Ricketts analysis /certified fixed orthodontic courses by Indian dental academy

RICKETTS ANALYSIS
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


In a reading at the Reunion meeting of the
Illinois Alumni, Chicago, March 1960, he stated
that he was often asked the question:
“ What do you men get from cephalometric
film that we don’t get from clinical
examinations, models and photographs?”
Ricketts produced his analysis with the intent
of reviewing the purpose and usefulness of the
cephalometric survey and to stress the use of
this technique in treatment planning and
estimating growth.

.

The purpose of the analysis is objective and
encompasses the 4 C’s of cephalometrics :
1.
To characterise or describe the existing
conditions.
2.
To compare one individual with
another or the same individual with himself at a
later time.
3.
To classify certain descriptions into
various categories.
4.
To communicate all these aspects to the
clinician, to a fellow research worker, or to a
parent.

AIM: To clarify the science of
cephalometrics and free it from some of the
confusion and misuse pervading the
discipline.
He also wanted to point out that the use
of cephalometrics to describe and classify a
malocclusion was one thing (Analysis) and
the act of treatment planning as a result of this
classification and description was another
thing (synthesis).

The Landmarks used were:


CC= Center of craniumpointof intersection of the basion
Nasion plane and the facial axis.
DC=Point in the center of condylar neck along the Ba- Na
Plane
PM= Suprapogonion/ protrubrance mentiThe point at
which the symphysis mentalis changes from convex to
Concave
Ptv= point of intersection of thedistal outline of ptm fissure
and perpendicular to the F-Hplane.
Xi= Geometric center of the ramus


Ricketts(Angle 1960):
Superficial Analysis:
1.Facial Angle
2. Facial axis( x-y axis)
3.Facial Convexity( A- Pog)
4. Lower Incisor position and angulation.
5. Upper Incisor position
6. Esthetic Plane

Deep Structure Analysis:
1. Cranial Base Angle
2. Cranial Base Length
3. Condyle or Fossa position
4. Condyle Axis
5. Mandibular Plane Angle

Ricketts(Angle 1981):
I. Lateral Analysis
1.Facial Axis
2.Facial Angle
3.Mandibular Plane Angle
4.Mandibular arc( Mandibular Bend)
5.Point A to Facial plane
6.Palatal Plane to Frankfort horizotal plane
7.Denture Height /lowerfacial height/ Oral Gnomom
8.Lower incisor to Apog line(mm) and (Angulation)
9.Upper Incisor to Apog(1960)
10.Upper molar to Ptv
11.Interincisal Angle
12.Lower Lip to E Line

II. Frontal Analysis
1. Nasal width
2.Mandibular width
3.Maxillary width
4.Molar width
5.Actual intermolar width
6.Intercuspid width
7.Denture Symmetry
8. Upper to Lower Molar relation :


1. Facial axis (X-Y axis)
Angle between basion-Nasion
plane and Foramen rotundum –
Gnathion
Ricketts used Huxley’s Basion
– Nasion plane and measured its
crossing of the Y axis as a
means of describing the face
height.
He calls it the X-Y axis angle
to distinguish it from the Y-axis
of Downs.
It seemed to be more useful in
assessing facial height and
prognosing the direction of
growth of the face”.

Mean value in 9 years olds : 90° ± 3.5°
X-Y axis < 90° →long faces with
retropositioned chin
X-Y axis > 90°(+6 to +10) → More Favourable
X-Y axis > 90°( +10 to +12) → Closed bite
tendencies with short facial vertical dimension
Protrusive chin or forward growing chin
Note: X-Yaxis does not measure the true length of
the face.


