This document provides information on the assessment and treatment planning for orthognathic surgery. It discusses evaluating patients' medical history, dental evaluation, facial analysis, cephalometric analysis, occlusal evaluation, and soft tissue evaluation. The goal of treatment is to improve function, esthetics, stability, and minimize treatment time. Skeletal maturity must be assessed before surgery. Various classification systems are used to evaluate facial proportions and asymmetries. Thorough examination is needed to develop an appropriate treatment plan for orthognathic surgery.

1. 1

2. ORTHOGNATHIC SURGERY:
DIAGNOSIS AND TREATMENT
PLANNING
2

3. • Art and science of
diagnosis, treatment
planning and execution of
treatment by combining
orthodontics and OMFS to
correct musculoskeletal,
dento-osseous and soft
tissue deformities of the
jaws and associated
structures.
3

4. TREATMENT OBJECTIVES:
• Correction of the dental malocclusion
• Improvement of facial appearance
• Long term stability of results achieved.
4

5. PRESENTING COMPLAINTS
• Disturbance of function
▫ Jaw function
▫ Breathing
▫ Speech
▫ TMJ pain secondary to TMJ dysfunction
• Disturbance of appearance
5

6. ASSESSMENT SCHEME
• Appearance versus occlusion?
• Clinical examination and radiographic analysis.
• Profile and occlusion planning
▫ Tests for profile prediction
▫ Tests for feasibility
▫ Tentative treatment plan
▫ Definitive treatment plan.
6

7. GOAL
1. Function
2. Esthetics
3. Stability
4. Minimize treatment time
7

8. SYSTEMIC PATIENT EVALUATION
• GENERAL PATIENT EVALUATION
▫ Medical history
▫ Dental evaluation
▫ Dental history
▫ Dental health
• SOCIAL-PSYCHOLOGIC EVALUATION
• ESTHETIC FACIAL EVALUATION
▫ Front-face analysis
▫ Profile analysis
8

9. • CEPHALOMETRIC EVALUATION
▫ Soft tissue
▫ Skeletal relations
▫ Dental relations
• PANORAMIC OR FULL-MOUTH
PERIAPICAL EVALUATIONS
• OCCLUSAL EVALUATION
▫ Functional
▫ Static
• MASTICATORY MUSCLE AND TMJ
EVALUATION
9

10. SOFT TISSUE EVALUATION:
• Three functional groups are involved:
▫ The pterygomassetric tissues
▫ The linguovestibular musculature
▫ The suprahyoid group
10

11. THE PTERYGOMASSETRIC GROUP OF
SOFT TISSUES:
• Masseter, internal pterygoid, temporalis,
external pterygoid, skin subcutaneous tissue,
fascia, ligaments and periosteum.
• Any corrective procedure which involves
lengthening the mandibular ramus without at
the same time increasing the length of the
pterygomassetric tissue , inevitably increases the
tension exerted by these tissues on the ramus.
Postoperative relapse usually follows.
11

12. Coronoid process (enlongation and
hypoplasia)
Temporalis
Mandibular angle (gonial angle) Masseter
Ramus and angle Medial pterygoid
Alveolar process teeth
Condyle Lateral pterygoid
Mandibular body Neurovascular bundle and
suprahyoid musculature
12

13. ANTEGONIAL NOTCH (Hovell 1965):
• This notch is a marker of pterygomassetric
activity, giving some hope of a sufficiently active
matrix within which enlongation of the
mandibular ramus by bone grafting might
succeed during the growing period. Absence of
notch points to inadequate muscular function to
support ramal enlongation and relapse is almost
certain.
13

14. LINGUVESTIBULAR GROUP OF SOFT
TISSUES:
• TONGUE, CHEEK AND LIPS
• Teeth and dental arches lie in position of
muscular neutrality, surgical and orthodontic
alterations change this balance. stability
depends on repositioning the segments in a new
state of equilibrium.
14

15. SUPRAHYOID GROUP OF SOFT TISSUES:
• Geniohyoid, Mylohyoid, Anterior Belly of
Digastric, Hyoglossus, lower facial integument.
• These together resist the forward translation of
the anterior mandible, irrespective of the site
chosen for osteotomy. The greater the distance
the chin is advanced the greater the force of
resistance.
15

