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1. CEPHALOMETRICS
AS A DIAGNOSTIC AID
 Introduction
 Definition
 Types of cephalogram
 Uses
 Anatomic landmarks
 Lines and planes of lateral cephalometrics
 Cephalostat
 Steiner analysis
 Downs analysis
 Tweed’s analysis
 Wits appraisal
 Sassouni analysis
 McNamara analysis
 Ricketts analysis
1

2. INTRODUCTION
‘Beauty is the finest expression of human emotion. The art that
was produced in the past has survived because it was expressed in the
highest, finest and most sensitive manner possible. The beauty that
survives knows no limits either of time or place’.
- Wuerpel
Ever since God created man in his image, man has been trying to
change man into his image. Orthodontists, in their attempts to treatment
planning with brought various analysis into being.
In 1922, Pacini introduced a method for standardized head
radiography and failed due to large fixed distance from X-ray source to
the cassette.
Dr. Herbert Hofrath of Germany and Dr. B. Holly Broadbent of
U.S. published a new X-ray technique and its application in orthodontia.
In 1946, Dr. Charles Tweed developed Tweeds diagnostic
triangle. First true classic full scale cephalometric analysis developed by
William B. Downs in 1948.
In 1953, Dr. C.C. Steiner presented his famous Steiner’s
analysis. Riedel in 1952 developed SNA and SNB angle. Sassouni
(1995) described total archial analysis.
Rickets (1960) give dynamic analysis to study morphology of a
patient at different stages of development or treatment. Jacobson’s
‘Wits’ appraisal (1975) was used for assessing horizontal disharmony of
the jaw.
For surgical correction quadrilateral analysis Dipaolo (1970) and
an analysis by McNamara (1984) developed.
2

3. DEFINITION
Cephalometrics includes measurements, description and appraisal
of the morphologic configuration and growth changes in the skull by
ascertaining the dimensions of lines, angles and planes between
anthropometric landmarks established by physical anthropologists and
point selected by orthodontists.
TYPES OF CEPHALOGRAM
1) Lateral cephalogram
2) Frontal cephalogram
USES
1) Helps in orthodontic diagnosis, by enabling study of skeletal,
dental and soft tissue structures of the craniofacial region.
2) Helps in classification of malocclusion.
3) Helps in treatment planning.
4) Evaluation of treatment results.
5) Helps in predicting growth related change.
6) It is also valuable aid in research work.
ANATOMIC LANDMARKS
1) Nasion – Most anterior patient on naso frontal suture.
2) Sella – Midpoint of hypophyseal fossa.
3) Si – Most inferior patient of lower contour of sella turcica.
4) SP – Most posterior patient on posterior contour of sella turcica.
5) Se – Midpoint of the entrance of sella. At the same level of jugum
sphenoidal.
3

4. 6) Point A (subspinale) – Deepest midline patient in the curved bony
outline from the base of alveolar proceeds of the maxilla. i.e.
between ANS and Prosthion.
Donovan - Junction of maxillary basal bone and alveolar bone.
Higley – Deepest midline point between ANS and Prosthion on the
premaxilla.
Jacobson – Anterior limit of maxillary denture base.
7) Prosthion – Alveolar rim of maxilla or the lower most anterior
point on the alveolar portion of the premaxilla in the median plane
between upper central incisors.
8) Is (Incisor spurious) – Tip of crown of most anterior maxillary
central incisor.
9) AP 1 (Apicale 1) - Root apex of the most anterior mandibular
central incisor.
10) Ii (Incisor inferius) - Tip of crown of most anterior mandibular
incisor.
11) AP 1 – Root apex of most anterior maxillary incisor.
12) Intradental – Alveolar rim of mandibular.
13) Point B (Supramentale) – Most anterior part of mandibular base
or it is the most posterior point in the outer contour of the
mandibular alveolar process, in the median plane.
Donovan – Junction of mandibular basal bone and alveolar
process.
Jacobson – Anterior limit of mandible
14) Pog - Most anterior point on bony chin in median plane.
15) Gn
Brodie – Located by taking the midpoint between most anterior
and inferior points on the bony chin.
Craig – Patient of intersection of facial and mandibular plane.
4

