Hard tissue cephalometric analysis

Hard tissue cephalometric
analysis
www.indiandentalacademy.com

CONTENTS
Introduction
• Definition and classification
• Various analyses:
Lateral cephalometric analysis:
Downs analysis
Steiner’s analysis
Tweeds analysis
WITTS appraisal
Rickett’s analysis
McNamara analysis
Rakosi’s functional analysis
Bjork analysis,Jarabak anaylsis
COGS analysis
Quadrilateral analysis

• Pitchfork analysis
• Postero-anterior cephalometric analyses:
purpose
Ricketts analysis
Grummons analysis
• Conclusion

CEPHALOMETRIC
ANALYSIS
A COLLECTION OF NUMBERS INTENDED TO
COMPRESS MUCH OF THE INFORMATION FROM
THE CEPHALOGRAM INTO A USABLE FORM OF
DIAGNOSIS,TREATMENT PLANNING, AND/OR
ASSESMENT OF TREATMENT EFFECTS.

• Only after completion of
thoughtful,systematic evaluation should
cephalometric tracings be done.
• Ceph analysis is used to asses
compare,express and predict the spatial
relationships of the soft tissues and the
craniofacial and dentofacial complexes.

Systematic approach to patient facial analysis

• The analysis can be : objective
subjective
• Objective:quantification of spatial
relationships by angular or linear
measurements.
• Subjective:visualization of changes in
spatial relationships of areas or anatomical
landmarks.

It provides information about sizes
and shapes of the craniofacial
components and their relative
positions and orientations.

Requisites
Cephalometric analysis with a reasonable
clinical base should be:
1. Use reference points that are clearly
defined and easy to locate.
2. Rely more than one bone reference
plane since these planes are themselves
variables.

3 consider natural head position because
resulting values then often reflect the
actual appearance of the patient better.
4 Be clearly structured in skeletal and
dentoalveolar assesments and always
distingiush b/t different
planes(sagittal,vertical,transeverse)
5 Include as few measurements as
possible,so that an optimal overview is
maintained at any time.

6 Include graphical representation,which
is useful for immediate understanding and
which enhances communication with non-
orthodontic colleagues and with patients.
7 Be structured so that it can be changed
without difficulty when better insight
requires an adaptation.

Classification of ceph.
analysis
• Basic methods of classification:
• A)Methodological classification:Basic units of
classification are angles and distances in mm:
angular analyses
linear analyses
angular analysis :
dimensional analysis eg:Down’s analysis
(considers various angles in isolation comparing
them with avg norms)
proportional analysis eg:Koski’s analysis

Methodological
Anglular
Dimensional
Analysis
Eg:Down’s

Methodological
Angular
Proportional
Analysis
Eg:
Koski’s analysis

• Linear analyses:
Orthogonal analyses –a ref plane is established with various
ref points projected onto it perpendicularly after which
distances b/t the projections are measured
geometrical
Total orthogonal analyses eg: de Coster
arithmetical
(ref points projected onto H AND V ref planes,distances
b/t projected points measured)
Partial orthogonal analysis
Archial analysis eg: Sassouni analysis
(ref points projected by drawing arcs)

Total geometric
Orthogonal analysis:

Coben’s
Total Orthogonal
Arithmetical Analysis

Arcial analysis
Sassouni’s archial
analysis

Linear analyses contd.
• Dimensional linear analyses
- Direct method
- Projected method
• Proportional linear analyses:
based on relative rather than absolute
values,measurements compared to each
other than to norms

• B) Normative classification:accr to concepts
on which norms have been based on
Mononormative analyses- averages are norms
Multinormative analyses
Correlative analyses- to asses indiv variations
of facial str,to establish their mutual
relatioship
• C)Accr. to area of analyses:
Dento skeletal analyses
Soft tissue analyses
Functional analyses

DOWN'SANALYSIS

Downs analysis contd.
• Position of mandible used to determine
facial balance.
• 4 basic facial types:
Retrognathic - recessive lower jaw
Mesognathic - ideal / average
Prognathic - protrusive
True prognathism – pronounced protrusionwww.indiandentalacademy.com

• Choice of reference plane - FH plane
• Control material-20 white
subjects(12-17yr)

1. SKELETAL PATTERN
2. DENTAL PATTERN

SKELETAL PATTERNS
Facial angle (87.5°)
Angle of convexity(0°)
A-B plane (-4.6°)
Mandibular plane angle (21.9°)
Y-axis (59.4°)

1) Facial angle
• Measures degree of retrusion or
protrusion of lower jaw .
• (Na – Pog ) Facial line + FH
• in prominent chin, in
retrusive chin

Mean Reading : 87.5o
Range : 82o
– 95o

2) Angle of convexity
• Measures the degree prominence of
maxillary basal arch at its anterior
limit (point A) relative to total facial
profile
• + reading – A-Pog anterior to N-A
i.e, prominence of maxillary denture
base relative to mandible

Mean Reading : 0o
Range : -8.5o
– 10o

3) A-B plane
• Measures the relation of anterior limit ofrelation of anterior limit of
apical bases to each otherapical bases to each other relative to the
facial line.(N-Pog)
• Estimate of difficulty in obtaining correct
axial inclination and incisor relation

Mean Reading : -4.6o
Range : 0o
– - 9o

A –B plane contd.
• Usually negative – as point B is behind A
• Large ve- : class II facial pattern

4) Mandibular plane angle
• MP : tangent to gonial angle and lowest
point of symphysis.
• MPA : MP related to FH

Range : 17o
– 28o

4)Mandibular plane angle
contd.
High MPA:
• unfavorable hyperdivergent facial pattern
• Can occur both in retrusive and protrusive
faces
• But not sufficient alone to indicate nature of
difficulty that may be experienced during
treatment

