Ceph ricketts, tweed, margolis,bjork analysis

Ricketts, Tweed,
Margolis, Bjork and
Sassouni Analyses
www.indiandentalacademy.com

Introduction
The Art and Science of Cephalometrics is
not new. Ever since Camper investigated
prognathism craniometrically in 1791,
researchers are interested in the
ethnographic determination of facial
form and pattern.

Determining of the ideal facial form
and pattern and applying it to diagnose
and correct the deviations from normal
has been the ultimate goal of
Orthodontics.
In the same process many
orthodontists have tried to analyze the
facial form and pattern according to
their concepts and views.

We will be seeing about the significant
and important of such analyses, the
RICKETTS, TWEED, MARGOLIS, BJORK
and SASSOUNI analyses.
 A Cephalometric analysis is a
collection of numbers intended to
compress the information from a
cephalogram in to a usable form for
diagnosis, treatment planning &
assessment.

Therefore, cephalometric analysis
provides information about size and
shape of craniofacial components and
their relative position and orientation.
The aims of these analyses tend to vary;
ranging from studies on facial growth,
the location of malformation, studies to
assess the treatment response, etc.

Classification of Analyses
Cephalometric analysis can be
classified in different ways
 Methodological Classification
 Classification according to the area
of analysis
 Normative classification

Methodological classification
Based on the basic units of the
analysis they can be classified into:
 Angular Analysis – The basic units
are angle in degrees.
 Linear Analysis – The facial skeleton
is analysed by determining certain
linear dimensions.

 Angular analysis
 1. Dimensional Analysis: - the various
angles are considered in isolation and
then compared with average figures. E.g.
Down’s Analysis.
 2. Proportional Analysis: - is based on the
comparison of various angles to establish
significant relations between the separate
parts of the facial skeleton. E.g. Sassouni’s
Analysis.

 3. Analysis to determine position: -
analysis in which angular measurements
may also be used to determine position of
parts of facial skeleton are included under
this category. E.g. Steiner’s analysis.
 Disadvantages:
 The primary reference plane to which the
angles measured is assumed to be
constant.
 But this is rarely so.
 Angles are subject to change with Age,
Sex, & Ethnicity.www.indiandentalacademy.com

 Linear Analyses
 1. Orthogonal linear Analysis: - A
reference plane is established, with the
various reference points projected on it
perpendicularly, after which the difference
between the projections all measured.
Further subdivided into :
 A. Total Orthogonal Analysis : -
 Geometrical – De Coster Method.
 Arithmetical –Eg: Coben’s Analysiswww.indiandentalacademy.com

 B. Partial Orthogonal Analysis :- the
method differs from total orthogonal
analysis in that measurements are always
made in one plane only Eg: Willy’s
Analysis.
 C. Archial Analysis: - Here the reference
points are not projected perpendicularly
but by drawing arcs with the aid of
compasses. E.g. Sassouni’s Analysis.

 2. Dimensional linear Analyses :
Based on evaluation of certain linear
measurements, either direct or in projection
 Direct dimensional linear Analysis: gives
linear measurements as the distance bet
two points. Results are given in absolute
terms, so that age has to be taken in to
account.
 Projected Linear Dimensional Analysis:
determines the distances between certain
reference points that have been projected
on to a reference line.www.indiandentalacademy.com

Classification according
to area of analysis
 Dentoskeletal Analysis.
 Soft tissue Analysis.
 Functional Analysis.

Normative classification
 Analysis may be classified according
to the concept on which normal
values have been based.
 Mononormative Analysis: single norm is
used.
 Multinormative Analysis: a series of
norms including Age, Sex are used.
 Correlative Analysis: used to assess
individual variations of facial structure
to establish their mutual relationships.

Overview of the
classification
methodological
Angular linear
orthogonal
dimensional
Total
partial
Geometrical
arithmetical
Dimensional
Proportional
positional
Direct
projected

Classification acc to area
Dento skeletal Soft tissue Functional
Normative classification
mono multi Correlative

Ricketts Analysis

Ricketts Analysis
Robert Ricketts, one of
the pioneers of
Orthodontics has
contributed greatly to
the understanding of
clinical Cephalometrics.

