Cephalometry (2)

CONTENTS
• Title
• Introduction
• History
• Radiographic films
• Cephalostat
• Tracing technique
• Anatomic landmarks
• Analyses
• Limitations
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INTRODUCTION
• Supplemental diagnostic aid
• Abstracting human head into geometric
shape
• Prediction of size, growth pattern,
morphology

DEFINITION
Cephalometrics includes the
measurement, description, and
appraisal of morphological
congifuration and growth
changes in the skull. (Moyers)
1953

HISTORY
• Dürer first analyzed the human face.
• Pacini & Carrera.(1922)-first X-ray
pictures of skull in standard lateral view
• Hofrath & Broadbent- standardized
methods for production of
cephalometric radiographs (1931).

RADIOGRAPHIC FILMS
• Basically screen films
• ↓ Exposure
• ↓ Sharpness
• Green films
• Flourescent phosphorescent crystals

DOSIMETRY
Lateral
cephalogram
Kvp = 60 Kw
mA = 25-40 ma
Posterio Anterior
Kvp = 60 Kw
mA = 60 ma

CONVENTIONS
• The lateral projection
• The postero-anterior projection
• The oblique projection

CEPHALOSTAT
• Head holder or cephalometer
• Broadbent principle
• Frankfurt plane parallel to floor
• Mid sagittal plane parallel to cassette

CEPHALOSTAT

CEPHALOSTAT
• components:
• X - Ray source
• Adjustable cephalostat
• Film cassette with intensifying
screen (8” x10”)
• Film casette holder

IMAGE FORMATION

LATERAL PROJECTION
152.4 cm 15 cm

POSTERO-ANTERIOR PROJECTION
152.4 cm 15 cm

TRACING TECHNIQUE

TRACING TECHNIQUE
• Lateral or P-A cephalograms
• acetate matted tracing paper [0.003” 8x10”]
• sharp 3 H drawing pencils
• protractor ,tooth symbol tracing template
• dental casts of teeth in occlusion
• viewbox
• sharpner eraser
• black cardboard sheet

LATERAL CEPHALOGRAM

ANATOMIC LANDMARKS
SE
FMN

ANATOMICAL LANDMARKS
Unilateral
Nasion Anterior nasal spine
Point A Superior prosthion
Incision superius Incision inferius
Infradentale Point B
Pogonion Gnathion
Menton Basion
Sella posterior nasal spine

ANATOMICAL LANDMARKS
Bilateral
Orbitale Gonion
Condylion Articulare
Porion
Pterygomaxillary fissure
Sphenoethmoidal point
Frontomaxillary nasal suture

FRONTAL BONE

NASION (N)
The most
anterior point
of the fronto
nasal suture in
the median
plane

FRONTOMAXILLARY NASAL SUTURE
The most superior
point of the suture
where the maxilla
articulates with the
frontal and nasal
bones.
(Robert E Moyers
1988)

GLABELLA (G)
The height of
curvature of bone
overlying the
frontal sinus

NASAL BONE

SPHENOID BONE

SELLA (S)
This is the point
representing the
midpoint of the
pitutory fossa
(Sella turcica). It is a
constructed point in
the median plane.

SELLA (S)

Pterygomaxillary fissure (Ptm)
A bilateral teardrop
shaped area of
radiolucency, the
anterior shadow of
which represents the
posterior surfaces of
the tuberosities of the
maxilla
(Robert E Moyers
1978)

OCCIPITAL BONE

BASION (Ba)
The median point of
the anterior margin of
the foramen magnum
can be located by
following the image of
the slope of the
anterior border of the
basilar part of the
occipital bone to its
posterior limit. (Coben)

Bolton point (Bo)
The highest point in
upward curvature of
the retrocondylar
fossa of the occipital
bone
(Broadbent 1931)

ZYGOMATIC BONE

Orbitale (Or)
The lowest point in
the inferior margin
of the orbit,
midpoint between
right and left
images (Arne
Bjork1947)

TEMPORAL BONE

Anatomical Porion (Po-a)
The superior point of
the external auditory
meatus(the superior
margin of the
temporomandibular
fossa, which lies at the
same level, may be
substituted in the
construction of
Frankfort horizontal)

Machine Porion (Po-m)
The top of the ear
rod shadows, the
external auditory
meatus (Robert E
Moyers 1973)

MAXILLA BONE

Point A (Subspinale)
The point at the
deepest midline
concavity on the
maxilla between
the anterior nasal
spine and
prosthion
(Downs 1948)

Prosthion (Pr)
The lowest and most
anterior point on the
alveolar portion of
the premaxila, in the
median plane,
between the upper
central incisors

Anterior nasal spine
(ANS or Spinal point)
This is the tip of
the bony
anterior nasal
spine, in the
medial plane. It
corresponds to
the
anthropometrical
point acanthion.