16. M. M. House patient classification:
• Philosophical patient: rational, sensible,
calm and composed in different situations.
• Exacting patient: have all of the good
attributed to the philosophical patient; however,
may require extreme care, effort and patience.
This patient is methodical, precise, accurate and
at times makes severe demands. He likes each
step in the procedure explained in detail.
16

17. • Indifferent patient: questionable or unfavorable prognosis.
This patient evidences little if any concern; he is apathetic,
uninterested and lacks motivation. The indifferent patient
pays no attention to instructions, will not cooperate and is
prone to blame the dentist.
• Hysterical patient: emotionally unstable, excitable,
excessively apprehensive and hypertensive. The prognosis is
often unfavorable and additional professional help
(psychiatric) is required prior to and during treatment.
emotionally unstable, excitable, excessively apprehensive and
hypertensive. The prognosis is often unfavorable and
additional professional help (psychiatric) is required prior to
and during treatment.
17

18. Obtaining psychological information:
• Surgery can be stressful (specially facial
surgeries)
• marital status, available social support, history
of drug or alcohol abuse, psychological
counseling and current life satisfaction.
• Practical and emotional readiness
• Open ended questions and silence
18

19. 19
Moderate and realistic expectations Satisfied
Extreme and less realistic expectations Disappointed

20. 20

21. METHODS – TO ASSESS SKELETAL
MATURITY
Use of hand wrist radiographs
FISHMAN’S SKELETAL MATURITY INDICATORS
1. 3rd finger proximal phalanx shows equal width of epi & diaphysis
2. Epi = diaphysis in middle phalanx of 3rd finger
3. Epi = diaphysis in middle phalanx of 5th finger
4. Appearance of adductor sesmoid of thumb
5. Capping of epiphysis in distal phalanx of 3rd finger
6. Capping of epiphysis in middle phalanx of 3rd finger
7. Capping of epiphysis in middle phalanx of 5th finger
8. Fusion of epi & diaphysis in distal phalanx of third finger
9. In proximal phalanx of 3rd finger
10.In middle phalanx of 3rd finger
11. In the radius
21

22. 22

23. 23

24. 24

25. SKELETAL MATURATION: VERTEBRAE
• CVMS I—flat C2, C3 and C4 inferior vertebral body borders, as well as bodies of both
C3 and C4 being trapezoid in shape;
• CVMS II—concavities present at the lower border of C2, flat lower borders of C3 and
C4, and both C3 and C4 being trapezoid in shape;
• CVMS III—concavities present at the lower borders of C2 and C3, no concavity present
at the lower border of C4, and C3 and C4 being either trapezoid or rectangular,
horizontal in shape;
• CVMS IV—concavities present at the lower borders of C2, C3 and C4, as well as both
C3 and C4 being rectangular, horizontal in shape;
• CVMS V—concavities present at the lower borders of C2, C3 and C4, as well as both C3
and C4 being rectangular, horizontal to square in shape;
• CVMS VI—concavities present at the lower borders of C2, C3 and C4, as well as both
C3 and C4 being square to rectangular, vertical in shape.
25

26. 26

27. 27

28. 28

29. Habits and resultant malocclusion
Habits Malocclusion
Thumb sucking Labial tipping of maxillary anteriors
Increased overjet
Anterior open bite
Narrow maxillary arch
Tongue thursting Proclination of anterior teeth
Anterior open bite
Bimaxillary protusion
Posterior open bite (lateral tongue thurst)
Posterior cross bite
High arched palate
Mouth breathers Long narrow face
Contracted upper arch
Posterior cross bite
Short flaccid upper lip
Anterior open bite
29

30. GENERAL FACIAL ANTHROPOMETRIC
RELATIONS:
FRONTAL FACE EVALUATION:
30

31. 31
0.30
0.35
0.35

32. 32
0.65
0.75
0.66
Female- 1.3:1
Males – 1.35:1

33. PROFILE EVALUATION:
33

34. • The distance from the outer canthus of eye to the
angle of the mouth should be equal the distance
from the nasal columella to the chin
• Lateral edge of the alar rim should lie vertically
below the medial canthus of the eye, or slightly
lateral to it’s position.
• The medial limbus of the eye should lie vertically
above the angle of the oral commisure.
• The vermillion exposure of the lips should be equal.
• Intercanthal distance should be equal to palpebral
fissure distance.
34

