Cephalometrics in orthodontics /certified fixed orthodontic courses by Indian dental academy

Cephalometrics in Orthodontics

INDIAN DENTAL ACADEMY
www.indiandentalacademy.com

CEPHALOMETRICS

Cephalometric radiography:- is the production of skull
radiographs ,which are useful in making measurements
of the cranium and oro-facial complex.

PACINI- IN 1922 DEMONSTRATED THE BASIC PROCEDURE
OF CEPHALOMETRICS.

It was in 1931, HOFRATH in GERMANY
and BROADBENT in UNITED STATES published
articles in which they had refined the technique and applied
these principles to orthodontics.

Cephalostat

60"
60" 15"
15"
Film Plane
Film Plane
Source Plane
Source Plane

X-ray Source
X-ray Source
Mid-saggital X-ray Film in
X-ray Film in
Mid-saggital Cassette
Plane
Plane Cassette
Patient in Head
Patient in Head
Positioning Device
Positioning Device

Purpose of Cephalometrics
•Study craniofacial growth
•Diagnosis
•Planning orthodontic treatment
•Evaluation of treated cases

Cephalometrics is a technique
employing oriented radiographs
for the purpose of making head
measurements.

Purpose of
Cephalometrics
Study craniofacial growth
Diagnosis
Planning orthodontic treatment
Evaluation of treated cases
Cephalometrics is a technique
employing oriented radiographs for
the purpose of making head
measurements.

Cephalostat
60"
60" 15"
15"
Film Plane
Film Plane
Source Plane
Source Plane

X-ray Source
X-ray Source
X-ray Film in
X-ray Film in
Mid-saggital Plane
Mid-saggital Plane Cassette
Cassette
Patient in Head Positioning
Patient in Head Positioning
Device
Device


Cephalostat


Cephalometric Values for
Selected Groups
White Black Israeli Chinese Japanese
SNA 82 85 82 82 81
SNB 80 81 78 79 77
ANB 2 4 4 3 4
U1-NA 4 mm, 22 7 mm, 23 5 mm, 24 5 mm, 24 6 mm, 24
L1-NB 4 mm, 25 10 mm, 34 6 mm, 29 6 mm, 27 8 mm, 31
U1-L1 131 119 124 126 120
GoGn-SN 32 32 35 32 34
L1-MnPl 93 100 93 93 96
L1-FH 62 51 57 57 57
Y axis 61 63 61 61 62

from Proffit,Contemporary Orthodontics, 1992

What Are We Trying to
Accomplish?
Find out skeletal classification
 anteroposterior
 vertical
Find out angulation of incisors
Consider soft tissue
 facial profile
 airway considerations

What Are We Trying to
Accomplish? (In other words)
Is the patient Class I, II, III skeletal?
Does the patient have a skeletal open bite
growth pattern, or a deep bite growth pattern,
or a normal growth pattern?
Are the maxillary/mandibular incisors
proclined, retroclined or normal?
Is the facial profile protrusive, retrusive, or
straight; can the patient breathe normally?


USES OF CEPHALOMETRICS

1. It gives a 2 dimensional view
of a three dimensional
object.

2. Reliability of
cephalometrics is not always
accurate,
as there can be errors in
identifying the landmarks or
tracing etc.


CEPHALOMETRICS
DEFINITION
Scientific study of the measurement of
the head.
CEPHALOMETRIC RADIOGRAPHY
is a standardized method of production
of skull radiographs,which are useful in
making measurements of the cranium and
the orofacial complex.The radiograph thus
obtained is called a cephalogram.

DISCOVERED BY-
IN 1931,HOFRATH IN GERMANY
AND BOARDBENT IN U.S.A
Provided a standardized
cephalometric technique using a high
power x-ray machine and a head
holder called a CEPHALOSTAT.

TYPES OF
CEPHALOGRAMS
LATERAL FRONTAL

WHY CEPHALOMETRICS?
Aids in orthodontic diagnosis by enabling
the study of skeletal,dental and soft tissue
structures of the craniofacial region.
Aids in establishing the facial type.
Helps in the classification of skeletal and
dental abnormalities.
Helps in treatment planning.

Aids in evaluating the treatment results
and recognizing changes brought about
by treatment.
Aids in predicting growth changes and
changes associated with surgical
treatment.
Study of relapse in orthodontics.
Valuable aid in research work.

OBTAINING A
CEPHALOGRAM
CEPHALOMETRIC EQUIPMENT
CEPHALOSTAT,X-RAY SOURCE & A
CASETTE HOLDER.
Cephalostat-2 ear rods-prevent movement
of the head in the horizontal plane.
Vertical stabilization of the head-orbital
pointer that contacts the lower border of
the left orbit.

The upper part of the face is supported
with the help of a forehead clamp which is
positioned above the region of the nasal
bridge.
The distance between the x-ray source
and the midsagittal plane of the patient is
5 feet.