5. 16) Go – Constructed point at the intersect of lines tangent to posterior
margin of ascending ramus and mandibular base.
Hingley – Intersection of posterior ramal and mandibular plane.
17) Me –
Sassouni - Most caudal point in the outline of the symphysis or the
inferior most point on mandible.
18) Ar (Articulare) -
Bjork – Point of intersection of the posterior margin of ascending
ramus and outer margin of cranial base.
19) Cd (Condylion) – Most superior point on the head of the condyle.
20) Or (Orbitale) – Lower most point of the orbit in radiograph.
21) ANS – Tip of bony anterior nasal spine in the median plane.
22) PNS – The intersection of continuation of anterior wall of
pterygopalatine fossa and the floor of nose.
23) Basion – Lowest point on the anterior margin of foramen magnum
in the median plane.
24) Ptm (Pterygomaxillary fissure) – Anterior wall represents
maxillary tuberosity outline, posterior wall represents anterior
curve of pterygoid process.
25) Po (Porion) –
Tweed – 4.5mm above geometric center of ear rod.
Craig – Uppermost point on the soft tissues overlying the external
auditory meatus.
Ricketts – True Porion, located directly over that of basion and
downward and forward from internal auditory canal.
Moorrees – Center of ear rods.
Higley – Highest point on the root of the left external auditory
meatus.
5

6. 26) BO (Bolton point) –
Broadbent – Highest point in the upward curvature of the
retrocondylar fossa.
Higley – Highest point in the concavity behind the occipital bone.
27) D point – Center of symphysis given by Steiner.
28) Op (Opisthion) – Most posterior point of the bony margin of the
foramen magnum.
29) AC (Acanthion) – Tip of ANS.
30) J point – Located at the junction of the anterior border of ramus
and the corpus of mandible.
31) DS (Dorsam selae) – Square bone forms posterior boundary of
sella turcica.
32) Broadbent registration patient (R) – Perpendicular from sella on
Nasion – Bolton plane.
6

7. LINES AND PLANES OF LATERAL CEPHALOMETRICS
1) Blumenbach’s plane (Resting horizontal plane) - It is the plane
formed as the skull, minus the mandible rest on a flat horizontal
surface. Entails the skull resting anterior on maxillary teeth and
posterior either on occipital condyles or on the mastoid process.
2) Broadbent’s line (S-N reference line) – From sella to nasion.
3) Broadbent Bolton line – Line from Bolton patient to nasion.
4) Broca’s line – Extends from true anatomic prosthion to the lower
most point of the occipital condyle. When skull is resting on
horizontal surface.
5) Camper’s line – Line extending from tip of ANS to the centre of
external auditory meatus. Camper’s plane is a triangular plane
formed by two lines from tip of ANS to each external auditory
meatus.
6) Decoster’s line – This is the only line that is not linear connection
of two points. It represents an actual anatomical contour of the
planoethmoidal line from internal plate of frontal bone down
through roof of cribriform plate to the anterior portion of sella
turcica.
7) Frankfort horizontal plane) – Its origins date back to the
international congress on prehistoric anthropology and
archaeology, held in Frankfort in 1882. The line runs from
orbitale to porion. It is supposed to represent the ideal horizontal
position of the head when the patient stands erect.
8) Palatal plane – Line running from ANS to PNS.
9) His plane – Runs from acanthion to opisthion.
10) Hold way line – Also referred as harmony line was developed by
R.A. Holdaway and is strictly a soft tissue profile assessment
7