35. 35

36. Symmetry grids:
36

37. RULE OF FIFTH:
37
(Bell et al 1980)

38. Upper 1/3rd of face.
• Appropriate hairstyle.
38
MIDDLE 1/3 OF FACE:
• Eyebrows to subnasale

39. EYES:
• Supraorbital rim----12
anterior to the globe
• Lateral orbital rim (LOR) -
---8-12 mm behind the
most anterior projection
of the globe.
• Nasal bridge- 5mm to
8mm anterior to the globe
• Infraorbital rim (OR)----
(-2)- 2 mm to the globe
39

40. 40

41. • A common malrelation, lateral canthal dystopia,
occurs when the outer canthi are inferiorly
positioned
• The upper and lower eyelids are evaluated for
right-to-left symmetry and specifically for the
presence of ptosis, ectropion, or entropion
• The presence of scleral show between the lower
eyelid and pupil are assessed, it is commonly
associated with infraorbital hypoplasia,
exophthalmos.
41

42. NOSE:
• History of nasal trauma, nasal airway obstruction, allergies,
sinus problems,predominant mouth breathing vs. nasal
breathing, aesthetic concerns and previous surgeries.
• Shape of the dorsum- convex, concave.
• Nasal bridge- 5-8 mm anterior to globe
• The direction of nasal tip rotation, either turned up or down.
• Decreased nasal projection contraindicates Maxillary
advancement.
• Finally, proportions of the alar base width (A I-A I) to the
nasal length (N-Prn) are determined. An attractive
proportional nose has an alar width to length of 0.60
42

43. 43
5-8mm

44. 44
NASAL TIP
PROJECTION
(GOODE):
BC> 55 to 60% of AB
NASAL PROJECTION
Pn – Sn – 16 to 20 mm
Pn-Sn: Sn-Nb – 2:1

45. 45
COLUMELLA-LOBULE RELATIONSHIP- RATIO- 2:1
If this value approaches 1:1 ----- suggestive of lack of nasoskeletal support for the
alar base and imply maxillary and / or middle third deficiency

46. 46
Nasolabial angle: 85- 105 degree---imaginary line tangent to the
columella (C) and the upper lip Vermillion (Ls) and intersecting at the
Subnasale (Sn).

47. CHEEKS
47
Malar
prominence
Infraorbital
prominence
Paranasal
prominence

48. 48
• The malar prominence is normally a distinct
convexity located 15 mm directly inferior to the
lateral canthus of the eye.
• Abnormal : Flat or concave.
• The infraorbital prominence : Located on a line
directy below the pupil of the eye at the
horizontal level of the infraorbital rim. It is flat
to convex.

49. 49
CHHEK BONE-
NASAL BASE-
LIP CURVE
CONTOUR

50. • The protrusion or retrusion of the upper lip - It
relates to an imaginary line through subnasale and
perpendicular to the FH plane.
• The most prominent portion of the vermilion of the
upper lip -Not more than 2 mm ahead or behind this
line.
• Ideally, upper lip vermilion should just touch this
line.
• Normally the upper lip projects slightly (2 mm)
anterior to the lower lip in repose.
50
Lower one third

51. • Upper lip: Females
20±2mm Males - 22
±2mm
• Lower lip: Females - 40
±2mm Males - 44 ± 2mm
• The lower lip - 25% more
vermilion exposed
• An interlabial separation -
0 to 3 mm exists in repose
51

52. • The ratio of the vertical
distance from subnasale (Sn)
to upper lip stomion and that
from upper lip stomion to
soft-tissue gnathion (Gn) is
about 1 :2.
• The ratio of the vertical
distance from subnasale to the
vermilion cutaneous margin
of the lower lip (Li) and that
from the vermilion cutaneous
margin of the lower lip to soft-
tissue menton is about 1: 1
• The width of the lips from
commissure to commissure is
normally about equal to the
interpupillary distance
52