5) Y- axis / Growth Axis
• Indicates the degree of downward,
rearwards or forward position of the chinposition of the chin
in relation to the upper face.
• Acute angle at S-Gn with FH

Range : 53o
– 66o

b) Dental patterns
1. Cant of the occlusal plane
2. Inter-incisal angle
3. Incisor – occlusal plane angle
4. Incisor mandibular plane angle
5. Protrusion of maxillary incisors

Planes
1. FH plane
2. Palatal plane
3. Occlusal plane
4. Mandibular plane

1) Cant of occlusal plane
• OCCLUSAL PLANE:
overlapping cusps of 6s & incisal
overbite OR
overlapping cusps 4s & 6s.
CANT: Slope of occlusal plane to FH
• When ant part lower than posterior, angle is large
Class II pattern
• Long rami tend to angle

Mean Reading : 9.3o
Range : 1.5o
– 1.4o

2) Interincisal angle
Line through incisal edges and apex of
roots of incisors.
Small in anteriorly tipped teeth.

Mean reading : 135.4o
Range : 130o
– 150o

Mean reading : 1.4o
Range : -8.5o
– 7o

4) Incisor occlusal plane angle
• Relates lower
incisors to functional
surface at occlusal
plane.
• Mean 14.5°
• Range 3.5 to 20°

5)Protrusion of maxillary incisors
• Distance b/t incisal
edge to A-Pog.
• Mean 2.7mm
• Range –1 to +5mm

The polygon / wiggle
• Vorheis & Adams (1951)
• developed a polygon to express this
large
grp of ceph readings graphically.

The Polygon contd.
• Central vertical line along which means
are located.
• The range (max & min) to right and left,
located at each angle of the polygon,
each horizontal marking=1mm or 1 degree
• Readings on left indicate class II type of
face; on right class III type

• Zig zag pattern
skeletal(upper ½)
• Poygon subdivided
Dental pattern
• Effective comprehensive method of
quantitaively & qualitatively illustrating a
static ceph analysis.

STEINER’SANALYSIS

• Cecil c. Steiner
• Selected what he considered to be the
most meaningful parameters & evolved a
composite analysis
• Maximum clinical information with
minimum measurments.

STEINER’S ANALYSIS
SKELETAL ANALYSIS
DENTAL ANALYSIS
SOFT TISSUE ANALYSIS

a)Skeletal analysis
• Relates upper & lower jaws to skull & to each
other.
• Choice of reference plane:
S-N(Ant Cr. Base)
• On lat ceph. landmarks like porion & orbitale
not easily identified.
• Adv : S & N midline points that are moved
min. when head deviates from true profile
position

Skl analysis contd.
1. SNA
2. SNB
3. ANB
4. OP to SN
5. PM to SN

Mean reading : 82o
Det position of maxilla to cranial
base

• > 82 ° : relative forward positioning of
maxilla.
• < 82° : relative recessive positioning of
maxilla.

Mean reading : 80o

SNA and SNB interpretations are valid only if
the SN plane is normally inclined to the true
horizontal (6°) and the position of N is normal

3)ANB
Relative
forward /backward
positions
of the jaws
to each other.

ANB
Mean reading : 2o

• > 2 ° : class II skeletal tendency, larger
the angle greater the A-P discrepancy of
maxillary to mandibular apical bases.
• < 2° : mandible is located ahead of the
maxilla,class III tendency.

Mean reading : 14o

Mean reading : 32o
MP: GONION-GNATHION
Indication of vertical
proportions of face
>32° unfavorable
growth pattern www.indiandentalacademy.com

Relative position of
upper incisors to
lower incisors.
Mean reading :
130o

• Compares the prominence of the chin with
the prominence of the lower incisor,
establishes the balance b/t them.
• The more prominent the chin the more
prominent the incisors can be and vise-
versa.This imp rel is reffered to as
HOLDAWAY RATIO.

TWEEDS ANALYSIS

• Developed this analysis as an aid to
treatment planning, anchorage preparation
and determining the prognosis of
orthodontic cases.
• Emphasis on placement of mandibular
incisors for the preservation of results.

• Tweeds triangle : formed by
FHP
MP
IMP (Long axis of lower incisors)

• 3 angles : FMA = 25°
IMPA = 90°
FMIA = 65°
• FMA =16 to 28° prognosis good
28 to 35° fair
> 35° bad prognosis,extractions may
further complicate the problem
• Recommended FMIA maintained at 65° to 70°

1. Analysis determines the final position the
lower incisors should occupy at the end of
treatment , once this position of incisors
determined , the space requirement could be
calculated and decision regarding extraction
made.
2. Prognosis could be relatively accurately
based on the configuration of the triangle.

WITS APPRAISAL

Is the ANB angle a reliable
indicator of jaw discrepancy
or not?

• Example of ANB not
reflecting the degree
of A-P jaw
disharmony

Craniofacial skeletal variations affects ANB:
1. The A-P spatial relationship of jaws
relative to the cranium
2. The rotational effect of the jaws relative to
cranial reference planes : ant cranial base.

• Any change in the relative forward or
backward positioning of nasion by virtue
of an excessively long or short Ant cranial
base (S-N) or
• Relative posterior - anterior positioning of
jaws within the skl craniofacial complex will
directly influence the ANB reading.
• Reliability of ANB suspect in cases where
MPA is > 38° or < 27°

Anteroposterior relationship of the jaws relative to cranium

Rotational effect of the jaws relative to the anterior cranial base

• Purpose of WITS:
To identify cases where ANB reading donot
accurately reflect the extent of A-P jaw
dysplasia.
• It is a measure of extent to which jaws are
related to each other A-P ly.