Ricketts should be given a great deal of
credit for establishing the science of
Cephalometric growth forecasting and
Computerized cephalometrics.
Ricketts analysis is the forerunner to the
computerized cephalometrics.
Also known as Ricketts’ summary
descriptive analysis.

The mean measurements given are
those of a normal 9 year old child.
The growth dependent variables
are given a mean change value that
is to be expected and adjusted in
the analysis.

Landmarks
This is a 11- factor summary
analysis that employs specific
measurements to
Locate the chin in space.
Locate the maxilla through the
convexity of the face.
Locate the denture in the face.
Evaluate the profile.

This analysis employs somewhat less
traditional measurements & reference
points, which are as follows:
A6 -- Upper molar -- A pt. on the Occ.
Plane perpendicular to the distal
surface of the crown of the upper first
molar.
B6 -- Lower molar -- A pt. on the Occ.
Plane perpendicular to the distal
surface of the crown of the lower first
molar.

C1 – Condyle -- A point on the
condylar head in contact with &
tangent to the ramus plane.
DT -- Soft tissue -- The point of
anterior curve of the soft tissue chin
tangent to the esthetic plane.
CC -- Center of cranium -- The point of
the intersection of Ba-Na plane & the
facial axis.

A6
B6
C1
DT
CC

CF - Points from plane at pterygoid --The
point of intersection of pterygoid root
vertical to the FHP.
PT -- PT point -- The junction of the
pterygomax. Fissure & the foramen
rotundum.
DC – Condyle -- The point in the center of
the condylar neck along Ba-Na plane.

En – Nose -- A point on the soft tissue
nose tangent to the esthetic plane.
Gn – Gnathion -- Apoint on the
intersection of the facial & the mand.
Plane.
Go – Gonion -- A point at the
intersection of the mand. Plane &
ramus.

GN
CF
PT
DC
GO
EN

PM – Suprapogonion -- Point at which
the shape of the symphysis mentalis
changes from convex to concave- also
known as protuberance menti.
Pog – Pogonion -- Point on the bony
symphysis tangent to the facial plane.
Po – Cephalometric -- Intersection of
facial plane & the corpus axis.

Ti – Ti point -- Point of intersection of
occ. Plane & the facial plane.
Xi -- Xi point -- It is located at the
center of a rectangle enclosing the
ramus, at the intersection of its
diagonals. First FH plane & then
pterygoid vertical is drawn. The
rectangle is constructed by means of
drawing 4 planes tangent to points R1,
R2, R3 & R4.

PM
Pog
Po
TI
Xi

Planes
Frankfurt horizontal -- Extends from
porion to orbitale.
Facial plane -- Extends from nasion to
pogonion.
Mandibular plane -- Extends from
cephalometric gonion to cephalometric
gnathion.

FH

Facial plane

Mandibular plane

Pterygoid vertical -- A vertical line
drawn through the distal radiographic
outline of the pterygomax. fissure &
perpendicular to FHP.
Ba-Na plane -- Extends from basion to
the nasion. Divides the face and
cranium.

Occlusal plane -- Represented by line
extending through the first molars &
the premolars.
A-pog line -- Also known as the dental
plane.
E-line -- Extends from soft tissue tip of
nose to the soft tissue chin point.

FH
BA-N
PtV

Occl.Plane

Occl.Plane
A-Pog/
Dental plane

Occl.Plane
A-Pog/
Dental plane
E-plane

Interpretation
This consists of analyzing:
Chin in space.
Convexity at point A.
Teeth.
Profile.

Chin in Space
This is determined by
Facial axis angle.
Facial (depth) angle.
Mandibular plane angle.
Lower facial height.
Mandibular arc.

Facial axis angle
 The angle formed by the intersection
of the facial axes & cranial axes (Ba-
Na).
 Mean value is 90˚ ± 3˚.
 It does not changes with growth.
 This angle indicates growth pattern of
the mandible & also whether the chin
is upward & forward or downward &
backwards. www.indiandentalacademy.com

Facial (depth) angle
 Angle formed by FH plane & facial
plane
 Changes with growth.
 Mean value is 87˚± 3˚ with an increase
of 1˚ every 3 years.
 Indicates the horizontal position of the
chin & therefore suggests whether cl.II
or cl.III pattern is due to the position of
the mandible.