8. reference line. Runs from soft tissue pogonion to vermilion border
of upper lip.
11) Huxley’s line – Runs from nasion to basion and referred as nasion
– basion line. It would be the near perfect base reference line for
research purposes on growth and development.
12) Mandibular plane – Four different mandibular planes.
Steiner – Line joining Go and Gn
Downs – Line joining Go and Me
Tweed and Ricketts – Straight line tangent to the lower most
border of mandible.
Bimpler’s line – Line from menton to antigonial notch.
13) Margolis line – Line runs from nasion to spheno-occipital-
synchondrosis.
14) Occlusal plane – 3 occlusal planes.
First plane – Line joining midpoint of overlap of M-B cusps of
upper and lower first molars with point bisecting overbite of
incisions. Used by Downs and Steiner.
Second plane – Used by Ricketts and in Wits analysis called as
functional occlusal plane and is line joining the midpoint of the
overlap of M-B cusp of Ist
molars and buccal cusps of premolars or
deciduous molars.
Third plane – Line joining midsection of molar cusps to the tip of
upper incisors.
15) Orbital plane – Plane perpendicular to FH plane at orbitale.
16) Ramal plane – Line tangent to posterior border of ramus of
mandibular.
17) Rickett’s esthetic line –Extends from soft tissue tip of nose to the
most anterior portion o profile of soft tissue chin.
8

9. 18) Von Ihering’s line – Orbitale to center of external auditory
meatus.
19) Y-axis – Given by Downs and extends from sella to gnathion.
CEPHALOSTAT
An 8 × 10 inches film cassette equipped with approximate film and
intensifying screen is placed either horizontally or vertically in the
cephalostat cassette holder.
A distance of 15 cm from midsagittal plane of the cephalostat to
the film cassette is often used. The patients head is fixed by two ear-rods
that are inserted into ear holes so that upper border of ear holes rest on
upper part of ear rods. The head is oriented with the FH plane parallel to
the floor and midsagittal plane vertical and parallel to the cassette. The
standardized FH plane is achieved by placing the infra-orbital pointer at
the patients orbit and adjusting the head vertically until the infra-orbital
pointer and two ear rods are at same level. The upper part of face is
supported by forehead clamp positioned at nasion.
Projection is taken when teeth are in centric occlusion and the lips
relaxed. The focus film distance is usually 5 feet i.e. 152.4cm.
Milliamperage should be 10MA, KVP is about 60-90Kv and
exposure time is not longer than 3 seconds.
STEINER ANALYSIS (1953)
C. C. Steiner selected what he considered to be the most
meaningful parameters and evolved a composite analysis. He proposed a
appraisal of skeletal, dental and soft tissue analysis. He considered SN
plane as a reference plane.
L – Project the most anterior point of the body of the mandible to the line
SN.
9

10. E – Erect the line from the most distal point of head of condyle,
perpendicular to the line SN.
Skeletal analysis
1) SNA angle - 820
2) SNB angle - 800
3) ANB angle - 20
a. Class- I – ANB - 0-50
b. Class-II – ANB - ≥ 60
c. Class-III – ANB - < 00
4) SND angle - 760
5) Mandibular plane to SN - 320
6) Occlusal plane to SN - 14.50
Dental analysis
1) UI to NA (angle) - 220
2) UI to NA (linear) - 4mm
3) LI to NB (angle) - 250
4) LI to NB (linear) - 4mm
5) Interincisal angle - 1300
6) Holdaway ratio - 1:1
SL - 51mm
SE - 22mm
Steiner analysis for Indian population
Sidhu S.S. in 1970 gave the Indian (Maharashtrian) norms. Sample
size was 25 and all were male with the age group of 13-16 years.
1) SNA - 82.7 ± 7.42
2) SNB - 79.4 ± 7.84
10

11. 3) ANB - 3.3 ± 3.64
4) UI to NA - 25 ± 9.42
5) LI to NB - 32 ± 7.22
6) SL (mm) - 53 ± 11.78
7) UI to NA (mm) - 6.7 ± 3.74
8) LI to NB (mm) - 7.6 ± 2.68
9) FH to SN - 6 ± 5.86
10) Distance of U6 to NA - 23.3 ± 2.56
11) Distance of L6 to NB - 17.9 ± 2.96
Gamm and Gianelly in 1970 gave S.D. to the values of Steiners
analysis.
Parameters Mean S.D.
SNA 80.60
3.3
SNB 780
3.1
ANB 2.50
1.7
SND 75.20
2.8
Pg to NB 2.5mm 1.5mm
I/I 125.40
7.9
OP 17.30
4.1
MP 32.80
3.5
UI/NA 5.2mm 1.2mm
UI/NA 230
6.1
LI/NB 4.7mm 1.5mm
LI/NB 27.50
4.5
11