CEPHALOMETRIC
LANDMARKS
LANDMARK-Is a point serving as a guide for
measurement.An ideal landmark is located
reliably on the skull and behaves consistently
during growth.
It should not be assumed that all the landmarks
are equally reliable and valid.
The reliability,reproducibility and dependability of
a landmark is affected by-


#The quality of the cephalogram.
#The experience of the tracer.
#Confusion with other landmarks.
The cephalometric landmarks should have
the following attributes-
A) Should be easily seen on the radiograph.
B)Uniform in outline.

C)Should be easily reproducible.

D)Landmarks should permit valid
quantitative and qualitative measurements
of lines and angles projected from them.

E)Measurements should be amenable to
statistical analysis.


CLASSIFICATION OF
LANDMARKS

1)ANATOMIC LANDMARKS
2)DERIVED LANDMARKS
3)UNILATERAL LANDMARKS
4)BILATERAL LANDMARKS
5)IMPLANTS

ANATOMIC LANDMARKS
They represent actual anatomic structures
on the skull e.g. ANS,Na
DERIVED LANDMARKS
These are obtained secondarily from
anatomic structures in a
cephalogram.e.g.Ar(Articulare),Ptm(Pteryg
omaxillary fissure)

IMPLANTS
They are artificially inserted radio opaque
markers, usually made of inert metal.
They are ‘PRIVATE POINTS’ and their
position can vary from subject to subject.
They are ideal for longitudinal studies on
the same subject.

UNILATERAL LANDMARKS

NASION-The most anterior point
midway between the frontal and the
nasal bones in the frontonasal suture.

ANTERIOR NASAL SPINE/ANS

It is the tip of the sharp bony process of
the maxilla in the midline.


PROSTHION

The lowest and the most anterior point
on the alveolar process in the median
plane between the central incisors.

SUBSPINALE/POINT A
It is the deepest point in the midline
between the ANS and the alveolar crest,
between the two central incisors. It is also
called as subspinale.

Pink dot-pt.A

INFRADENTALE/(Id)
The highest and the most anterior point in
the alveolar bone in the midline between
the lower central incisors.

Blue dot-(Id)

SUPRAMENTALE/Pt.B

It is the deepest point in the midline
between the alveolar crest and the
mental process.

Pink dot-pt.B

POGONION(Pog)

It is the most anterior point of the bony
chin in the median plane.

Red dot-(Pog)

MENTON(Me)

It is the most inferior midline point on
the mandibular symphysis.

Yellow dot-Me

GNATHION(Gn)
It is the most antero -inferior point on the
symphysis of the chin. It is constructed by
intersecting a line drawn perpendicular to
the line connecting menton and pogonion.

Orange dot-(Gn)

BASION(Ba)

It is the median point on the anterior
margin of foramen magnum.

POSTERIOR NASAL
SPINE(PNS)
The most posterior point in the bony
hard palate in the sagittal plane.
Marks the distal limit of the maxilla.

SELLA(S)

The point representing the midpoint of
sella tursica.


GLABELLA:It is the most prominent point
of the forehead in the mid-saggital plane.
SUBNASALE:The point where the
lowest border of the nose meets the outer
contour of the upper lip.

●G

●Sn


BILATERAL LANDMARKS
1)ORBITALE(Or)
The lowest point on the inferior bony
margin of the orbit.


G0NION

It is a constructed point at the junction
of ramal plane and mandibular plane.


CONDYLION/(Co)

The most superior point on the head of
condyle.

ARTICULARE/(Ar)

It is a point at the junction of the
posterior border of the ramus and
inferior border of the basal part of the
occipital bone.

Blue dot-(Ar)

PTERYGOMAXILLARY
POINT/Ptm
It is the intersection of the inferior border
of foramen rotundum with the posterior
wall of pterygomaxillary fissure.
It is a bilateral tear drop shaped area of
radiolucency.


PORION/(Po)

The highest bony point on the upper
margin of the external auditory meatus.


BOLTON POINT

The highest point at the posterior
condylar notch of the occipital bone.

Bo


THE KEY RIDGE-The lowest most point
on the contour of the anterior wall of the
infratemporal fossa.
CHELION:It is the lateral terminus of the
oral slit on the outer corner of the mouth.


LINES AND PLANES IN
CEPHALOMETRY
Cephalometrics makes use of certain lines
or planes. These lines are obtained from
connecting two landmarks.
Based on their orientation the lines or
planes are classified into:
Horizontal and vertical planes.

HORIZONTAL PLANES
1)S.N.PLANE- It is the cranial line
between the center of sella tursica and the
anterior point of the fronto nasal
suture(nasion).
It represents the anterior cranial base.

FRANKFORT HORIZONTAL
PLANE
This plane connects the lowest point of
the orbit(orbitale)and the superior point
of the external auditary meatus(porion).


OCCLUSAL PLANE

It is a denture plane bisecting the
posterior occlusion of the permanent
molars and premolars(or deciduous
molars in mixed dentition)and extends
anteriorly.

MANDIBULAR PLANE
Several mandbiular planes are used in
cephalometrics,based on the analysis
being done. The most commonly used
ones are-
TWEEDS-Tangent to the lower border of
the mandible.
STEINERS-A line connecting gonion and
gnathion.
DOWNS-A line connecting gonion and

PALATAL PLANE

It is a line linking the anterior nasal
spine of the maxilla and the posterior
nasal spine of the palatine bone.