METHOD OF WITs
Avg reading:
-1mm for males
0mm for females

In skeletal class II
cases BO located
well behind AO

• In skeletal class III
BO in front.
• WITs reading
negative

WITs appraisal applied

Application of WITs appraisal

Application of WITs appraisal to
class III

• The more the wits readings deviate
from -1mm in males and 0mm
in females the greater the horizontal jaw
disharmony.

Occlusal plane angulation
• The effect on WITS
value of the occlusal
plane angulations and
distance betweeen the
points A and B

• To sum up wits appraisal is a linear
measurement and not an analysis per se.
• It is an adjunctive diagnostic aid that may
prove useful in
-- assessing the extent of antero posterior
skeletal dysplasia and
--in determining the reliability of ANB

Steiner’s chevrons
• Whereas the ideal ANB relationship of
maxilla to mandible as described by points
A & B is 2°,the chevrons describe
anticipated axial inclinations of the
maxillary and mandibular incisors to the
NA & NB lines at various ANB
relationships

Example of
chevron
• ANB was 6 at the end of
treatment,
• Acceptable compromise
relations of maxillary
incisor to NA line are 18 ,
0mm
• Of mandibular incisors are
29 ,5mm
• Skeletal the patient is still
class II but dental relation
masks the underlying
skeletal discrepancy

McNAMARA ANALYSIS

McNamara (1984)
normative standards used was derived
from sources:
• Lateral cephalogram of children comprising of
the Bolton’s Standards
• Selected values from a group of untreated
children from Burlington research center.
• Sample of young adults from Ann Arbor having
excellent dental and facial pattern.

Skeletal Vs Dentoalveolar
components
of malocclusion

Skeletal Vs dentoalveolar
components of malocclusion
• Maxillary skeletal
protrusion
• Maxillary
dentoalveolar
protrusion

• Soft tissue evaluation:
nasolabial angle
cant of the upper lip
airway analysis
• Hard tissue evaluation

Craniofacial skeleton has been divided into five sections
 Maxilla to cranial base
 Maxilla to mandible
 Mandible to cranial base
 Dentition
 Airway

Maxilla to cranial base

SOFT TISSUE EVALUATION
1. NASOLABIAL ANGLE
2. CANT OF UPPER LIP

Nasiolabial angle : 102o +
8o

Cant of the Upper lip :
Women : 14o +
8o
Men : 8o +
8o

MAXILLA TO CRANIAL BASE

• Hard tissue evaluation:
A-P orientation of maxilla relative to
cranial base.
distance of point A to NASION
PERPENDICULAR.

Mcnamara-hardtissue evaluation
Maxilla to cranial base
• A to Pog
IN WELL BALANCED
FACES:
0mm ( MIXED
DENTITION)
1MM( ADULTS)

• Maxillary
skeletal
protrusion

• Maxillary skeletal
retrusion

Maxilla to mandible

• 2 relations-
Anteroposterior relationship
Vertical relationship

• Anteroposterior relationship:
linear relationship exists between
effective midface length(Co –point A) and
that of mandible length(Co-Gn)

• Any given MFL corresponds to an
effective mandibular length within a given
range.
• The lengths of either midface or mandible
described in the analysis is not gender or
age dependent,but related only to the
component part size.
• Terms small ,medium,large used instead of
mixed dentition ,adult female , adult male

Normative
standards

Co
A
Gn
Maxillomandibular differential = Midfacial length – Effective
mandibular length

Ideal maxillomandibular differential
Small - 20mm
Medium - 25 – 27mm
Large - 30 – 33mm

Which Jaw?
• In the event of maxillomandibular
differential greater or smaller than the
normative values,next step is to identify
which jaw is to large or small or both or at
fault

• Maxillomandibular
relationships:
1.maxilla position
normal,mandible 9mm
deficient
2.skeletal midfacial
deficiency of
4mm,mandibular skeletal
excess 5mm

Vertical relationship:
• Lower anterior face height
• Mandibular plane angle
• Facial axis angle

• Vertical maxillary
excess
• Downward and
backward rotation of
mandible
• Increase in lower
anterior face height

• Vertical maxillary
deficiency
• Upward and backward
rotation of mandible
• Reduction the lower
anterior face height

Lower anterior face height(LAFH):
• ANS to menton
• Correlates well with effective MFL
• Ideal:
MFL LAFH
• Small indiv 85mm 60-62mm
• Medium size indiv 94mm 65-67mm
• Large size 100mm 73-77mm

• To asses LAFH
balance effective
maxillary length
correlated with lower
anterior facial height

• Excess LAFH:
effective MFL is
93mm, the LFH
should have been 65 –
66mm for balance

• Relationship b/t LAFH
and forward and
backward positioning
of chin point
• Excess LAFH causes
mandible to rotate
back,mandibular
retrusion.

Mandibular plane angle
• Anatomic FH and MP(GO-ME)
• Avg = 22 +/- 4 °
• Higher measurement –excess LFH
• Lesser angle-deficiency in LFH
• Effect of short/long mandibular ramus not
considered here

• MPA 22°

• High mandibular plane
angle ,excessive
LAFH

Angle b/t
PTM-Gn and Ba-N
Avg=90°
Here FAA of –5 °
excessive vertical
development of face

Mandible to cranial base

Mixed Dentition = 6-8mm behind nasion
perpendicular
Adult woman = 4-0mm behind nasion
perpendicular
Adult men = 2mm behind to 2mm ahead
of nasion perpendicular

Dentition

4-6mm
1-3mm

Airway Analysis

RICKETTS ANALYSIS
Landmarks:
A6 - upper molar
B6 - lower molar
C1 - point on head of
condyle
in contact with the
tangent to ramus plane
CC - centre of craniumCC
CF - PtV+FH
PT – f.rotundum+PMF