53. • Smile:
• vermillion of the upper lip ---- cervicogingival
margin/ 1-2 mm of exposed gingiva
• Amount of upper lip relation during smiling is
affected by:
▫ A-P relation of maxilla or mandible to cranial base
as well as to each other
▫ Overjet/ overbite
▫ Angulation of anterior dentoalveolus
▫ Occlusion plane angulation
▫ Clinical crown length
▫ Neuromuscular function
53

54. • GUMMY SMILE
Anatomic short upper lip, Vertical maxillary excess,
Mandibular protrusion with open bite, Decreased
interlabial gap, Vertical maxillary deficiency,
Anatomically long upper lip (natural change with
ageing, esp. in males), Mandibular retrusion with
deep bite.
• GULL WING
Normally the upper lip tubercle hangs slightly inferior
to the vermilion on either side of it, however, the
tubercle may be superior to the adjacent vermilion
or entirely absent. Such a deformity has been called
a "gull-wing" upper lip.
54

55. TEETH
• It is important to differentiate between an asymmetry
caused by facial muscle dysfunction, an intrinsic lip
deformity, or an underlying skeletal-dental-soft-tissue
asymmetry such as hemifacial microsomia.
• When a dental-skeletal asymmetry is noted-a cant of the
maxillary occlusal plane relative to the globes-it is
important to determine the magnitude of the cant and
which side, if either, is at the correct vertical level
• Tooth exposure during smiling is highly variable
depending on which facial muscles are activated .
Normal tooth to lip relationship 2.5± 1.5
55

56. • The lower teeth are seldom exposed at rest.
• When they are, it generally indicates
(1) poor support of the lower lip because of an
anteroposterior chin deficiency,
(2) severe mandibular dentoalveolar protrusion,
or
(3) hypotonicity of the lower lip.
56

57. LABIOMENTAL FOLD
• Lowe lip – chin contour:
“S” shape – 130’
• Deep curve – vertical
mandibular deficiency,
Class II(deep bite)
• Flatness – Class III
57

58. CHIN:
• Chin projection - Lie 2 to 6 mm (3+ 3 mm)
behind subnasale perpendicular line
• Normal: Knobby appearance
58

59. • Mandibular inferior border
definition
• The mandibular angle in profile is
normally well defined, with a subtle but
definite submandibular depression.
• Neck – chin angle and length
• The neck-chin area normally exhibits an
obtuse angle (110 degrees), and the
distance from pogonion to the neck-chin
angle is about 50 mm
• Presence of double chin & adipose tissue
should be noted.
59

60. OCCLUSAL CANT
• Occlusal plane should be parallel to
interpupillary plane
• TMJ AKYLOSIS – Reduced ramus height on
affected side leads to compensatory increase on
opposite side can cause occlusal canting
60

61. Temporormandibular Joint:
• Presurgical TMJ dysfunction or undiagnosed
TMJ pathosis may result in unfavourable
outcomes such as postoperative pain, condylar
resorption, malocclusion, jaw dysfunction and
facial deformity.
61

62. 62

63. CEPHALOMETRIC ANALYSIS
FOR ORTHOGNATHIC
SURGERY (COGS)
BURSTONE AND CO-WORKERS ANALYSIS

64. This analysis, especially designed
for the patients who require
maxillofacial surgery, was
developed to use landmarks and
measurements that can be altered
by common surgical procedures.

65. • The successful treatment of the orthognathic surgical
patient is dependent on careful diagnosis.
• Cephalometric analysis can be an aid in the diagnosis
of skeletal and dental problems and a tool for stimulating
surgery and orthodontics.
• Cephalometric analysis also allows the clinician to
evaluate changes after surgery.

66. COGS system measures horizontal and
vertical position of facial bones by use of a
constant coordinate system
• the size of bones are represented by direct
linear dimensions and
• their shapes by angular measurements.

67. • Sella (S)
• Nasion (N)
• Articulare (Ar)
• Pterygomaxillary
fissure (PTM)
• Subspinale (A)
• Pogonion (Pog)
• Supramentale (B)
• Menton (Me)
• Gnathion (Gn)
• Gonion (Go)
• Anterior nasal spine (ANS)
• Posterior nasal spine
(PNS)
• Mandibular Plane (Me-
Go)
• Nasal floor (ANS-PNS)
LANDMARKS

68. 68

69. The baseline for comparison of most
data in this analysis is a constructed
plane called the horizontal plane (HP),
which is a surrogate frankfort plane,
constructed by drawing a line 70 from
the line S-N line.
Most measurements will be made
either parallel or perpendicular to HP.

