lateral Cephalometry

Cephalometric
Omar Yousry
BDS, MSc Orthodontics CU
Morth RCSEd UK
Dr Omar Yousry BDS MSc Orthodontics CU,
MORTH RCSEd UK

Cephalometric
Scientific measurements of the head using standardized skull R/G
• developed in 1930's by Broadbent (USA)/Hofrath (Germany)
Standardized::
• Collimated X-ray source - 5 feet from midsagittal plane of pt
• Cephalostat - head positioner
• Aluminium wedge - increases soft tissue definition
• Film - placed 1 foot behind midsagittal plane of pt with
• Rare earth metal intensifying screen
• Radiation dose/exposure ::: 6 micro Sv
• Natural head position:
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Cephalometric
Standardized::
• Radiation dose/exposure ::: 3- 6 micro Sv
• Natural head position:
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Cephalometric
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Cephalometric
Head position
Soft tissue
Magnification
Occlusion
STANDARDIZATION
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Cephalometric
Filtration
Collimation
Attenuation
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Cephalometric
Standardized::
• Radiation dose/exposure ::: 3- 6 micro Sv
• Natural head position ???
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Lateral Cephalometry
Uses:
Shows : sagital + vertical, Skeletal + Dental + soft tissue
1- Diagnosis and treatment planning (If needed)
2- During active treatment e.g. end of functional appliance
treatment
3- Towards end of treatment must be clinically justifiable
4- During I out of retention - assessment of relapse
5- Assessing I monitoring growth- pt's own growth or comparing
with "norms" for sex, age and race (use of templates e.g. Bolton)
6- (research) - Bjork's implant studiesDr Omar Yousry BDS MSc Orthodontics CU,
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Uses:
Shows : sagital + vertical, Skeletal + Dental + soft tissue
1- Diagnosis and treatment planning (If needed)
Objective and measurable description of the malocclusion and
dentofacial malformations
Relation between main components (skull base, maxilla, maxillary
dentoalveolus, Mandible, mandibular dentoalveolus)
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Tracing
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Cephalometric Analysis
1- Numerical (Metric):
angles or linear
• angular measures is better: not affected by
magnification
2- Graphic:
Template analysis: compare patient tracing by
superimposition on normal template
• Can be used as a guide for planning orthognathic
surgery
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Landmarks
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Landmarks
Reliablity of the point = Valid + reproducible
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Landmarks
Y axis:
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Measurements
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Down Analysis 1948
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Reference line: FH plan
facial plan
Md plan
Occ plan
Y - axis
Po – Or
N – Pg
tangent – Me
intercuspal
S GN
Skeletal
Measurements:
Facial angle N Pg - FH (88)

Down Analysis 1948
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facial plan
Md plan
Occ plan
Y - axis
Po – Or
N – Pg
tangent – Me
intercuspal
S GN
Skeletal
Measurements:
Facial angle
cnvexity angle
N Pg - FH
N A - A- Pg
(+ve II - -ve III)

Down Analysis 1948
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facial plan
MD plan
Occ plan
Y - axis
Po – Or
N – Pg
tangent – Me
intercuspal
S GN
Skeletal
Measurements:
Facial angle
cnvexity angle
Md plane angle
growth axis (Y)
AB angle
N Pg - FH
N A - A- Pg
Tng Me - FH
S Gn - FH
A B - N Pg
(-ve III +ve II)

Down Analysis 1948
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facial plan
MD plan
Occ plan
Y - axis
Po – Or
N – Pg
tangent – Me
intercuspal
S GN
Skeletal
Measurements:
Facial angle
cnvexity angle
Md plane angle
growth axis (Y)
AB angle
N Pg - FH
N A - A- Pg
Go Me - FH
S Gn - FH
A B - N Pg
Dental
Measurements:
Occ. Cant
interincisal angle
L1 / Occ P
L1/ Md P
U1 to A-Pog (mm)
OP / FH
U1 / L1

Down Analysis 1948
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Steiner Analysis 1953
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Reference line: SN plan
(superimpose)
Skeletal
Measurements:
SNA
SNB
ANB
SN-OP
SN-MdP (Go-Gn)
y axis - SN