2.Facial( depth) Angle :
It is the angle formed between the
facial plane (N-Pog) and the
Frankfort Horizontal Plane.
It provides information of the
horizontal position of the chin.
Also suggest if a skeletal class II or
III pattern is due to position of
the mandible
Mean value for 9 year olds :
87° ± 3.0°
Age adjustment : +1° every 3 years

3. Mandibular Plane Angle
The mandibular plane:
(Go-Gn) to FHP
26° ± 4° at 9 years of
age, and reduces 1° every 3
years to adulthood.
High mPA suggests : open
bite
Low mPA implies : deep
bite

4.Mandibular arc
(Mandibular Bend):
It measures the angulation
of the condylar process
to the body of the mandible.
It is the angle between the
Condyle axis(Xi through
center of condyle neck)
Posterior extent of the corpus
axis(pm to Xi)
Norm = 26º+/- 2º
A total increase of 3º is seen
every 5 years

5. Facial convexity (point A to facial
plane).

Ricketts states that “A direct
measurement of point A to the
facial plane was a useful
description of contour to the
bony profile”.
Clinical norm at 9 years of
age : 2.0 mm.
Age adjustment : -1 mm every
3 years, gradually decreases to
0 mm at adulthood.

High convexity (+ve readings)→
Convex-facial profile
class II skeletal pattern.
Low values (-ve readings →
Concave facial profile
Class III skeletal relationship
However Convexity is also somewhat dependent
on the facial type and is further a challenging
orthodontic objectivity.
The usual objectivity in almost all orthodontic
practices is close to straight profile.

6.Palatal Plane to F-H plane:
Angle between the F-Hplane
and the Palatal plane
( ANS- PNS)
The Objective in orthodontic
treatment is that the
Palatal plane should be parallel to
the F-H plane
The desired value shoud be 0º or
180º


7.Denture Height/ Lower
Facial Height:
It is the angle made by
the ANS, Xi and Pm points
It describes the convergence /
Divergence of the Oral cavity
The norm= 47º +/ 4º
High Values are seen in
Skeletal openbite
Low values= skeletal
deepbite

8. Lower incisor position
and Angulation :
The A-Pog line/ denture
plane → To measure the
position of the lower anterior
teeth.
Measuring the position of
lower incisor w.r.t. the NB
line in effect is relating the
lower incisor to itself because
the position of B is determined
by the lower incisor in the first
place.

Mean value for 9 year olds (lower incisor
position) :
Ideally → 1.0 mm (± 2mm) ahead of the
A-Pog line.
It defines the Protrusion of the lower
arch.
Mean value
for 9 year(lower
incisor angulations) :
22°±4°,


9. Upper Incisor
Position :(1960)
The distance between
the incisal edge of the
maxillary
central
incisor to the A-Pog
line was originally
reported to be 5.7 ± 3
mm.
This was later
refined to a clinical
norm of
(3.5 ± 2.3) mm.

10.Upper molar to Ptv(mm):
The distance from the
pterygoid vertical to the distal of
the upper molar
Average: Age of patient + 3mm
Eg: In 11Years Patient it is
11+3= 14mm
Helps to determine:
1. If the malocclusion is due
to the upper or lower molar
2. In deciding whether
extractions are necessary


11.Inter incisal angle:
This angle give an idea of the interarch relationship
Ricketts did not agree with downs norm of 135º
as he said that the sample were chosen with bias.
So he suggested a lower angle= 125º- 126º
as this lower angle will provide a good plateau on
the upper incisor for articulation of the lower incisor
and smooth incisal guidance


12. Esthetic plane (E-plane) :
The Ricketts’ esthetic plane runs from the
tip of the nose to the soft-tissue pogonion.
In adulthood the lips should be contained
within the nose-chin line for esthetic
purposes.
Patterns in which lips protrude ahead of this
line have been evaluated as disproportionate
with facial disharmony.
This line is employed for the purpose of
describing the relationship of the mouth to the
other structures..

The lower lip ranges from +2 mm to -2 mm from the
E-line.
The normal value for the 9 year old is -2 mm
EN : Point on soft tissue nose tangent to E-line.
DT : Point on anterior curve of soft tissue chin
tangent to E-line (Lip normally lies 2 mm behind
E-line).
1. This measurement is an indication of soft tissue
balance between the lips and profile.
2.