12. Comparison of Steiners values with Gamm and Gianelly’s value
and Maharashtrian norms (Indian)
Parameters
Steiner’s
values
Gamm &
Gianelly
Maharashtrian
norms
SNA 820
80.60
± 3.3 82.70
± 7.42
SNB 800
780
± 3.1 79.40
± 7.84
ANB 20
2.50
± 1.7 3.30
±3.64
SND 760
75.20
± 2.8 -
MP 320
32.80
± 3.5 -
OP 14.50
17.30
± 4.1 -
UI to NA 220
230
± 6.1 250
±9.42
UI to NA 4mm 5.2 ± 1.2mm 6.7 ± 3.74mm
LI to NB 250
27.50
±4.5mm 32 ± 7.22
LI to NB 4mm 4.7 ± 1.5mm 7.6 ± 2.68
I/I 1300
125.40
±7.9 -
Holdaways ratio 1:1 - -
SL 51mm - 53 ± 11.78
SE 22mm - -
DOWN ANALYSIS (1948)
Downs observed following four basic facial types.
1) Retrognathic – A recessive lower jaw
2) Mesognathic – An ideal o average lower jaw
3) Prognathic – A protrusive lower jaw
4) True prognathism – Pronounced protrusion of lower face.
Downs elected to use FH plane as a reference base from which to
determine the degree of retrognathism, prognathism or orthognathism.
Sample – 20 children, 12 to 17 years of age with excellent
occlusion with a mean age of 14.5 ± 2.5 years were taken.
Measurements Range Mean
A) Skeletal measurements
1) Facial angle
2) Angle of convexity
3) A-B plane angle
820
±920
100
±-8.50
-90
±0
87.80
00
-4.60
12

13. 4) Mandibular plane
angle
5) Y-axis
280
to 170
660
to 530
21.90
59.40
B) Dental measurements
1) Cant of occlusal
plane
2) Interincisal angle
3) LI to mandibular
plane
4) LI to occlusal plane
5) Distance UI to A-
Pog
1.5-140
130-150.50
-8.5-70
3.50
-200
-1mm to 5mm
9.30
135.40
1.40
14.50
2.7mm
Vorrhies and Adams (1951) made a graphic portryal of 10 values
calculated by Downs.
But later on in 1952 it was modified by Wylie and his polygon
shows not only mean but the maximum and minimum range for each
measurement.
Downs analysis for Maharashtrian
This study was done by Kotak V.B. (1960)
Not mentioned any sample size.
Measurements Mean Range
1) Facial angle 84.980
79-91
2) Angle of convexity 3.75 -14 to 13
3) A-B plane angle -4.85 -10 to 3.5
4) Mandibular plane 22.73 11-34
13

14. 5) Y-axis 61.85 54.5-68.5
6) Cant of occlusal plane 11.55 0-18
7) Interincisal angle 119.6 105.5-134.5
8) LI to mandibular plane 17.13 5-29
9) LI to occlusal plane 29.22 21-41
10) UI to A-Pog (mm) 7.5 3.5-11
TWEED’S ANALYSIS – 1946
Tweed has focused on how cephalometrics might be applied in
diagnosis and treatment planning for daily clinical orthodontics. It
consists of a triangle formed by FH plane, mandibular plane and axis of
lower incisor.
A sample of 95 was taken and average values seen were
FMPA – 24.570
IMPA – 86.930
FMIA – 68.200
Hence FMPA of 240
, IMPA of 900
and FMIA of 650
were workable
figures ad still used.
Tweeds projected scale (FMIA formula)
1) When FMPA is 300
or more – FMIA should be 650
or more upto
700
.
2) If FMPA is 250
±40
– FMIA should be 680
or 700
.
3) If FMPA is 200
or less – IMPA should not exceed 940
.
Tweeds head plate correction
If FMPA ore than 250
then IMPA should not be 900
or more.
e.g. If FMPA showed 280
, then IMPA would have to be positioned
at 870
. This is termed as Tweed’s head plate correct.
Cephalogram correction
To achieve the FMIA requirements of 650
we require tipping of
mandibular incisors lingually and will require shortening both the side of
dental arch.
14

