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Prepared by:- Bilal A.M.Prepared by:- Bilal A.M.
Faculty of dentistry-Mansoura university -Faculty of dentistry-Mansoura u...
Tracing roentgenograms
Instruments required for tracing:
(1) Paper:
Trace a lene or acetate paper (0.003)" thickness, one ...
A soft pencil (NO. 3) is used for the rest of the
stractures as seen on the film, which have a certain
thickness, close to...
It is of good routine to use one colour for the midsagittal
structures and an other for bilateral ones. This help to
keep ...
The light should be cold, two or three intensities
of light controlled by switch is important
because the films or their d...
A photo – retouching table or a box constructed
with two (10 – watt) fluorescent bulbs and a milk
glass cover the size of ...
Tracing technique:
•1- Distinguishing marks should be put on the right and left sides
of the roentgenogram.
•2- Place the ...
•3- Profile tracing:
Should be started from
the outer out line of
the roentgenogram
and continued to the
inner parts:
Trac...
Then, trace the bony profile:
A- The lower border of the mandible, posterior
border of the ramus, draw the posterior borde...
D- Come back to sella turcica and trace the
planum, and anteriorly the cribriform plate,
continued more anteriorly and upw...
Tracing in details:
1- The soft tissue profile:
Only on the lateral films, it does not offer any difficulty if the
film is...
At the level of nasion, some cephalostats use a rest
against that area and the out line of the soft tissues is
pressed in....
2- The bony structures: From above to down:
(1)The frontal bone:
The external plate goes down ward with a convexity at
the...
2-The nasal bone:
Starts from nasion and goes down ward and forward,
it is continued down ward and backward to form the
la...
3-The maxilla:
The anterior contour of the palate and the a lveolar
bone.Extend on the profile between the anterior nasal
...
4-The incisors:
The most prominent one should be traced, the upper
central incisors does not offer difficulty, but in the
...
5- The chin:
Start at infra dentale, curves posteriorly to point B (supra
– mentale), goes down ward and forward to pognoi...
6- the mandible:
posterior to the symphysis, the lower border extends to
the gonion, at the level of the bicuspids, it has...
7- The ramus:
Upward and backward up to the neck of the condyle
which is more backwardly inclined. The posterior
border ca...
8- The head of the condyle:
Unless an open mouth film is token it can not
be accurately located, as it being masked
genera...
3- Upper face:
It is the area between the cranial base and the
palate. Antero – posteriorly we find:
(1)The orbit:
The roo...
The midlines between the two
shadows should be defined oblique
line crosses the orbital cavity.
It represents the greater ...
(2) Maxillo – zygomatico – temperal sulcus:
It is a vertical line which can be straight or like situated
just posterior to...
It goes from the cribri from plate, down to the floor of the
nose at the level of the upper first molar, and curves
upward...
(3) The pterygo maxillary fissure Ptm:
It forms a boucle just above and posterior to the posterior
nasal spine and the sof...
4- Midlface:
It is represented by the hard palate which is
enclosed between the floor of the nose and the
roof of the pala...
At the level of Ptm it makes a U-turn and
comes anteriorly to the upper central
incisor from the alveolar process of the
i...
5- Cranial base:
Cranial base is the demakration that the brain makes with
the face and the neck.
Traditionally, it is div...
A- Anterior cranial fossa:
Extends from the frontal bone to the lesser wing of
sphenoid. It represented bilaterally by the...
B- Middle cranial base:
Extends from lesser wing of sphenoid to the
petrous bone.
petrous bone
C- Posterior cranial fossa:
Extends bilaterally from the occipital bone
posteriorly and the petrous bone anteriorly.
In th...
6- cranial base lines:
1- Posterior arm (The clivus):
It extends between the foramen magnum and sella
turcica on the mid s...
2- The hinge (sella – turcica):
Saddle shaped , pituitary fossa, situated on the mid
sagittal area at the centre of corpus...
In the body around sella, there is a sphenoidal sinus of
varying size.
In roentgenographic cephalometry, because its
accur...
3-Anterior arm:
Divided in two lines, the roof of the orbit above
and the planum with the cribriform plate below:
A- Roof ...
B- Planum:
Is separated from the orbital roof and anterior
clinoid just anterior to sella. It is flat and horizontal.
It j...
7- The teeth:
The accuracy in drawing the teeth depends on
their symmetry and the good orientation of the
head.
The key te...
2- Canines:
Not always easy to locate. One method may be to
start from the molars and eliminate progressively,
the bicuspi...
Any measurement involving the axis of the
lower incisor should be allowed a large
margin of tracing errors.
Besides these ...
6- The orbital lines.
7- The lesser wings of the sphenoids.
8- The crista galli.
9- The nasal septum.
10-The lateral walls...
Location of the porion:
The porion is not distinguishable on the roentgeno-
gram. It actually is approximately 3mm. above ...
Since the tissues of the outer ear canal are sensitive
to pressure, insertion of the ear rods in the same
position is unce...
Determination of the right and left sides:
•In all cephalomertic roentgenograms the centeral
ray goes through the ear rod ...
•The left side of the mandible is superior to the right,
and the line denoting the inferior border must cross
over the cor...
•In the incisor region, the full crown usually
can be seen a long with the labial root out line.
The lingual root outline ...
•To obtain correct condylar morphology by
using a template: two profile
cephalograms are taken the one with the
teeth in f...
Errors in tracing:
•Some degree of error is inherent in tracing film, some
errors are duo to the character of the film tra...
•The denser the structure, the whiter the
reproduction on the film. Actually only the teeth
offer a well delimited and com...
•Practically, even if the face is perfectly oriented and if
the bilateral structures are symmetrical, they are not
necessa...
•While asymmetry between the two sides of
the mandible should be bisected severe
asymmetry should be traced as found.
•The...
•Some can not be located accurately on either
(T.M.J) unless an open mouth is taken.
•Generally, for height and depth prop...
Lateral land marks
1- Nasion (N):
•The midlle point on the fronto-
nasal suture, intersected by the
median sagittal plane....
2- Sella Turcica (s):
•Sella trucica is the pituitary fossa of the sphenoid
bone. Sella (s) is the centre of the sella tur...
4- Subnasale (sn):
The point at which the nasal septum between
the nostrils merges with the upper cutaneous
lip in the mid...
5- Sub spinale (point A):
•The deepest midline point in the curved bony outline
contour of the alveolar process of the max...
6- Prosthion (Pr):
The lowest, most anterior interdental point on the
alveolar mucosa in the median plane between the
maxi...
7- Incisor superius (I.S):
The most forward incisal point of the most prominent
maxillary central incisor.
8- Apicale ┴ (A...
9- Incisor inferius (I.I):
The most forward incisal point of the most prominent
mandibular central incisor.
10- Apicale T ...
11- Infra dentale (I.d):
The highest, most anterior, interdental point
on the alveolar mucosa in the median plane
between ...
12- Supra mentale (point B):
The deepest point on the contour
of the mandibular alveolar process
betweeninfradentale and p...
13- Pogonion (Pog):
Most anterior point of the bony chin.
14- Gnathion (Gn):
•According to martin and saller (1956): it is the
lowest point in the median plane of the mandible,
whe...
•In cephalomertic, it is the mid point between the
most anterior and inferior points on the bony chin.
•Measured at the in...
15- Gonion (Go):
•The lowest, posterior and most outward point on
the angle of the mandible.
•This is obtained in cephalom...
•When the angles of both sides of the mandible
appear on the profile roentgenogram, the point
midway between the right and...
16- Menton (Me):
•The lowest point on the chin,
•from which the face height is
• measured.
17- Articulare (Ar):
•The point was introduced Bjork (1974)
•The point of intersection of the external dorsal
contour of t...
18- Condylion (cd):
•Most superior point on the
• head of the condyle.
19- Orbitale (or):
•The lowest point on the inferior bony margin of the
orbit. In cephalometric roentenogram the orbitale
...
20-Anterior nasal spine (ANS):
The median, sharp, bony process of
the maxilla at the lower margin
of the anterior nasal op...
21- Posterior nasal spine (PNS):
•Process formed by the united projecting ends of
the posterior borders of the palatal pro...
22- Anterior point for the occlusal plane (APocc):
•A constructed point, the midpoint of the incisor
over bite in occlusio...
24- Basion (Ba):
•The most forward and lowest point on the
anterior margin of the foramen magnum.
•Bjork and palling prvid...