70. CRANIAL BASE
Ar to N is designated as cranial base
length.
Ar-N is relatively stable anatomical
plane
It can be changed :
• by cranial surgery that effects N -
LeFort II and III osteotomies
• Slightly altered with auto
correctional rotations of
mandible – Ar moves closer to N.

71. Ar - PTM
Ar to PTM refers to horizontal
distance between posterior aspects
of the maxilla and the mandible.
The greater the distance between
Ar- PTM , the more the mandible
will lie posterior to the maxilla ,
assuming that all other facial
dimensions are normal.

72. PARAMETER MALES FEMALES
Ar – PTM
(mm)
37.1+- 2.8 32.8+-1.9
PTM – N (mm) 52.8 +- 3 50.9+-3
CRANIAL BASE

73. HORIZONTAL SKELETAL PROFILE
All the measurements are made parallel to HP.
This is very practical as most of the surgical
corrections are primarily made in
anteroposterior direction.

74. ANGLE OF CONVEXITY
Formed by the line NA and a line A-
Pg
This angle gives an indication of the
overall
facial convexity BUT not a specific
diagnosis which is at fault , the
maxilla or the mandible
Positive angle = convex face
Negative angle = concave face
MALE FEMALE
N-A-Pg
(Angle)
(degrees)
3.9 +-6.4 2.6+-5.1

75. N-A AND N-B AND N-Pg
A perpendicular line from HP is
dropped through N.
The inferior anatomic point is
horizontally measured in
relation to superior structure
with plus being anterior and
minus posterior.
▫ N-A : used to determine
anterior part of maxilla -
retrusive /protrusive
▫ N-B : used to determine apical
base of mandible in relation to
the nasion.
▫ N-Pg : indicates the
prominence of chin.

76. HORIZONTAL MALE FEMALE
N-A 0.0+-3.7 -2+-3.7
N-B -5.3+-6.7 -6.9+-4.3
N-Pg -4.3+-8.5 -6.5+-5.1

77. VERTICAL SKELETAL PARAMETER
• N- ANS
• ANS- Gn
• MP- HP
• N-PNS
Reflect an anterior ,
posterior or complex
dysplasia of face.

78. VERTICALSKELETAL
PARAMETERS
MALE FEMALE
N-ANS
perpendicular HP
54.7+-3.2 50+-2.4
ANS-Gn
perpendicular HP
68.6+-3.8 61.3+-3.3
PNS-N
perpendicular HP
53.9+-1.7 50.6+-2.2
MP-HP Angle 23.0+5.9 24.2+-5

79. VERTICAL DENTAL PARAMETER
• 1- NF and 1- MP : to measure
anterior maxillary dental
height and mandible
anterior dental height from
incisal edges to NF and MP
respectively.
• 6-NF and 6-MP : to measure
vertical posterior maxillary
and mandibular dental
height. Perpendiculars are
dropped from mesiobuccal
tip of cusp of first molars to
NF and MP respectively.

80. DENTAL SKELETAL
PARAMETERS
MALE FEMALE
1-NF (Angle) 111.0+-4.7 112.5 +-5.3
1-MP (Angle) 95.9+-5.2 95.9+-5.7

81. MAXILLA AND MANDIBLE
• ANS-PNS : shows effective
length of maxilla
• Ar-Go : length of mandibular
ramus.
• Go-Pog : length of mandibular
body.
• Ar-Go-Gn : relation between
ramal plane and MP
• B-Pg : describes the
prominence of chin
related to mandibular
denture base.

82. MAXILLA-MANDIBLE MALE FEMALE
PNS-ANS 57.7+-2.5 52.6+-3.5
Ar-Go (linear) 52.0+-4.2 46.8+-2.5
Go-Pg (Linear) 83.7+-4.6 74.3+-5.8
Ar-Go-Gn Angle 119.1+-6.5 122+-6.9

83. DENTAL PARAMETERS
HP-OP:
• Increased – skeletal open bite
, lip incompetency , increased
facial height, retrognathia ,
increased MP angle.
• Decreased- deep bite ,
decreased facial height or lip
redundancy.

