Cephalometrics (2)

CephalometricsCephalometrics
www.indiandentalacademy.comwww.indiandentalacademy.com

IntroductionIntroduction
 The assessment of craniofacial structures forms aThe assessment of craniofacial structures forms a
part of Orthodontic diagnosis.part of Orthodontic diagnosis.
 Earlier craniometry was introduced. This involvedEarlier craniometry was introduced. This involved
measurements of craniofacial dimensions of skullsmeasurements of craniofacial dimensions of skulls
of dead persons.of dead persons.
 This method is not practical in living individualsThis method is not practical in living individuals
due to soft tissuie envelop which made directdue to soft tissuie envelop which made direct
measurements difficult and for less reliablemeasurements difficult and for less reliable
 Cephalometry was later introduced with the workCephalometry was later introduced with the work
of Paccini in 1922 and later by Board Bent inof Paccini in 1922 and later by Board Bent in
U.S.A and Hofrath in GermanyU.S.A and Hofrath in Germany
 Cephalometrics is used to describe the analysisCephalometrics is used to describe the analysis
and measurement made on the cephalometricand measurement made on the cephalometric
radiographsradiographs

Types of cephalogramsTypes of cephalograms
 Lateral cephalogramLateral cephalogram:-Provides:-Provides
lateral view of skull. Giveslateral view of skull. Gives
horizontal and mesio distalhorizontal and mesio distal
dimensions of skull. Gives dentaldimensions of skull. Gives dental
and skeletal relationship of skulland skeletal relationship of skull

Frontal cephalogramFrontal cephalogram
 Its also known as anterio posteriorIts also known as anterio posterior
cephalogram.it gives anteriocephalogram.it gives anterio
posterior width of skull. it helps inposterior width of skull. it helps in
orthodontic diagnosis .it relatesorthodontic diagnosis .it relates
skeletal and dental asymmetries.skeletal and dental asymmetries.

Uses of cephalometricsUses of cephalometrics
 Helps in orthodontic diagnosis by enabling theHelps in orthodontic diagnosis by enabling the
study of skeletal dental and soft tissuestudy of skeletal dental and soft tissue
structures of craniofacial regionstructures of craniofacial region
 It helps in classification of skeletal and dentalIt helps in classification of skeletal and dental
abnormalities and also helps in establishingabnormalities and also helps in establishing
facial typefacial type
 It helps in planning treatment of an individualIt helps in planning treatment of an individual
 It helps in evaluation of the treatment.It helps in evaluation of the treatment.
 It helps in predicting growth related changesIt helps in predicting growth related changes
and changes associated with surgical treatmentand changes associated with surgical treatment
 Cephalometrics is a valuable aid in researchCephalometrics is a valuable aid in research
work involving the cranio dentofacial regionwork involving the cranio dentofacial region

Technical aspectsTechnical aspects
 The cephalometrics radiographs areThe cephalometrics radiographs are
taken using an apparatus, it consists oftaken using an apparatus, it consists of
an x-rays source and a head holdingan x-rays source and a head holding
device called cephalostat. It consists of 2device called cephalostat. It consists of 2
ear rods that prevent the movement ofear rods that prevent the movement of
head in horizontal plane.head in horizontal plane.
 Vertical stabilization of the head is broghtVertical stabilization of the head is broght
by an orbital pointer that contacts theby an orbital pointer that contacts the
lower border if left orbit. The upper partlower border if left orbit. The upper part
of the face is supported by the foreheadof the face is supported by the forehead
clamp positioned above the region ofclamp positioned above the region of
nasal bridgenasal bridge

 The distance between the x-raysThe distance between the x-rays
source and the mid sagital plane ofsource and the mid sagital plane of
the plane is fixed at 5 feetthe plane is fixed at 5 feet

