Guide to Postero-Anterior Cephalometric Analysis Techniques

POSTERO-ANTERO CEPHALOMETRIC
ANALYSIS
www.indiandentalacademy.com

CONTENTS
 INTRODUCTION
 METHOD OF ANALYSES:
RICKETTES ANALYSIS
HEWITT ANALYSIS
SVANHOLT & SOLOW ANALYSIS
GRAYSON ANALYSIS
CHIERICI ANALYSIS
GRUMMON’S ANALYSIS
 CONCLUSION
 BIBLIOGRAPHY

INTRODUCTION
Malocclusions and dentofacial deformities constitute
three-dimensional conditions or pathologies. Orthodontic
patients requires comprehensive three- dimensional
diagnostic examination.
The assessment of postero-anterior and basilar
cephalometric views are particularly important for dento-
alveolar and facial asymmetries; dental and skeletal
crossbites and functional mandibular displacements

A postero anterior cephalogram can be
analysed so that the vertical, transverse, and
sagittal dimensions can be evaluated .Vertical
asymmetry can be observed readily in a postero
anterior cephalogram by connecting bilateral
structures or landmarks, by drawing the
transverse planes, and by observing their
relative orientation

METHODS OF
ANALYSES

1. RICKETTES ANALYSIS (1972)
2. HEWITT ANALYSIS (1975)
3. SVANHOLT & SOLOW ANALYSIS (1977)
4. GRAYSON ANALYSIS (1983)
5. CHIERICI ANALYSIS (1983)
6. GRUMMON’S ANALYSIS (1987)

RICKETT’S ANALYSIS
 Given by:Robert M. Ricketts., Ruel W. Bench, James J.
Hilgers,and Robert Schulhof in1972
 The frontal & lateral films should be correlated together
to evaluate the patient three- dimensionally.
 According to them, in order to provide a better method of
communication, a new classification system for each
parameter was devised.
 The normal value represented by the mean & the amount
of variation around that mean was established which was
acceptable from a clinical point of view :

 Nasal cavity width -
measured from NC to NC
 Mandibular width -
measured
Ag to Ag (at eminence
above notch);

 Maxillary width - two frontal
lines, left and
right, are constructed from
the medial margins of the
zygomaticofrontal sutures to
Ag points,and the maxillarv
width is evaluated on left
and right sides separately by
relating J point or point
jugale (defined as the
crossing of the outline of the
tuberosity with that of the
jugal process) to these lines.
In this way the maxillary
width is evaluated in relation
to the mandible;

 Symmetry - a midsagittal
plane is constructed by
dropping a line through
the top of the nasal
septum or crista galli,
perpendicular to the line
connecting the centres of
the zygomatic arches.
 Asymmetry is evaluated
by relating point ANS and
pogonion to this
midsagittal plane;

 Intermolar width -
measured from the buccal
surface of the first
permanent molars
transversely;
 Intercuspid width - the
width between the tips of
the lower cuspids;

 Denture symmetry - the
midpoints of the upper
and lower central incisor
roots are related to the
midsagittal plane;
 Upper to lower molar
relation - the differences
in width between the
upper and lower molars.
 The measurement is
made at the most
prominent buccal contour
of each tooth.

 FIELD I :The denture problem (Occlusal Relation)
Factor Measured
value (mm)
Clinical
norm (mm)
Clinical
deviations
from norm
Molar
relation Left
0 1.5 -1.0
Molar
relation
Right
-0.5 1.5 -1.3
Intermolar
width
54.8 54.5 .2
Intercanine
width
22.7 23.9 -0.4
Denture
midline
.5 0 .3

 FIELD II:The Skeletal problem (Maxillo-Mandibular
Relation)
Factor Measured
value
Clinical
norm
Clinical
deviations
from norm
Max-Mand
width Left
-10.7 mm -10.8 mm .0
Max-Mand
width right
-11.4 mm -10.8 mm -0.2
Max-Mand
midline
.7 deg 0 deg .3