84. DENTAL MALE FEMALE
OP-HP Angle 6.2 deg+-5.10 7.1+-2.5 deg

85. Wits appraisal
85
Linear measurement between maxilla
and mandible not affected by the
cranial base
The point BO and AO are established
by dropping a prependicular plane
from point B to OP and point A to OP
In males BO is 1mm ahead of AO
Females BO and AO coincides

86. GRUMMON’S ANALYSIS
• This analysis provides clinically relevant information about
specific locations and amounts of facial asymmetry.
• The information can be co-realted with lateral cephalometric
data to complete a three dimensional facial assessment.
• This is a comparative and quantitative postero-anterior
cephalometric analysis.

87. The analysis consist of :
◦ Horizontal planes
◦ Mandibular morphology
◦ Volumetric comparison
◦ Maxillomandibular comparison of asymmetry
◦ Linear asymmetry assessment
◦ Maxillomandibular relation
◦ Frontal vertical proportions

89. 1. Zygomaticofrontal
sutures (Z)
2. Zygomatic arches
(ZA)
3. Medial aspects of the
jugal processes (J)
4. One parallel to the z-
plane through menton
CONSTRUCTION OF HORIZONTAL PLANES

90. MSR
Runs vertical from Cg
through ANS to the chin
area, and will typically be
nearly perpendicular to the
Z- plane.

91. • Left sided and right sided
triangles are formed
between the head of the
condyle (Co) to the
antegonial notch (Ag) and
menton (Me).
• A vertical line from ANS to
ME visualizes the mid-
sagittal plane in the lower
face.
• Linear , angular and
anatomy can be measured.
MANDIBULAR MORPHOLOGY

92. Condylion (Co)
Antegonial notch (Ag)
Menton (Me) and
The intersection with
a perpendicular form
Co to MSR
VOLUMETRIC COMPARISON

93. • perpendicular to MSR from
Ag and from J, bilaterally
• Lines connecting Cg to J
and Ag
• THIS PRODUCES TWO
PAIRS OF TRIANGLES.
EACH PAIR IS BISECTED
BY MSR.
• Method to assess
symmetries in both the
jaws.
MAXILLOMANDIBULAR COMPARISON OF ASYMMETRY

94. Soft tissue
analysis
94

95. 95

96. 96

97. 97

98. 98

99. Errors in cephalometry
• Radiographic projection error
• External orientation error/ Internal orientation
error
• Errors in landmark identification
• Error within the measuring system
• Evaluator bias –
▫ variation in landmark identification between
evaluators
▫ The evaluators expectation can result in bias of the
values
99

100. PHOTOCEPHALOMETRY:
• Imposes the discipline of cephalometry on the
use of lateral photographic techniques.
100

101. Balanced Angular Profile Analysis
• Developed by Heung Sik Park
• Photogrammetric profile analysis
• BAPA is composed of 11 landmarks
• Compares individual facial balance or harmony
to those of attractive or average faces.
101

102. 102

103. 103

104. 104

105. 105

106. Tongue assessment:
• Congenital or acquired causes
of macroglossia:
▫ Muscular hypertrophy
▫ Glandular hyperplasia
▫ Hemangioma
▫ Lymphangioma
▫ Down syndrome
▫ Beckwith- weidmann
syndrome
▫ Acromegaly
▫ Myxedema
▫ Amyloidosis
▫ Tertiary syphilis
• Pseudo macroglossia
▫ Habitual posturing of tongue
▫ Hypertrophied tonsils and
adenoid tissue that displace
the tongue forward
▫ Low palatal vault, decreasing
oral cavity volume
▫ Transverse, vertical,
anteroposterior deficiency of
the mandible or maxillary
arches that decrease the
orbital cavity volume
▫ Mandibular deficiency
▫ Tumors that displace the
tongue.
106

107. Clinical features:
• Grossly enlarged and/ or wide . Broad and flat
• Open bite (anterior/ posterior)
• Mandibular prognathism
• Class III malocclusion with or without anterior
and posterior cross bite.
• Chronic posturing of tongue between the teeth at
rest
• Buccal tipping of posterior teeth
107