15. According to Tweed’s head plate correction for every 20
correction
1mm of space is required. For both side of arch it will become 2mm.
The measurement taken from cephalogram combined with actual
arch length discrepancy and this is the total discrepancy in millimeters.
WIT APPRAISAL (1975)
Wits appraisal of jaw disharmony given by Jacobson is measure of
the extent to which the jaws or related to each other anteroposteriorly. As
a measurement from the cranial base do not necessarily provide are liable
expression of A-P Jaw relationship in the dentofacial complex.
Reference plane common is both dentures is that of occlusion,
hence the effects of rotation of jaw are not affecting the overall
assessment of the jaw.
Sample of 46 adults with excellent occlusion were taken. (21 M & 25 F)
Construction - Draw perpendicular from point A & B on the maxilla and
mandible on to the occlusal plane.
The points of contacts of the perpendicular onto the occlusal plane
are labeled AO and BO respectively.
Wits reading
Males – 1 mm
Females – 0 mm
The more the wits reading deviates from -1 mm in males and 0 mm
in females the greater the horizontal jaw disharmony
Class-II - Positive wits reading
Class-III - Negative wits reading
If AO ahead of BO then wits appraisal positive
SASSOUNI ANALYSIS (1955)
15

16. Sassouni wanted a system based on relationships of anatomical
structures to each other with in the frame work of the individual patients
i.e. he wanted to let the patients own amatory serve as the clue to what is
none al of abnormal to himself.
Thus he developed a system that utilizes a series of portions of
circles in the form of arcs, that have a common center formed by
intersection of composite of anatomical planes to form what has become
known as the Sassouni archial analysis.
This analysis is 3-dimensional and inclusive of all the important
structures of facial skeletal.
Sample – 50 children with normal occlusion
Point O – It is the center of the focal area where the four horizontal
planes of the face i.e. cranial base, palatal, occlusal and mandibular
converge.
Planes
Draw a plane parallel to supraorbital plane tangent to Si. Four
planes converge toward focal area called center or point O. Generally 3 of
the 4 planes meet, while the fourth is divergent. This shows the plane,
which is not integrated in the facial balance. Occasionally only two
planes meet at the same point two others are parallel or meeting in front
or beyond point O. In these cases the junction of the cranial base &
mandible planes should be taken as the center O.
Arcs- From O as of center, draw arcs from N, ANS, A, Te & Sp.
Norms
1. Planes – Four planes are converging toward a focal center O.
2. Facial angles – Cranial base plane to palatal plane angle is equal to the
palato-mandibular angle.
3. Arcs-
16

17. a. The arc – from N should pass through ANS, tip of UI,
pogonion. If whole lower face is anterior or posterior to the arc
from N, draw a second are from ANS down. This should pass
through tip of UI and pogonion.
b. The arc from point A down should pass through point B.
c. The arc from Sp (Dorsam Sella) should pass through gonion.
d. The arc from Te (Temporale) should be tangent to the mesial
contour of U6.
Vertical proportions
1) Anterior vertical proportions
Put the point of compass on ANS & open compass to supraorbitale,
then transfer this dimension by rotating the compass until it intersects
anterior arc at the menton. Distance from ANS to supraorbitale should be
equal to that from ANS to Me.
2) Post vertical proportions
From PNS to cranial base plane & then from PNS to Go.
Both distances should be equal.
Anteroposterior evaluation of profile
In normal profile ANS, IS, and Pog should be located on anterior arc
It ANS & Pog both posterior to anterior arc then the profile is
retroarchial which essentially is normal. This situation may be due to the
fact that nasion is to far anterior.
It ANS is on anterior arc Pog is not there are two possibilities.
1. Pog is anterior to arc
2. Pog is post to arc
17