This line is useful in evaluating functional
abnormalities of the lip.

DeepStructuresAnalysis(An
gle 1960)
1. Cranial Base Angle :
This is measured as the angle
N-S-Ba.
The average value = 129.6°
ranges from 114° to 144°.


2. Cranial Base length :
The length of the anterior
cranial base SN was not
measured linearly but was
expressed as the unusual
angle formed by the
intersection of lines S-Gn
and N-Gn or the S-Gn-N
angle.
Mean value : 35°
Range : 25° - 42°

3. Condyle or Fossa
Position :
A line S-Ba was bisected,
and this point was called
SOR (Spheno-occipital
Reference). The condylion
was measured to that point.
The average location of
condylion was 1.3 mm
upward and 1.9 mm
backward from S.O.R.


4. Condyle Axis :
It is the DC-xi line.
The angle made by DC-xi
with the Basion-Nasion plane
hovers around the ideal of
90° to the line N-Ba, but is
expressed as plus or minus
from the 90° ideal.
(DC is the point in the center
of the condyle neck along the
Ba-N plane).
5. Mandibular plane angle


Later new horizons have developed the need
for orthodontic criteria in terms of transverse
assessment such as
-Development of palatal widening and
maxillary orthopedics
-Demonstration of mandibular posturing
appliances( Frankel appliances)
-Characteristic changes in the frontal view with
extraoral traction.
-There was an awakening awareness of the
relationships between respiration and growth

Frontal Analysis:
1. Nasal width
2.Mandibular width
3.Maxillary width
4.Molar width
5.Actual intermolar width
6.Intercuspid width
7.Denture Symmetry
8. Upper to Lower Molar relation


1.Nasal cavity width
2.Mandibular width
3.Maxillary width
4.Symmetry
5.Intermolar width
6.Intercuspid width
7.Denture symmetry
8.Upper to lower
molar relation


1.Nasal Width:
Measures the width of the Nasal cavity
because of the importance of attaining normal
respiration in the orthodontic patient.
Norm in adults = 29- 33mm
0.5 mm increase each year from 17 to 23years
2. Mandibular Width:
Measured from antegonion to
antegonion( trihedral eminences)
Norm at 8 years =75mm
Inscrease of 1.25 each year
At 18 yrs =88.5mmwww.indiandentalacademy.com

3.Maxillary width – two frontal lines, left and right, are
constructed from the medial margins of the
zygomaticofrontal sutures to antigonion points, and the
maxillary width is evaluated on the left and right sides
separately by relating ‘J’ point or point jugale to these
lines.
 10 mm distance is desirable
4.Symmetry:
By measuring ANS and pogonion to the
midsagittal plane
Clinical norm = 0+/-2mm
No change if symmetric
Increases in Asymmetries

5.Intermolar width – measured from the
buccal surface of the first permanent molars
transversely.
Clinical norm B6 - B6= 56+/- 2mm
May narrow with mesial drift,but essentially no
change
6. Intercuspid width – the width between
the tips of the lower cuspids
Clinical norm B3- B3= 22.5+/-2mm at 8 years
26mm+/-1.5mm at 13years
Crowns converge, then diverge in eruption

7.Denture symmetry – the relationship of the
midpoints of the upper and lower central incisor roots
to the midsagittal plane.
Ideally the midsagittal plane should fall on all the
midpoints.
8.Upper to Lower Molar relation
It is an indicator of the Molar crossbite,as it
describes the width difference between the buccal
surface of upper and lower molars
The average value= 1mm+/- 1mm


Peter Elbe, Valiathan Ashima, Suresh
M (J.P.F.A 2000)
Did a comparitive study among
south Indians and North Indians using
Ricketts Lateral cephalometric analysis
The sample consisted of 100
subjects( 18- 25years)
50 North Indians (25M 25 F)
50 South Indians (25M 25 F)


Results:

South
Indians

Facial axis
89.02º
Facial Angle
88.71º
Mandibular
18.9 º
Plane Angle
Convexity of point A
02.13
Lower Incisor to Apog 03.63
Upper Molar to Ptv(mm) 23.66
Lip to E- Line(mm)
-0.42
Mandibular Arc
39.12º
Lower Facial Height
39.20º
Palatal plane angle
01.33º
Inter incisal Angle
120.12º

North
Indians

Norms

87.76º 90º+/-3
87.89º 87+/-3
19.00º 26+/-4
01.64
2+/-2
03.26
1+/- 2
21.78 21yrs +3
-1.73 -2+/-2mm
38.74
22+/- 4
39.86
47
01.12 0º/180º+/-3
123.14º 126º

Rakosi`s Analysis
presented by Thomas

Rakosi (1992)

Aims: To assist

the clinician in making diagnosis
and planning therapy with functional appliances.
Four major areas of emphasis in cephalometric
diagnostic assessment for patients treated with
functional appliances were

1.Accomplishment of growth increments and the direction
or vector of growth.
2. Assessment of the magnitude of growth change
3.Inclination and position of the upper and lower incisors,
as it helps to forecast the reciprocal growth increment of
the jaw bases.
4. To differentiate between skeletal and dentoalveolar
malocclusion and provide information on a combination of
factors a) etiology of malocclusion
b) The therapeutic possibilities for treatment

3)Se:Midpoint of the
entrance to the sella
4)Sn-Subnasale,skin point
where nasal septum mergers
with upper lip
6) Apmax-To determine the
length of the maxilla->By
drawing aperpendicular from
point A to the palatal plane.
18) Apman-To determine the
length of the mandible->By
drawing a perpendicular
from Pog to the Mandibular
plane

23)FH-Rasc- Intersection of the F-H and the posterior margin
of the ascending ramus.
26) S`= Contructed point for assessing length of maxillary
basea perpendicular line from se to the palatal plane.
27) APOcc= Anterioorly drived point for determining occlusal
planeMiddle of incisor overbite in occlusion
28)PPOcc= Posteror point for determining occlusal plane
most distal contact between the most posterior molars in
occlusion


Rakosi`s Cephalometric Analysis:
I.Facial Skeleton
II.Jaw Bases
III.Dentoalveolar Relationships
I.Analysis Of the Facial Skeleton
1. Three Angular Measurements
Saddle angle, Articular angle, Gonial angle
2. Four Linear Measurements
Anterior and posterior face height
Anterior and Posterior cranial base length

Saddle Angle(N-S- Ar):
Assesses the relationship
between anterior and postero
Lateral cranial bases
Large Saddle Angle = Posterior
condylar Position
when mandible is posteriorly
located relative to the cranial
base and maxilla
Difficult to influence with
Functional appliance
therapy

Articular Angle(S-Ar_G0):
Angle between upper and
lower parts of the posterior
contours of the facial
skeleton.
Mean Value= 143+/- 6º
Its size depends on the position
of the mandible
Large = Mandible is
Retrognathic
Small= Mandible is
prognathic

Influenced during orthopedic/orthodontic therapy,
Decreases during, a)Anterior positioning of
the mandible
b)Closing the bite
c)Mesial migration of the
posterior segment
Increases, a)Posterior relocation of the mandible
b)opening the bite
c)Distal driving of the posterior teeth

Children at 9years with horizontal growth pattern = 139.5º
Children at 9years with vertical growth pattern = 142.4º


Gonial Angle (Ar- Go- Me):
angle between a)tangents
to the body of mandible
b)Posterior
border of the ramus
mean Value= 128+/- 7º
9 yr old child with horizontal
growth pattern= 125.5º avg
9 yr old child with vertical
growth pattern= 133.4º avg


It gives information on :
i)The form of mandible
ii)The mandibular growth direction
Acute/ small angle= Horizontal growth of the
mandible
It is favourable for anterior positioning of
mandible with an activator
In case of Large angle= Activator treatment
is contraindicated