 FIELD III: Denture to Skeleton
Factor Measured
value
(mm)
Clinical
norm
(mm)
Clinical
deviations
from norm
Molar to
Jaw Left
5.6 6.2 -0.3
Molar to
Jaw Right
6.2 6.2 -0.0
Denture
Jaw
midline
.5 0 .3
Occlusal
Plane Tilt
-0.7 0 -0.4

 FIELD V: The Determination Problem (Craniofacial
Relation)
Factor Measured
value
Clinical
norm
Clinical
deviations
from norm
Postural
Symmetry
1.1 deg 0 deg .5

 FIELD VI: The Internal Structure Problem (Deep
Structure)
Factor Measured
value
Clinical
norm
Clinical
deviations
from norm
Nasal Width 24.6 mm 24.9 mm -0.2
Nasal
Proportion
53.7 deg 59.0 deg -1.2
Maxilla
Proportion
99.6 deg 103.1 deg -0.7
Mandible
Proportion
87.2 deg 88.6 deg -0.4
Facial
Proportion
95.1 deg 97.5 deg -0.8

HEWITT ANALYSIS
 Given by:A.B.Hewitt in 1975
 The facial complex consists of numerous constituent
parts it is therefore the degree of harmony between the
parts which determines the symmetry of the whole.
 This study was devised to establish a method for the
analysis of overall facial symmetry in terms of its
component, each of which is capable of individual
variations between the right and left sides.

Method:
 63 cephalometric PA radiograph of normal children
 Age range: 9 to 18 years with a mean of 14 years.
 20 males, 43 females.
 No child with a degree of clinically evident or
unacceptable facial asymmetry or gross deviation of
dental occlusion was included.
 Facial disharmony may be expressed as variation in
shape or of size.
 Deviations in the shape of the face may be assist by
determining the angle of divergence of two facial axis
that is the anatomical axis of the middle and lower
third of the face.www.indiandentalacademy.com

 A line was drawn between
the following points to
form an axis X which
represents the middle
third of the face:
1. Sella
2.Bisector of line joining the
medial extent of orbits.
3.Bisector of line joining the
right and left orbitale.

4. Bisector of line joining the
right and left mastoidale.
5. Anterior nasal spine.
6. Bisector of line joining
bilateral zygomatic
points.
7. Bisector of lines joining
right and left molar
points.

 The following points were
joined by a line to form an
axis N which represents
the lower third of the face:
condylar points.
2. Menton.
bilateral gonial points.

 The angle of divergence
of the axes is
proportional to the
degree of asymmetry
between the middle and
lower third of the face.
 The angle between the
two axis can be bisected
to give the arbitary
anatomical axis of the
face.
 In order to assist the
relative asymmetry of
the component areas of
the facial complex, a
method of triangulation
was used.

 Triangles are drawn on
both sides of the tracing:
1. Triangle A: between the
extreme superior extent
of the head of condyle,
exteme mesial extent of
the head of the condyle
and sella to represent
the cranial base region.
2. Triangle B: between
sella, mastoidale and the
root of zygoma
representing the lateral
maxillary regions.

3. Triangle C: joining sella,
anterior nasal spine and
the root of zygoma
representing the upper
maxillary region.
4.Triangle D: drawn
between the root of the
zygoma, upper molar
points and the anterior
nasal spine representing
the right and left middle
maxillary region.

5. Triangle E: joining ANS,
upper molar points and
the point of intersection
of a line drawn between
the bilateral upper molar
points and the arbitary
anatomical axis
representing the right
and left lower maxillary
region.

6.Triangle F: drawn between
upper molar points,
upper incisal points and
the point of intersection
of a line joining the
upper molar points and
the anatomical axis,
representing the right
and left dental regions.
7.Triangle G: drawn
between the condylar
points, gonion and
menton to represent the
mandibular component
of the face.

 Conclusion:
He concluded that the
cranial base regions and
the maxillary regions
exhibit an overall
asymmetry with a larger
side being the left where
as the mandibular and
dentoalveolar regions
exhibit a greater degree of
symmetry.