Mandibular plane angle.
 Angle formed by FH plane & mand. Plane.
 Mean -- 26˚± 4˚ with 1˚decrease every 3 yrs.
 High angle -- open bite – vertically growing
mandible.
 Low angle – deep bite – horizontally growing
mandible.
 Also gives an indication about ramus height.
 Low angle – well developed ramus & vice-
versa www.indiandentalacademy.com

Lower facial height
Angular measurement.
Angle formed by the intersection of a
line from ANS to Xi point and the
corpus axis.
Clinical normal is 47o
±4.
Remains constant with age, any change
is due to treatment mechanics.
Indicates skeletal open bite or deep
bite.

Mandibular arc
Angular measurement formed by the
condylar axis and the backward
extension of corpus axis.
Mean – 26o
±4, decreases by 0.5/yr
High angle – square and forwardly
growing mandible.
Low angle – short ramus and vertical
growth.

LFH
Mandi arc

Convexity at point A
This gives an indication about the
skeletal profile.
Direct linear measurement from point A
to the facial plane. The normal at 9 yrs
of age is 2mm & becomes 1mm at 18 yrs
of age, since mandible grows more than
maxilla.
High convexity – Cl II pattern.
Negative convexity – Cl III pattern.www.indiandentalacademy.com

Teeth
There are three parameters to
assess the dental status.
Lower incisor protrusion.
Lower incisor inclination &
Upper molar position.

Lower incisor protrusion
This is a linear measurement from tip of
mandibular incisor to A-Pog/dental
plane
Ideally the incisor should be located 1
mm ahead of this line.
Since A-Pog line is an indication of max-
mand relationship, this value relates
lower incisor to both max and mandi.
Constant with age, any change wouldwww.indiandentalacademy.com

Lower incisor inclination
Angle formed between A - PO line & axis
through the lower Central incisor.
 Mean value is 22 ˚± 4˚.
No age changes.
Indicates inclination of lower incisor in
relation to max-mandi plane.

Upper molar position.
 The distance from the pterygoid
vertical to the distal of the upper
molar.
 Gives the space available for upper
molars.
 On avg. this measurement should
equal the age of the patient + 3mm.www.indiandentalacademy.com

Assists in determining whether the
malocc. Is due to the position of upper
molar or lower molar.
Also useful in deciding whether
extraction, headgear is necessary or
not.

Soft tissue profile
Evaluation of the relationship of the
lower lip to the E-plane.
The lower lip is chosen as the labial
surface of the lower lip is influenced by
both the upper & lower incisors.
Mean = –2mm ± 2mm. As the nose grows
& the chin develops, the lips gradually
contact into the face with a flattening of
0.25mm every year.

Ricketts frontal analysis
ROCKEY MOUNTAIN ANALYSIS
Ricketts PA analysis, divides the
problem in to 5 areas
Field 1 – denture problem (occl relation).
Field 2 – skeletal problem (max-mandi
relation)
Field 3 – denture to skeleton.
Field 4 – cranio facial relation.
Field 5 – internal structure problem.

This incorporates the following
measurements.
Nasal cavity width – measured from
NC to NC (NC – widest point on the
nasal capsule).
Mandibular width – measured from
Ag to Ag (Ag – antegonial notch).

Maxillary width – 2 frontal facial lines
are constructed from the inside margins
of the ZF suture to the Ag points. This is
related to ‘J’ point or point jugale
(crossing of the outline of the tuberosity with
that of the jugal process).
Calculated seperately for both sides.
In this way max width compared in
relation to mandi width.

Symmetry – assessed by constructing a
mid sagittal plane hrough nasal septum
and crista galli.
The position of ANS & Pogonion is noted.
Inter molar width – measured from
buccal surfaces of first molrs (both
upper & lower)
Inter canine width – width between the
tips of lower canines.

Denture symmetry – the mid points of
the upper and lower central incisor
roots in relation to mid line is noted.
Upper to lower molar relation – the
difference in width between upper &
lower molars are noted at the most
prominent buccal contour of the tooth.