Other cephalometric land marks:
Pterygo maxillary fissure (Ptm):
An oval shaped radiolucency resulting from the
fissure be...
Porion (P):
The mid point on the upper edge of the external
auditory meatus.
As a cephalometric landmark it is located in ...
Key ridge (KR):
The lowest point of the zygomatico – maxillary ridge.
Acanthion (Ac):
Tip of the anterior nasal spine.
Cli...
Clinoidale (Cl):
Most superior point on the contour of the
anterior clinoid.
Bolton point (BP).
Spheno occipital synchon-d...
Broad bent registration point (R):
Mid point on a perpendicular from the centre of
sella to the Bolton – nasion line.
Sphe...
Alveolar point (Al.P):
The lowest point of the a lveolar process at the
midline between the maxillary central incisors.
Oc...
Sphenoidale (SPH):
Point of the greatest convexity between the
anterior contour of the sella turcica and planum
sphenoidal...
Endo basion (E.b):
The perpendicular projection of the anterior border of
the foramen magnum on a tangent through the lowe...
Tuber culum sellae (T.S):
Anterior boundary of the sella turcica.
Zygoin (Z):
The most lateral projection of the zygomatic...
Euryon (Eu):
The most lateral point on the side of the head.
Fronto temporale (Ft):
The most anterior point of the termpor...
Mandibular notch (M.N):
The concavity between the coronoid and
condyloid process of the mandible.
Ophryon (Oph.):
Mid sagi...
Poster-antrior cephalomeric landmarks
Glabella (Gl):
The most anterior point of the frontal bone in
the midsagittal plane ...
Soft tissue points: (Burstone 1959)
Soft tissue points: (Burstone 1959)
Glabella (G):
Determined by a tangent to the forehead from
a line passing through subn...
Soft tissue nasion (N`):
The most cocave or retruded point in the
tissue overlying the area of the frontonasal
sutures, th...
Nasal crown (Nc):
A point a long the bridge of the nose halfway
between soft-tissue nasion and pro nasale.
Pronasale (Pn):...
Subnasale (sn):
The point where the maxillary lip and nasal
septum form a definite angle.
If the depression is a gentle cu...
Soft – tissue sub spinale (A`) (ss):
The point of greatest concavity in the midline
of the upper lip between subnasale and...
Labiale superius (Ls):
The most prominent point on the upper lip as
measured from a perpendicular to nasal floor.
Stomion (sto):
The junction in the midline of the upper and
lower lips.
Labiale inferius (Li):
The most prominent point on the lower lip as
determined by a perpendicular from nasal
floor.
Soft – tissue supra mentale – point B`
(Sm):
The point of the greatest concavity in the
midline of the lower lip between t...
Soft – tissue pogonion (Pog`):
The most prominent or anterior point on the
soft – tissue chin in the mid sagittal plane.
Soft – tissue gnathion (Gn`):
The mid point between the most anterior and
inferior points of the soft – tissue chin in the...
Superior labial sulcus:
The deepest point on the upper lip as determined by
a line drawn from subnasale inclined so that i...
Inferior labial sulcus:
The most concave point on the lower lip as
determined by a line tangent to the menton
and labrale ...
Cephalometric lines and planes:
1- The commenly used horizontal lines and planes:
•S – N line:
The cranial line between the centre of sella turcica (s)
an...
•Bolton plane:
(Broad bent – Bolton line): BP- N:
The line connects nasion to the upper most point
on the posterior end of...
•Frankfort horizontal plane (FH):
Plane intersecting right and left porion and left
orbitale. It is drawn on the profile r...
•Palatal plane:
Line connecting the anterior nasal spine (ANS) and the
posterior ansal spine (PNS).
•Occlusal plane: (OCC)
The occlusal plane of the teeth, a line drawn between
points representing one half of the incisor o...
•Mandibular plane:
Several mandibular planes are used, depending on the
analysis:
The most common ones are:
A.A tangent to...
•Alternative lines and planes:
• A.B Plane:
Line between A point (sub spinale) and B- point (supra
mentale) it represents ...
•Facial plane:
A line from the anterior point of the fronto- nasal
suture (N) to the most anterior point of the mandible
(...
•Ramus line:
A line tangent to the posterior border of the
mandibular ramus either from:
A- A point posterior to the mandi...
•Orbital plane (O.P):
Perpendicular to Frankfort horizontal plane from
orbitale.
•S – BP plane:
Line connecting sella with the Bolton
point. This line indicates the posterior
portion of the cranial base....
•Blumenbach's plane:
The plane drawn through the points on
the skull, without the mandible, which
touch a flat horizontal ...
•Broca's line:
Prosthion to lowest point on the occipital
condyle when the skull is resting on a
horizontal surface.
•Camp...
•Camper's plane:
Line from tip of the anterior nasal spine
(acathion) to the centre of the bony external
auditory meatus i...
•Cranial length:
Galbella to opisthocranion.
•De caster's line:
The plano-ethmodial line from the anterior
contour of sell...
•His's line:
Extends from acanthion to opisthion and divides the
face into an upper and a lower dental part.
•Hamy's line:...
•Huxley's line:
Nasion to basion.
•Krogman's Nassion parallel:
Sella – nason to Frankfort horizontal.
•Martins line:
Nasio...
•Margolis line:
Nasion to top of spheno occipital
synchondrosis.
•Montagus line:
Nasion to porion.
•P-O plane:
Porion – or...
•Pterygo maxillary fissure (PTM):
The fissure formed by the retromolar
tuberosity of the maxilla and the anterior
curve of...
•Rickets esthetic line:
Tangent to the tip of the nose and the most
anterior point on the chin.
•Salzmann's basal arch:
Th...
It includes Down's a point (subspinale) and B
point (supra mentale), Axel lunds trom's apical
base (which is a line around...
These are the areas to which tweed referred
as (basal bone).
•Schmidt's plane:
Ophryon to inion.
•Schwalbe's line:
Galbell...
•Super orbital line:
A line from the anterior clinoid process a
long the roof of the orbits, bounded
anteriorly by the fro...
•Von thering's line:
Orbitale to the centre of the bony external
meatus (Frankfort horizontal).
•Cranial base references p...
•Mandibular references planes:
•1- A line tangent to the lower border of
the mandible especially when the
antegonial notch...
•Middle face references planes:
•1- The palatal plane (joining ANS and
PNS).
•2- The occlusal plane which bisects the
maxi...
Cephalometric angles:
•Angle of convexity (Downs):
Angle between (nasion – subspinale – pogonion) (N-
point A- pog).
This ...
A positive angle suggests
prominence of the maxillary
denture base relative to the
mandible. A negative angle
of convexity...
•Facial angle (Downs):
Frankfort plane intersection
of nasion – pogonion line
(inner lower angle).
Facial angle establishe...
•FMIA (Tweed):
Angle between Frankfort plane and the
mandibular incisor plane.
This measures the procumbency of the
mandib...
•N-S-Gn:
Angle between SN line with the line
connects N with the chin point (Gn).
It is used in locating the anterior end ...
•N-S-MP:
Projection of line SN with a tangent to the lower
border of the mandible (MP).
•N-ANS-PNS:
Angle from nasion (N) to
the anterior nasal spine
(ANS) to posterior nasal
spine (PNS).
•S-N-A angle:
Angle between points sella – nasion – subspinale
(point A).
It represents antero
posterior relationship
of t...
•S.N.B angle:
Angle between points
sella rasion – supra
metnale (point B).
It shows the anterior
limit of the mandibular
b...
•SNA – SNB Angle:
The angle formed by
subspintale (point A)
rasion supramentale
(point B).
It indicates the antero
posteri...
•S-N-I:
Angle between SN line and the line connects N to
tip of _ (tip of the maxillary central incisor).
This is used to
...
•B.P – SN (Broad bent):
Formed by the lines s (sella) – N (Nasion) and s
(sella) – B.P (Bolton point).
By connecting the p...
•Y-axis angle:
It is read at the angle toward the profile of the face
below the Frankfort horizontal.
It is indicator of t...
•N-S-MI (maxillary first molar):
Angle between SN line with S-MI line.
(line froms to the notch between the mesial
and the...
Dawn's analysis
•The control materials studied was derived from 20
living individuals ranging in age from 12 to 17 years
a...
Skeletal criteria :-
Facial angle :- ( 1948 )
This angle is an expression of the degree of
recession or protrusion
of the ...