BASION-NASION PLANE

Line connecting the basion and nasion.
Represents the cranial base.

VERTICAL PLANE

A-POG LINE: It is a line from point A on
the maxilla to pogonion on the
mandible.

FACIAL PLANE

It is a line from the anterior point of the
frontonasal suture (nasion)to the most
anterior point of the
mandible(pogonion).

BOLTON’S PLANE

This is a plane that connects the
Bolton's points posterior to the occipital
condyles and nasion.

Bo


FACIAL AXIS

It is point from Ptm point to
cephalometric gnathion.

ESTHETIC PLANE/E
PLANE
Is a line between the most anterior point of
the soft tissue nose and the soft tissue
chin.


FRONTAL CEPHALOGRAM
(P-A VIEW)

This provides an antero-posterior view
of the skull.


The goal of lateral ceph
Analysis is to establish
the
Antero-posterior and
Vertical relationships of
the
Five major cranio-facial
units.
1.The cranium and cranial base

2.The naso-maxillary complex

3.The Mandible

4.The Maxillary dentition

www.indiandentalacademy.com Mandibular dentition.
5.The

STEINERS ANALYSIS

Steiner’s analysis is divided into 3 parts:-

1. Skeletal Analysis
2. Dental Analysis
3. Soft tissue analysis


Soft Tissue Analysis

‘S-LINE’ : According to Steiner the lips in a well balanced faces
Should touch a line extending from the soft tissue contour of the
Chin to the middle of the ‘S’ formed by the lower border of the
Nose.

THIS LINE IS REFERRED TO AS THE ‘S’ LINE.


STEINER’S ‘S’ LINE

THE ‘S’ LINE

DOWN’S ANALYSIS
-1952

DOWN’S :-Study based on 20 Caucasian subjects ,ranged
In age from 12 to 17 years of age and were equally divided
As to sex.

All the individuals possessed clinically excellent occlusions.


DOWN –divided his analysis into 2
components----

1. The skeletal component helped in
defining the underlying
facial type .

2. The dental component is used to establish
if the dentition is
placed normally in relation to the
underlying bony structures.


Y-AXIS
(GROWTH AXIS)

Angle formed by joining
Sella-gnathion line with
The F-H plane.

Mean value- - 59degrees

DOWN’S POLYGON

The graph divided into:-

1.Skeletal pattern on the
top half of the graph

2.Denture polygon on
the lower half of the
graph.

Wigglegram:- helps us in
Visualizing the type of
malocclusion I.e, Skeletal
or dental..

WITS APPRAISAL

A.J.O-1975


Wits appraisal

Functional occlusal
plane


A functional occlusal plane is drawn through the
overlapping
Cusps of first pre-molars and first molars.

Perpendiculars are drawn to the occlusal plane
from points
A and B .

The points of contact of these perpendiculars on
the occlusal
Plane are termed AO and BO.

The distance between points AO and BO gives the
antero-
Posterior relation between the two jaws,.

TWEED’S TRIANGLE

TWEED’S DIAGNOSTIC FACIAL TRIANGLE

TWEED- developed this analysis as an aid to:

•Anchorage preparation
•To treatment planning
•And determining the prognosis of orthodontic cases

Tweed’s analysis is based primarily on the deflection
of the mandible as measured by the Frankfurt Mandibular
plane Angle(FMA) and the posture of the lower incisor.
It is done to determine the final position the lower incisor
Should occupy at the end of the treatment.

Dr.Tweed established that prognosis could be predicted
relatively accurately based on the configuration of the
triangle

Tweeds triangle is formed by:
1. Frankfurt horizontal plane
2. The mandibular plane
3. The long axis of lower incisor.s

The three angle’s formed are:
• Frankfort-Mandibular Plane(FMA) Angle----
• FH Plane with mandibular plane.
• Lower Incisor to Mandibular plane(IMPA)Angle-----
• Long axis of lower incisor with mandibular plane.
• Frankfort Mandibular Incisor Angle (FMIA)--------
• Long axis of lower incisor with FH plane.

FMA=25degrees
IMPA=90degrees
FMIA=65degrees.

Based on the FMA angle the prognosis can be
predicted:-
1. FMA 16 to 28 degrees- prognosis good
Apprx. 60% of malocclusions have FMA between 16 to 28

2.FMA from 28 to 35 degrees prognosis fair.
Extractions necessary in majority of cases

3.FMA above 35 degrees , prognosis bad ,,extractions frequently
complicate the problem.


OTHER IMPORTANT CEPHALOMETRIC
ANALYSIS
McNamara's ANALYSIS
RAKOSI’S ANALYSIS
GRUMMON’S –FRONTAL ASYMMETRY
ANLYSIS
SCHWARZ ANALYSIS
NHP –ANALYSIS

BURSTONE’S-HARD TISSUE ANALYSIS(COGS)
BURSTONE’S –SOFTY TISSUE ANALYSIS(COGS)

HOLDAWAY’S SOFT TISSUE ANALYSIS
ARNETT-SOFT TISSUE CEPH.ANLYSIS(STCA)


THANK YOU FOE WATCHING


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