SVANHOLT & SOLOW ANALYSIS
 Given by: SVANHOLT.P & SOLOW.B in 1977
 Aim: To analyse one aspect of transverse
craniofacial development, namely the relationships
between the midlines of the jaws and the dental arches

 Lo- latero orbitale- the
intersection of the lateral
orbital contour with the
innominate line
 ORP- orientation plane
 Om- orbital midpoint- the
projection on the line lo-lo
of the top of the nasal
septum at the base of the
crista galli

 Mx- maxillare- the
intersection of the lateral
contour of the maxillary
alveolar process and the
lower contour of the
maxillozygomatic process
of the maxilla
 M- mandibular midpoint-
located by projecting the
mental spine on the lower
mandibular border,
perpendicular to the line
Ag-Ag

 CPL-compensation
line
 MXP-maxillary plane
 Iif- incision inferior
frontale- the midpoint
between the
mandibular central
incisors at the level of
the incisal edges

 MLP-mandibular
plane
 Isf- incision superior
frontale- the midpoint
between the maxillary
central incisors at the
level of incisal edges

1. Transverse maxillary
position - mx-om/ORP;
2. Transverse mandibular
position - m-om/ORP;
3. Transverse jaw
relationship - CPL/MXP;

4. Upper incisal position -
isf-mx/MXP;
5. Lower incisal position —
iif-m/MLP;
6. Upper incisal
compensation - isf-
mx/m;
7. Lower incisal
compensation - iif-m/mx.

 Dentoalveolar compensations will move the midpoint of
the dental arch away from the symmetry line within one
jaw towards the compensation line CPL.
 If the dental arch midpoint reaches the compensation
line, the compensation is complete.
 If the midpoint of the dental arch does not reach the
compensation line,there is incomplete dentoalveolar
compensation.
 Displacements of the midpoints of the dental arch in a
direction opposite to the direction from the jaw symmetry
line to the compensation line are called Dysplastic

GRAYSON ANALYSIS
 Given by:Barry H. Grayson,, Joseph G. McCarthy,, and
Fred Bookstein in 1983
 It’s a three-dimensional, multiplane cephalometric
analysis
 This analysis permits the visualization of skeletal
midlines at selected depths of the craniofacial complex.
 This localizes craniofacial asymmetry in the
posteroanterior and basilar views.

 Three separate acetate
tracings are made on the
same radiograph,
corresponding to
structures of the lateral
view in or near the three
planes

 A- orbital rims are
outlined
 B- pyriform aperture
 C-maxillary and
mandibular incisors
 D- midpoint of the
symphysis.
 This represents the
anatomy of the most
superficial aspects of
the face as transected
by line A
First tracing

 A- greater and lesser
wings of the sphenoid
 B- most lateral cross
section of the zygomatic
arch
 C-coronoid process
 D- maxillary and
mandibular first
permanent molars
Second tracing

 E- body of the mandible
 F- mental foramina .
 These structures, all
located on or near plane
B , represent a deeper
coronal plane.
Second tracing

 A- upper surface of the
petrous portion of the
temporal bone
 B- mandibular condyles
with the outer border of
the ramus down to the
gonial angle
 C- mastoid processes
with the arch of temporal
and parietal bones
connecting them .
Third tracing

 In the A plane (the
pyriform aperture, orbits,
and incisors), the centrum
of each orbit is located ,
and the point Mce halfway
between them is
identified.
 The most lateral point on
the perimeter of each
pyriform aperture is
marked, and the point Mp
halfway between them is
marked.

 The midpoint Mi, between
the maxillary and the
mandibular central
incisors, and the gnathion
Mg are identified.
 To view the midline ,
straight lines are
constructed connecting
Mce with Mp, Mp with Mi,
and Mi with Mg. This
results in a segmented
construct whose angles
express the asymmetry of
the structures of this
plane.