CCD Analysis
This the computerised cephalometric
analysis of Ricketts.
Comprehensive Computer Description
Analysis.
Ricketts is the first analysis to be
computerised.
Rocky mountain data in conjunction
with Ricketts investigations developed
this.

This contains six fields similar to
the frontal analysis.
1. Denture problem.
2. Skeletal problem.
3. Denture to skeletal problem.
4. Cranio facial relation.
5. Internal structures.
6. Esthetic problem.

Tweed’s Analysis

Tweed’s analysis
Charles. H . Tweed , is
credited with the
development of the
Diagnostic Facial
Triangle.
His idea was to develop
cephalometrics so that
clinical orthodontists can
use them to diagnose
and treat patients in
every day practice.www.indiandentalacademy.com

Diagnostic Facial Triangle
The normal inclinations of the
mandibular incisors and the variations
found in the FM angle and the effects
on facial esthetics when that angle
was overly large, was of great interest
to him.
This gave him the impulse to draw a
triangle on the head film.

Tweed conceived his diagnostic facial
triangle as a basis for diagnosis and
treatment planning.
It consists of three essential angles
Frankfort mandibular plane angle –
FMA
Incisor mandibular plane angle – IMPA
Frankfort mandibular incisor angle –
FMIA www.indiandentalacademy.com

In addition consideration is so given
to:
ANB angle.
Sella – Nasion line -- SN Line.
Frankfort plane: Connected a
point 4 ½ mm above geometric center
of the ear rod with the lower border of
the orbit.

Mandibular plane: drawn along the
lower border of the mandible and
extended posteriorly to connect with the
FH.
This line goes through menton
anteriorly.
Incisor-mandibular plane angle (IMPA):
constructed by drawing a line through
the apex and incisal edge of the lower
central incisor, extending it to meet the
FH & mandibular planes to form a
triangle.

A sample of 95 cases were taken &
average values found are
 FMA – 24.57o
 IMPA – 86.93o
 FMIA – 68.20o
But figures of 25o
, 90o
, and 60o
, were
found to be workable and are still
widely used.

IMPA
FMIA
FMA

Though it is usually said that the IMPA
should be 90o
to get a stable result, the
reality is that IMPA is dependant on
the variable FMA.
There seems to be an inverse relation
between these two.
With every degree increase in FMA, the
IMPA decreases by the same amount.

So the FMIA which is nearly a constant is
used by many clinicians now.
Accepted FMIA at end of treatment
should be atleast 65o
.
In Class II cases there seems to be an
increase in this value and 70o
is accepted
as normal.
A value of 62o
is kept as the guiding line
between extraction & non-extraction
cases. www.indiandentalacademy.com

Anchorage preparation using tweeds
triangle
A dotted line through the apex of
lower incisor is dran upward, to
intercept the FH plane, at an angle of
65o
.
The line through the original
inclination of the incisor is drawn in
solid line.

The difference in distance is the
amount of incisor movement needed.
Anchorage preparation is directly
proportional to it.
The bigger the line is greater
anchorage control needed.

Arch length considerations
When the mandibular incisors are tilted
lingually to secure an FMIA of 65o
, the
arch length will decrease.
This is given by the equation 5mm = 12o
So to tip the incisors lingually by 12o
, a
space of 10 mm ( 5mm on both sides) is
needed.

Margolis analysis

The Margolis maxillofacial triangle is a
means for measuring the overall facial
growth pattern.
The interdependence of the size of the
angles of the triangle makes it a
valuable aid in dentofacial studies
since it reveals the relative difference
in size and relationship of specific
maxillofacial areas to each other.

In this manner, it is possible to
determine specific sites of growth
change.
The three sides of the triangle are:
The cranial base line, N-X
The facial line, N-M
The mandibular line, M-X

Landmarks
Na – nasion,
S – sella,
So – highest point on the spheno
occipital synchondrosis,
So-Na – cranial base.
Na-Pog – facial line
NXM – craniomandibular angle.
NMX – facio mandibular angle.
MNX – cranio facial angle.www.indiandentalacademy.com

Na
M
X

Construction of the
triangle
Draw the facial line, construct both the
mandibular plane and cranial base line
and extend them posteriorly, until
they meet.
Margolis proposed that similar
triangles can be constructed with
Bolton plane or the S-N plane.