Cephalometric landmarksCephalometric landmarks
 There are two types:There are two types:
 1.anatomical land marks1.anatomical land marks
 2.derived land marks2.derived land marks
 Anatomical landmarks represent actual landmarks of skull.Anatomical landmarks represent actual landmarks of skull.
 Derived landmarks are obtained secondarily from anatomicalDerived landmarks are obtained secondarily from anatomical
structures from cephalogram.structures from cephalogram.
 1.NASION: The most anterior part of midway between the frontal1.NASION: The most anterior part of midway between the frontal
and the nasal bone on the frontonasal suture.and the nasal bone on the frontonasal suture.
 2.ORBITALE:The lowest point on the inferior bony margin of the2.ORBITALE:The lowest point on the inferior bony margin of the
orbit.orbit.
 3.PORION:The highest point on the upper margin of external3.PORION:The highest point on the upper margin of external
auditary meatus.auditary meatus.
 4.SELLA:The point representing the mid point of the pitutary fossa4.SELLA:The point representing the mid point of the pitutary fossa
and sella tursica.It is the constricted point on the midsagitaland sella tursica.It is the constricted point on the midsagital
plane.plane.
 5.POINT A: It is the deepest point in the midline between the5.POINT A: It is the deepest point in the midline between the
anterior nasal spine and alveolar crest between the two centralanterior nasal spine and alveolar crest between the two central
incisors.It is also called subspine.incisors.It is also called subspine.

 POINT B: It is the deepest point in the midline between thePOINT B: It is the deepest point in the midline between the
alveolar crest of mandible and the mental process.It is alsoalveolar crest of mandible and the mental process.It is also
called supra mentale.called supra mentale.
 BASION: It is the median point of the anterior margin of foramenBASION: It is the median point of the anterior margin of foramen
magnum.magnum.
 BOLTONS POINT: It is the highest point at the post condylarBOLTONS POINT: It is the highest point at the post condylar
notch of the occipital bone.notch of the occipital bone.
 ANTERIOR NASAL SPINE: It is the anterior tip of the sharp bonyANTERIOR NASAL SPINE: It is the anterior tip of the sharp bony
process of the maxilla in the midline of lower margin of anteriorprocess of the maxilla in the midline of lower margin of anterior
nasal opening.nasal opening.
 GONION: It is the constricted point at the junction of ramal planeGONION: It is the constricted point at the junction of ramal plane
and the mandibular plane.and the mandibular plane.
 POGONION: It is the most anterior part of the bony chin in thePOGONION: It is the most anterior part of the bony chin in the
median plane.median plane.
 MENTON: It is the most inferior midline point on the midlineMENTON: It is the most inferior midline point on the midline
symphysis.symphysis.
 GNATHION: It is the most anterio inferior point on the symphysisGNATHION: It is the most anterio inferior point on the symphysis
of the chin.It is constricted by intersecting a line drawnof the chin.It is constricted by intersecting a line drawn
perpendicular to the line connecting menton and pogonion.perpendicular to the line connecting menton and pogonion.

 ARTICULARE: It is the point at the junction of the posteriorARTICULARE: It is the point at the junction of the posterior
border of the ramus and the inferior border of the basilarborder of the ramus and the inferior border of the basilar
part of the occipital bone.part of the occipital bone.
 CONDYLION:The most superior point on the head of theCONDYLION:The most superior point on the head of the
condyle.condyle.
 PROSTHION:The lowest and the most anterior point on thePROSTHION:The lowest and the most anterior point on the
alveolar bone in the midline between the upper centralalveolar bone in the midline between the upper central
incisor.It is also called supra dentale.incisor.It is also called supra dentale.
 INFRADENTALE:The giughest and most anterior point onINFRADENTALE:The giughest and most anterior point on
the alveolar process in the median plane between thethe alveolar process in the median plane between the
mandibular central incisors.mandibular central incisors.
 POSTERIOR NASAL SPINE: The intersection continuation ofPOSTERIOR NASAL SPINE: The intersection continuation of
the anterior wall of the pterygopalatine fossa and the flloorthe anterior wall of the pterygopalatine fossa and the flloor
of the nose making distal limit of the maxilla.of the nose making distal limit of the maxilla.