 A midline is constructed
for the B plane (the
sphenoid, zygomatic arch
etc.).
 Intersection of the
shadows of the greater
and lesser wings of
the sphenoid, are
identified, and their
bisector Msi is recorded
 Midpoints Mz for the
centre of the zygomatic
arches

 Mc for the tips of the
coronoid processes
 Mx for maxillare on the
left and right zygomas
 Mf for the left and right
mental foramina.
 Vertical line segments are
constructed to link these
points

 In plane C
 Md- heads of the
condyles
 Mm-innermost inferior
points on the mastoid
processes
 Mgo- gonions
 This yield bisecting points
 Segments Md – Mm, Mm
– Mgo

 If the midline constructs of
A, B, and C planes are
superimposed on the
posteroanterior tracing,
one can observe a
phenomenon we call
warping within the
craniofacial skeleton
 The midline constructs
deviate progressively
laterally as one passes
from plane C, through
plane B, to plane A toward
the anterior of the face to
the P-A composite.

 Three horizontal
planes of the face
were drawn
 In the basilar-view
planes, key triangles
are constructed A, B,
and C, each of which
may be referred to
this primary
(posterior) midsagittal
plane.

 Superpositioning of the
triangles clearly
demonstrated the
warping of the
craniofacial complex
 The craniofacial
skeleton is most
severely deviated from
the midsagittal plane at
the level of the
mandible; the severity
of asymmetry
decreased in a cephalic
direction.

The study of structures in various coronal
and transverse planes makes it possible to
measure and record the three-dimensional
relationship of anatomic structures to one
another.

 Given by: Chierici G in 1983
This method focuses on the
examination of the
asymmetry in the upper face
 A line connecting the lateral
extent of the
zygomaticofrontal sutures
on each side (line zmf-zmf)
is constructed
 Line X is drawn through the
root of the crista galli
perpendicular to zmf-zmf
Line
line X

 Examination of the
different structures &
landmarks on both right
& left sides on the same
plane & the deviation of
the midline structures
can identify asymmetry

GRUMMON’S ANALYSIS
 Given by:Duane C. Grummons, & Martin A. Kappeyne
Van De Coppello in 1987
 Since the advent of cephalometric radiography,
orthodontists have focused on the lateral x-ray as
their primary source of patient skeletal and dentoalveolar
data.
 However, the frontal (PA) and basilar views also contain
valuable information for diagnosis and treatment planning
procedures.
 Various dental and skeletal widths and skeletal
asymmetries that are not available from the lateral
cephalogram can be quantified from a frontal radiograph

 Such frontal and asymmetry information is vitally
important in:
1. Orthodontic surgery planning
2. Differential tooth eruption with segmental TMJ splint
therapy
3. Functional jaw orthopedics including three dimensional
improvements in facial or dental proportions or symmetry.
Limitations of Previous Analyses:
 Angular measurements and ratios are absent from
previous frontal analyses.
 Nor do they measure mandibular morphology, which can
be seen clinically to play the major role in asymmetries.

 A new PA analysis has been developed to provide
clinically relevant information about specific locations and
amounts of facial asymmetry.
 There are two forms of this Grummons analysis—
Comprehensive frontal asymmetry analysis
Summary frontal asymmetry analysis
 Parameters :
1. Horizontal planes
2. Mandibular morphology
3. Volumetric comparison
4. Maxillomandibular comparison of asymmetry
5. Linear asymmetry assesment
6. Maxillomandibular relation
7. Frontal vertical proportions

 Four planes are
drawn to show the
degree of parallelism
and symmetry of the
facial structures
 First plane connect
the medial aspects of
the zygomatic frontal
sutures (Z-Z)

 Second plane
connects the centers
of the zygomatic
arches (ZA)
 Third plane connects
the medial aspects of
the jugal processes
(J).
 Fourth plane is drawn
at menton parallel to
the Z plane.

 MSR has been
selected as a key
reference line
because it closely
follows the visual
plane formed by
subnasale and the
midpoints between
the eyes and
eyebrows.
MSR

 MSR normally runs
vertically from Cg through
ANS to the chin area, and
nearly perpendicular to
the Z plane.
 The relation of MSR to the
center of the cervical
vertebrae can alert the
clinician to possible head
rotation when the PA
headfilm was taken.

 Construction of MSR may
have to be modified if the
patient has anatomic
variations
 If the location of Cg is in
question, an alternative
method of drawing MSR
is to draw a line from the
midpoint of the Z plane
through ANS.
 If there is upper facial
asymmetry, MSR can be
drawn as a line from the
midpoint of the Z plane
through the midpoint of an
Fr-Fr line.