Anterior and Posterior facial
height:
a)Posterior face height(S-Go)
of 9yr old with horizontal
growth pattern= 69.5mm
Growth increment( 915yrs)=11.05
vertical growth pattern at 9yrs=
64.1mm
Growth increment( 915yrs)=10.8mm

b)A reverse ratio is seen,Anterior face height(NaMe) of 9 year old with
horizontal growth pattern= 103mm
Vertical growth pattern= 106.6mm
So Jarabak in 1972 setup a ratio to determine the
growth direction;
Posterior face height X 100
----------------------------------Anterior face height
Ratio 0f <62ºVertcal growth pattern
>62ºHorizontal growth pattern

The assessment of growth direction is very
important in functional appliance therapy, for
determining
1.whether functional appliance therapy should
be used .
2.The construction details, type of construction
bite, etc.(high/ low)


Anterior and posterior cranial base
length:
a)Anterior cranial base length(SeN):
. Superior entrance to sella turcica(Se)
to Nasion
In 9-year-old average length of
anterior cranial base is
68.8mm horizontal growth patterns a
63.8 mm with a vertical growth vector.
The incremental change between 9 and
15 years = 4.46 mm in the horizontal
pattern
3.52mm in the vertical pattern.

b)Posterior (lateral) cranial base length (SAr).
A short posterior cranial base occurs in
vertical growth patterns or skeletal open bites,
which gives a poor prognosis for functional
appliance therapy.
In 9-year-old children with a horizontal
growth pattern the average length was
32.2mm, with an increment of 9.16mm in the
following 6 years,
As opposed to 30mm with an increment of
4.47mm in the vertical pattern.

II.Analysis of the jaw bases
1.The angles between the vertical reference lines
represent the sagittal relationship (e.g., S-N-A, S-N-B)
2.whereas those between the horizontal lines assist in
evaluating the vertical relationship (e.g., base plane
angle, inclination angle).
3.The linear measurements give an indication of the
length of the maxillary and mandibular bases as well as
the ascending ramus.
4.A morphologic assessment, particularly of the
mandible, is also important in forecasting the growth
direction.

S-N-A:
The angle S-N-A expresses the
sagittal relationship of the anterior
limit of the maxillary apical base
(point A) as related to the anterior
cranial base
It is large in prognathic maxilla
Small in Retruded maxilla
Growth direction
Mean
Horizontal
Vertical

9yrs
15yrs
79.5 81.28
79.73 81.57
79.0 80.57

Moderate decrease in SNA =>Activator therapy
Large decrease in SNA= Special activator(Clark
twin block)


S-N-B the angle S-N-B expresses the
sagittal relationship between the
anterior extent of the mandibular apical
base and the anterior cranial base.
It is large in Prognathic mandible
Small in Retrognathic mandible
Growth direction 9yrs 15yrs
Horizontal
77.2
80.5
Vertical
74.3 75.9
.Again based on the growth pattern
myofunctional appliances can be used
for sucessful treatment by anteriorly
positioning the mandible


Base plane angle (Pal-MP).
The base plane is the angle,
between the maxillary and
mandiblular jaw bases
Also used to determine the
inclination of the mandibular plane.
Growth direction 9yrs 15yrs
Horizontal
23.4
20.5
Vertical
32.9 30.9
The age dependent decrease in this
angle corresponds to the general
trend toward a more horizontal
growth pattern (Moss,graber 1970)

Inclination angle:
The inclination angle gives
an assessment of the
inclination of the maxillary
base.
It is the angle formed by
the Pn line(perpendicular
dropped from N-Se at N`)
and the palatal plane.
A large angle upward and
forward inclination

Small angle downward and backward tipping
of the anterior end of the palatal plane or
maxillary base.
This angle is not correlated with the growth
pattern or facial type.
However Functional or therapeutic influences can
alter the inclination of the maxillary base.Hence
there is need for periodic assessment during
active treatment.