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(superimpose)
Skeletal
Measurements:
SNA
SNB
ANB
SN-OP
SN-MdP
Dental
Measurements:
U1 – NA (angle)
U1 – NA (mm)
L1 – NB (angle)
L1 – NB (mm)
U1 – L1 (angle)
L1 – chin (mm)
22⁰
4 mm
25⁰
4 mm
4 mm

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Skeletal
Measurements:
SNA
SNB
ANB
SN-OP
SN-MdP
Dental
Measurements:
U1 – NA (angle)
U1 – NA (mm)
L1 – NB (angle)
L1 – NB (mm)
U1 – L1 (angle)
L1 – chin (mm)
Soft tissue
measurement:
S line
(both lips touch)
Soft Tissue
Pogonion -
middle S (lower
border of the
nose)

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Reference line: SN plan N point
variability ??
Skeletal
Measurements:
SNA
SNB
ANB
SN-OP
SN-MP (Go.Gn)
Y axis – SN
82
80
2
14 (inc. in OB)
32
Dental
Measurements:
U1 – NA (angle)
U1 – NA (mm)
L1 – NB (angle)
L1 – NB (mm)
U1 – L1 (angle)
NB – Pog (mm)
22⁰
4 mm
25⁰
4 mm
135
4 mm
Soft tissue
measurement:
S line
(both lips touch)
Soft Tissue
Pogonion -
middle S (lower
border of the
nose)

Wits Appraisal 1975
• ANB chabnges In cases of:
1- vertical position of N point
2- Antroposterior position of N point
3- Long or short face (LAFH)
4- Jaw rotations
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Wits Appraisal 1975
• Due to ANB
• Normal: -1 mm Males (AO is behind BO
& zero mm in Females (AO and BO coincide)
• Class 2: AO ahead of BO
• Class 3: BO ahead of AO
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Wits Appraisal 1975
• Due to ANB
• Normal: -1 mm Males (AO is behind BO
& zero mm in Females (AO and BO coincide)
• Class 2: AO ahead of BO
• Class 3: BO ahead of AO
• Drawbacks to Wits analysis:
1- Left and Right molar outlines may not always coincide
2- Occlusal plane may differ in mixed vs permanent dentition
3- If curve of Spee is deep then it may be difficult to create a straight
occlusal plane
4- Angulation of functional occlusal plane to pterygomaxillary vertical
plane was shown to decrease from age 4 to 24
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Holdaway Analysis 1984
• (LI-NB/Pg-NB)
• Evaluate the relative prominence of the
mandibular incisors, as compared to the size
of the bony chin.
• 2mm=acceptable
• 3mm=less desirable
• 4mm=correction indicated
• extraction or genioplasty
• If extraction is indicated thick lips move half
the value of teeth (50:100) , while thin lips
move the same value as teeth (100:100)
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• (LI-NB/Pg-NB)
• Evaluate the relative prominence of the
mandibular incisors, as compared to the size of
the bony chin.
• H line: tangent to the chin and upper lip
• H angle made between H line and line joining N’-
pog’ .
• According t haldawy the ideal face should have H-
angle from 7-15 degrees .
• Skeletal convexity at a point is measured for
N’-pog’ line to point A .
• Average value +2 to -2 , assessing facial skeletal
convexity in relation to lip positionDr Omar Yousry BDS MSc Orthodontics CU,
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1. Facial Angle: N’ Pog’ / FH (90
degree)
>90 degree: mandible too protrusive <90 degree:
recessive lower jaw
2. Upper lip curvature: Depth of sulcus from a line
drawn perpendicular to FH & tangent to tip of
upper lip (2.5mm)
Lack of upper lip curvature – lip strain Excessive
depths could be caused by lip redundancy or jaw
overclosure

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3. Skeletal convexity at point A
(-2to 2mm)
Measured from point A to N’-Pog’ line
4. H-Line Angle (7-15 degree)
Formed between H-line & N’-Pog’ line
Measures either degree of upper lip prominence or
amount of retrognathism of soft tissue chin
If skeletal convexity & H-line angles don’t
approximate, facial imbalance may be evident

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5. Nose tip to H-line (12mm maximum)
Measurement should not exceed 12mm in
individuals 14 yrs of age
6. Upper sulcus depth (5mm)
Short/thin lips - Longer/thicker lips-

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7.Upper lip thickness (15mm)
Measured horizontally from a point on outer
alveolar plate 2mm below point A to outer border
of upper lip
8. Upper lip strain
Measured from vermillion border of upper lip to
labial surface of maxillary CI
Measurement should be approx same as the upper
lip thickness (within 1mm)

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9. Lower lip to H- line (0mm)
Measured from the most prominent outline of the
lower lip to the H line
10. Soft tissue-chin thickness (10-12mm)
Measured as distance between bony & soft tissue
facial planes
In fleshy chins, lower incisors may be permitted to
stay in a more prominent position.