•The inferior inside angle of its intersection
with the Frankfort horizontal is designated as
the facial angle.
•The mean ...
•If angle smaller than normal this indicates : A
skeletal class II malocclusion, with a retrognathic
mandible.
•If facial ...
•Angle of convexity :
( Na – point A – pog ).
•This is a measure of the protrusion of the maxillary
oart of the face in re...
•The mean value of the angle is 0O
( the angle of
convexity would concide with the facial plane ) and
becomes 180O
.
•Norm...
•If point A anterior, the angle was read in a plus
degree ( + ).
•The rang was + 10O
( convex ) to – 8.5O
( concave ).
•Ma...
•This angle reveals the convexity or concavity of the
skeletal profile.
•If angle larger than normal this indicates : A
sk...
•A-B plane to facial plane angle : ( Down's ) :-
•The angle formed by the intersection of the A-B
plane with the facial pl...
•Average value : ( - 4.6O
± 3O
) range ( 0 to – 9O
) .
•In normal class I skeletal relationship, where point A
is anterior...
•If point A is posterior to the facial plane, the angle
is expressed as a ( + ) number.
•Zero and positive measurements in...
•Mandibular plane angle :-
( MP to FH )
•This is a measure of the relationship between the
Frankfort horizontal plane and ...
•If the angle is larger than normal ( as in skeletal
class II division I ) it indicates a vertical growth of
the mandible....
Y-( Growth) Axis
The y-axis is measured as the acute angle formed by
the intersection of a line from the sella turcica to
...
The y-axis indicates the degree of the downward,
rearward, or forward position of the chin in relation
to the upper face.
...
An increase in the y-axis is suggestive of vertical
growth exceeding horizontal (or forward) growth of the
mandible.
The r...
( In the appraisal of severe malocclusions, where
the incisors in extreme positions of supra or infra
occlusion, molars an...
•Denture criteria :-
•Occlusal plane angle :-
( OP to FH )
•Cant of the Occlusal plane :
In order to make
angular readings...
When the anterior part of the plane is lower than the
posterior, the angle would be positive. Larger
positive angles are f...
•Inter incisal angle :-
( T to ⊥ )
•This angle relates the angular position of the long axis of
the upper and lower centra...
•Mansoura measurements :
•Male : 122.8O
± 12O
.
•female : 122O
± 8.6O
.
•Mean : 122O
± 1.8O
.
•If angle smaller than normal this indicates :-
•Class I bimaxillary protrusion in which fullness of
the lips are seen, an...
If angle larger than normal this indicates :-
Class II division 2 malocclusion which associated with
deep anterior over bi...
Therefore, in cases of deep anterior over bite, not
only is it important to correct the vertical problem, but
it is also i...
•Lower incisor to Occlusal plane :-( T to OP )
•This angle indicates the inclination of the lower
central incisor in relat...
Mean value : 14.5O
with a range from 3.5O
to 20O
.
This angle is larger than normal in class II division
1 and smaller tha...
•Lower incisor to mandibular plane :- ( T to MP )
•This angle reveals the inclination of the loser central
incisor in rela...
•All previous studies have located the mandibular
plane tangent to the lower border of the
mandibular at gonion and the lo...
•As the latter point is not in the midline and
appositional growth occure in this area, the
lowest point of the mandible i...
As the relationship of the lower incisors to
the mandibular plane is a right angle (90)
so the labial tip of the incisors ...
Upper incisors to Apo line :-
(The protrusion of the maxillary)
incisors is measured as the
distance between the incisal
e...
The reading is negative if the incisal edge lies behind
the point A-pogonion line and
suggests a retruded position
of maxi...
Tweed's analysis :-
•In order to study the human dentition, Tweed
selected one hundred patients of both sexes and
various ...
Tweed's triangle :-
•It is formed by the Frankfort horizontal
plane, mandibular plane and a line drawn
through the long ax...
•The Frankfort mandibular incisor angle ( FMIA ) : is
formed by the Frankfort plane and the line drawn
through the long ax...
•Any reading below 65O
indicates a procumbency of the lower
incisors to basal bone.
•Any reading above 65O
indicates a lin...
•With a short ramus and an obtuse gonialongle the
IMPA may read below 90O
.
•While in squared jaw individuals, the angle m...
•By using the Tweed's triangle, Tweed assessed the linear
arch length. To determine if extraction of teeth is needed or
no...
The incisal reduction ( IR ) :-
•A line drawn from the apex of the most
procumbent lower incisor to a point 65O
on the
Fra...
•When the line falls lingual to the mandibular incisor,
the reading is a minus and indicates the lower teeth
are in procum...
•Conversely, when the IR line lies labial to the lower
incisors, the reading is a plus and indicates : the
mandibular inci...
•The mass tooth discrepancy : is determined from
the figures which represents the available space,
Required space, and the...
Tweed's objectives :-
•The best balance and harmony of facial
lines ( facial esthetics ).
•Stability of the denture after ...
Tweed's formula for treatment :-
•Non. Extraction – FMIA 65O
or greater with sufficient
arch length.
•Border line – FMIA 6...
•Harmony of Tweed's clinical findings :
( balanced and harmony ) :-
•FMA : from 16O
to 28O
progonosis from excellent to
go...
•Determining the tooth mass discrepancy :-
( All measurements are made in the mandible ) :-
•1- Available space :-
The lin...
The wire is easy contoured so that it runs
along the buccal cusps of the premolars and
the incisal edges of the anterior t...
•2 - The IR or incisal reduction :-
This is determined cephalometrically by dropping
a line from the FH at a 65O
angle to ...
•If the line falls lingual to the lower incisor, or if FMIA
less than 65O
, the IR must be a minus reading.
•If the IR lin...
•4- The required space :-
The sum total of the mesio-distal widths of each
tooth mesial to the first molars.
This will inc...
•5- If the required space is lees than the corrected
available space :-
The tooth mass discrepancy is recorded as a plus
f...
•Tweed analysis :- N.B :
•A cephalometric evaluation can not be considered
complete without including the soft-tissue faci...
Ricketts analysis
•Ricketts established live minimum
cephalometric measurements :-
•1-Facial angle :-
As established by Do...
The mean is 85.4O
± 3.7O
.
One degree represents 1.5 mm of difference in
position of the chine. Relative to the nasion poi...
•2- X – Y axis :- ( Facial axis )
•A line from sella to gnathion.
•X – y axis is an indicator of the facial height.
•This ...
•A differenc of one degree represents a lmost 2 mm
of height relative to depth.
•The average angle is 93O
or plus 3O
.
•Th...
•This suggests that x-y measurement less than zero
tend towards greater length in facial from as opposed to
depth.
•The x-...
•3- Maxillary incisors to A.point – pogonion line :-
•The A point – pogonion line is an indicator of denture
position in r...
•4-Mandibular incisors to A. point – pogonion line :-
•The average mandibular
• incisor tip is located
•approximately 0.5m...
•One standard deviation of inclination is 6.4O
.
•The range of angulations is from -11O
to + 53O
the
range of standard dev...
Facial contour :-
•This is A. point related to the facial line.
•It is used to determine the relationship of the
maxilla t...
•There fore direct measurement from A.point to the facial
line is used to measure variation of the profile a straight line...
•Faces with a convexity or concavity of not more
than 2 mm are regarded as being orthognathic.
•Those with up to 5 or 6 mm...
•Facial esthetic line ( E-
line ) :-
•The facial esthetic line
extends from the tip of the
nose to the end of the chin.
•T...
•The lower lip is on an
average 0.3 forward to this
line with a standard of 3
mm.
•The upper lip is on an
average 1 mm pos...
•Mansoura measurements :-
•Male : upper lip : -2.23 ± 1.96 mm.
Lower lip : -0.12 ± 2.7 mm.
•Female: upper lip : -5.2 ± 2.1...
•This reference line
describes facial esthetics
and lip position.
•Dentures that are forward
( class I bimaxillary
protrus...
•Larger noses or large chin
buttons or combination of the
two cases produce
erroneous measurements of
the lips to the E- l...
Sassouni's analysis
•In order to study the stracture of the skull for the
purpose of growth analysis and treatment, Sassou...
•From these planes he determines the centre, and
then he uses the reference 0, after analysis of these
planes, the problem...
•Steps of the analysis :-
•1- Construction of the planes.
•2- Locate the centre O.
•3- Construction of the arcs.
•4- Const...
A- Construction of the planes.