108. • Diastema
• Crenations of tongue
• Glossitis
• Assymetry in maxillary and mandibular arches
• Difficulty in eating and swallowing
• Airway difficulties
• Drooling
• Instability in orthodontic mechanics and
orthognathic surgery stability.
108

109. PROFILE PLANNING
• Reasoned prediction of the probable effects
alternative facial osteotomies (or hard tissue
corrections) on facial profile, and the use of
resulting predictions to formulate a treatment
plan. (HENDERSON 1974).
109

110. 110

111. PURPOSE
• To establish orthodontic goals
• To develop surgical objectives
• To create the predicted profile
• significant IMPORTANCE in two phase
treatment
• Initial: to establish orthodontic surgical goals
• Final: after orthodontic treatment to determine
exact vertical and anteroposterior changes to be
achieved.
111

112. Visual treatment objectives
• Accurate and realistic visual treatment
objectives are made from lateral cephalometric
tracing and data obtained from systemic patient
evaluation.
• Pretreatment visual treatment objectives
• Immediate presurgical prediction objectives
112

113. Pretreatment visual treatment
objective:
• Overall treatment planning
• Orthodontic prediction tracing----
▫ Presurgical orthodontic tooth movement and
resultant tissue changes
• Surgical prediction tracing
▫ Surgical repostioning of the jaw and resultant soft
tissue changes
113

114. Presurgical visual treatment objective
• Few days before surgery
• Definative surgical procedure and soft tissue
changes
114

115. Advantages:
• Accurately predicts the soft tissue profile
• Assess the various treatment options
• Analyze the need for extraction
• Need for adjunctive surgical procedure
(genioplasty)
• Orthodontic movement can be monitored
• Post surgical skeletal movements assessed
• Communication
115

116. Dental model analysis
• Arch length
• Tooth size analysis
• Tooth angulations
• Arch width analysis
• Occlusion
• Curve of occlusion
• Missing, broken or crowned teeth
116

117. • To determine intended occlusion and arch form
• To decide the exact amount and direction of the
movement of the arches or segments of the
arches.
117

118. MOCK SURGERY AND SPLINT
FABRICATION:
• Mock surgery is performed to mimic the planned
surgical procedure. It is also a powerful tool to
demonstrate the treatment plan to the patient.
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.
118

119. • To determine the magnitude & direction of
skeletal movements
• To determine the size and shape of osteotomies
especially interdentally
• To provide a splint for surgical correction
119

120. ADVANTAGES
• 3 Dimensional view
• Increased accuracy
• Accurate model surgery movements
120

121. DISADVANTAGES
• Condyles are never perfectly symmetrical
mounted
• Measurements errors related to instruments and
perspective
121

122. TYPES OF FEASIBILITY MODEL SURGERY
• Whole arch – hand articulating models into best
possible occlusion
• segmental – sawing the upper , lower or both
models into the dentoosseous segment to be
produced at the surgery and reassembling them
into the best possible occlusion by using a simple
hinge type articulator to help hold the model
bases.
122

123. Technique:
• Lockwood key spacer planning system
(lockwood in 1974)
• The anatomical technique
123

124. 124

125. 125

126. 126

127. SOFT TISSUE CHANGES AFTER
SURGERY:
• The movement of the nasal tip (point C): this
moves with point A (Subnasale) provided there
has been no associated collmellar surgery or
nasal bone tip grafting.
▫ Lefort I- 1:3
▫ Lefort II- 2:3
▫ Lefort III- 1:1
• Genioplasty alone advances the I point by about
1mm in standard augmentation procedure.
127

128. • The movement of upper lip (point F): compared
with the tip of the upper incisor.
▫ One third of the advancement of the incisor tip in
orthodontic movement
▫ One third to one to one movement in surgical
advancement
▫ Average- 2/3 advancement of F compared with incisor
tip.
• The important clinical factor to watch is the
strechability of the lip, the bulk of the soft tissue in
it.
• The movement of lower lip (H point): the point B
the overlying soft tissue supramentale move in 1:1
relationship.
128