DC-centre of condyle neck
Gn-facial+MP
Go-ramus +MP
PM-suprapogonion
Pog-on bony symphysis tangent
to facial plane
PO-facial plane+corpus axis
Xi point

Ricketts-landmarks
Location of Pog
Points:
CF - PtV+FH
PT - ptf+f.rotundum
CC-cranium centre
PM - supragonion
PO - corpus axis +facial plane

Obtaining Xi point

RICKETTS analysis-planes
• Facial axis(Pt-Gn)
• Facial plane(N-Pog)

RICKETTS analysis-planes
• Pterygoid
vertical(PtV):distal r/g
outline of pterygomaxillary
fissure and perpendicular
to
FH plane
• Ba- Na
• FH

Mandibular incisor
protrusion to A-Pog
plane(Dental plane)

PLANES:
1 FH- porion to orbitale
2. Facial plane -nasion to gnathion
3. Mandibualr plane-gonion to gnathion
4. PtV-pterygoid verticalvertical line drwn through
the distal r/g outline of the pterygomaxillary
fissure and perpendicular to the frankfort
horizontal
5. Ba-na-divides face and cranium

6. Occlusal plane- line extending through
first molars and premolars
7. A-Pog line-dental plane

LANDMARKS:
1. A6- upper molar- point on the occlusal plane
located perpendicular to the distal surface of the
crown of the upper first molar.
2. B6-lower molar-point on the occlusal plane
located perpendicular to the distal surface of the
crown of the lower first molar
3. C1-condyle-point on the condyle head in contact
with and tangent to the ramus plane

4. DT-soft tissue-point on the anterior curve of the
soft tissue chin tangent to the esthetic plane or
E-Line.
4. CC-centre of cranium-point of intersection of
basion-nasion plane and facial axis.
5. CF-point of intersection of the pterygoid root
vertical to the frankfort horizontal plane.
4. PT-the junction of pterygomaxillary fissure and
the foramen rotundum:

• The outline of the foramen rotundum can
be located by using the template designed
for the purpose or can be approximated at
10:30 position on the circular outline of
the superior border of the
pterygomaxillary fissure.
8. DC-point in the centre of the condyle neck
along the BASION-N plane

9. Gn-gnathion-poitn at the intersection of facial
and mandibular planes
10. Go-gonion-point a the intersection of ramus and
mandibular planes
11. PM-suprapogonion-point at which the shape of
the symphysis mentalis changes from convex to
concave=protuberence menti.
12. Pog-pogonion-point on the bony symphysis
tangent to the facial plane.
13. PO-intersection of facial plane and the corpus
axis www.indiandentalacademy.com

14. TI point-point of intersection of occlusal
and facial planes.
15. Xi-Xi point

Ricketts analysis-axes
Corpus axis(Xi-PM)
To describe morphology of
mandible & evaluate dentition
changes

Ricketts analysis - axis
Condylar axis
( DC-Xi)
Used to describe morphlogic
features of the mandible

Ceph tracing using
ricketts analysis

CHIN IN SPACE
 Facial axis angle: 90°
lesser angle- retropositioned chin
greater angle – forward positioned chin
 FACIAL DEPTH ANGLE:87° +/- 3°
indication of horizontal position of chin
whether class II or class III is due to mand.
 MANDIBULAR PLANE:26° +/- 4.5°
EG:Steep MPA indicates open bite may be due to skl
morphologic characteristics of mandible

Convexity of Point A
Mean : 2 mm +/- 2 mm
Adjusted mean:-1mm/yr
High convexity= class II skl pattern

Mandibular incisor protrusion
to A-Pog plane(Dental plane)
Defines protrusion of lower
arch.
Mean= 1mm ahead of A-Pog

Upper molar position(to PtV)
Mean:Age + 3mm
Adjusted mean:+1mm/yr
DET whether maloccl is due to u6
or L6 position.also deciding if
extractions are necessary.

Charles J. Burstone – 1978
University of Connecticut
COGS – Cephalometrics for Orthognathic Surgery

COGS
 Chosen landmarks and measurements can
be altered by various surgical procedures.
comprehensive appraisal-includes all
facial bones and a cranial base reference.
 Rectilinear measurements can be readily
transferred to a study cast for mock surgery.

 Critical facial skeletal components can
be examined.
 Standards and statistics are available for
variations in age and sex from 5 to 20
 Consists of a series of measurements that
can be computerised.

H-P line
• Baseline for
comparison of most
data
• Constructed plane
• By drawing a line
7 ° to SN

Cranial Base1.Ar-N:length of the cranial base
(not an absolutevalue,
proportional,so that can be
correlated with
mandibular,maxillary lengths)
2.Ar-PTM : measure horizontal
distance b/t poterior aspects of
mandible & maxilla.The greater
the distance,the more the
mandible will lie posteriorly to
maxilla
Males=37.1 +/- 2 mm
Females = 32.8 +/- 1.9 mm
3. PTM –N :
Males = 52.8 +/- 4.1 mm
females= 50.9 +/- 3.0 mm
s

b. HORIZONTAL SKELETAL
PROFILE
1. N-A-Pg=angle of skeletal facial convexity
- indication of overall facial convexity
measurement doesn’t indicate if
due to maxilla or mandible
+ angle-convex face
- angle –concave face
Mean :
Males : 3.9 +/- 0.4 °
females: 2.6 +/- 5.1 °