 BROADBENT REGISTRATION POINT : it is the mid point ofBROADBENT REGISTRATION POINT : it is the mid point of
the perpendicular from the center of selle tursica to thethe perpendicular from the center of selle tursica to the
bolton plane.bolton plane.
 CHELION: It is the lateral terminus of the oral slit on theCHELION: It is the lateral terminus of the oral slit on the
outer corner of the mouth .outer corner of the mouth .
 PTM POINT:It is the intersection of the inferior border ofPTM POINT:It is the intersection of the inferior border of
the foramen ratandum with the posterior wall of thethe foramen ratandum with the posterior wall of the
pterygo maxillary fissure.pterygo maxillary fissure.
 GLABELLA:It is the most prominent point of the forehead inGLABELLA:It is the most prominent point of the forehead in
the midsagital plane .the midsagital plane .
 SUBNASALE:The point where lower border of the noseSUBNASALE:The point where lower border of the nose
meets the outer counter of the upper lip.meets the outer counter of the upper lip.

LINES AND THE PLANES INLINES AND THE PLANES IN
THE CEPHALOMETRICSTHE CEPHALOMETRICS
 HORIZANTAL PLANESHORIZANTAL PLANES::
 1.S-N PLANE1.S-N PLANE:Connects sella and:Connects sella and
nasion represents anteroir cranialnasion represents anteroir cranial
base.base.

 FRANKFORT HORIZANTAL PLANEFRANKFORT HORIZANTAL PLANE..
 This plane connects the lowest pointThis plane connects the lowest point
of the orbit and the pornion.of the orbit and the pornion.

 PALATAL PLANE:It is the line linkingPALATAL PLANE:It is the line linking
the anterior nasal spine of maxillathe anterior nasal spine of maxilla
and posterior nasal spine of palatineand posterior nasal spine of palatine
bone.bone.

 OCCULSAL PLANEOCCULSAL PLANE: It is the denture: It is the denture
plane bisecting occlusion ofplane bisecting occlusion of
permanent molars and premolarspermanent molars and premolars
and extend anteriorly.and extend anteriorly.

 MANDIBULAR PLANE:MANDIBULAR PLANE: SeveralSeveral
mandibular planes are used inmandibular planes are used in
cephalometrics.cephalometrics.
 1.tangent to lowerborder of1.tangent to lowerborder of
mandible.mandible.
 2.A line connecting gonion and2.A line connecting gonion and
gnathiongnathion
 3.A line connecting gonion menton3.A line connecting gonion menton

 BASION – NASION PLANE: It is theBASION – NASION PLANE: It is the
line connecting the basion and theline connecting the basion and the
nasion . It represents the cranialnasion . It represents the cranial
base.base.

 BOLTONS PLANE:This is the planeBOLTONS PLANE:This is the plane
that connects the boltons pointsthat connects the boltons points
posterior to the occipital condyle andposterior to the occipital condyle and
the nasion.the nasion.

Vertical planesVertical planes
 A-POG LINE; It is the line from pointA-POG LINE; It is the line from point
A on the maxilla to pogonion on theA on the maxilla to pogonion on the
mandible.mandible.

 FACIAL PLANE: It is the line fromFACIAL PLANE: It is the line from
anterior point of the fronto nasalanterior point of the fronto nasal
suture to the most anterior part ofsuture to the most anterior part of
the mandible.the mandible.