Key Ridge (KR)
The lowermost point
on the contour of
the shadow of the
anterior wall of the
infratemporal fossa.
(Viken Sassouni
1971)

Posterior nasal spine (PNS)
The intersection of
a continuation of the
anteror wall of the
pterygopalatine
fossa and the floor
of the nose, marking
the dorsal surface
of the maxilla at the
level of the nasal
floor.

MANDIBLE

Articulare (Ar)
The point of
intersection of the
images of the
posterior border of
the condylar process
of the mandible and
the inferior border
of the basilar part
of the occipital bone
(redefined by coben
after Bjork)

Point B
(sm-supramentale)
The point at the
deepest midline
concavity on the
mandibular
symphysis
between
infradentale and
pogonion(Downs
1948)

Condylion (cd)
The most
superior point
on the head of
the condylar
head.

Gnathion (Gn)
This is the most
anterior point on the
alveolar process, in
the median plane
between the
mandibular central
incisors.

Gonion (Go)
The constructed
point of
intersection of
the ramus plane
and the
mandibular plane

Infradentale (Id)
The highest and
most anterior point
on the alveolar
process, in the
median plane
between the
mandibular central
incisors

Menton (Me)
The most
inferior midline
point on the
mandibular
symphysis.

Pogonion (Pog)
The most
anterior point of
the bony chin in
the median plane.

Point D
A point at the
center of the
mass of the
symphysis(Cecil
C.Steiner 1959)

Point C
At the center of
the condyle
(Cecil C
Steiner1953).

POSTEROANTERIOR
PROJECTION

ANATOMIC LANDMARKS
Midline structures
• Crista galli
• Floor of the hypophyseal fossa
• Septal structures of the nose

ANATOMIC LANDMARKS
Bilateral structures
• Frontozygomatic sutures
• Zygomatic arch
• Mastoid processes
• Antegonion
• Foramina rotunda

Mastoid (ma)
The lowest point
of the mastoid
process

Frontozygomatic sutures
point at the medial
margin of the
zygomaticofrontal
suture

Zygomatic arch
Point at the most
lateral border of the
centre of the
zygomatic arch

Antegonion
The highest point in
the antegonial notch

Anterior Nasal Spine

Condylar

Coronoid

CEPHALOMETRIC
PLANES

CEPHALOMETRIC PLANES
SN
FRANKFURT PLANE
PALATAL PLANE
OCCLUSAL PLANE
MANDIBULAR
PLANE

CEPHALOMETRIC PLANES
Anterior
maxillary
line
Posterior
maxillary
line

CLASSIFICATION OF
ANALYSES
• Methodological classification
• Normative classification
• According to the area of analysis

METHODOLOGICAL CLASSIFICATION
1.Angular Analyses:
Dimensional analyses
Eg: Down’s analyses
Proportional analyses
Eg : Koski’s (1952)
Analyses to determine position
Eg: SNA & SNB

METHODOLOGICAL CLASSIFICATION
2. Linear analyses:
Orthogonal analyses
Eg: de Coster method
Dimensional linear analyses
Eg: length of mandibular base
Proportional linear analyses

NORMATIVE CLASSIFICATION
1. Mononormative classification
Arithmetical norms
Geometrical norms
2. Multinormative analyses
3. Correlative analyses

ACCORDING TO THE AREA OF ANALYSIS
1. Dento skeletal analyses
2. Soft tissue analyses
3. Functional analyses

STEINERS ANALYSIS

SKELETAL ANALYSIS
SN
A
B
SNA-82°
SNB-80°

SKELETAL ANALYSIS
SN
OCCLUSAL PLANE
MANDIBULAR
PLANE
Occlusal
Plane
14.5°
Mandibular
Plane
32°