18. It Pog is on anterior arc & ANS is not, there are also two possibilities
1. ANS is anterior to arc
2.ANS is posterior to arc
Any combination of maxillary protrusion and/or mandibular
retrusion called as skeletal Class II.
Any combination of maxillary retrusion and/or mandibular
protrusion called as skeletal Class II.
Size of corpus of mandible
It Go located on posterior arc and Pog is on anterior arc then
corpus length is equal to the cranial base (Sp to N). This is for 12 year of
age.
Before 12 years corpus of mandibular is small and after 12 year
corpus is larger than cranial base.
Vertical balance
The anterior upper and lower face heights should be equal. The
posterior upper and lower face heights should be equal.
ANS to cranial base = ANS to mandibular plane and
PNS to cranial base = ANS to mandibular plane
The tip of UI is situated at the midpoint between ANS and Pog.
The tip of LI is situated at the midpoint between A and B.
Interpretation
Skeletal deep bile cases
• 4 bony planes of face are not steep to each other and center O is
away from profile.
• Cranial base angle (supraorbital to clivus angle) is small.
18

19. • Upper and lower incisors have long axis nearly parallel and are
vertically extruded while molars are intruded.
• Total post height is nearly equal to ant facial height
Skeletal open bile cases
• 4 bony planes are steep to each other bringing the
center O close to the profile.
• Cranial base angle and genial angle are obtuse. PFH
half the AFH.
Skeletal Class II cases
• Large cranial base angle, small gonial angle with short
ramus.
• Palate is tipped down word and backward
Skeletal Class III cases
• Small cranial base angle
• Large genial angle and palate is tipped upward at PNS
and downward at ANS.
SASSOUNI PLUS
After Sassouni’s death in 1983, a new champion of archial
analysis, Dr. Richard Beistle arose to continue work of teaching and
promoting this great analysis.
Beistle represents 11 points now called as Sassouni plus.
19

20. The first eight components are from original Sassouni, the last
three which form the plus form of the last three which form the plus form
of the analysis.
1. Skeletal AP alignment
2. Skeletal vertical dimension
3. Maxillary incisor position
4. Maxillary AP length
5. Maxillary AP position
6. Maxillary 6 position
7. Mandibular AP length
8. Mandibular AP position
9. Mandibular incisor position
10.Growth direction indicator
11.Upper lip angle
1. Skeletal AP length
It ANS and Pog both post to anterior arc profile is retroarchial
It may be due to
- N too for anteriorly
- Entire lower face too far posteriorly.
- Combination of both.
If ANS to Pog both anterior to anterior arc profile considered
prearchial.
It may be due to
- N positioned too far posteriorly
- Entire lower face too far anteriorly
- Combination of both.
A point and B point ideally showed be on basal arc.
20

21. 2) Skeletal vertical dimension
At age 4 years AUFH = ALFH
At age 12 years ALFH is more by 6mm and
At adulthood ALFH is more by 10mm
3) Maxillary incisor position
Tip of UI should be on anterior arc or within range of 0 to 3 mm
ahead of anterior arc.
4) Maxillary AP length
Drop cribriform perpendicular on PNS
It PNS is on cribriform perpendicular and ANS on anterior arc then
maxilla is normal.
5) Maxillary AP position
If ANS and PNS both back of anterior arc and cr perpendicular by
the same amount – maxillary retruded.
If ANS and PNS ahead of there respective reference line – maxilla
is protruded.
6) U6 position
Mesial surface should be tangent to midfacial arc.
7) Mandibular AP length
Measured from anterior and posterior arc at Go and Pog.
8) Mandibular AP position
If Go and Pog displaced in opposite direction an abnormally large
mandible or abnormally small mandible is indicated.
9) LI position
IMPA angle is seen in this.
It is 950
± 50
.
10) Growth direction indicator
21