 FACIAL AXIS:- A line from ptmFACIAL AXIS:- A line from ptm
point to cephalometric gnathionpoint to cephalometric gnathion

 E PLANE:- or the esthetic plane is aE PLANE:- or the esthetic plane is a
line between the most anterior partline between the most anterior part
of soft tissue nose and soft tissueof soft tissue nose and soft tissue
chinchin

DOWNSDOWNS
ANALYSISANALYSIS
 It consists of ten parametersIt consists of ten parameters
• 5 skeletal parameters5 skeletal parameters
• 5 dental parameters5 dental parameters
 Skeletal parameters:-Skeletal parameters:-
 FACIAL ANGLE =87.8FACIAL ANGLE =87.8
 Ranges from 82-95 It indicates anteroRanges from 82-95 It indicates antero
posterier postioning of the mandible inposterier postioning of the mandible in
relation to upper facerelation to upper face
 Increases in case of skeletal class IIIIncreases in case of skeletal class III
 Decreases in case of skeletal class IIDecreases in case of skeletal class IIwww.indiandentalacademy.comwww.indiandentalacademy.com

Angle of convexity = 0Angle of convexity = 0
 Ranges from -8.5 to 10Ranges from -8.5 to 10
 Angle is formed by the intersection of a line from nasionAngle is formed by the intersection of a line from nasion
to point –A & a line from point-A to pogonion .to point –A & a line from point-A to pogonion .
 This angle reveales the convexity or concavity of skeletalThis angle reveales the convexity or concavity of skeletal
profileprofile
 Increases in maxilary prominenceIncreases in maxilary prominence
 Decreses in mandible prominenceDecreses in mandible prominence

A-B plane angle:A-B plane angle:
 Mean value is -4.6,it ranges from 9 to 0Mean value is -4.6,it ranges from 9 to 0
 Angle is formed between a line connecting point-A &Angle is formed between a line connecting point-A &
point-B and a line joining facil plane .point-B and a line joining facil plane .
 It indicates the maxillo mandibular relationship in relationIt indicates the maxillo mandibular relationship in relation
to facial plane.to facial plane.
 Increases in cases class iii mal occlusionIncreases in cases class iii mal occlusion

MANDIBULAR PLANE ANGLE:21.9MANDIBULAR PLANE ANGLE:21.9
 Formed by the intersection of theFormed by the intersection of the
mandibular plane with the F.H plane .mandibular plane with the F.H plane .
 Decreases horizantal growing faceDecreases horizantal growing face
 Increases vertical growing individualIncreases vertical growing individual
 Increased mandibular plane is suggestiveIncreased mandibular plane is suggestive
of a vertical growth.of a vertical growth.
 Ranges from : 17- 28Ranges from : 17- 28

Y- axis-59Y- axis-59
 Ranges from 53 to 66Ranges from 53 to 66
 Angle is obtained by joining sella gnathion line with theAngle is obtained by joining sella gnathion line with the
F.H plane .F.H plane .
 Increase in case of classII facial pattern.Increase in case of classII facial pattern.
 Decrease indicates greater horizantal growth of mandible.Decrease indicates greater horizantal growth of mandible.

DENTAL PARAMETERSDENTAL PARAMETERS
CANT OF OCCLUSAL PLANE :9.3CANT OF OCCLUSAL PLANE :9.3
Is formed between the occlusal plane and the F.H plane .Is formed between the occlusal plane and the F.H plane .
Ranges from 1.5 to 14 degreeRanges from 1.5 to 14 degree
This angles gives the measure of the slope of the occlusal planeThis angles gives the measure of the slope of the occlusal plane
relative to F-h planerelative to F-h plane

Inter incisal angle:135.4Inter incisal angle:135.4
 Ranges from 130-150.5 degreeRanges from 130-150.5 degree
 Angle is formed between the long axis of upper 7& lowerAngle is formed between the long axis of upper 7& lower
incisors .incisors .
 Increases in class II, division 2 case.Increases in class II, division 2 case.
 Decreases in class I bi maxillary protrusionDecreases in class I bi maxillary protrusion

Incisor occlusal plane angle 14.5Incisor occlusal plane angle 14.5
degreedegree
 Ranges from 3.5-20 degreeRanges from 3.5-20 degree
 Inside inferior angle formed by the intersection betweenInside inferior angle formed by the intersection between
the long axis of lower central incisor and the occlusalthe long axis of lower central incisor and the occlusal
plane .plane .
 Increses in case of lower incisor proclinationIncreses in case of lower incisor proclination

Incisor mandibular plane angle :Incisor mandibular plane angle :
1.41.4
 Angle is formed by the intersectionAngle is formed by the intersection
of the long axis of the lower incisorof the long axis of the lower incisor
and the mandibular plane.and the mandibular plane.
 Range is -8.5 to 7.Range is -8.5 to 7.
 Increase in angle is indicative ofIncrease in angle is indicative of
lower incisor proclination.lower incisor proclination.