DENTAL ANALYSIS
A
N Upper incisor
to NA
22° & 4mm

DENTAL ANALYSIS
A
B
N
Lower incisor
to
NB
25° & 4mm

DENTAL ANALYSIS
Inter incisal
Angle
131°

SOFT TISSUE ANALYSIS

American
white
American
black
Israeli Chinese
(Taiwan)
Japanese
SNA 82
SNB 80
ANB 2
Max 1-NA 4 mm
22
Mand 1-NB 4mm
22
Interincisal
angle 131
GoGn-Sn
32
Mand 1
-MP
93
Mand 1-FH
62
Y Axis 61 www.indiandentalacademy.com

TWEED ANALYSIS

TWEED ANALYSIS
FMPA-25°
IMPA-90°
FMIA-65°

WITS APPRAISAL

WITS APPRAISAL
BO ahead
1 mm
(normal)Func
Occ pl
A
B
BO
AO

McNAMARA ANALYSIS

McNAMARA ANALYSIS
FH
N
A
N to A┴
0±2mm

McNAMARA ANALYSIS
FH
N
N to Pog┴
0 to -4mm

McNAMARA ANALYSIS
FACIAL
AXIS ANGLE
Ba-N
Ptm-Gn
0°

McNAMARA ANALYSIS
Mandibular
plane angle
22+4

McNAMARA ANALYSIS
EFFECTIVE
MAXILLARY
LENGTH
93.6±3.2mm
MANDIBULAR
LENGTH
121.6±4.5mm
Co
A
Gn

McNAMARA ANALYSIS
Lower anterior
Face height
67.2±4.7mm
ANS
Me

McNAMARA ANALYSIS
1 to Point A
Distance
4mm
A

McNAMARA ANALYSIS
NASO LABIAL
ANGLE
90-110°
Co

McNAMARA ANALYSIS
Mand 1
to
Point APo
Distance
1-2mm
Co
A

RAKOSI JARABAK’S
ANALYSIS

RAKOSI JARABAK’S
ANALYSIS
Carried in 3 stages:
1. Analysis of facial skeletal
2. Analysis of maxillary & mandibular
base
3. Dento-alveolar analysis

Analysis of facial skeletal
SADDLE
ANGLE
123±5°
SN
Ar

ARTICULAR
ANGLE
143±6°
S
Ar
Go

GONIAL
ANGLE
128±7°Ar
Go
Me

Sum of posterior angles
• Saddle angle
• Articular angle
• Gonial angle
396±6°

U/GONIAL
ANGLE
52-55°Ar
Go
N

L/GONIAL
ANGLE
72-75°
Go
Me
N

Analysis of mandibular variation
MANDIBULAR
PLANE
ANGLE
32°
SN

RAKOSI JARABAK’S
ANALYSIS
Angle of
Inclination
85°
SN N’
Pal

RAKOSI JARABAK’S
ANALYSIS
Pn to
Occlusal plane
75°
SN
Pn
Occ pl

RAKOSI JARABAK’S
ANALYSIS
Pn to
Mandibular plane
65°

RAKOSI JARABAK’S
ANALYSIS
palatal plane
To
Occlusal plane
11°
Pal
Occ pl

RAKOSI JARABAK’S
ANALYSIS
Occlusal plane
To
MP
14°
MP
Occ pl

RAKOSI JARABAK’S
ANALYSIS
Y-axis angle
66°
S
Gn
P O

RAKOSI JARABAK’S
ANALYSIS
Inter incisal
angle
135°
Co

RAKOSI JARABAK’S
ANALYSIS
Max 1 to SN
102±2°Co
SN

RAKOSI JARABAK’S
ANALYSIS
Max 1
to
palatal palne
70±5°
Co
Pal

RAKOSI JARABAK’S
ANALYSIS
Mand 1
to
mandibular palne
90±3°
Co
Man pl

Bibliography
• Athanasiou:Orthodontic Cephalometry
• Rakosi: Atlas and Manual of
Cephalometric Radiography
• Moyers:text book of orthodontics
• McNamara:A method of cephalometric
evaluation :Am J Orthod 86:449-69
• Jacobson A: the witts appraisal of jaw
disharmony Am J Orthod 67:125-
138,1975

Cephalometry (2)

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