22. Beistle split the gonial angle and uses the upper and lower portions
of it to evaluate growth direction.
The upper position of split gonial angle represents slant of ramus.
Lower portion of angle represents slant of the body of mandibular corpus.
Total gonial angle 120-1320
Upper gonial - 52-550
Lower gonial - 70-750
If upper gonial angle is large and lower is small indicating strong
horizontal growth pattern.
If upper gonial angle is small and lower is large indicating strong
downward and backward grower.
11) Upper lip angle
Constructed by drawing a line tangent to anterior most tip of upper
lip i.e. soft tissue subnasale and extending it upward to intersect the optic
plane, which is parallel to FH.
Angle is measured inferiorly and posterior at the intersection
If 900
or less Retruded
91-990
Flat
100-1150-
Normal
116 or more Protruded
McNAMARA’S ANALYSIS (1984)
The analysis proposed by McNamara is an effort to relate teeth to
teeth, teeth to jaws, each jaw to the other and the jaws to the cranial base.
Sample - 277 children 8 to 10 years of age with Class II
malocclusion were selected.
Effective maxillary length – Condylion to point A
Effective mandibular length – Condylion to Gn
Lower face height – ANS to Me
22

23. Anatomic portion is used
Measurements
a) Relating maxilla to cranial base – Determine by measuring
distance of point A to Nasion perpendicular.
b) Relating mandible to cranial base – Determined by measuring
distance from Pog to Nasion perpendicular.
Age Point A-NP Pog – NP
9 years 0mm -8mm to –6mm
Adult 1mm in front -2 to +2mm
c) Relating maxillary and mandibular height
9 years Adult male Adult Female
Effective maxillary length- 85mm 100mm 94mm
Effective mandibular length- 105mm 130mm 120mm
LFH - 60mm 70mm 66mm
d) Mandibular plane angle
FH to Go – M = 230
Low mandibular plane angle – Adequate ramus height
High mandibular plane angle – Short vertical height
e) Relating upper incisors to maxilla
Horizontal position
- Distance between point A perpendicular to the
facial surface of upper incisors = 4 mm
Vertical position
- Incisal edge of upper incisors lies 2-3 mm below
the upper lip at rest.
f) Relating the lower incisor to mandible
Horizontal position
23

24. - Distance between A-Pog line and facial surface of
lower incisor = 2 mm
Vertical position
- Vertical position of lower incisors is evaluated on
the basis of existing anterior facial height.
RICKETS ANALYSIS (1960)
In this analysis mean value are given that change with growth and
those that remain stable.
Points
Pt- Located at lower border of foramen rotendum.
CC – Intersection of facial axis and cranial axis i.e. N to Ba.
Xi – Centroid of ramus
Pm – Protrubrance menti between point B and Pog.
Variables norms S.D. For 9 years old+age adjust
1) Facial axis 900
±3 No adjustment
2) Facial angle 870
±3 +10
Every 3 years
3) Mandibular plane 260
± 4 –10
every 3 years
4) Lower facial height 470
± 4 No adjustment
5) Palatal plane to PH 00
(1-2.5)0
6) Convexity of point A 2 ± 2mm –1mm for every 3 years
7) LI to Apog 1mm ± 2 No adjustment
8) U6 to Ptv Age± 3 increase 1mm/year upto maturity
9) Interincisal 1220
± 50
10) Lower lip to E line –2 ± 2mm Less protrusive with growth
Interpretation
24

25. 1. Facial axis
Indicate chin is upward and forward or down ward and backward.
2. Facial angle
Indicate mandibular prognathism or retrognathism.
3. Mandibular plane angle
Low mandibular plane angle – Adequate ramus height
High mandibular plane angle – Short vertical height of ramus
4. Palatal plane to FH
Indicate position of nasal floor and it is a objective in orthodontic
treatment to bring palatal plane parallel to the FH plane.
5. Maxillary convexity or convexity of point A
Helps in locating the position of maxilla with relation to cranial
base and it can be change with age and with mandibular growth.
6. Denture height
Angle made by connecting ANS, Xi and Pm points. Its
effectiveness represents the denture heights or lower facial height or
vertical relation between maxillary and chin.
7. LI to A Pog line
Helps in assessing lower incisor position in relation to existing
skeleton.
8. Upper molar to PTV
It is the indicator of upper denture position in the arch
anteroposteriorly.
9. Interincisal angle
Helps in assessing degree of proclination or retroclination of
maxillary and mandibular incisors.
10. Lower lip and E line
Protrusion or retrusion of lower lip.
25

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