On the basis of the study conducted, it
was found that:
Craniofacial angle – has a standard
value of 72.8 ± 2.36. This angle records
the anterior developmental limit or
position of the body of the mandible at
pogonion. The smaller the angle, the
more receeding the chin.

 Faciomandibular angle – has a
standard value of 67.40 ± 2.770. This
records the extent of vertical growth &
development of the mandible.
 Craniomandibular angle –value of
39.60 ± 3.26. This also records the
extent of vertical growth of the
mandible. A large angle indicates
deviations in vertical growth and large
gonion angle or a short ramus or both.

 The mandibular base line when
extended posteriorly, touches the
occipital bone posterior to the
foramen magnum or falls below it.
 The facial line intersects the lingual
surface of the crown of the
mandibular incisor.

The mandibular incisor may be lingual
to the facial line in well-developed
face, when the mental eminence is
prominent, or when the incisors are
lingually Inclined.
Incisor mandibular plane angle is
90o
±3o
.

Bjork’s Analysis

Bjork’s Analysis
Prof. Arne Bjork, is well known for his
works on implants studies and growth
rotations.
Apart from growth studies he also
investigated the effects of variations in
jaw growth on prognathism and the
relationship between facial form and
occlusion.

He devised a facial diagram in which
the linear and angular configurations
determine the amount and distribution
of facial prognathism.
This facial diagram that implicates
these changes constitutes the Bjork’s
Analysis.

The landmark study was conducted
with three groups of Scandinavian
school children.
Roentgenograms taken at a distance
of 155 cms were used.
The facial diagram was constructed
and analysed.

Landmarks
A – Articulare.
Dd – Chin angle, pt of intersection of
mandibular plane and line tangent to
ID.
Gn – Gnathion.
Id – Infradentale.
Ii – Incisus inferius.
Is – Incisus superius.

Kk – gonial angle.
N – Nasion.
Or – orbitale.
Pg – Pogonion.
Po – Porion.
Pr – Prosthion.
S – Sella.
Ss – Sub spinale.

Construction of facial
diagram
A line drawn from the apex ANS to
the nasion, to the center of sella
turcica (S), to articulare to the Gonial
angle (KK), to Chin angle (DD), and
from these to infradentale (Id).

The general shape of the skull is
determined by the shape of the
cranium, the central base and the
facial skeleton.
Change in any of the angular lines of
the facial diagram produces effects on
facial prognathism.
The reference line used in the facial
diagram is sella – nasion plane.

Angles
Angles are formed at each of these
junctions.
 At nasion the angle is measured to 4
different points, measures the facial
profile in relation to the cranial base.
 Nasion to
 Anterior nasal spine.
 Prosthion.
 Infradentale.
 Pogonion. www.indiandentalacademy.com

 Angle formed at sella by lines Sella
nasion to articulare or Sella nasion
to basion (Saddle angle).
 This provides a means of
measuring the shape of he cranial
base.
 Angle at articulare – formed by
lines from Sella articulare to
gonion.
 This shows the forward and
backward position of the mandible.

 Gonion angle – made by a line from
articulare and tangent to the
mandibular base.
 Chin angle – is measured by a line
from infradentale passing through
pogonion and a line tangent to the
base of the mandible.

 Angle formed by a line bisecting another
line through the anterior and posterior
margin of foramen magnum and cranial
base plane through sella nasion. This angle
denotes the position of the head.
 Angle formed by the lines sella - nasion
and nasion to a fixed point on the
forehead. This fixed point on the forehead
is obtained by bisecting a line from
anterior fontanelle to nasion and
projecting a perpendicular from this to the
forehead. Denotes the inclination of fore
head. www.indiandentalacademy.com

Interpretation
Angular changes
 At Sella turcica - Reduction of the
angle at sella turcica produces
forward displacement of the
temporomandibular joint and
forward displacement of the jaws
with an increase in prognathism of
the facial profile.

 At Articulare – reduction of this
angle also increase the degree of
prognathism and it shortens the
height of the upper part of the face
as well.
 This brings the base of the
mandible more parallel with the base
of the skull and increase mandibular
prognathism

 At Gonion – Reduction of this angle
does not increase facial prognathism
and may actually reduce it.
 At Chin – Reduction of the angle at
the chin also reduces mandibular
prognathism.