Upper incisor to A- pog line:Upper incisor to A- pog line:
2.7mm2.7mm
 Is a linear measurement between theIs a linear measurement between the
incisal edge of the maxillary centralincisal edge of the maxillary central
incisor and the line joining point-A toincisor and the line joining point-A to
pogonion.pogonion.
 Measurement is more in ptsMeasurement is more in pts
presentin with upper incisorpresentin with upper incisor
proclination.proclination.

STEINER ANALYSIS:STEINER ANALYSIS:
 DIVIDED INTO 3 PARTS :DIVIDED INTO 3 PARTS :
 1. SKELETAL ANALYSIS1. SKELETAL ANALYSIS
 2. DENTAL ANALYSIS2. DENTAL ANALYSIS
 3. SOFT TISSUE ANALYSIS3. SOFT TISSUE ANALYSIS

Skeletal analysis:Skeletal analysis:
SNA Angle:82 degreeSNA Angle:82 degree
 Angle formed by the intersection ofAngle formed by the intersection of
S.N plane and a line joining nasionS.N plane and a line joining nasion
and point-A .and point-A .
 Increases in the cases of prognathicIncreases in the cases of prognathic
maxillamaxilla
 Decreases in cases of retrognathicDecreases in cases of retrognathic
maxillamaxilla

S.N.B angle : 80 degreeS.N.B angle : 80 degree
 Angle between the S.N plane and theAngle between the S.N plane and the
line joining nasion to point – B.line joining nasion to point – B.
 Increases in prognathic mandibleIncreases in prognathic mandible
 Decreases in retrosive mandibleDecreases in retrosive mandible

ANB ANGLE:2 DEGREEANB ANGLE:2 DEGREE
 Angle id formed by the intersectionAngle id formed by the intersection
of lines joining nasion to point-Aof lines joining nasion to point-A
and nasion to point –B.and nasion to point –B.
 Increases in class II skeletalIncreases in class II skeletal
tendencytendency
 Decreases in class III relation shipDecreases in class III relation ship

Mandibular plane angleMandibular plane angle
32degree32degree
 Angle formed between S.N plane andAngle formed between S.N plane and
the mandibular plane.the mandibular plane.
 Decreases horizantal growing faceDecreases horizantal growing face
 Increases vertical growing indivualIncreases vertical growing indivual

Occlusal plane angle: 14.5Occlusal plane angle: 14.5
 Angle is formed between the occlusalAngle is formed between the occlusal
plane and the S.N plane .plane and the S.N plane .
 Indicates the relation of the occlusalIndicates the relation of the occlusal
plane to the cranium and face.plane to the cranium and face.
 Also indicates the growth pattern ofAlso indicates the growth pattern of
an individual.an individual.

DENTAL ANALYSISDENTAL ANALYSIS
 UPPER INCISOR TO N-A ANGLE –22UPPER INCISOR TO N-A ANGLE –22
 Angle is formed by the intersectionAngle is formed by the intersection
of the long axis of upper centralof the long axis of upper central
incisor and the line joining nasion toincisor and the line joining nasion to
point-A.point-A.
 This angle indicates the relativeThis angle indicates the relative
increases of upper incisorincreases of upper incisor
 Increase in class II divisionIncrease in class II division
malocclusionmalocclusion

Upper incisor to N-A linearUpper incisor to N-A linear
 Is a linear measurement between theIs a linear measurement between the
labial surface of upper central incisorlabial surface of upper central incisor
and the line joining nasion to point –and the line joining nasion to point –
A.A.
 Increase in proclined upper incisorIncrease in proclined upper incisor