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Sassouni 1955
• in a well-proportioned face: 5
Horizontal planes will project
toward a common meeting point
(posterior to the occipital contour
‘O’)
• "skeletal open bite." : maxilla is
rotated downward posteriorly and
the mandible rotated downward
Anteriorly.
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Sassouni 1955
• Using O as the center, Sassouni constructed
the following two arcs:
Anterior arc: It is the arc of a circle, between
anterior cranial base and the mandibular
plane, with O as the centre and O-ANS as
radius.
Posterior arc: It is the arc of a circle, between
anterior cranial base and mandibular base
plane, with O as centre and OSp as radius ( Sp
the most posterior point on the rear margin of
sella turcica).
• Sassouni’s approach was popularized as
archial analysis.
• Class I: neutral, open bite and deep bite
• Class II: neutral, open bite and deep bite
• Class III: neutral, open bite and deep bite
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Sassouni 1955
• A well-proportioned face as defined by Sassouni is
expected to possess normal occlusion. To the
contrary, of 50 persons with normal occlusion
examined, only 16 were found to have a well-
proportioned face.
• Unfortunately, as a face becomes more
disproportionate, it is more and more difficult to
establish the center for the arc, and the
anteroposterior evaluation becomes more and more
arbitrary. (i.e increasing anterior-posterior
discrepancies the analysis becomes more arbitrary
and less reliable.)
• Although the total arcial analysis described by
Sassouni is no longer widely used, his analysis of
vertical facial proportions has become an integral
part of the overall analysis of a patient. In addition to
any other measurements that might be made, it is
valuable in any patient to analyze the divergence of
the horizontal planes and to examine whether one of
the planes is clearly disproportionate to the others.
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Harvold Analysis 1974
• "unit length" of the maxilla and
mandible.
The maxillary unit length: from TMJ, (the
posterior wall of the glenoid fossa) to lower
ANS (the point on the lower shadow of the
anterior nasal spine where the projecting
Spine is 3mm thick.)
The mandibular unit length: is measured
from the TMJ to the anterior point of the
chin. (TMJ to Prognathion)
indicates the size discrepancy between the
jaws.
NOT vertical distance of the jaws
NOT The position of the teeth
Lower face height: from upper ANS (the
similar point on the upper contour of the
spine where it is 3mm thick) to menton
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Tweed Analysis 1966
FH-MP > 25 vertical growing
FH-MP < 25 horizontal growing
FH-MP > 30 : extraction would be necessary*
Tweed stressed the importance of the FH-L1 angle recommending that it be
maintained at 65° to 70° (FH – MP : 16-35)Dr Omar Yousry BDS MSc Orthodontics CU,
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Use: Determining the best
position of the lower
incisors (stability
prognosis)
Three angles:
L1/MP 87 (85-95) ?
L1/FH 68 (65 - 70)
FH/MP (25) vary

Bjork Analysis 1966
7 signs of mandibular rotation (Bjork 1969):
1- condylar inclination
2- mandibular canal inclination
3- lower border (antigonial)
4- symphysis inclination
5- inter-incisal angle
6- inter-molar angle
7- lower facial height
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Bjork - Jarabak Analysis 1972
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Facial Polygon: Indicate Md
rotation (forward – back)
5 points: Nasion
Sella
Menton
Gonion
Articular
5 Angles:
1- Nasion Angle
2- Saddle or Cranial Base Angle
3- Articular Angle
4- Gonial Angle
5- Chin Angle
(Me-N -S )
( N-S -articulare )
( S- articular-Go)
(Articular - Go-Me) (upper gonial – lower
gonial)
( infradental –pog & pog- MandP )
1- S-N
2- S-Ar
3- Ar - Go
4- N - Me
5- S - Go
6- Go – Me

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1- S-N
2- S-Ar
3- Ar - Go
4- Go – Me
5- N - Me
6- S - Go