1- Anterior cranial base planer or Basal plane
( OS ) :-
Two parts, first draw a tangent fr...
•2- Palatal plane ( ON ) :-
It is perpendicular to the midsagittal plane, going through
the anterior nasal spine ( ANS ) a...
• In deep over bite ( deep curve of spee ) take the
occlusal surfaces of the molars and premolars do not
use the incisors....
B- Locate the centre O.
To locate the centre O make sure when you put the
tracing paper on the film that you are taking th...
O is the centre or the midpoint of the shortest vertical
line beyond which the planes will diverage.
O will located up in ...
C- Construction of the arcs.
a - For the antero-posterior
dimension :-
1- Anterior arc.
2- Basal arc.
3 - Mid facial arc.
...
1- Anterior arc.
The anterior arc is the arc of a circle, between the
anterior cranial base plane and the mandibular
plane...
•2- Basal arc :-
Using the centre O to point A as a radius and
draw another arc but if ANS is closer to the anterior
arc t...
4- Posterior arc :-
Between the anterior cranial base plane and
the mandibular plane, of a circle with its centre
at O and...
b -Arcs for the vertical dimensions :-
•1- From as a centre to supra orbitale ( eye brow ) as
a radius make a small arc an...
•In deep bite : you will find parallel planes and
centre O will shift away from the profile.
•In open bite : steeper plane...
•Evaluation of the profile :-
•1- From the anterior arc :-
Evaluate the labial surface the maxillary incisors
pogonion and...
•C- ANS on the arc and pogonion is not on the arc
:
•1- ANS on the arc and pog anterior to the arc this
means chin protusi...
•2- From the basal arc :-
Normally from A will pass through point B or
approximating this area.
•3- From mid facial arc :-...
•4- Posterior arc :-
Normally it passes through the gonion
and indicates either the chin is protrusive or
retrusive.
In we...
•The vertical balance :-
The outer upper and lower facial height
should be equal in adult male, the lower face
height is l...
In posterior vertical height the upper
posterior and lower posterior heights should
be equal i.e the upper posterior and l...
•Axes :-
•M, M', M Axis of –
6
•m, m' Axis of –
6
•I, I', I Axis of ⊥
•I, I' Axis of T
•The Sassouni norm :-
In a well-proportioned face the four planes :-
•1- that tangent to the sella and parallel with anter...
•3- If a circle has centre O, an arc that passes
through the posterior wall of the sella turcica will
pass also through th...
•The axial relation of the maxillary and
mandibular teeth to the maxillary and
mandibular teeth to the palatal plane and
m...
•Since the norm concept can not be
accepted as absolute for the individual,
Sassouni advocales measure ment of
proportiona...
•Steiner's analysis (1953)
•1- SNA angle:
•Used by riedel in 1950 and
•then Steiner in 1953.
•It provides in formation
• o...
•If it greater than 80, it
indicates protrusion of
the maxilla (skeletal
class II mal occlusion).
•If lt less than 80, it
...
•This angle influenced
by antero postemrior
position and also
bertical position of
nasion.
•If nasion is more
forward, hig...
Age change:
•This angle imdergpesminor age changes, there is
proportional growth between the maxilla and
anterior cranial ...
2- SNB angle:
•It provide information of
the antero posterior
position of the apical base
of the mandible either
protruded...
•If the angle is smaller
than normal (class II)
malocclusion that is
caused by a
retrognathic mandible).
•If the angle is ...
Age changes:
•This angle increase with
age, because the mand ible
grows more than the
maxilla, and the growth is in
horizo...
3- ANB angle :-
•It is the difference
between SNA and SNB
agles.
•It indicates the antero-
posterior position of the
maxil...
If the value is larger than
the mean, this means that
maxillary protrusion or
mandibular retrusion, but it
will not tell y...
•If the value is smaller than
the mean, this means that
maxillary retrusion or
mandibular protrusion
(class III skeletal
m...
Factors affecting the values of SNA, SNB and
ANB.Angles:
(a) Size of the anterior crania base if it is
large or small this...
The method of Richard reidal:
(1)Because the points S and N are both
located in hard, nonyielding tissue, are
directly and...
4- SND angle:
(1)Point d: the middle of the symphysis. It is
used to represent the anterior aspect of the
mandible in a sa...
(3) The cross section of
the body of the mandible is
only considered.
(1)Alveolar process is
ignored because it is
influen...
It is well surrounded by sturdy
done, it is protected from
outside influences and is well
isolated from the area where
mov...
Point D can also be used to
determine chnges, in the
position of the mandibular
teeth within the mandible. To
do so, erect...
D point is sued as a reference
point, and is transferred to
subsequent tracings by coping it
directly from the first.
Copy...
Denture criteria:
Upper incisor to NA:
(linear).
•The upper incisor
should lie on the line
NA in such a way that
the most ...
•Rior position of the
incisal edge ot he upper
central incisor, with
reference to the NA line.
•The clinician can decide
w...
•This angle indicates the
inclination of the upper
central incisor.
•The axial inclination of to
NA line is 22.
•It is pre...
•It is preferred to use NA line
instead of facial plane
because NA is established by
two fixed points plane
because NA is ...
•Clinically, this angle is important in torgue control
when retracting or advancing upper incisors.
Mansoura measurements:...
Lower incisor to NB: (angle):
•This angle reveals the
•inclination of the lower
• central incisor.
•The axial inclination ...
Lower incisor to NB
(linear):
•This measurement gives an
idivation of the antero-
posterior linear measurement
of the lowe...
•This measurement is larger
than normal, (protrusive or in
positive direction) in
malocclusions associated with
a convex p...
Pogonion to NB (linear):
•The degree of prominence
of the chin should contribute
to a determination of the
placement of th...
•This distance will vary so wide
by among individuals that an
average or norm measurement
of it would have little diagnost...
•He beleives that the overlying
soft tissues one of average
thickness and arrangement,
acceptable results can be
obtained ...
•This measurement indicates
the amount of bony chin
buttons present in the
symphysis of the mandible.
•Clinically, this me...
•A good chin enhances the profile and allows a
more labial placement of the lower incisor to
prevent a dished in appearanc...
Inter incisal angle:
This angle was illustrated in the downs analysis.
This angle used as a
supplementary method
of apprai...
Occlusal plane angle (occl – SN):
The angle of the occlusal plane to SN (principle of
downs) except that this analysis use...
A cephalometric survey of a case of malocclusion
would be incomplete without the appraisal of the
location of the teeth in...
SN to mandibular plane agnle (go. Gn To
SN)"
The angle go-gn to SN is very useful in:
(1)Measures the degree of warpage or...
(2) As an indication of the growth history. The line
Go-Gn has been taken to represent the body of the
mandible ( Riesel )...
•Upper incisor to SN :-
•This angle reveals the inclination of the central
incisor, as related to the cranial base line ( ...
•Mean value is ( 104O
) .
•A larger than normal
angle indicates class II
division 1 and class III
malocclusion.
•A smaller...
•Modification of Tweed- Holdaway and
Steiner :-
Dr. Tweed selected 100 people of both sexes and
different age groups whom ...
He then proceded to make a comprehensive
cephalometric analysis of these patients using the
statistical data as the normal...
Dr. Holdaway, who feels that Dr. Tweed's
estimate has some merit, none the less claims that
the relationship of the mandib...
•2- He then put the patients into specific groupings
and found that the median normal for ANB was
( 2O
) Further study sho...
•4- These findings challenged D. Tweed's formula.
•There is no doubt that the angle ANB definitely
influences the axial in...
•6- Proportionately, as the procumbency of the
uppers diminishes, the incisal edge of the
maxillary incisors lies closer t...
Dr. Steiner, has formulated what he refers to as
( the ideal acceptable Arrangements ) Rather than
be committed to a stati...
•The lower line: symbolizes the long axis of
the lower central as it relates to the NB line
in mm. and degrees.
At an ANB ...
•A patient with an FMA between 15O
to 35O
and an
ANB of -1O
to +5O
may be considered one that falls
within a normal range....
•Michigan analysis.
•SNA. ( Steiner 1953 )
•SNB. ( Steiner 1953 )
•ANB. ( Steiner 1953 )
•Facial angle : ( Down's
1948 )
•...
•Downs used FH as a reference plane because it
gives him the natural position of the head in
determining this angle.
•Ther...
2- Button like chin, and in assessing SNB in a
case you may find its value indicates a class II but
facial angle tells you...