↓ articulare
↓ gonion
↓chin angle

Linear changes
 Shortening of the line from nasion to
sella when other lines are constant
produces pronounced increase in
prognathism.
Shortening of the line from sella to
articulare increases prognathism and
shortens the height of the face;
provided articulare remains
unchanged. www.indiandentalacademy.com

Increase in the line from the articulare to
gonion increases mandibular
prognathism however, if the ramus is
parallel to the facial profile, there is no
increase in prognathism.
Increase in the length of line from
gonion angle to chin angle produces a
pronounced increase in facial
prognathism.
Increase in facial height produces a
slight increase in the prognathism.www.indiandentalacademy.com

 The prominence of the facial
skeleton, in relation to the brain case,
determines the general shape of the
facial profile.
 Facial prognathism may be due to
 Shortening of the cranial base.
 Angular deflection of the cranial base.
 A small ramus – cranial base angle.
 Increased jaw length.

Bjork also found no difference in the
procumbency of mandibular incisors in
crowded dental arches when compared
to arches with teeth in regular
alignment.
Extraction of teeth in the presence of
facial prognathism, as distinct from
alveolodental prognathism, is of little
use in the attempt to reduce
prognathism. www.indiandentalacademy.com

Sassouni Analysis

Introduction
An example of the archial analysis
Sassouni analysis was infact an
extension of his thesis work.
Dr. Viken Sassouni, native of Lebanon,
graduated from the University of
Pennsylvania.
This paper won him first prize in the
essay contest of AAO.

This analysis was the first
cephalometric method to emphasize
vertical as well as horizontal
relationships, and the interaction
between vertical and horizontal
proportions.
It emphasizes on the theory of
proportions and states that size is
secondary as long as the skulll is
proportionate.www.indiandentalacademy.com

According to Sassouni, the
architecture of the skill, is the result
of the interaction of many forces, such
as,
Genetic forces, growth forces,
muscular forces at rest (relatively
static), functional muscle forces
(dynamic), and environmental forces
on the adaptable bony substance.

The analysis was developed in order to
find if some acceptably constant
relationships in the architecture of the
head.
The findings of this analysis was based
on tracings of 100 lateral head x-ray
films from the files of Philadelphia
Centre for Research in Child Growth
taken with the Broadbent Bolton
Cephalometer.www.indiandentalacademy.com

Terminology
Planes
Mandibular base plane, OG – A plane
tangent to the inferior border of the
mandible.
Occlusal plane, OP – A plane through
the mesial cusps of the permanent first
upper & lower molars & incisal edges
of upper & lower central incisors.

 Palatal plane, ON – A plane
perpendicular to the mid sagittal
plane, going through the ANS – PNS.
 Anterior cranial base – Structurally
the floor of the anterior cerebral
fossa.
 Anterior cranial base plane or Basal
plane, OS’ – A plane parallel to the
axis of the upper contour of the
anterior cranial base and tangent to
the inferior border of the sella turcica.www.indiandentalacademy.com

 Ramal plane, RX’ – A plane tangent to
the posterior border of the ascending
ramus.
Arcs
 Anterior arc – The arc between anterior
cranial base & mandibular plane with O
as center and O-ANS as radius.
 Posterior arc - The arc between cranial
base & mandi plane, with O as center &
O-S’ as radius (S’ -- most posterior point
on the rear margin of sella turcica).

Axes
There are 4 axes used. They are,
1. MM’M” - Axis of 6
2. II’I” - Axis of 1
3. ii’ - Axis of I
4. mm’ - Axis of 6

M
M’
M”
I
I’
I”

This analysis cosists of 2 parts – Facial
& Dental
Facial: - The mandible, palate and
anterior cranial base are examined in
sequence followed by the
interrelationship between the various
planes and arcs.
Followed by dental analysis and their
interelationship.