129. • As a general rule lower lip moves back by 60% of the
movement of supramentale in the mandibular set
back preperations. But in advancement procedures
will depend on whether or not it starts from a
position of entrapment behind the upper incisors. If
so then advancement brings it front of the upper
teeth and a deep labiomental furrow is converted
into a smooth curve , with a greater degree of
forward movement of the lower lip. If not there is
relatively little forward movement of the vermillion
of the lower lip.
129

130. • The movement of the chin: pogonion and the
soft tissue pogonion (point J) move consistently
in 1:1 ratio when the whole mandible or anterior
mandible is advanced or set back.
• Sliding augmentation or genioplasty will add 4
to 6 mm to the chin for each standard slide.
Reduction genioplasty is less predictable and
less satisfactory. About 2/5th of the set back of
Po may be expected at J.
130

131. 3-D VIRTUAL PLANNING
• A cone beam or fan CT-scan is obtained and a virtual 3D-
model of the patients skull is generated.
• The mandible is segmented (defined) in preparation for
performing the virtual osteotomies.
• A cephalometric analysis is performed. A problem list is
then generated.
• Using the clinical exam and skeletal problem list, a
treatment plan is formulated.
• A soft tissue overlay can be helpful in the analysis of the
deformity.
131

132. 3D Virtual osteotomy planning 132

133. 133

134. 3D virtual profile prediction
• Planning is based on the clinical examination,
evaluation of pictures and cephalometry. In
order to visualize profile changes
134

135. classification for surgical treatment
planning of maxillomandibular
asymmetry (J.P. REYNEKE. BJOMS 1997)
135

136. • Type I: that caused by asymmetry of the symphysis of the mandible. The
maxilla and the body of the mandible are symmetric with the dental
midlines in the centre of the face.
• Type II: that in which the discrepancy is primarily in the body, ramus or
condyle of the mandible. The maxillary dental midline coincides with the
facial midline and the mandibular dental midline coincides with the
symphysial midline.
• Type III: that in which the maxillary midline is still coincident to the facial
midline but the mandibular midline is asymmetric to the maxillary midline
and the symphysis is still more asymmetric to the mandible.
• Type IV: that in which the discrepancy involves the maxilla, mandible, and
the symphysis. The maxillary midline is asymmetric to the facial midline
while the body of the mandible to the maxillary midline is further
asymmetric (mandibular midline is asymmetric), and the mandibular
symphysis is asymmetric to the body of the mandible.
• Subtypes Ic, IIc, IIIc, and IVc
• Type C: depicts facial asymmetry caused by a cant in the occlusal plane
while the maxillary and mandibular dental midlines and symphysis
coincide. The table indicates the surgical treatment plans recommended for
the above classification.
136

137. 137

138. 138

139. Henderson classification.
1. Symmetrical Disproportion Of Jaws
Mandibular enlargement
Mandibular deficiency
Maxillary enlargement
Maxillary deficiency
Bimaxillary disproportion
2. Asymmetrical Disproportion Of Jaws
Unilateral mandibular enlargement
Unilateral mandibular deficiency
Unilateral maxillary abnormalities
3. Cleft lip and Cleft Palate
139

140. DEFINITIVE TREATMENT PLANNING
ESTABLISHMENT OF PRIORITY ⇰ Problems
PRE- SURGICAL
• Preparation of arches to obtain good dental relationship
▫ Level upper and lower arches
▫ Resolve Spacing or crowding
• Establish coordinated transverse dimensions Some time
major changes like alteration of arch width.
• Extraction
• In case of deep curve of spee- intrusion of lower anterior teeth
• In case of open bite, like it should not open post-operatively
• Removal of dental compensation (Establish normal
inclination of incisors) is one key to successful T/T, which
often requires extraction of teeth
140

141. Preparation for Surgery
• Removal of third molars 6 months before
mandibular osteotomy.
• Check for any TMJ problems.
• Manipulate models mounted in an articulator to
check for interferences and occlusion (Model
Surgery).
• Splint fabrication (1 or 2 splints).
141

142. •
•
142

143. Conclusion
• More emphasis to patient’s complaint
• Accurate clinical examination & adjunctive
procedures
• More time spending in diagnosis and treatment
planning

144. 144