• Jarabak sum:
1. Saddle Angle - Na, S, Ar –
2. Articular Angle - S-Ar-Go, -
3. Gonial Angle - Ar-Go-Me.
Normal: 396 degrees
higher: clockwise rotation
lower: anticlockwise rotation
Jarabak ratio:
Posterior /anterior facial height
ratio:
S Go / N Me
62%
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Rickets Analysis 1960
CC= Center of cranium point of
intersection of the basion Nasion
plane and the facial axis.
DC= Point in the center of condylar
neck along the Ba- Na Plane
PM= Suprapogonion/ protrubrance
menti , The point at which the
symphysis mentalis changes from
convex to Concave
Ptv= point of intersection of the
distal outline of ptm fissure and
perpendicular to the F- Hplane.
Xi= Geometric center of the ramus
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Xi-point:
the geometric centre of the ramus.
Steps in the construction of the Xi-point:
• By construction of planes perpendicular to FH and
PTV. These constructed planes are tangent to points
(Rl, R2, R3, R4) on the borders of the ramus.
• The constructed planes form a rectangle enclosing
the ramus.
• Xi is located in the centre of the rectangle at the
intersection of diagonals.
R1.:The deepest point on the curve of the anterior
border of the ramus, one-half the distance between
the inferior and superior curves.
R2: A point located on the posterior border of the
ramus of the mandible.
R3.: A point located at the centre and most inferior
aspect of the sigmoid notch of the ramus of the
mandible.
R4: A point on the border of the mandible directly
inferior.
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• Condylar axis:
DC - Xi
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• Axis of the
corpus of the
mandible:
Xi - Pm
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1960:
Superficial Analysis:
1.Facial Angle –
2. Facial axis( x-y axis) –
3.Facial Convexity( A- Pog) –
4. Lower Incisor position and angulation. –
5. Upper Incisor position –
6. Esthetic Plane
Deep Structure Analysis:
1. Cranial Base Angle –
2. Cranial Base Length –
3. Condyle or Fossa position –
4. Condyle Axis –
5. Mandibular Plane Angle
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1981
Lateral Analysis:
1.Facial Axis –
2.Facial Angle –
3.Mandibular Plane Angle –
4.Mandibular arc( Mandibular Bend) –
5.Point A to Facial plane –
6.Palatal Plane to Frankfort horizotal plane –
7.Denture Height /lowerfacial height/ Oral Gnomom –
8.Lower incisor to Apog line(mm) and (Angulation) –
9.Upper Incisor to Apog(1960) –
10.Upper molar to Ptv –
11.Interincisal Angle –
12.Lower Lip to E Line
Frontal Analysis –
1. Nasal width -
2.Mandibular width –
3.Maxillary width –
4.Molar width –
5.Actual intermolar width –
6.Intercuspid width –
7.Denture Symmetry –
8. Upper to Lower Molar relation
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Mandibular arc (Mandibular Bend):
measures the angulation of the condylar
process to the body of the mandible.
It is the angle between the Condyle axis(Xi
through center of condyle neck) Posterior
extent of the corpus axis(pm to Xi)
Norm = 26º+/- 2º A total increase of 3º is seen
every 5 year
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Fronatal analysis: (PA)
1.Nasal cavity width
2.Mandibular width
3.Maxillary width
4.Symmetry
5.Intermolar width
6.Intercuspid width
7.Denture symmetry
8.Upper to lower molar relation
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McNamara Analysis 1984
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Reference
line:
N Perpendicular (on FH)
McNamara line
Skeletal NP - A (mm)
NP - Pog (mm)
Maxillary length (midfac)
Mandibular length
0 – 1
-8 /-4/ 0 /+2
Cd – A 85/94/100
Cd - Gn 105/120/130

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Reference
line:
McNamara line
NP - Pog (mm)
Mandibular length
lower ant. Facial height
Md plane angle MP/FH
Facial axis(PTM Gn/Ba N)
0 – 1
-8 /-4/ 0 /+2
Cd – A 85/94/100
Cd - Gn 105/120/130
ANS – Me 57/66/ 79
22
perpendicular

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Reference
line:
McNamara line
NP - Pog (mm)
Mandibular length
0 – 1
-8 /-4/ 0 /+2
Cd – A 85/94/100
Cd - Gn 105/120/130
ANS – Me 57/66/ 79
22
perpendicular
Dental U 1 – A
L1 – A Po
4 – 6 mm
1 – 3 mm

