the mandibular angle.

26. Hard tissue landmarks
Menton (Me): the most
inferior point on the
symphysis of the
mandible in the midline.

27. Hard tissue landmarks
 Porion (P): the most superior
point of the external auditory
meatus (anatomic point);
machine porion is the
uppermost point on the outline
of the rods of the
cephalometer.

28. Hard tissue landmarks
 Condylion (Co): the most
postero-superior point
on the head of the
condyle

29. Hard tissue landmarks
 Gnathion (Gn): the
lowest, most anterior
midpoint on the
symphysis of the
mandible.

30. Hard tissue facial planes
Frankfort horizontal
plane (FH): extends
from porion to orbitale.

31. Hard tissue facial planes
 Anterior cranial base
(SN): formed by a line
drawn from sella to
nasion.

32. Hard tissue facial planes
 Occlusal plane (OP):
formed by a line drawn
through the mesial cusp
contact of the first molar
teeth and dividing the
incisor overbite.

33. Hard tissue facial planes
 Mandibular plane
(MP): extends from
gonion to menton

34. Skeletal antero-posterior relationships
 Maxillary antero-posterior position.
The analysis gives an indication of
the antero-posterior position of the
maxilla in relation to the anterior
cranial base. The angle between the
anterior cranial base (SN) and a line
drawn between the nasion (N) and
A-point is measured and should be
82° for a normal maxilla.
SNA =
82

35. Skeletal antero-posterior relationships
 Mandibular antero-posterior
position. The SNB angle is
measured between SN and a line
drawn between N and B-point
and it relates the antero-posterior
position of the mandible to SN.
This angle should be 80° for a
normal mandibular position.
SNB = 80

36. Skeletal antero-posterior relationships
 ANB angle. This angle gives the
clinician an indication of the inter-
relationship between the upper
and lower jaw. In class II
mandibular deficient cases the
angle will be increased while in
class III cases the angle will be
decreased. An angle of2° indicates
a normal relationship.
ANB = 2

37. Cephalometric tracing

38. Study cast

39. The models allow analyzing:
 occlusion
 shape of the dental arches
 position
 size and shape of the teeth
 position of the jaws in relation to the skull base

40. pre-surgical orthodontic consideration
 Undesirable angulation of the anterior teeth occurs as a
compensatory response to a developing dentofacial deformity.
 Dental compensations for the skeletal deformity are corrected
before surgery by orthodontically repositioning teeth properly over
the underlying skeletal component
 This pre-surgical orthodontic movement accentuates the patient's
deformity but is necessary if normal occlusal relationships are to be
achieved when the skeletal components are properly positioned at
surgery.

41. presurgical orthodontic decompensation

42. Mock surgery and fabrication of splints
 Based on the results of the clinical and cephalometric analysis, a
problem list and treatment plan are generated. The mounted
models can then be moved into the planned position for correction
of the skeletal disorder
 The models are fixed in the new positions with wax or glue. Mock
surgery is performed to mimic the planned surgical procedure.
Finally, the reoriented models after mock surgery are used to
fabricate the surgical splints that will be used in the operating room
to reposition the osteotomized segments

43. Mock surgery and fabrication of splints

44. Mock surgery and fabrication of splints

45. Mock surgery and fabrication of splints

46. Osteotomy Procedures

47. 1. Maxillary procedures
 Maxillary osteotomies are based on the Le Fort fracture
lines. Unlike fractures, however, osteotomies terminate at
the posterior maxillary wall and aim to separate the
pterygoid plates from the posterior maxilla

48. Lefort I Osteotomy
A periosteal elevator is inserted between the nasal
mucosa and the lateral wall of the nose on one side
For this procedure the buccal sulcus approach is used.

49. A curved pterygoid chisel is placed with the curvature
pointing medially and inferiorly between the tuberosity
and the pterygoid plates.
The horizontal osteotomy is usually made at the level of
the nasal floor at a safe distance (~5 mm) from the apices
of the teeth.
Lefort I Osteotomy

50. The nasal septum has to be separated from
the palate with either an osteotome or septum
The lateral nasal wall is then separated using a nasal
osteotome or saw.
Lefort I Osteotomy

51. Down fracture Fixation
Lefort I Osteotomy

52. Segmental maxillary procedures
 Historically, a wide variety of segmental maxillary
procedures have been described mostly with eponymous
names, such as Wassmund and Wunderer (anterior
segmental osteotomies), or Schuchardt’s buccal segment
osteotomy. These procedures all have in common surgical
approaches through limited incisions. With experience and
understanding of the blood supply these procedures are
largely obsolete

53. Segmental maxillary procedures
Anterior maxillary osteotomy Posterior maxillary osteotomy

54. Segmental maxillary procedures

55. Segmental maxillary procedures
Indications
 Transverse discrepancies.
 Vertical discrepancies.
 Asymmetry.
 Severe open bite deformity.
 Accentuated occlusal curves, which cannot be levelled
orthodontically.
 Severe bi-maxillary protrusion. Elimination of spacing within
an arch.

56. 2. Mandibular procedure
 Osteotomies have been described at almost every part
of the mandible in order to achieve forward, backward,
or rotational re-positioning.

57. Bilateral sagittal split osteotomy (BSSO)

58. Bilateral sagittal split osteotomy (BSSO)
For this procedure the transoral approach to the
mandibular angle and the transoral approach to the
lateral mandibular body is used.

