Cephalometric Analysis

• Types LATERAL CEPHALOGRAMFRONTAL CEPHALOGRAM

• USES

Helps in orthodontic diagnosis.Helps in classification of skeletal and dental

abnormalities.Helps in planning treatment of an individual.Helps in evaluation of treatment results.Helps in predicting growth related changes.

LANDMARKS

Horizontal Planes in Cephalometry

Cephalometric Analysis

• Downs Analysis

• Steiner Analysis

• Tweed Analysis

• Wits Appraisal

Downs Analysis

• It is one of the most frequently used cephalometric analysis.

• Downs analysis consists of ten parameters of which five are skeletal and five are dental.

Skeletal ParametersFACIAL ANGLE

• It is the inside inferior

angle formed by

intersection of nasion -

pogonion line and F.H.

plane.

• Average value- 87.8’

( 82 – 95’)

• Significance - Indicates

antero - posterior

positioning of mandible in

relation to upper face.

Angle is increased in

skeletal class III with

ANGLE OF CONVEXITY

• Angle formed at the

inersection nasion-point A

to point A – pogonion.

• Average value; 0’

( -8.5 to 10’).

• Significance- A positive

angle suggest a prominent

maxillary denture base in

relation to mandible.

• Negative angle is

indicative of prognathic

profile.

A-B PLANE ANGLE

• Angle formed at the

intersection of point A –

point B line to nasion –

pogonion line.

• Average value- -4.6’

( -9 to 0’)

• Significance- indicative

of maxillo mandibular

relationship in relation to

facial plane.

• Negative since point B

is positioned behind point

A.

• Positive in class III

malocclusion.

MANDIBULAR PLANE ANGLE

• Angle formed at the

intersection of mandibular

plane with F.H.

Plane.

• Average value-

21.9’ ( 17 to 28’)

Y-AXIS

• Angle formed b/w sella

gnathion to F.H. plane.

• Average value; 59’ ( 53’

to 66’)

• Angle is larger in class

II facial patterns.

Indicates growth pattern

of a individual.

CANT OF OCCLUSAL PLANE

• Angle formed b/w

occlusal plane to F.H.

Plane

• Average value- 9.3 (

1.5 to 14’)

• Gives a measure of

slope of occlusal plane

relative to F.H. Plane.

INTER INCISAL ANGLE

• Angle between long axes

of upper and lower

incisors.

• Average value: 135.4’ (

130 to 150.5’)

• Decreased in case of

bidental protrusion

INCISOR OCCLUSAL PLANE ANGLE

• This is the inside inferior

angle formed by the

intersection between the

long axis of lover central

incisor and the occlusal

plane and is read as a

plus or minus deviation

from a right angle

• Average value: 14.5” (

3.5 to 20’)

• An increase in this

angle is suggestive of

increased lower incisor

proclination.

INCISOR MANDIBULAR PLANE ANGLE

• This angel is formed by

intersection of the long

axis of the lower incisor

and the mandibular plane.

• Average value: 1.4’(-8.2

to 7’)

• An increase in this angle

is suggestive of increased

lower incisor proclination.

UPPER INCISOR TO A-POG

• This is a linear

measurement between

the incisal edge of the

maxillary central incisor

and the line joining point

A to pogonion. This

distance is on an average

4mm mm(rang-1 to 5

mm)

• The measurement is

more in patients

presenting with upper

incisor proclination.

STEINER ANALYSIS

• SKELETAL PARAMETERS

SNA ANGLE

SNB ANGLE

ANB ANGLE

MANDIBULAR PLANE ANGLE

OCCLUSAL PLANE ANGLE

• DENTAL PARAMETERS

UPPER INCISOR TO N-A ANGLE

UPPER INCISOR TO N-A LINEAR

LOWER INCISOR TO N-B ANGLE

LOWER INCISOR TO N-B LINEAR

INTER INCISOR ANGLE

• SOFT TISSUE ANALYSIS

S LINE

SNA (Maxillary position) 82.0

SNB (Mandibular position) 80

ANB (Maxillary/Mandibular relation) 2

lncisor to NA (Upper incisors to NA mm) 4mm

lncisor to NA (Upper incisors to NA degree) 22

lncisor to NB (Lower incisors to NB mm) 4mm

lncisor to NB (Lower incisors to NB degree) 25

lnter-incisal angle 131

Mandibular plane angle 32

SN to occlusal plane 14

TWEED ANALYSIS

Makes use of three planes

1. Frankfort horizontal plane

2. Mandibular plane

3. Long axis of lower incisors

FMA (Frankfurt plane to

mandibular plane)16-35

FMIA (Frankfurt plane to lower

incisor angulation)85-95

IMPA (Lower incisor to

mandibular plane)60-75

WITS APPRAISAL

• Measures the relationship of maxilla and mandible to each other and to the sagitalplane

• Used where ANB are not realiable

• Perpendicular are drawn from point A and point B to the functional occlusal plane to form AO and BO