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Reference
line:
McNamara line
NP - Pog (mm)
Mandibular length
0 – 1
-8 /-4/ 0 /+2
Cd – A 85/94/100
Cd - Gn 105/120/130
ANS – Me 57/66/ 79
22
perpendicular
Dental U 1 – A
L1 – A Po
4 – 6 mm
1 – 3 mm
Soft
tissue
Nasolabial angle
cant of upper lip (NP)
102
14

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Reference
line:
McNamara line
Air way Upper pharynx diameter
lower pharynx diamater
Smallest distance from
Post. Pharyngeal wall
to ant. Half of soft
palate (17 mm)
Post Ph wall – tongue
(13 mm )

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Reference
line:
McNamara line
NP - Pog (mm)
Mandibular length
0 – 1
-8 /-4/ 0 /+2
Cd – A 85/94/100
Cd - Gn 105/120/130
ANS – Me 57/66/ 79
22
perpendicular
Dental U 1 – A
L1 – A Po
4 – 6 mm
1 – 3 mm
Soft
tissue
Nasolabial angle
cant of the upper lip
102
14
Air way Upper pharynx diameter
lower pharynx diamater
Post. Ph wall - soft
palate (17 mm)
Post Ph wall – tongue
(13 mm)

Enlow Counterpart analysis
Changes in proportions in one part of the head
and face can either add to increase a jaw
discrepancy or compensate so that the jaws fit
correctly even though there are skeletal
discrepancies
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Enlow Counterpart analysis
Changes in proportions in one part of the head and face can either add to
increase a jaw discrepancy or compensate so that the jaws fit correctly even
though there are skeletal discrepancies
If anterior face height is long, facial balance and proper proportions are
preserved if posterior face height and mandibular ramus height also are
relatively large.
Short posterior height can lead to a skeletal open bite tendency even if
anterior face height is normal because the proportionality is disturbed.
If the maxillae is long (6) , there is no problem if the mandible (7) also is long,
but malocclusion will result if the mandibular body length is merely normal.
If both maxillary and mandibular lengths are normal but the cranial base is
long, the maxilla will be carried forward relative to the mandible and
maxillary protrusion will result.
Similarly short maxilla will compensate perfectly for a long cranial base.
if maxilla rotated down posteriorly, a long ramus, acute gonial angle would
compensate and allow normal facial proportions and normal occlusion.
but even a slightly short ramus would produce downward-backward
mandibular rotation and a long face-open bite tendency.
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Template Analysis
• Quickly provides an overall impression of the way in which the patients dentofacial
structures are related.
• Types of Templates:
1. Schematic (michigan,burlington) : show changing positions of selected landmarks
with age on a single template
2. Anatomically complete (broadbent-bolton,alabama) : different one for each age
The first step in template analysis is to pick the correct template (developmental age -
SN distance the same)
Analysis using a template is based on: series of super impositions of the template,
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Template Analysis
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Registration Evaluate
1. Cranial base
superimposition:
registering SN at N maxilla and mandible to the
cranial base
2. Maxillary
superimposition:
maximum contour of the maxilla maxillary dentition to the
maxilla (V –AP)
3. Mandibular
superimposition:
mandibular canal or the
symphysis of mandible along the
lower border.
of mandibular dentition to
mandible

Template Analysis
• Cranial base super imposition
1. increase in the lower face height.
2. downward rotation of the mandible.
3. maxilla is rotated down posteriorly.
• Superimposition of the Bolton template on the
maxilla:
forward protrusion of the maxillary incisors but
shows that the vertical relationship of the
maxillary teeth to the maxilla for this patient is
nearly ideal.
• Superimposition of the Bolton template on the
mandible:
the patient's mandible is longer than the ideal,
but the ramus is shorter and inclined posteriorly.
All the mandibular teeth have erupted more than
normal, especially the incisors.
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Down Steiner
Reference
lines
FH plan (Po – Or)
facial plan (N – Pg)
MD plan (tangent – Me)
Occ plan (intercuspal )
Y – axis (S GN )
SN plan
MD plan (Go – Gn)
Y – axis (S Gn)
Skeletal Facial angle
cnvexity angle
Md plane
growth axis (Y)
AB angle
N Pg - FH
N - A- Pg
T. Me - FH
S Gn - FH
A B - N Pg
87
0
22
59
4.5
SNA
SNB
ANB
SN-OP
SN-MP (Go.Gn)
Y axis – SN
82
80
2
14 (inc. in OB)
32
Dental Occ. Cant
interincisal
L1 / Occ P
L1/ Md P
U1 to A-Pog
OP / FH
U1 / L1
9.3
135
14.5
1.4
2.7
U1 – NA (angle)
U1 – NA (mm)
L1 – NB (angle)
L1 – NB (mm)
U1 – L1 (angle)
NB – Pog (mm)
22⁰
4 mm
25⁰
4 mm
135
4 mm
Soft tissue S line
(both lips touch)
Soft Tissue
Pogonion - middle
S (lower border of
the nose)