Sign convention:
A perpendicular to HP drawn through N.
The inferior anatomic point is horizontally measured in relation to the
superior structure, with + being anterior and – being posterior.
2.N-A : horizontal position of A is measured to this
Perpendicular .measurement describes the horizontal position of
Apical Base of the maxilla in relation to N ---to determine if
anterior part of maxilla is protrusive or retrusive.
M ean :
males= 0.0 +/- 3.7mm ; females = -2.0 +/- 3.7 mm
3.N-B
Mean :
males= -5.3 +/- 6.7 mm ; females= -6.9 +/- 4.3 mm
4.N-Pg = prominence of chin
if unusually large or small,then compare
with N-B & B-Pog: this determines if discrepancy is in the
alveolar process, the chin or the mandible proper
MEAN:
MALES = -4.3 +/- 8.5 mm ; females = -6.5 +/- 5.1 mmwww.indiandentalacademy.com

Horizontal Measurements
N-A-Pg

Diagnosis of:
• Horizontal maxillary hypolasia/hyperplasia
• Horizontal mandibular hypo/hyperplasia
• Horizontal genial hypo/hyperplasia
Used in planning of treatments:
• Augmentation /reduction genioplasty
• Ant mandibular horizontal advancement or
reduction
• Total mandibular horizontal advancement or
reduction

c. Vertical skeletal dysplasia
1. middle 1/3 facial ht
(N-ANS) ╧ HP
Anterior components males= 54.7+/- 3.2mm
females= 50 +/- 2.4mm
2. lower 1/3 facial ht
( ANS- Gn ) ╧ HP
males = 68.6 +/- 3.8mm
females= 61.3 +/- 3.3mm
Posterior components 3. posterior maxillary ht
(length of perpendicular line from HP
intersecting PNS)www.indiandentalacademy.com

Vertical skeletal dysplasia contd.
4. MP-HP angle = relates the posterior facial
divergence with respect to anterior facial
height.
MP angle + posterior maxillary height
define Vertical dysplasia of posterior
components

Helps in Diagnosis of:
• anterior , posterior or total vertical
maxillary hyperplasia or hypoplasia.
• clockwise or counterclockwise rotations
of maxilla and the mandible.

Vertical dental dyspalsia
• Anterior component:
Anterior maxillary height : upper1-NF
Anterior mandibular height : lower1 – MP
indicate how far incisors have erupted in relation to
NF and MP
• Posterior conponent:
Posterior maxillary height :Upper 6 – NF
Posterior mandibular height : Lower 6 - MPwww.indiandentalacademy.com

Vertical Measurements

These value should be related with ANS-Gn
and MP-HP to establish whether the origin
of maxillary or mandibular discrepancies is
skeletal , dental or a combination of both.

d. MAXILLA and MANDIBLE
1. PNS- ANS: total effective length of maxilla
With ANS-N and PNS-N quantitatively describes maxilla
in the skull complex
males = 57.7 ± 2.5 mm ;females =52.6 ± 3.5mm
2. Ar- Go ( linear): length of mandibular ramus
males= 52±4.2 mm ;females =46.8±2.5mm
3. Go- Pg (linear): length of mandibular body
males = 83.7±4.6mm ; females = 74.3±5.8mm
4. B- Pg : prominence of chin rel to mand. Denture base
males = 8.9 ± 1.7mm; female = 7.2 ± 1.9mm
By comparing with N-Pg distance chin prominence rel to
face
5. Ar- Go- Gn

Maxilla and Mandible

Diagnosis of:
• variations in ramus height that effect open
bite or deep bite
• increased dimension of mandibular body
length
• acute or obtuse Go angles
• assesment of chin prominence:
prominence of chin related to mandibular
denture base.by relating to N-Pog asses
the prominence of the chin in relation to
the face.

DENTAL

Assessment of Dental anomolies
• OP : line drawn from the buccal groove of both
first permanent molars through a point 1mm apical
to the incisal edge of the central incisor in each
arch
1.OP angle: upper- HP,OP lower – HP
males= 6.2 ± 5.1mm ;females =7.1 ± 2.5mm
2.A-B: relationship of maxillary and
mandibular apical base to OP
(linear measurement than familiar ANB)
males= -1.1±2.0mm ;females = -0.4 ± 2.5mm

Diagnosis of:
• Increased OP-HP :skl open bite,lip
incompetence,increased facial
hieght,retrognathia
• Decreased OP-HP:
• A-B: large A-B with point B posterior to
point A ,mandibular denture discrepancy
that predisposes to class II malocclusion.

3. upper incisor – NF angle
males = 111.0 ±4.7° ;females = 112.5± 5.3°
4. lower incisor - MP angle
males = 95.9 ± 5.2° ; females = 95.9 ± 5.7mm
Indicate procumbency or recumbency of
incisors,vital in assessing long term stability of the
dentition.

Dental Measurements

Rakosi’s functional analysis

1. Analysis of facial skeleton
2. Analysis of mandibular and maxillary
base.
3. Dento-alveolar analysis

Analysis of facial skeleton

1. Saddle angle
• sella-nasion –
articulare.(angle b/t
posterior and anterior
cranial base)
• Sphenooccipital
synchondrosis

• Large saddle angle:
posterior position of
the fossa
Retrognathic profile
• Mean = 123 + / - 5 °

2. Articular angle
• S-Ar - Go
Can be altered by
orthodontic treatment.
Mean = 143 +/- 6°

• Bite opened by
Extrusion of posterior
teeth or distalisation
large S-Ar - Go
Retrognathic profile

3. Gonial angle
• Ar–Go - Me
• Expression of form of
mandible.
• Relation b/t body and
ramus.
• Also part in growth
prognosis.