Mandible
The mandible shows three main types
Curved – the upward traction forces at
gonion & downward pulling forces at
the mention are in equilibrium.
Oblique – upward & downward forces
are strong that we have a notch
anterior to the gonial insertion of
masseter.
Horizontal – upward traction forces at
gonion seem to be greater than the
downward pulling forces at mention.www.indiandentalacademy.com

Curved Obliqu
e
Horizontal

Palate
The palate also presents three types
Horizontal – the line connecting ANS
and PNS passes through the bony
structure of the palate.
Convex – the line passes above the
bony structure of the palate.
Concave – the line passes below the
bony structure of the palate.

Horizontal Convex
Concave www.indiandentalacademy.com

Relationship between the palate
and mandible
Generally, with a curved mandible, we
find a horizontal palate;
With an oblique mandible, we find a
convex palate; and
With a horizontal mandible, we find a
concave palate.

Key Ridge
This presents two shapes
Vertical and straight, or l-like
Double curved, like a reverse 3 or like
( ∑).
Correlation bet key ridge & palate
Concave / convex palate - ∑-like key
ridge.
Horizontal palate -- l-like key ridge.
When upper & lower faces are not equal

Relationship between the
planes
If we prolong all the 4 planes they all
meet together posteriorly at the same
point O in a well proportioned face.
Sassouni states that, this is not only a
condition but also the definition of
such a face.

Relationship betweent point O and the
bony profile:
In a well-proportioned face, if we draw
a circle with O as center, and with O-
ANS as radius, it passes through,
pogonion, the incisal edge of the
upper central incisor, the ANS, nasion,
& the fronto-ethmoid jn, i.e. all these
points are equidistant from o.

Posterior relationship
If from point O as center, we draw circle
passing through posterior wall of sella
turcia, it also passes through the gonion.
The gonion and the posterior wall of
sella turcia are equidistant from 0.
Anterior cranial base and corpal length
of mandible are equal in length &
position.

Relationship between anterior and
posterior arcs
 In a proportioned face, the proportion
between anterior & posterior arcs is a
function of:
 The angle S’OG.
 The ratio of both radii – Ra (O-ANS)
Rp (O-SP
)
 The combination of both this is the
facial index.

The mandibulo cranial angle (S’OG) is
unique to each face.
The palato cranial angle (S’ON) is
equal to palato mandibular angle
(NOG).
The Occluso palatal angle (NOP)
equals 1 to ½ occluso mandibular
angle (POG), i.e. angle POG is always
larger than NOP in a well-proportioned
face. www.indiandentalacademy.com

Classification of faces
With the criteria that all the planes meet
posteriorly at point O, we classify facial
types in to 4 types.
Type I -- Anterior cranial base does not
pass through O.
Type II – Palatal plane does not pass
through O – most common.

Type III – occlusal plane does not pass
through O.
Type IV – Mandibular plane does not
pass through O.
Subdivisions:
In each of these types, the plane which
does not meet the others at point 0
may pass either above – A
Or below – B

I a
I b

Results of the study
It was also found that –
A well proportioned face has normal
occlusion.
Normal occlusion is necessary but not
sufficient to define well-proportioned
face
Type II facial pattern is the mostwww.indiandentalacademy.com

Facial proportions
 We can classify vertical proportions
(both anterior and posterior) by
comparing LFH & UFH.
 Equal : The distance from ANS to
mandibular plane (LFH) and cranial base
plane (UFH) are equal.
 Minus: Lower face is smaller than upper
face
 Plus : Lower face is larger than upper face
 Based on ANS for anterior face and
PNS for posterior face.www.indiandentalacademy.com

Correlation between the facial
patterns and anterior vertical
proportions:
Types IA & IIB have lower anterior face
height larger than the upper
Types IB, IIA & IVB have lower anterior
face smaller than the upper.

Types III A & III B have upper and
lower faces which are approximately
equal.
Type IV A may have lower face smaller
or larger than upper.
Therefore types IA, IIB, IB, IIA & IV B
are dependent on ANS and type IVA is
caused by the position of either
menton or gonion.www.indiandentalacademy.com

Classification of the
profile
Based on the anterior arc and the points
on the arc, we can classify facial profile
in to:
Archial: anterior arc passes through Na,
ANS, upper incisal edge, pogonion.
Prearchial: ANS, upper incisor edge and
pogonion are situated anterior to the
anterior arc passing by Na.www.indiandentalacademy.com

Postarchial : ANS, upper incisor edge
and pogonion are situated posterior to
the anterior arc passing by Na.
Convex : ANS & upper incisor edge are
situated anterior to the anterior arc
passing by Na and pogonion.
Concave : ANS & upper incisor edge
are situated posterior to the anterior
are passing by Na and pogonion.