•Angle of convexity ( Down's ) :-
•A-B to facial plane angle ( Down's ) .
•A-B to occlusal plane : ( Bushra 1974 )
•It mea...
•Mansoura measurements :-
•Male : 0.96 ( ± ) 2.25 mm.
•Female : 0.94 3 ( ± ) 3.22 mm.
•Mean : 0.24 ( ± ) 2.75 mm.
There ar...
•Wits appraisal ( Jacobson
1975 ) :-
The wits appraisal of jaw
disharmony is a measure of
the extend to which the jaws
are...
•The points of contact on the
occlusal plane are labeled Ao and
Bo.
•The normal value : for
Female, is 0 i.e Ao and Bo
con...
•SN. To Mandibular plane :- ( Steiner )
It is formed by intersection of the SN line with the
mandibular plane.
•There are ...
•From Go-Gn ( Steiner ) :-
•The angle formed by SN and mandibular
plane provides information in vertical and
antero poster...
•In higher or steep mandibular plane
angle ( larger angle ) :-
oRamus is short, corpus is short i.e
oral size of the mandi...
•Clinically :-
•(1) Patients with higher or steep mandibular
plane angle : have – Large lower face height
– Retrusive chin...
2- Patients with flat mandibular plane angle : have
– The posterior facial height is smaller than the
anterior lower face ...
•SN to palatal plane angle
•It gives information regarding position of ANS, PNS
or rotation of the plate. PNS may be tippe...
•If you have smaller angle : this means that
there is no displacement of PNS down ward in
counter clock wise direction.
•T...
•If the angle is greater than 8O
: this means
that the ANS tipped down ward and this is
associated with large anterior fac...
•Palatal plane to Mandibular plane :-
( used in 1936 by Schwarz and picked up by
Sassouni ).
•It can figures if there is s...
•It is usually associated with large anterior
facial height, and small posterior facial height.
•Large angle suggest open ...
•Cranial base angle :-
( used by Pjork 1947 and Ricketts )
•It is formed by 2 lines SN and SBa.
•It denotes the of glenoid...
You are measuring the angle in midsagittal plane but
the glenoid fossa is bilaterally positioned so it may
implied for the...
•In acute angle cases : TMJ will be forward
and the mandible is carried forward creating
class III or protrusive mandible....
•Frankfort horizontal to mandible Plane
angle :-
( Tweed 1946 and Down ).
•It is very similar in information gained by SN
...
•Facial axis ( Ricketts ) :-
•It is constructed of Na – Ba and gnathion –
foramen – rotundum.
•It is an expression of grow...
•If the chin is too forward, you will have large value,
if it is too posterior, you will have small value.
It is very simi...
If the angle is larger, this denotes that
the growth is in horizontal direction.
•Try to relate facial axis with the facia...
•Posterior facial height to anterior
facial height :-
•The mean value is 65 % ( it is the percentage
of S- Go to Na-Me ).
...
•Lower anterior face height to total pace height :-
•The mean value of ( ANS - Me to Na - Me ) is 54.6 % .
•Larger values ...
Aging reduced lower facial height and
persons with low anterior facial height aged
early.
•At 6 years in males and females...
•T to Mandibular plane ( IMPA ) :- ( Tweed )
•It relates the axial inclination of the most labial
incisor to the mandibula...
•In class III the lower incisors are lingually
inclined and the mandibular plane is small and
mandibular plane is flat, an...
•T to FH ( FMIA ) :- ( Tweed )
•It express lower incisor to bony profile, the
average is 65O
.
•If IMPA is large, FMIA wil...
•So when we see crowding the reason may
be either duo to improper angulation by
orthodontic treatment or duo to late growt...
•T to ⊥ ( Down's )
•T to NA ( Steiner )
•It relates the ⊥ to denture base either angular
or linear.
•T to NB ( Steiner ) :...
 lateral cephalometric analysis in orthodontic
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 lateral cephalometric analysis in orthodontic
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 lateral cephalometric analysis in orthodontic
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 lateral cephalometric analysis in orthodontic
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 lateral cephalometric analysis in orthodontic
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 lateral cephalometric analysis in orthodontic
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lateral cephalometric analysis in orthodontic

Lateral cephalometric radiograph tracing lateral cephalomertic analysis types of cephalomertic analysis

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lateral cephalometric analysis in orthodontic

  1. 1. Prepared by:- Bilal A.M.Prepared by:- Bilal A.M. Faculty of dentistry-Mansoura university -Faculty of dentistry-Mansoura university -
  2. 2. Tracing roentgenograms Instruments required for tracing: (1) Paper: Trace a lene or acetate paper (0.003)" thickness, one side glossy and one side matted, has good transparency even when seven or eight tracings are super-imposed. Other transparent waterproof paper maybe used. (2) T. square: Makes parallel and projected lines easier to trace. (3) Pencils: Hard and soft pencils indifferent colours. A hard pencil (NO. 10) is used for accuracy, that is true for well defined lines as: The contour of the profile and the lower border of the mandible.
  3. 3. A soft pencil (NO. 3) is used for the rest of the stractures as seen on the film, which have a certain thickness, close to 1mm. as: supra or bital roof, the palate, the contour of the teeth (un less perfect superimposition)., the clivus. As it becomes more accurate and decreases the amount of individual errors. (4 H) pencil should be used if the tracing is to be made on paper. (2 B) pencil be used if the tracing is made directly on the film. Coloured pencils: will help when doing an analysis, many lines cross in nearly the same area.
  4. 4. It is of good routine to use one colour for the midsagittal structures and an other for bilateral ones. This help to keep in mind that the flat surface of the film represents depth and volume. (4) viewing box: Should be large enough to accommodate the lateral and posterior – anterior films simultaneously. It is advisable to trace an inch grid with thin lines on the transparent surface with India ink. This helps orient the films.
  5. 5. The light should be cold, two or three intensities of light controlled by switch is important because the films or their different areas do not have the same darkness. To see the soft – tissue of the profile, hide bony structure and use the most intense light. If one area is not clearly differentiated, look through a black paper cone only at this area.
  6. 6. A photo – retouching table or a box constructed with two (10 – watt) fluorescent bulbs and a milk glass cover the size of (8 x 10) inch film can be used. It should be possible to vary the amount of light. (5) A transparent millimeter rules 12 mm long. (6) Two triangles (one small and plain, one large). (7) A small protractor, long arm dividers, and an artgum eraser. And paper clipsor scotch tape.
  7. 7. Tracing technique: •1- Distinguishing marks should be put on the right and left sides of the roentgenogram. •2- Place the roentgenogram on the tracing table, place tracing paper on top of the film, attach the left hand margins of the paper to the corresponding side of the film with scotch – tape or paper clips to permit folding the tracing paper back to check direct by on structural details use a hard fine pencil line. •
  8. 8. •3- Profile tracing: Should be started from the outer out line of the roentgenogram and continued to the inner parts: Trace the soft tissue profile while hiding the rest with a black paper.
  9. 9. Then, trace the bony profile: A- The lower border of the mandible, posterior border of the ramus, draw the posterior border of the brain case. B- Locate the foramen magnum. C- Trace the odontoid process of the axis, go up ward and trace the clivus up to sella turcica (part of and trace the clivus is hidden by the ear rods), forward and upward, trace the roof of the orbit up to the supra orbital ridge. Here, come down word tracing the laTeral and lower borders of the orbit.
  10. 10. D- Come back to sella turcica and trace the planum, and anteriorly the cribriform plate, continued more anteriorly and upward by the inner plate of the frontal bone. E- In the midface, trace the palate (floor of nose and roof of mouth), posterior by the pterygo maxillary fissure, just below and behind the palate, trace the soft – palate, the pharyngeal wall, and the root of toungue. F- Trace the teeth, mainly the first permanent molars, the canines, and the most prominent incisors
  11. 11. Tracing in details: 1- The soft tissue profile: Only on the lateral films, it does not offer any difficulty if the film is not burned out, if the viewing box has in tense light, and if the bony structures are hidden by a black paper. Possible deformations: At the level of nasion, some cephalostats use a rest against that area and the out line of the soft tissues is pressed in. At the level of the lips and chin, the outline is different (changing the position of the landmarks). When the lips and mental muscles are at rest or in contraction. This difference, may have a diagnostic value concerning the vertical shortness of the lips, compared to the bony anterior lower face.