Gonial angle continued
• Mean = 128 +/- 7°
• Large angle
Tendency for posterior
rotation of mandible
with condylar growth
directed posteriorly

Upper and lower gonial angles of
Jarabak
• Divided by N – Go
• Upper angle:
ascending ramus - N-Go
50 + /- 2°
Large upper angle
Horizontal growth
changes

• Small upper angle
caudal growth
• Large lower angle
vertical growth
Small lower angle
Sagittal growth

Mandibular variations due to
rotations
Gonial angle has marked influence on:
direction of growth.
profile changes.
position of lower incisors.

• Magnitude of Go is determined by relationship
B/T:
ANTERIOR FACE HEIGHT
LENGTH OF RAMUS
Ant face height obtuse Go
eg:skl open bite
large basal plane angle

• Cause for increased gonial angle:
1. Adaptation of Go to increased AFH.
2. The AFH adapts to a prior large Go by
increase in alveolar process height.

4. Sum of posterior angles
Sum of saddle,articular
gonial angle=
396 +/- 6°
 396 °= vertical
direction of growth
< 396 °= horizontal
growth

5. Facial height
• Posterior facial
height(S- Go)
• AFH= N-Me
greater PFH
Horizontal growth

• To estimate the direction of growth =
JARABAK RATIO
PFH
* 100 = 1%
AFH
MEAN :62- 65 %
Ratios of <62 % indicates a vertical growth pattern,
>65% indicates horizontal growth pattern, PFH

6. Anterior cranial base length
Measured b/t centre of
superior entrance to
Sella to N point.
Used to compare length of
jaw bases
Increases ¾ mm annually
18yr = 75.4 mm ( males)
70.1 mm (females)

7.Posterior (lateral) cranial base
• Sella to articulare
Short cranial base seen in
vertical growth pattern
,skl open bit,poor
prognosis for functional
appliance therapy
Midface appears prognathic,
secondary in AFH

B. Analysis of jaw bases
1. SNA angle
Mean=81°
>84 °=maxillary
prognathism
<78°= maxillary
retrognathism

2. SNB angle
Mean=79°
>82=prognathic
mandible
<77°=retrognathism
mandible

3. ANB
Mean=2°

4. SN- Pog:
determines basal position of mandible.If the chin projects to
a marked degree, the difference b/t SNB and SN-Pog is
large.
76° at 6yr ; 80° at 16yr
5.SN –Pr and SN- Id
• Relation b/t alveolar process of maxilla and mandible with
the cranial base
• These above angles determine relationships in sagittal
plane.

7.Jaw base analysis-basal plane
angle
Pal –MP
Defines the angle of inclination
of mandible to maxillary base
• Angle also serves to det the
rotation of mandible.
Mean = 25 °
• Large BPA
mandible rotated back
vertical growth pattern
• Small BPA
Mandible rotated forward
Horizontal type growth

• BPA dependent on :
1. Mandibular inclination
2. Maxillay angulation
Retro-inclination of maxilla
relatively smaller BPA
ante-inclination
Larger BPA

PAL-Occl and Occ- MP
• BPA divided by OP:
upper angle= 11°
lower angle =14°
Lower angle imp in
assessing prognosis for
opening the bite
If>20° good prognosis ,if
< 7° poor prognosis
poor for treatment of deep
overbite.

8.Angle of inclination-J ANGLE
• Pn line (perpendicular
from soft tissue
nasion) and palatal
plane.
• Angle used to asses
maxillary rotation.
• Large J =
anteclination of lower
face.

J angle
• Angle used to asses
maxillary rotation.

9. SN-MP
• Gives the inclination of the mandible to ACB.
• Mean- 32°
>32°=posterior inclination
<32°= anterior inclination
• The angle registers vertical dysplasias,changes b/t
selle and fossa and below fossa.
eg: open bite with large SN-MP indicates that the
molars have erupted in disproportion to incisors.

• If both SN –MP and the BASAL PLANE
ANGLE are large, the dysplasia must lie
below the fossa (the ascendng ramus in too
short)

10. Y –axis (S-N – Gn)
• Determines position of the mandible
relative to cranial base as an additional
check.
• Mean= 66°
• >66° = mandible posterior position
• <66° = mandible anterior position rel to Cr.
base

11.Linear measurement of jaw
bases
a)extent of mandibular
base
Go – Pog
It is 3mm longer then
SE-N upto 12yr , after
12yr it is 3.5mm longer .
Mean = 68mm at 8 yr
Annual increase of 2mm for
boys
1.4 mm for girls

b.extent of maxillary
base:distance from PNS
to Point A projected onto
palatal plane.
Mean = 45.5mm at 8yr
Annual increase:
1.2 in boys
0.8mm in girls

c)length of ascending
ramus:
Go – Condylion
Constructed condylion
Mean at 8yr is 46mm
Annual increase of 2mm for
boys 1.2 mm for girls upto
16yr

d)Width of ascending
ramus:
Det at height of occlusal
plane
Mean- 27mm at 8yr
At 16yr 32.5mm for boys
30.5mm for girls

C.Dentoalveolar analysis
a.Axial inclination of upper incisors:
Long axis of maxillary incisor extended to incisor
extended to intersect SN line and posterior angle is
measured. mean=102° , attained 2yr after eruption
Also angle formed with palatal plane
measured. Enlarged angle signifies very upright
Incisors, smaller than average angle indicates protrusion
mean = 70+/- 5°
These 2 measurements used in treatment planning
Eg: regarding need for root torquing.