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Rickets McNamara
Reference
lines
CC, CF, DC,C1, Pm, Pt, PTV, Xi,
Dt, En, UL, LL, ,A1, Ar, B1, Br
facial axis: Pt – Gn
facial plan: N – Pog
mandibular axis (DC – Xi – Pm)
McNamara line
Skeletal Facial axis
facial depth
Md plane
lower facial ht
Md arc
A point convex
Ba-N/Pt-Gn
FH / N Pog
FH / Go-Gn
ANS-Xi-Pm
DC- Xi – Pm
A - N Pog
90
87
26
45
26
2 m
NP - A (mm)
NP - Pog (mm)
Maxillary length(Cd – A )
Mandibular length(Cd - Gn)
L ant. Fac. Ht.(ANS – Me )
Md plane angle (MP/FH)
0 – 1
-8 /-4/ 0 /+2
85/94/100
105/120/130
57/66/ 79
22
perpend.
Dental L1 / A Pog
L1 – A Pog
U 6 – PTV
Interincisal
Mx. depth
Angle
mm
Age + 3 (21)
U1 / L1
FH / N – A
22
1 m
24,12
130
90
U 1 – A
L1 – A Po
4 – 6 mm
1 – 3 mm
Soft tissue E line: tangent chin and nose Nasolabial angle
cant of the upper lip
102
14
Frontal PA analysis:
width, symmetry, U&L molars
Airway analysis:
Upper / lower pharynx diameter
Pharyngeal wall to (soft palate, tongue)

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Wits Holdaway Harvold Tweed Bjork – Jarabak Sassouni
Ao- Bo
points
on occlusal
plan
Ratio:
(LI-NB/Pg-NB)
4 mm
H line
H angle
(N’ – Pog’)
"unit
length" of
the maxilla
and
mandible.
Triangle
(stability
prognosis
Three
angles:
Facial
polygon
7 signs
5 points
5 angles
6 linear
5 planes:
SN/FH/
MxP/OP/MdP
meet at “O”
“Sk. Open bite”
Male: -1
female : 0
N’ – Pog’ :
with FH
to A point
.
Upper lip:
curve
depth
thickness
strain
.
lower lip:
to H line
depth
chin thick
.
Nose to H line
TMJ (Post.
Glenoid) -
lower ANS
(3mm)
TMJ to
Prognathion
Lower face
height:
upper ANS
to menton
L1/MP:
87
L1/FH
68
FH/MP
(25)
Jarabak sum:
1. Saddle Angle
2. Articular
3. Gonial Angle
396 degrees
Jarabak ratio:
Posterior
/anterior facial
height ratio:
S Go / N Me
62%
archial analysis:
Ant arch:
O - ANS
Post arch:
O - post S
I,II,III:
neutral,
open bite or
deep bite

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counterpart Template
Changes in proportions in one part of
the head and face can either add to
increase a jaw discrepancy or
compensate so that the jaws fit
correctly even though there are
skeletal discrepancies
Quickly provides an overall impression of the way
in which the patients dentofacial structures are
related.
Types of Templates:
1. Schematic (michigan,burlington) : show
changing positions of selected landmarks with age
on a single template
2. Anatomically complete (broadbent-
bolton,alabama) : different one for each age
The first step in template analysis is to pick the
correct template (developmental age - SN
distance the same)
Analysis using a template is based on: series of
super impositions of the template,