Rotation of the Jaw bases:
can be evaluated by the base plane angle
and the Inclination angle.
These rotations are of special interest in
treatment with functional appliances since
they show whether such appliance are
indicated and provide the criteria in appliance
construction.
a)Rotation of the mandible is due to both
growth dependent and functional influences..
For this reason it is possible to influence
therapeutically to a moderate degree the
rotation of the mandible.

b)The pattern of rotation of the maxillary base can be
observed by sequential measurements of the inclination
angle.
Environmental influences such as neuromuscular
dysfunction, occlusal forces, gravity, and
nasorespiratory malfunction (according to LinderAronson) can modify this inclination.
An upward and forward tipping of the anterior part of
the maxilla is often seen in confirmed mouthbreathers.
A downward and backward tipping of the anterior part
of the maxillary base is seen as a natural compensation
in patient with vertically growing faces.

c)Mutual relationship of the
rotating jaw bases. Rotation of
the mandible can be decisive in
establishing the vertical
proportions of the facial skeleton.
1) Convergent rotation of the jaw
bases:
creates a severely deep overbite
Is difficult to manage using
functional methods.
2)Divergent rotation of the jaw bases:
causes marked open bite problems.
In severe cases or thognathic
surgery is required for the
correction.


3.Cranial rotation of both bases. In this
horizontal growth pattern there is a
relatively harmonious rotation of both jaws
in an upward and forward direction. The
upward and forward rotation of the maxilla
compensates for the upward and forward
mandibular rotation, offsetting what could
be a deep bite. The result is a normal
overbite.
4.Caudal or downward and backward rotation
of both bases in a relatively harmonious
manner. The downward and backward
maxillary rotation offsets what could be an
open bite created by the downward and
backward mandibular rotation.

The therapeutic control of the vertical dimension is usually
more difficult than of the sagittal dimension. If a causal
therapeutic skeletal reconstruction is not possible, some
compensatory form of treatment is indicated. (functional
appliance therapy)
This means, for example, that if the vertical morphogenetic
pattern cannot be altered an occlusal adjustment must be
achieved by retroclination of the maxillary base, often with
tooth sacrifice.
( orthodontically)
Again, orthognathic surgery is the ultimate corrective
procedure if the magnitude of the malrelationship transcends
orthodontic or orthopedic growth guidance procedures.

Linear measurement of the jaw bases.
If the mandible is retrognathic, the question arises
whether its size is relatively small or large. This is
important in considering the etiology and therapy for
each patient.
The length of the maxillary and mandibular bases, and
of the ascending ramus, is measured relative to Se-N.
(schwarz 1958 ) in his “roentgenostatic analysis”
The ideal dimension relative to Se-N is calculated by
using the following formula:
N-Se: ManBase
20:21
Ascending ramus: ManBase
5:7
MaxBase: ManBasewww.indiandentalacademy.com 2:3

Extent of the mandibular base.
Determined by measuring the distance
gonion-pogonion (projected
perpendicular to the mandibular plane).
Ideally the mandibular base should be
3mm longer than Se-N up to the twelfth
year and 3.5mm longer after the twelfth
year.
Growth direction
Horizontal
Vertical

9yrs(mm) 15yrs
67.59
77.35
65.23 73.5

Extent of the maxillary base:
There are two “ideal” measurements for the
evaluation of this dimension:
1. Related to N-Se
2. The other to the length of the mandibular
base.
As Johnston(1976) points out, the mandible
outgrows the maxilla.
Growth direction
Horizontal
Vertical

9yrs(mm) 15yrs
44.56
48.6
44.0 47.16


Since the growth potential of the mandibular base is
greater than that of the maxillary base, the angle SN-B increases and A-N-B thus decreases.
This corroborates the impression of many clinicians
that the mandible is less retrognathic after 12 years
of age.
The growth advantage, with the mandible
outgrowing the maxilla by as much as 5mm, is of
special value to functional appliance proponents
and, of course, to the Class II patients being treated.