• Lower incisors
Posterior angle b/t MP
and long axis of lower
incisor
Mean 90 +/- 3°

b. Position of incisor
Upper incisor
Mean:
4+/- 2mm

Lower incisor position
mean
- 2 to +2mm

Bjork analysis
• Vast study 600 patients,90 cph
measurements
• Special feature :
polygon N–S-Ar - Go-Gn to assess and
predict the direction of growth changes in
lower face

1. Sum of Saddle, articular, gonial angle > 396
degree clockwise growth changes.
<396 degree anticlockwise
2. At 11yr, ant Cranial Base (S-N) = GoMe
3. S-Ar :Ar-Go = 3:4
4. PFH * 100/ AFH
56 –62% clockwise growth ,long face
65 –68% anticlockwise growth

Jarabak analysis

Quadrilateral analysis

• Di paolo ; 1962
• Indivisualized approach to ceph analysis:
attempts to identify skl deviations in size
and position both in vertical and
horizontal dimensions regardless of the
dentoalveolar considerations.
• Proportionate analysis

Two parts :
skeletal assessment
dental assessment

SKELETAL ASSESMENT
• concept of lower facial proportionality:
in a balanced facial pattern 1:1
proportionality b/t maxillary base length
and mandibular base length.
max lth = mand. Lth = ALFH + PLFH
2

SKL assesment contd.
• Construction of quadrilateral :
ANS-PNS and Go Gn
1. Maxillary base length-
Plr. Pt A to Palatal plane
PTM to Palatal plane
2. Mandibular base length –
Pt B to Go Gn (ant .limit)
point J to GoGn( post. limit)

• Anterior lower facial height: projection of point A
on the Palatal plane to projection of point B onto
Go-Gn plane.
• Posterior lower facial height: projection of PTM
onto Palatal plane to projection of Pt J onto Go-Gn
plane.
• Anterior facial height: projection of point A onto
palatalplane to Nasion on the cranial base.

• ALFH
• PLFH
• AUFH
• AUFH : ALFH
45 :55
• Angle of facial convexity
165 – 178°

SAGITTAL RATIO
Assessing the rel A-P positon
of the maxillary mandibular
bony bases
When ALFH & PLFH are
parallel & bases are equal a
proportional rel exits
The ratio of A:B and C:D of
similar isoceles triangle is the
sagittal ratio.
In balanced skl patterns,sagittal
ratio:
1 : 1.5 +/- 0.05(adolescence)
1 : 1.45 +/- 0.05 (adult)
Sagittal angle = 23 +/-1°www.indiandentalacademy.com

• Angle of facial convexity:
formed by intersection of ALFH and AUFH
It relates the quadrilateral to upper face
The degree of facial convexity will vary
depending on the skeletal type and the
position of the quadrilateral as it relates to
the upper face.

• Depends on:
1. rel size differences of maxillary and mandibular
bony bases
2. rel. position of the maxillary and mandibular
bony bases.(sagittal ratio)
3. vertical dysplasia of the lower face
(ALFH:PLFH)
4. Spatial rotation of the lower face( quadrilateral)
to the UAFH.

FACIAL TYPES
• TYPE 1 ;NORMODIVERGENT PATERN:
Equal maxillary and mandibular basal arch
Length, avg vertical height = arch length
• Type 2 : hypodivergent pattern:
predominant horizontal growth pattern
reduction on LFH SKL DEEP BITE
avg Vertical ht deficieint to dental base length
• Type 3 ; hyperdivergent pattern:
predominant vertical growth pattern
increase LFH skl open bite
avg vertical height excessive compared to denture base
length

DENTAL ASSESSMENT
• Pt A line :5 +/- 1 mm
• Pt B line:2 +/-1 mm
• Pogonion line

ADVANTAGE OF
QUADRILATERAL ANALYSIS
Differentiates b/t jaw size and jaw position
Eg:distinction b/t Mandibular excess and
mandibular prognathism or mandibular
retrusion and deficiency.
Information critical for surgical or
nonsurgical
orthodontic treatment.www.indiandentalacademy.com

Pitchfork analysis
• Johnston
• Differentiate B/T Skeletal and dental
changes , to evaluate combined treatment
effect along the functional occlusal plane
• Growth and displacement of maxilla and
mandible are measured relative to the
cranial base ( SE registration)
• The changes in position of upper and lower
incisors and molars are measured relative to
basal bone( regional superimposition)www.indiandentalacademy.com

• All these measurements are made parallel to mean
functional occlusal plane and are given signs
appropriate to the nature of their contribution to
molar and overjet changes or corrections.
• As a result ,the algebraic sum of the various
skeletal and dental changes equals the treatment
change in molar relationship and incisal overjet.

Pitch fork analysis

• Maxilla+mandible =ABCH
• ABCH+U6+L6 =molar correction
• ABCH + u1 +L1 = overjet correction

POSTERO-ANTERIOR
CEPHALOMETRY

TRACING

LANDMARKS

Need for PA cephalometrics:
Facial assymetry identification
Gross examination- morphology,shape,size of
skull,bone density,sutural morphology
Diagnosis, Treatment planning
Growth assessments
Evaluation of treatment results

Limitations:
• Errors related to X-ray projection,the measuring
system,identification of landmarks.
• Maintaining position of head in head holder
difficult,tilt affects linear measurements.
• The diagnostic interpretation of ratios for clinical
applications in individual cases is difficult.