Lower incisor to N-B,angle:25Lower incisor to N-B,angle:25
 Angle is formed between the labialAngle is formed between the labial
surface of lower central incisor andsurface of lower central incisor and
the line joining nasion to point –B.the line joining nasion to point –B.
 Increases in proclined lower incisorsIncreases in proclined lower incisors

Lower incisor to N-b linear-4mmLower incisor to N-b linear-4mm
 Increase in lower proclined incisorsIncrease in lower proclined incisors

Inter incisor angle 130 toInter incisor angle 130 to
131degree131degree
 Increases in class II div II malIncreases in class II div II mal
occlusionocclusion

SOFT TISSUE ANALYSISSOFT TISSUE ANALYSIS
 According to steiner the lips in aAccording to steiner the lips in a
well balanced position should touchwell balanced position should touch
a line extending from soft tissuea line extending from soft tissue
counter of chin to the middle of thecounter of chin to the middle of the
S formed by lower border of nose .S formed by lower border of nose .

TWEED ANALYSISTWEED ANALYSIS Makes use of 3 planes that fromMakes use of 3 planes that from
diagnostic triangle.diagnostic triangle.
 FH planeFH plane
 Mandibular planeMandibular plane
 Long axis of incisorLong axis of incisor
 1.Frankfort mandibular plane angle1.Frankfort mandibular plane angle :the:the
angle is 25.angle is 25.
 2.IMPA :Incisor mandibular plane angle2.IMPA :Incisor mandibular plane angle
9090
 3. FMPA:Frankfort mandibular incisor3. FMPA:Frankfort mandibular incisor
angle 65angle 65

Tweed analysisTweed analysis

WITS APPRAISALWITS APPRAISAL
 It is used when ANB angleIt is used when ANB angle
considered not so reliable.considered not so reliable.
 In case of skeletal classII tendencyIn case of skeletal classII tendency
BO is usually behind AO.PositiveBO is usually behind AO.Positive
reading.reading.
 Skeletal class II the point BO isSkeletal class II the point BO is
located ahead of AO,negativ reading.located ahead of AO,negativ reading.

Wits apprasialWits apprasial

ERRORS IN CEPHALOMETRYERRORS IN CEPHALOMETRY
 1.Magnification:1.Magnification:these arrrors are becausethese arrrors are because
the x- ray beams are not parallel with allthe x- ray beams are not parallel with all
points of the object.points of the object.
 Thiss can be minimised by using a longThiss can be minimised by using a long
focus object distance. And short objectfocus object distance. And short object
film distance.film distance.
 2.DISTORTON2.DISTORTON landmarks and structureslandmarks and structures
not situated in the mid sagital plane arenot situated in the mid sagital plane are
usually bilateral and may cause dualusually bilateral and may cause dual
images in radiographimages in radiograph
 This can be minimised by recording theThis can be minimised by recording the
mid point of two imagesmid point of two images

Errors with in measuring systemErrors with in measuring system
 Human error may creep in during theHuman error may creep in during the
tracing and measurementstracing and measurements
 This can be minimised by use ofThis can be minimised by use of
computerized plotters and digitizerscomputerized plotters and digitizers

Errors in landmark identificationErrors in landmark identification
 Quality of radiograph image :- poorQuality of radiograph image :- poor
definition of radiographs may cause errordefinition of radiographs may cause error
 So recommended film should be usedSo recommended film should be used
 Motion blur may occur so stabilization ofMotion blur may occur so stabilization of
the object is necessarythe object is necessary
 Operator bias:- variation have beenOperator bias:- variation have been
observed in landmark identificationobserved in landmark identification
between operators. So it is advisable forbetween operators. So it is advisable for
the same person to identify and trace inthe same person to identify and trace in
patients who are subject to serialpatients who are subject to serial
supplement study.supplement study.

THANKTHANK
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