  12. 12. At the level of nasion, some cephalostats use a rest against that area and the out line of the soft tissues is pressed in. At the level of the lips and chin, the outline is different (changing the position of the landmarks). When the lips and mental muscles are at rest or in contraction. This difference, may have a diagnostic value concerning the vertical shortness of the lips, compared to the bony anterior lower face.
  13. 13. 2- The bony structures: From above to down: (1)The frontal bone: The external plate goes down ward with a convexity at the level of the supra orbital ridge, to nasion. The internal plate continues, the cribriform plate upward between the external and internal plate. The frontal sinus can be located with varying size. At the level of the frontal sinus, the supra orbitale can be located.
  14. 14. 2-The nasal bone: Starts from nasion and goes down ward and forward, it is continued down ward and backward to form the lateral wall of the nasal cavity, it meets the floor of the nose at naso spinale.
  15. 15. 3-The maxilla: The anterior contour of the palate and the a lveolar bone.Extend on the profile between the anterior nasal spine to curve back ward in a concavity at the deepest point of which lies point A. (subspinale). It continues anteriorly down ward, up to the junction with the incisor at prosthion. .
  16. 16. 4-The incisors: The most prominent one should be traced, the upper central incisors does not offer difficulty, but in the lower, the four incisors are super imposed and the apices are very difficulty to differentiate
  17. 17. 5- The chin: Start at infra dentale, curves posteriorly to point B (supra – mentale), goes down ward and forward to pognoion, curves back ward to gnathion and menton, and it continued to form the internal plate of the symphysis back to the incisors lingually.
  18. 18. 6- the mandible: posterior to the symphysis, the lower border extends to the gonion, at the level of the bicuspids, it has a convex shape, and is concave at the level of the insertion of the masseter (antegonial notch) it curves to reach gonion.
  19. 19. 7- The ramus: Upward and backward up to the neck of the condyle which is more backwardly inclined. The posterior border can be followed up to the point (articulare) where it is shadowed by the basisphenoid.
  20. 20. 8- The head of the condyle: Unless an open mouth film is token it can not be accurately located, as it being masked generally by the ear rods of the apparatus used. 9- The coronoid process: Can be located but not with enough accuracy to be used for land marks. 10- The alveolar process: Is difficult to locate accurately, may be guessed.
  21. 21. 3- Upper face: It is the area between the cranial base and the palate. Antero – posteriorly we find: (1)The orbit: The roof has been defined as double lines go down ward from the supra orbital ridge to lower most point orbitale.
  22. 22. The midlines between the two shadows should be defined oblique line crosses the orbital cavity. It represents the greater wings of sephenoid in the frontal film.
  23. 23. (2) Maxillo – zygomatico – temperal sulcus: It is a vertical line which can be straight or like situated just posterior to the lateral contour of the orbit, but extending farther below.
  24. 24. It goes from the cribri from plate, down to the floor of the nose at the level of the upper first molar, and curves upward toward orbitale. The lower most point at the curvature is the key-ridge being bilateral, the midline between the two shadows should be taken.
  25. 25. (3) The pterygo maxillary fissure Ptm: It forms a boucle just above and posterior to the posterior nasal spine and the soft palate. Its anterior contour represents the tuberosity of the maxille. Its posterior contour represents the ptergoid bone which is difficult to trace. Being bilateral, the midline between the two shadow should be taken.
  26. 26. 4- Midlface: It is represented by the hard palate which is enclosed between the floor of the nose and the roof of the palate. It extends from anterior nasal spine to posterior nasal spine (This land mark may be masked by the last molar).
  27. 27. At the level of Ptm it makes a U-turn and comes anteriorly to the upper central incisor from the alveolar process of the incisor area.
  28. 28. 5- Cranial base: Cranial base is the demakration that the brain makes with the face and the neck. Traditionally, it is divided into anterior, middle, and posterior fossae.
  29. 29. A- Anterior cranial fossa: Extends from the frontal bone to the lesser wing of sphenoid. It represented bilaterally by the roof of the orbits, and in the median plane by the cribriform plate of ethmoid and the planum sphenoidale.
  30. 30. B- Middle cranial base: Extends from lesser wing of sphenoid to the petrous bone. petrous bone
  31. 31. C- Posterior cranial fossa: Extends bilaterally from the occipital bone posteriorly and the petrous bone anteriorly. In the median plane it comprises the occipital bone, the foramen magnum, the clivus up to sella. As can be seen, the three fossae overlap antero-posteriorly.
  32. 32. 6- cranial base lines: 1- Posterior arm (The clivus): It extends between the foramen magnum and sella turcica on the mid sagittal plane. On the lateral film, it can be located at both extermeties but it is masked in its midsection by the ear rods. It is composed of the occipital and the sphenoid bones. The sulture or synchondrosis between them is difficult to locate. At the lower end it starts at basion situated just above the tip of the odontoid process of the axis, goes obliquely upward, crosses the instru-mental porion and continues up to the posterior clinoid of sella turcica.
  33. 33. 2- The hinge (sella – turcica): Saddle shaped , pituitary fossa, situated on the mid sagittal area at the centre of corpus sphenoidale. On the lateral film, its curved contour extends from anterior to posterior clinoids.
  34. 34. In the body around sella, there is a sphenoidal sinus of varying size. In roentgenographic cephalometry, because its accurate delineation, points have been defined all around its contour and at its center.
  35. 35. 3-Anterior arm: Divided in two lines, the roof of the orbit above and the planum with the cribriform plate below: A- Roof of the orbit: Bilateral, there fore, often two master shadows on the lateral film festooned by small crests on its superior surface. The midline and the general direction should be taken and can be represented by a continuous line starting at anterior clinoid, crossing the supra orbital ridge.
  36. 36. B- Planum: Is separated from the orbital roof and anterior clinoid just anterior to sella. It is flat and horizontal. It joins the cribriform plate at the level of the lesser wing. C- Cribriform plate: It represented by doted lines, it continues forward and curves slightly upward to join the internal plate of the frontal bone. D-Crista galli: Sometimes visible on the lateral, but dimly at the junction between ethmoid and frontal inner plate.
  37. 37. 7- The teeth: The accuracy in drawing the teeth depends on their symmetry and the good orientation of the head. The key teeth to trace are first permanent molars, the canines, and the central incisors. 1.Molars: Are generally well defined, on the occlusal surface no attempt should be made to draw each cusp, it may be the source of too many errors. Instead on approximate line demarcating the occlusal surface of upper and lower first permanent molars is enough.
  38. 38. 2- Canines: Not always easy to locate. One method may be to start from the molars and eliminate progressively, the bicuspids, then start from the incisors and go in opposite ways eliminating the laterals. This may be used for both lateral and postero-anterior cephalogram. 3- Incisors: The upper offer little difficulty. On the lateral the apex may sometimes be masked or not very sharp. The lower central incisor offers more difficulty as the four lower incisors are aligned nearly at the same level and have approximately the same size.
  39. 39. Any measurement involving the axis of the lower incisor should be allowed a large margin of tracing errors. Besides these key teeth, the others (except the lower and upper lateral incisors) do not offer much difficulty. Postero – anterior tracings should show the following: 1- The contour of the cranium. 2- The mastoid. 3- The lateral out lines of the ramus. 4- The lower border of the mandible. 5- The coronoid process.
  40. 40. 6- The orbital lines. 7- The lesser wings of the sphenoids. 8- The crista galli. 9- The nasal septum. 10-The lateral walls of the nose.
  41. 41. Location of the porion: The porion is not distinguishable on the roentgeno- gram. It actually is approximately 3mm. above the ear rod. The external auditory meatus used in cephalometrics for head fixation is not as a rule on the same bilateral plane and the integuments do not always rest on the ear posts.
  42. 42. Since the tissues of the outer ear canal are sensitive to pressure, insertion of the ear rods in the same position is uncertain.
  43. 43. Determination of the right and left sides: •In all cephalomertic roentgenograms the centeral ray goes through the ear rod or porion, the maxillary left first molar is closer to the ear rod than the maxillary first right molar. •The maxillary canine left is closer than the maxillary right canine. •The left jugal buttress is closer than the right. •The lower border of the body of the mandible on the left side is superior to the corresponding borders on the right side. •The posterior border of the ascending ramus on the left side is distal to that of the right.
  44. 44. •The left side of the mandible is superior to the right, and the line denoting the inferior border must cross over the corresponding line of the right side in the region of the angle and become the posterior or distal outline. •The candyle is frequently obsecured by the ear rod image and the petrous portion of the temporal bone. The tracing may have to be terminated 6 or 8 mm. below the condyle. •In most films, only the crowns of the molar teeth can be seen easily because of left and right side super imposition.