Length of the ascending ramus.
This measurement is made by
calculating the distance between
gonion and condylion.
The length of the ramus is important
in determining posterior face height
and subsequent relation to anterior
face height.
Growth direction
Horizontal
Vertical

9yrs(mm) 15yrs
48.9
58.67
44.47 51.7

Evaluation of the length of the jaw bases
Mandibular base. If the length of the mandibular
base corresponds to the distance N-Se (ManBase:
N-Se +3mm) then this expresses an age-related
normal mandibular length and we can expect an
average growth increment.
If the base is shorter, the growth increment will
probably be larger. I
f it is longer, the growth increment may will be
smaller.
This forecasting can be made more exact by using
two additional measurements, the lengths of both
the maxillary base and ascending ramus.

Maxillary base. There are two ideal values for
assessing the length of the maxillary base;
1)one related to the distance N-Se, the other to
the length of the mandibular base. A deviation
from the mandibular base-related norm means
that the maxillary base is too long or too short. If
the maxillary base corresponds to the
mandibular base-related norm, then the facial
skeleton
is
proportionally
developed,
particularly if the ramus length also corresponds
to these values. If the N-Se length does not
relate to these three proportionate measurements,
then the facial skeleton is proportionate but
either too large or too small.

Ascending ramus. If the ramus is too short in relation
to the other proportions, a large amount of growth
can be expected under the supposition that the growth
pattern is not vertical.
In the vertical type the ramus remains short.
To enhance the differential diagnosis, the
morphologic characteristics of the mandible should
also be studied.


Morphology of the mandible. The various facial
types
(orthognathic, retrognathic, prognathic) also reflect to
some degree the morphology of the mandible.
In the orthognathic type of face the ramus and body of
the mandible are fully developed and the width of the
ascending ramus is equal to the height of the body of
the mandible, including the height of the alveolar
process and the incisors. The condylar and coronoid
processes are almost on the same plane, and the
symphysis is well developed.

In the prognathic type the corpus is well
developed and is wide in the molar
region. The symphysis is wider in the
sagittal plane. The ramus is wide and
long, and the gonial is acute or small.
The prognathic type of mandible grows
horizontally. Even if there is an average
or slightly vertical growth direction in the
mixed dentition, shift of the mandible to a
horizontal growth direction can be
expected in the prognathic type of
mandible in the following years

In the retrognathic facial type the
corpus is narrow, particularly in
the molar region. The symphysis is
narrow and long. The ramus is
narrow and short. The coronoid
process is shorter than the
condylar process, and the gonial
angle is obtuse or large.
. In a retrognathic type of
mandible, shift of the growth
pattern in the opposite direction is
less likely and with much less
expressivity.

Analysis of the dentoalveolar relationships
I.Axial Inclination of the Incisors
Upper incisor axial
inclination: The long axis of the
maxillary incisors, as viewed on
the lateral cephalogram, is
extended to intersect the S-N line
and the posterior angle is
measured
Upto 7 years this angle
= 94 ° - 100 °
1 or 2 years after eruption the
inclination increases to an
average 102°

Larger angles=Incisor Procumbany/ Incisor crown
tipping
Incisor protrusion requires lingual tipping, a therapeutic
objective that can be performed quite successfully with
removable appliances, if there is adequate space.
However, before a decision on the mode of movement of
these teeth can be made, an assessment of their position
is necessary.


Lower incisors axial inclination: The posterior angle
between the long axis of the lower incisors and the
mandibular plane is the classic method of assessing axial
inclination of these teeth.
Average value often given is 90°
Between the sixth and twelfth years of life it increases
from 88° for the relatively upright deciduous incisors to
94°
A smaller angle may be indicative of lingual tipping of
the incisors, which is advantageous for functional
appliance treatment as it tips the lower incisors labially

II.Position of the incisors. Linear
measurements serve best to assess
the position of the incisors with
respect to the profile
Upper Incisors:The most
common method is to measure the
distance of the incisal edges to the
line N-Pog
Average position of the maxillary
incisors is 2 to 4mm anterior to the
N-Pog line.
The lower incisors vary from 2mm
posterior to 2mm anterior to this
line.