Analyses
• McNamara: useful in orthognathic planning, 'A' point should be on nasion perpendicular and Pog just
behind it
• Eastman (Mills, 1970): 'Eastman correction' can be applied if SNA is high/low and SN/MxP is normal (5-11)
This corrects for an aberrant position of nasion assuming sella is correct.
Calculation is:
(measured SNA - average SNA) / 2 = X
measured ANB ±X= Eastman corrected ANB
X is added where the measured SNA is lower than average and subtracted where measured SNA in higher,
e.g. in a case where measured SNA = 88° (normal = 82°)
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Analyses
How to asses skeletal relation antereo-posterior?
How to asses vertical skeletal relation?
Clinically – radiographically (two methods)
What point? Plane? Superimpose? Measure >> indicate what?
Eastman correction ???? Wits, effective length, cranial base angle, ..
Standardisation of Ceph – NHP,CO -
Importance of (aluminum wedge – ruler – chain - ..)
Errors and how to avoid
Dose ? Indications ? When to order CBCT
CVMS ???? Other methods,
ST analysis. NLA, LbMe, S line, H line, E line, ..
Importance of incisor inclination, interincisal angle, edge centroid, Holdaway, ..
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Simple Analysis
Skeletal (A –P) Skeletal (V) Dental Soft tissue Airway
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Skeletal (A –P) Skeletal (V) Dental Soft tissue Airway
N Pog – FH
N – A / A- Pog
FH - (Tan.Me)
S GN / FH
OP/FH U1/L1
U1 - APog
L1/ OP L1/MP
S line U PH diameter
L PH diameter
SNA, SNB,ANB SN – (Go.Gn)
S Gn / SN
U1 – NA U1/NA
L1- Nb L1 /NB
E line McNamara
A N Pog FH / (Go.Gn)
ANS. Xi. Pm
DC. Xi.Pm
NLb
Lb cant
NP – A
NP - Pog
Cd – A
Dd - Gn
PTM – Gn/ Ba N
ANS – Me
HOLDAWAY PA Frontal:
RICKETS
Ao – Bo (wits) PFH / AFH
TMJ – L. ANS
TMJ - Me
Saddle + artic +
gonial = 396
Tweed
Ant Arch:
ANS,N,Pog,
5 planes
meet at Occip.
Holdaway
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Simple Analysis
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Lateral Cephalometry Questions
What changes could occur to ANB if long face patient?
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SN plan refrence
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Fun occlusal plan
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H line
S line
E line
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Airway analysis
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PA analysis
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Sassouni
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Template
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Counter part
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Stability prognosis
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High angle , retroclined lower incisors
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Disadvantages of wits
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Disadvantages of FH
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Valid point
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Mx length
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A-P skeletal
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Mandibular plane angle evaluation in Down or Steiner analysis
Down: FH – MP (Tangent – Me)
Steiner: SN – MP (Go-Gn)
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Superimposition
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Superimposition
ArtificialMANDIBULAR
STABLE STRUCTURES
MAXILLARY STABLE
STRUCTURES
CRANIAL BASE
STABLE STRUCTURES
implants
(vitalium I tantalum)
• follicle of 3rd molar
prior to root
development
• inner border of
symphysis
• inferior dental
canal
• anterior chin point
• any distinct bony
trabeculae in
symphysis
often ANS to PNS
with best fit to
palatal vault
• key ridges
(zygomatic process
of maxilla)
• superior and
inferior surfaces of
posterior hard palate
• Sella-Nasion line
• DeCosters line
(after age of 7)
• Anterior wall
sella turcica
• greater wings of
sphenoid
• cribriform plate of
ethmoid
• orbital roof
• inner surface of
frontal bone
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Limitations
(Housten et al.,1986)
Measurements
errors
Landmark
Identification
Errors
Projection
Errors
General
Individual variationsEnvelope of error:
N, Pog, A, B >> horiz.
ANS, Me >> vertical
• Magnification
• Distortion
• NHP & CO
• 2 D for 3D
• R & left
superimposition
• Many invalid
landmarks
• Different analyses
with diff.
conclusions
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Limitations
(Housten et al.,1986)
Reducing errors:
1- careful selection of analysis
2- Clear understanding of point definition
3- Good quality film and standardisation
4- Duplicate measurements
5- Error calculation
6- Care when interpreting results
7- Automated computerised R/Gic identification of landmarks
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Problem List
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lateral Cephalometry

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