  45. 45. •In the incisor region, the full crown usually can be seen a long with the labial root out line. The lingual root outline from cinulum to apex is usually obscured and must be drawn from a knowledge of tooth morphology or from a template. •In the mandible, as in the maxilla, incisor teeth and molar teeth should be traced by tracing the teeth in rest position, the occlusal surface and incisal margins can be reproduced accurately.
  46. 46. •To obtain correct condylar morphology by using a template: two profile cephalograms are taken the one with the teeth in full occlusion is used to measure angles and lines. The second cephalogram is used to obtain condylar outline. This is taken with the mandible wide open, and the condyles down ward and forward.
  47. 47. Errors in tracing: •Some degree of error is inherent in tracing film, some errors are duo to the character of the film traced, and to the person doing the tracing. •Personal errors are recognized as a feature of all tracings, the experienced tracer will avoid errors duo to in experience. •Tracing should be limited to those parts necessary for required information. •It is advised that the tracer, having at hand a set of x ray films and a skull. It is only by comparing, at each step, on to the other, that clear visualization will emergy and anatomical accuracy be achieved.
  48. 48. •The denser the structure, the whiter the reproduction on the film. Actually only the teeth offer a well delimited and compact delineation. •The reproduction of bony structures depends on their orientation as well as their density. •This is one of the reasons why the image is clearer on the lateral than opstero-anterior film. •On the lateral film all structures besides median sagittal plane are bilateral and if symmetrical they double (for the same structure).
  49. 49. •Practically, even if the face is perfectly oriented and if the bilateral structures are symmetrical, they are not necessarily super imposed because the x-rays are not parallel but divergent. There fore, if double image is seen on the film, it does not necessarily mean asymmetry. However, without the frontal film, it is not possible to decide between asymmetry and malposition. Unless just one structure is asymmetrical. There fore, when double image is present (lower border of the mandible), check if all bilateral structures are double (e.g the roof of the orbit), if not it is a local asymmetry.
  50. 50. •While asymmetry between the two sides of the mandible should be bisected severe asymmetry should be traced as found. •The temperomandibular articulation and the condyle can not be seen on the profile roentgenogram when the teeth are in occlusion and must be traced from a film taken with the mouth wide open. This is used as a template. It will be good to strat with a lateral view, then try to find the corresponding structures on the frontal film. Some of them are clearer on the postero – anterior film than on the lateral and vice versa.
  51. 51. •Some can not be located accurately on either (T.M.J) unless an open mouth is taken. •Generally, for height and depth proportions use the lateral films and for breadth and symmetry use the frontal film. •The frontal film in more difficulty to interpret because the structures at different depth are super-imposed. (e.g) at the level of the odonoid process of the axis. •The next step is to clear this confusion of lines and shadows, to make a selective interpretation by tracing neatly the most significant structures.
  52. 52. Lateral land marks 1- Nasion (N): •The midlle point on the fronto- nasal suture, intersected by the median sagittal plane. •The junction of the frontal and nasal bones. •The soft – tissue nasion (N): The most concave or retruded point in the tissue overlying the area of the fronto-nasal suture. •The point of maximum convesity between nose and fore head. Cephalometric land marks
  53. 53. 2- Sella Turcica (s): •Sella trucica is the pituitary fossa of the sphenoid bone. Sella (s) is the centre of the sella turcica. 3- Se: The mid point of the entrance of the sella.
  54. 54. 4- Subnasale (sn): The point at which the nasal septum between the nostrils merges with the upper cutaneous lip in the mid sagittal plane.
  55. 55. 5- Sub spinale (point A): •The deepest midline point in the curved bony outline contour of the alveolar process of the maxilla. •At the deepest point between the anterior nasal spine and the prosthion. •The anterior limit of the maxillary basal arch.
  56. 56. 6- Prosthion (Pr): The lowest, most anterior interdental point on the alveolar mucosa in the median plane between the maxillary central incisors.
  57. 57. 7- Incisor superius (I.S): The most forward incisal point of the most prominent maxillary central incisor. 8- Apicale ┴ (Ap _) : The root apex of the most prominent maxillary central incision.
  58. 58. 9- Incisor inferius (I.I): The most forward incisal point of the most prominent mandibular central incisor. 10- Apicale T (Ap T): The root apex of the most prominent mandibular central incision.
  59. 59. 11- Infra dentale (I.d): The highest, most anterior, interdental point on the alveolar mucosa in the median plane between the mandibular central incisors.
  60. 60. 12- Supra mentale (point B): The deepest point on the contour of the mandibular alveolar process betweeninfradentale and pogonion.
  61. 61. 13- Pogonion (Pog): Most anterior point of the bony chin.
  62. 62. 14- Gnathion (Gn): •According to martin and saller (1956): it is the lowest point in the median plane of the mandible, where the anterior curve in the outline of the chin merges into the body of the mandible. •It is a point on the bony border palpated from below which lies posterior to the tegumental border of the chin. •
  63. 63. •In cephalomertic, it is the mid point between the most anterior and inferior points on the bony chin. •Measured at the intersection of the mandibular base line and nasion-pogonion line (facial plane). (Mandibular plane and facial plane).
  64. 64. 15- Gonion (Go): •The lowest, posterior and most outward point on the angle of the mandible. •This is obtained in cephalometrics by: bisecting the angle formed by tangents to the lower and posterior borders of the mandible.
  65. 65. •When the angles of both sides of the mandible appear on the profile roentgenogram, the point midway between the right and left sides is used. The midpoint in the curve of the mandible between the ramus and the lower border.
  66. 66. 16- Menton (Me): •The lowest point on the chin, •from which the face height is • measured.
  67. 67. 17- Articulare (Ar): •The point was introduced Bjork (1974) •The point of intersection of the external dorsal contour of the mandibular condyle and the temporal bone. •The mid point is used when the profile roent – gengram show double projections of the rami. •The ventral surface of the basilar part of the occipital bone intersects the posterior border of the ascending ramus and the outer margin of the cranial base.
  68. 68. 18- Condylion (cd): •Most superior point on the • head of the condyle.
  69. 69. 19- Orbitale (or): •The lowest point on the inferior bony margin of the orbit. In cephalometric roentenogram the orbitale located on the lower margin of the orbit directly below the pupil when the patient looks straight a head.
  70. 70. 20-Anterior nasal spine (ANS): The median, sharp, bony process of the maxilla at the lower margin of the anterior nasal opening.
  71. 71. 21- Posterior nasal spine (PNS): •Process formed by the united projecting ends of the posterior borders of the palatal processes of the palatal bones.
  72. 72. 22- Anterior point for the occlusal plane (APocc): •A constructed point, the midpoint of the incisor over bite in occlusion. 23- Posterior point for the occlusal plane (ppocc):- the most distal point of contact between the most posterior Molars an occlusion
  73. 73. 24- Basion (Ba): •The most forward and lowest point on the anterior margin of the foramen magnum. •Bjork and palling prvide a more specific roent – genographic definition: The perpendicular projection of the anterior border of the foramen magnum. On a target through the lower margin of the condylar head.
  74. 74. Other cephalometric land marks: Pterygo maxillary fissure (Ptm): An oval shaped radiolucency resulting from the fissure between the anterior margin of the pterygoid process of the sphenoid bone and the profile out line of the posterior surface of the maxilla. Appears as iverted tear-drops, its anterior margin represents the posterior margin of the tuberosity of the maxilla.
  75. 75. Porion (P): The mid point on the upper edge of the external auditory meatus. As a cephalometric landmark it is located in the middle of the metal rods of the cephalometer.
  76. 76. Key ridge (KR): The lowest point of the zygomatico – maxillary ridge. Acanthion (Ac): Tip of the anterior nasal spine. Clinoidale (Cl): Most superior point on the contour of the anterior clinoid.
  77. 77. Clinoidale (Cl): Most superior point on the contour of the anterior clinoid. Bolton point (BP). Spheno occipital synchon-drosis (So). Registration point (R). Bolton point (Bp): The highest point on the profile roentgenogram at the notches on the posterior and of the occipital condyles on the occipital bone.