The aim of orthodontic treatment is to achieve a
similar relationship to this normal guideline.
Uprighting of incisors that are tipped too far
labially with respect to the N-Pog line is possible
with removable appliances.
But if labially malpositioned incisors have a good
axial inclination already, then bodily movement is
required, and this is possible only with fixed
appliances and root torque.


Lower incisors
Tip of lower incisors to the N-Pog line
assists in determining the sagittal
discrepancy.
The lower incisors vary from 2mm
posterior to 2mm anterior to this line.
Incisors that are behind this line can be
moved labially, since space is available.
Incisors anterior to the facial plane that
must be moved lingually need space,
which may be obtained only by extraction
procedures.

Summary: The salient points of the cephalometric analysis for
the use of functional appliance therapy as follows:
1.Cephalometrics enables the anomaly to be located and a
differentiation made between skeletal and dentoalveolar
malocclusions.,
2.The cephalometric assessment helps determine the primary and
secondary dysplastic structures and possible autonomous
compensatory response before treatment.
3.It is possible to determine whether the jaw bases are anteriorly
or posteriorly positioned and whether short or long.
4.In the vertical plane the possible rotations of the maxillary and
mandibular bases can be observed and the growth pattern
delineated.
5.The position and inclination of the upper and lower incisors are
important from both a functional and an esthetic point of view.
6.Cephalometrics enhances the assessment of the influences of
neuromuscular dysfunction on the dentition. This is vital for
diagnosis and treatment planing with functional appliances.

References:
1.Peter Elbe, Ashima Valiathan, Suresh M:
Cephalometric comparison of South Indians
and NorthIndians using Ricketts Lateral Cephalometric
Analysis, JPFA Vol 14 December 2000page 113-117
2. Ricketts RM:Perspectives in the clinical application of
cephalometrics. Angle ortho 1981:51:page115-150
3.Ricketts RM:A foundation for cephalometric
communication,AJO 1960, 46: 330-57
4.Ricketts RM: “Cephalometric Synthesis”AJO1960 46:9
page 647-673

5. Ricketts RM: “Cephalometric Analysis and Synthesis”,
Angle ortho 1961, 31:3 page 141-156
6. Ricketts RM: A four step method to distinguish
orthodontic changes from natural growth” JCO
1975,April ,page 208- 228
7. Ricketts RM,Bench RW, Gugino CF, Hilgers jj,
schulhof R:Bioprogressive Therapy.(Rocky Mountain
Orthodontics: Denver) 1979 page 55-70
8.Jacobson A, Sadowsky PL. A Visualised treatment
objective. JCO 1977: 14:page 554

9.Thomas Rakosi: An Atlas and Manuelof Cephalometric
Radiography, 1982 page 46- 76
10. Thomas M Graber, Thomas Rakosi, Alexandre
G Petrovic: Dentofacial Orthopedics with Functional
Appliances, 2nd edition page 107- 124
11.Athanasios E Athanasiou: Orthodontic Cephalometry,
1995 page 271
12.Alexandre Jacobson: Radiographic Cephalometry,1995
Page 87- 95


13. Ruel W. Bench, Carl F. Gugino,
James J. Hilgers, Bioprogressive Part 3:Visualised
treatment Objective,1977, November, page 744-763
14.Ruel W. Bench, Carl F. Gugino,
James J. Hilgers, Bioprogressive Part 4: The
use of superimposition areas to establish treatment design,
1977, December page 820- 834


Thank you
For more details please visit


Ricketts analysis /certified fixed orthodontic courses by Indian dental academy

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Was ist angesagt?

Was ist angesagt? (20)

Ähnlich wie Ricketts analysis /certified fixed orthodontic courses by Indian dental academy

Ähnlich wie Ricketts analysis /certified fixed orthodontic courses by Indian dental academy (20)

Mehr von Indian dental academy

Mehr von Indian dental academy (20)

Ricketts analysis /certified fixed orthodontic courses by Indian dental academy