59. Bilateral sagittal split osteotomy (BSSO)
The first cut is made through the
lingual cortex a few mm above the
mandibular foramen parallel to the
occlusion. The corticotomy is
extended from the anterior to the
posterior borders of the ramus.

60. Bilateral sagittal split osteotomy (BSSO)
The second corticotomy is
made through the buccal
cortex in a vertical direction
at the level of the first or
second molar.

61. Bilateral sagittal split osteotomy (BSSO)
The third corticotomy connects
the first two osteotomy lines
along the anterior border of the
ascending ramus

62. Bilateral sagittal split osteotomy (BSSO)
The final split is completed with a thin
osteotome, splitting the entire
ascending ramus from the anterior to
the posterior border of the ramus.

63. Bilateral sagittal split osteotomy (BSSO)
After the bilateral split is
completed the large tooth
bearing segment can be
moved three dimensionally.

64. Bilateral sagittal split osteotomy (BSSO)
A plate can be applied across
the segments on the lateral
aspect of the mandible using
monocortical screws. A
minimum of two screws on
each side of the osteotomy is
necessary.

65. Vertical subsigmoid osteotomy
 The vertical subsigmoid osteotomy (VSS) is one of the simplest
osteotomies of the mandible
 In theory eliminates the risk of inferior alveolar nerve damage that
accompanies sagittal splitting.
 Has been shown it to be more stable than sagittal splitting for
mandibular set-back.
 May be indicated where appropriate in patients with pre- existing
TMJ problems.

66. Vertical subsigmoid osteotomy
Fixation by MMFOsteotomy

67. Inverted-L osteotomy
The osteotomies are performed
posterior and superior to the inferior
alveolar canal. The osteotomy is
usually performed using a
submandibular approach, especially
for difficult movements and those
requiring bone grafting

68. Inverted-L osteotomy
For large anterior and inferior movements, a gap will result between the proximal and
distal segments necessitating the need for bone grafting.

69. Genioplasty
For transverse genial deformitiesSliding advancement

70. Genioplasty
Downward movementsReducing chin height

71. The Surgical Correction of
Common Deformities

72. Mandibular Excess

73. Mandibular Excess
 Pre-surgical orthodontics will be required to correct arch
size discrepancy, overcrowding and to decompensate the
incisors
 posterior displacement of mandible can be achieved by:
 Bilateral sagittal split osteotomy
 Oblique subcondylar (subsigmoid) osteotomy (less
commonly)

74. Mandibular Deficiency

75. Mandibular Deficiency
 Currently, the BSSO is the most popular
technique for mandibular advancement.
 If the anteroposterior position of the chin is
adequate but a Class II malocclusion exists, a
total subapical osteotomy may be the
technique of choice for mandibular
advancement.

76. Maxillary Excess

77. Maxillary Excess
 Total maxillary osteotomies ( lefort I osteotomy) are
currently the most common procedures performed
for correction of anteroposterior, transverse, and
vertical abnormalities of the maxilla.

78. DISTRACTION OSTEOGENESIS
 When large skeletal movements are required, the associated soft
tissue often cannot adapt to the acute changes and stretching that
result from the surgical repositioning of bony segments. This failure
of tissue adaptation results in several problems, including surgical
relapse, potential excessive loading of the TMJ structures, and
increased severity of neurosensory loss as a result of stretching of
nerves. In some cases the amount of movement is so large that the
gaps created require bone grafts harvested from secondary surgical
sites such as the iliac crest.

79. DISTRACTION OSTEOGENESIS
Large deformity and correction by
Osteotomy and bone graft

80. DISTRACTION OSTEOGENESIS
 Distraction Osteogenesis involves cutting an osteotomy to
separate segments of bone and the application of an appliance
that will facilitate the gradual and incremental separation of bone
segments. The gradual tension placed on the distracting bony
interface produces continuous bone formation. Additionally, the
surrounding tissue appears to adapt to this gradual tension,
producing adaptive changes in all surrounding tissues, including
muscles and tendons, nerves, cartilage, blood vessels, and skin
distraction histogenesis

81. DISTRACTION OSTEOGENESIS

82. DISTRACTION OSTEOGENESIS
 DO involves several phases
1. During the surgical phase an osteotomy is completed and the
distraction appliance is secured.
2. The latency phase is the period when very early stages of bone
healing begin to take place at the osteotomy bony interface. The
latency phase is generally 7 days during which time the appliance
is not activated
3. distraction phase begins at a rate of 1 mm per day. This
distraction rate is usually applied by opening or activating the
appliance 0.5 mm twice each day

83. DISTRACTION OSTEOGENESIS
4. Once the appropriate amount of distraction has been
achieved, the appliance remains in place during the
consolidation phase, allowing for mineralization of the
regenerate bone
5. The appliance is then removed, and the period from the
application of normal functional loads to the complete
maturation of the bone is termed the remodeling period.

84. DISTRACTION OSTEOGENESIS

85. DISTRACTION OSTEOGENESIS : advantages
1. the ability to produce larger skeletal movements
2.elimination of the need for bone grafts and the
associated secondary surgical site
3.better long-term stability
4.less trauma to the TMJs
5.decreased neurosensory loss

86. DISTRACTION OSTEOGENESIS

87. DISTRACTION OSTEOGENESIS : disadvantages
1. The placement and positioning of the appliance to
produce the desired vector of bone movement is
technique sensitive and sometimes results in less than
ideal occlusal positioning, resulting in discrepancies
2. placement and removal of the distractors
3. as well as increased cost and longer treatment time, with
more frequent appointments with the surgeon and the
orthodontist.