PA cephalometric analyses:
1. Ricketts analysis
2. Svanholt and Solow analysis
3. Grummons analysis
4. Grayson analysis
5. Hewitt analysis
6. Cherici method

1. RICKETTS ANALYSIS
• Ricketts etal 1972
• Incorporates the following measurments:
1. Nasal cavity width (24.9mm)
2. Mandibular width (Ag –Ag)
3. Maxillary width ( J point to Frontal line)
J point= crossing of outline of the tuberosity with
that of the jugal process
evaluated in rel to mandible on right and left side
seperately.
molar – jaw = 6.2 mm ( on R and L)

Variables used in PA Ricketts
5.symmetry-
midsaggitalplane,
ANS,Pog to judge
assymetry
6.intermolar width=54.5mm
7.intercuspid width=23.9mm
8.denture symmetry
9.upper molar to lower
molar relation.
MAX-MAND width
=10.8mm

2)Grummons analysis
• Grummons and Kappeyene van de Coppello
• Comparitive quantitative PA ceph analysis
• No normative data
• Components of analysis:
Horizontal planes
Mandibular morphology
Volumetric comparison
Maxillomandibular comparison of assymetry
Linear assymetry assesment
Maxillomandibular relation
Frontal vertical proportions

Landmarks -grummons

a.4 horizontal planes
constructed:
• Medial aspects of
zygomaticofrontal
sutures(z)
• Centres of zygomatic
arches(ZA)
• Medial aspects of jugular
processes (J)
• Parallel to Z-Plane
through menton
• Midsagittal reference
line(MSR) =crista
galli(Cg),ANS,chin

b.Mandibular morphology
analysis grummons
• Left and right triangles
formed b/t
Co-Ag-Me.

c.Volumetric comparison analysis
• 4 points connected:
condylion
antegonial notch(Ag)
menton(Me)
intersection with a
perpendicular from Co to
MSR
L and R polygons are
superimposed with aid of
computer program and %
value of symmetry obtained

d.Maxillomandibular comparison of
assymetry
• 4 lines constructed:
1)perpendicular to MSR
from Ag and J
bilaterally.
2)lines connecting Cg
and J
3)Lines from Cg to Ag
If symmetric,2 triangles
formed
J-Cg-J and Ag-Cg-Agwww.indiandentalacademy.com

e. Linear assymetry analysis-
Grummons
• Linear distances to
MSR and the
difference in the
vertical dimension of
perpendicular
projections of bilateral
landmarks
Co,NC,J,Ag,Me to
MSR

f. Analysis of Maxillomandibular
relation
• Distances from buccal
surfaces of maxilalry
molar to J-perpendiculars
are measured.
• Lines connecting ANS-
Me and MSR lines also
drawn—reveals any dental
compensation for skeletal
assymetry

g. Analysis of Frontal vertical
proportions-Grummons
1. Upper facial ratio
Cg-ANS:Cg-Me
2. Lower face 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

• Summary facial assymetry analysis
components:
1.construction of horizontal planes
2.mandibular morphology analysis
3.maxillomandibular comparison of
facial asymmetry

PA analyses-GRAYSON analysis
• Method of analysis craniofacial assymetry with
the use of multiplane posteroanterior
cephalometry(1983).
• Landmarks, mid points and midlines are identified
in 3 different coronal or frontal planes at different
depths in the craniofacial complex.
• Hence this allows visualization of midlines and
midpoints in the third dimension (sagittal) in a PA
analysis.

3 different planes on lat ceph
• Three separate acetate
tracings are made on
the same PA r/g.
corresponding to the 3
different planes
indicated on the
lateral view

3 plane tracing-graysons
Tracing along the 1st
plane
• Trace orbital
rims,pyriform
aperture,maxillary and
mandibular
incisors,midpoint of
the symphysis

• Greater and leseer wing of
sphenoid
• Most lateral cross section
of zygomatic arch
• Coronoid process
• Maxillary &
mandibular molars
• Body of mandible
• Mental foramina

• Superior surface of
petrous temporal
• Mandibular condyles
with outer border of
ramus
• Mastoid process

• Midlines constructed for 3 planes:

• 3 tracings
superimposed
• Wraping of midlines
within craniofacial
skeletons observed
• Midline constructs
deviate progressively
laterally as one passes
from posterior to
anterior planes of the
face.

Conclusions:
• Cephalometric analyses are a means of obtaining
information AND NOT AN END IN ITSELF.
•Cephalometric analyses are merely aids in helping
the clinician arrive at a diagnosis and treatment
planning.
• All anteroposterior skeletal discrepancies cannot be
corrected to an ideal jaw relationship.
•Cephalometric measurements are not to be
regarded as final points or values and it is not
necessary that values should exactly tally.

• Variation in biology is a rule, therefore a normal
value is never a point so a mean is to be always
considered.
• Serial cephalograms taken during course of
treatment helps us to ascertain whether our treatment
goals are achieved.
• The Wits appraisal is a linear measurement and not
an analysis per se. It is simply an adjunctive
diagnostic aid that may prove useful in assessing the
extent of anteroposterior skeletal dysplasia and in
determining the reliability of ANB angle.www.indiandentalacademy.com

• We should strive to develop
cephalometric norms pertaining to
Indian backgrounds instead of those
meant for Caucasian norms.

References
• An atlas and manual of cephalometric
radiography ---Thomas Rakosi.
• Radiographic cephalometry-
Alexander Jacobson.
• Orthodontic cephalometry –
Athanosios E Athanasiou

2.Svanholt and Solow
• Analyses relation b/t midlines of jaws and
dental arches
• Has variables that are zero in symmetric
subjects

Variables:
1)Transverse maxillary
position=mx-om/ORP
2)trns. Mandibular position
m-om/ORP
3)trns jaw rel = CPL/MXP
4)Upeer incisal position=
isf-mx/MXP
5Lower incisal position=
iif-m/MLP
6)Upper incisor
compensation=
isf –mx/mwww.indiandentalacademy.com

7)lower incisal
compensation
=iif-m/mx

PA analysis-HEWITT analysis
• Triangulation of face:
• Cranial base region
• Lateral maxillary region
• Upper maxillary region
• Middle maxillary region
• Lower maxillary region’
• Dental region
• Mandibular region

• Beatly’s alternative to
ANB

Hard tissue cephalometric analysis

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