Pre
archial
Convex
Post
archial
concave

Well Proportioned Face
1. The four facial planes meet at O.
2. Anterior upper & lower faces are
equal.
3. posterior upper & lower faces are
equal
4. Archial profile.
5. The corpus of the mandible &
anterior cranial base are equal in size
and position relative to palatal plane.

Dental Analysis
 This part of the analysis is based on
the upper and lower first permanent
molars and the upper and lower
central incisors.
These teeth are the most significant
owing to their early eruption age, their
early extreme position (anteriorly and
posteriorly on the dental arch).

 The axes of 6 and 1 intersect at the
level of the bony orbital contour.
 They form, with the palatal plane, a
triangle whose palatal angles are
related as: angle M’= angle I’ + 10
degrees where M’ is the angle formed
by 6 axis and palatal plane and I’ is
the angle formed by 1 axis and
palatal plane.

Mandible
The Ramal plane and the 1 axis , form
with occl plane an isosceles triangle.
Angle R = Angle i.
The axes of 6 and 1 form a triangle
with the base along the mandibular
border.
The angles are related such that
m’=I’+5.


Relationship between teeth
axes and other planes
 If we prolong the 6 and 1 axes so
that after crossing each other at
point X, they intersect the anterior
cranial base plane, we find that if
forms a new triangle I”XM” that is
similar to the triangle IXM.
 So reciprocally angle I”=M & M”=I.

If we prolong 1 axis anteriorly to meet
the palatal plane, a new angle iNI’ is
formed which is equal to the angle
formed by the upper incisor to the
Occl. Plane. iNI’=OII’.
In other words the axial inclination of
lower central incisor to the palatal
plane is equal to the axial inclination of
the upper incisor to the Occl. Plane.

The preceding analysis enables us to
study growth by superimposing the
tracings of lateral X-Ray films.
Also used to make diagnosis and to
decide on treatment plan.

Sassouni suggests the diagnosis
should be carried out in the folowing
sequence:
Determination of malocclsion
( Independently of the clinical diagnosis).
Study of facial proportions using planes
and arcs.
Study of the axial inclination of the teeth
and their relation to the planes.

In diagnosis three view points are
possible:
The face is compared with the ideal and
the treatment plan decided by the
Orthodontist.
Compared to the average (on the
concept that majority is the normal) &
the type derived from the majority.
The face compared to the optimum for
that face , the decision set by the
architecture if the face itself.www.indiandentalacademy.com

Conclusion
There are numerable cephalometric
analysis given by different people each
expressing their ideas and ways to
analyse, classify, and treat the face.
All these analysis are still a two
dimensional representation of the three
dimensional structure.
Each has inherent deficiencies
associated with the analysis itself and
those because of radiological errors and
clinician’s experience.www.indiandentalacademy.com

The future of cephalometrics depends
on the three dimensional analysis, their
accuracy, validity and reproducibility.
A comprehensive universal analysis
incorporating the significant findings of
all the analysis including the PA analysis
is the need of the time.
Still the value of the information and
insight given by these traditional
analyses should not be ignored or takenwww.indiandentalacademy.com

References
 Radiographic Cephalometrics – Alex
Jacobson
 Orthodontic Cephalometry –
Athanasios E Athanasiou
 Contemporary Orthodontics – William
Proffit
 Practice Of Orthodontics, Volume 1 &
Volume 2 - J. A. Salzmann
 Clinical Orthodontics, Volume 1 -
Charles H Tweed

 A Roentgenographic Cephalometric
Analysis Of Cephalo- Facial – Dental
Relationships – Viken Sansouni
 The Diagnostic Facial Triangle in the
Control of Treatment Objectives -
Charles H Tweed, American Journal
of Orthodontics, June 1969.
 Perspectives In The Clinical
Application Of Cephalometrics –
Robert M Ricketts, Angle
Orthodontist, April 1981

Ceph ricketts, tweed, margolis,bjork analysis

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