 Left and right triangles are
formed from the heads of
the condylar processes or
the condyles (Co),the
antegonial notches (Ag),
and menton. These are
split by the ANS-Me line
and compared
 ANS-Me parallels the
visual dividing line from
subnasale to soft tissue
menton in the lower face.

 Two "volumes"
(polygons) are
calculated from the area
defined by each Co-Ag-
Me and the intersection
with a perpendicular
from Co to MSR
 Superimposition of both
the polygons done to
know the asymmetry

 Perpendiculars are drawn
to MSR from J and Ag,
and connecting lines from
Cg to J and Ag
 This produces two pairs of
triangles, each pair
bisected by MSR.
 If perfect symmetry is
present, the four triangles
become two, J-Cg-J and
Ag-Cg-Ag.

 The vertical offset as well
as the linear distance is
measured from MSR to
Co, NC, J, Ag, and Me
 Difference between the
left and right values will
indicate asymmetry

 To allow tracing of the
functional posterior
occlusal plane, an .014"
wire is placed across the
mesio-occlusal areas of
the maxillary first molars.
 The wire should extend
about 3mm buccally to
make it easy to recognize
on the headfilm

 Distances are
measured from the
buccal cusps of the
upper first molars (on
the occlusal plane)
along the J
perpendiculars.

 The Ag plane, MSR, and
the ANS-Me plane are
also drawn to depict the
dental compensations for
any skeletal asymmetries
in the horizontal or vertical
planes
(maxillomandibular
imbalance)

 Midline asymmetries
of the upper and lower
incisors and Me-MSR
are also provided

 Skeletal and dental
measurements are made
along the Cg-Me line with
divisions at ANS, A1, and
B1 . The following ratios
are calculated
1. Upper facial ratio— Cg-
ANS/Cg-Me
2. Lower facial ratio—
ANS-Me/Cg-Me
3. Maxillary ratio— ANS-
A1/ANS-Me

4. Total maxillary ratio—
ANS-A1/Cg-Me
5. Mandibular ratio— B1-
Me/ANS-Me
6. Total mandibular ratio—
B1-Me/Cg-Me
7. Maxillo-mandibular
ratio— ANS-A1/B1-Me

 The comprehensive fontal asymmetry analysis
consists of all the data described & three tracings.
 The horizontal planes, mandibular morphology, and
maxillo-mandibular comparisons have been combined
to produce the Summary Facial Asymmetry Analysis
 Conclusion: They concluded that head rotation and
improper construction of MSR can reduce the
effectiveness of this analysis
 This analysis is intended to provide a practical,
functional method of determining the locations
and amounts of facial asymmetry. It is of greatest
clinical value when integrated with data from lateral
and submental vertex radiograph.

Many articles & analyses have been published
on normative data related to the facial structures that
have been studied by means of lateral cephalograms.
However, publications describing the use of
posteroanterior cephalometric radiography are
relatively few.
In recent years there has been a growing demand for
extended roentgenocephalometric control material as a
result of the refinements in syndrome identification &
the advances in the treatment of craniofacial
anomalies
All the existing cephalometric data are of value for the
diagnosis of various types of craniofacial anomalies &
for monitoring growth of persons or groups of
corresponding age & race.

BIBLIOGRAPHY
 Athanasios E Athanasiou and Aart JW Van der Meij:
Orthodontic Cephalometry , Mosby-Wolfe
Publications,1997 ,3rd edn. , 162-172.
 Robert M. Ricketts, Rue W. Bench, James J. Hilgers,
Robert Schulhof, An overview of Computerized
Cephalometrics. Am J Orthod 61:1-28
 Grummons Dc, Kappeyne van de Coppello MA. A
Frontal asymmetry analysis. J Clin Orthod 21:448-65
 Grayson BH, McCarthy JG, Bookstein F. Analysis of
craniofacial asymmetry by multiplane cephalometry.
Am J Orthod 84: 217-24
 Hewitt Ab. A Radiographic study of facial asymmetry .
Br J Orthod 21: 37-40

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