  78. 78. Broad bent registration point (R): Mid point on a perpendicular from the centre of sella to the Bolton – nasion line. Spheno – occipital synchondrosis (so): The cartilaginous union of the anterior end of the basilar portion of the occipital bone and the posterior surface of the body of the sphenoid bone. Tragion (T): The notch just above the tragus of the ear. It lies 1-2 mm below the spina helicis which can be palpated.
  79. 79. Alveolar point (Al.P): The lowest point of the a lveolar process at the midline between the maxillary central incisors. Occipital condyle (O.C): The condyle on the occipital bone near the foramen magnum. Opisthion (O.P): The posterior midsagittal point on the posterior margin of the foramen magnum. Opithcranion (OPC): The posterior midsagittal point of the greatest cranial length from glabella.
  80. 80. Sphenoidale (SPH): Point of the greatest convexity between the anterior contour of the sella turcica and planum sphenoidale. Bregma (Br): The anterior end of the sagittal suture where it meets the coronary suture. Cheilion (ch): The lateral terminus of the oral slit i.e. (The outer corner of the mouth). Dorsum sella (D.S): The square shaped bone which forms the posterior boundary of the sella turcica.
  81. 81. Endo basion (E.b): The perpendicular projection of the anterior border of the foramen magnum on a tangent through the lower margin of the condylar head at the foramen magnum. Ethmoid triad (Eth.Tr): A point located on the planum sphenoid, the ethmoid line, midway between the greater wings of the sephenoidale bone. Ethmoidale (Eth): The lowest point on the cribri form plate of the ethmoid bone in relation to the sella – rasion line. The deepest sagittal point on the cribriform plate of the ethmoid bone in the anterior cranial fossa.
  82. 82. Tuber culum sellae (T.S): Anterior boundary of the sella turcica. Zygoin (Z): The most lateral projection of the zygomaticarch. Rhinion (RH): The most anterior intersection of the nasalbones, which forms the tip of the bony nose. Pterygo – maxillare (Ptm): The point where the pterygoid process of the sphenoid bone and the pterygoid process of the maxilla begin to form the pterygo maxillary fissure. The anterior wall represents the retromolar tuberosity of the maxilla and the posterior wall is the anterior curve of the pterygoid process of the sphenoid. The lowest point of the opening is used in cepha- lometric roentgenogram.
  83. 83. Euryon (Eu): The most lateral point on the side of the head. Fronto temporale (Ft): The most anterior point of the termporal line near the root of the zygomatic process of the frontal bone. Inion (n): The most elevated point on the external occipital protuberance, at the crossing of the midline with a tangent to the superior nuchal line. Lambda (La): Intersection of the sagittal and the lambdaidal sutures on the cranial vault.
  84. 84. Mandibular notch (M.N): The concavity between the coronoid and condyloid process of the mandible. Ophryon (Oph.): Mid sagittal point just above the galbella intersecting on arc from the fronto temporalis across the frontal bone. Vertex (v): The highest point of the head, in the midsagittal plane, when the head is help erectly or in the frank fort horizontal position. Postero-anterior cephalometric landmarks:
  85. 85. Poster-antrior cephalomeric landmarks Glabella (Gl): The most anterior point of the frontal bone in the midsagittal plane of the bony prominence joining the supra orbital ridges. Trichion (Tr): The mid point of the hair line at the top of the fore head. Nasion (N) Tragion (T) Orbitale (O) Prosthion (Pr) Infradentale (I.D) Gonion (Go) Gnathion (Gn)
  86. 86. Soft tissue points: (Burstone 1959)
  87. 87. Soft tissue points: (Burstone 1959) Glabella (G): Determined by a tangent to the forehead from a line passing through subnasale.
  88. 88. Soft tissue nasion (N`): The most cocave or retruded point in the tissue overlying the area of the frontonasal sutures, the intersection of the SN line with the soft – tissue anterior to rasion.
  89. 89. Nasal crown (Nc): A point a long the bridge of the nose halfway between soft-tissue nasion and pro nasale. Pronasale (Pn): The most prominent or anterior point of the nose.
  90. 90. Subnasale (sn): The point where the maxillary lip and nasal septum form a definite angle. If the depression is a gentle curve, subnasale is interpreted as the most concave point in this area as measured by a line angle 45 degrees from nasal floor.
  91. 91. Soft – tissue sub spinale (A`) (ss): The point of greatest concavity in the midline of the upper lip between subnasale and labrale.
  92. 92. Labiale superius (Ls): The most prominent point on the upper lip as measured from a perpendicular to nasal floor.
  93. 93. Stomion (sto): The junction in the midline of the upper and lower lips.
  94. 94. Labiale inferius (Li): The most prominent point on the lower lip as determined by a perpendicular from nasal floor.
  95. 95. Soft – tissue supra mentale – point B` (Sm): The point of the greatest concavity in the midline of the lower lip between the soft – tissue chin and labiale inferius.
  96. 96. Soft – tissue pogonion (Pog`): The most prominent or anterior point on the soft – tissue chin in the mid sagittal plane.
  97. 97. Soft – tissue gnathion (Gn`): The mid point between the most anterior and inferior points of the soft – tissue chin in the mid sugittal plane.
  98. 98. Superior labial sulcus: The deepest point on the upper lip as determined by a line drawn from subnasale inclined so that it forms a tangent with labiale superius.
  99. 99. Inferior labial sulcus: The most concave point on the lower lip as determined by a line tangent to the menton and labrale inferius. Menton (Me`): The most anterior and inferior point on chin. Determined by a line tangent to the lower lip and the chin.
  100. 100. Cephalometric lines and planes:
  101. 101. 1- The commenly used horizontal lines and planes: •S – N line: The cranial line between the centre of sella turcica (s) and the anterior point of the fronto nasal suture (nasion). This represents the anterior cranial base.
  102. 102. •Bolton plane: (Broad bent – Bolton line): BP- N: The line connects nasion to the upper most point on the posterior end of the occipital condyles on the occipital bone. (Bolton point).
  103. 103. •Frankfort horizontal plane (FH): Plane intersecting right and left porion and left orbitale. It is drawn on the profile roentgenogram from the superior margin of the acaustic meatus to orbitale.
  104. 104. •Palatal plane: Line connecting the anterior nasal spine (ANS) and the posterior ansal spine (PNS).
  105. 105. •Occlusal plane: (OCC) The occlusal plane of the teeth, a line drawn between points representing one half of the incisor overbite and one half of the cusp height of the last occluding molars.
  106. 106. •Mandibular plane: Several mandibular planes are used, depending on the analysis: The most common ones are: A.A tangent to the lower border of the mandible. B. A line between gonion (Go) and ganthion (Gn) steiner. C. A line between gonion (Go) and Menton (M) tweed.
  107. 107. •Alternative lines and planes: • A.B Plane: Line between A point (sub spinale) and B- point (supra mentale) it represents the anterior points of the basal arches of the jaws to one another and to the facial line.
  108. 108. •Facial plane: A line from the anterior point of the fronto- nasal suture (N) to the most anterior point of the mandible (Pog).
  109. 109. •Ramus line: A line tangent to the posterior border of the mandibular ramus either from: A- A point posterior to the mandibular condyle. B- A point immediately below the condyle. C- Articulare.
  110. 110. •Orbital plane (O.P): Perpendicular to Frankfort horizontal plane from orbitale.
  111. 111. •S – BP plane: Line connecting sella with the Bolton point. This line indicates the posterior portion of the cranial base. •Anonymous line: Gla bella to opisthion. •B Jork's line: Nasion to articulare (the point on the profile roentgenogram where the posterior border of the condyle intersects the contour of the temporal bone.
  112. 112. •Blumenbach's plane: The plane drawn through the points on the skull, without the mandible, which touch a flat horizontal surface. •Broad bent's line: Nasion to sella trucia mid point on the profile roentgenogram.
  113. 113. •Broca's line: Prosthion to lowest point on the occipital condyle when the skull is resting on a horizontal surface. •Camper's line: Line from the tip of the anterior nasal spine (acathion) to the external auditory meatus.
  114. 114. •Camper's plane: Line from tip of the anterior nasal spine (acathion) to the centre of the bony external auditory meatus in the right and left sides. •Camper's triangle: Camper's line and a line tangent to the facial profile. •Cranial base length: Nasion to botton point.
  115. 115. •Cranial length: Galbella to opisthocranion. •De caster's line: The plano-ethmodial line from the anterior contour of sella turcica to the roof of the cribri from plate and the internal plate of the frontal bone.
  116. 116. •His's line: Extends from acanthion to opisthion and divides the face into an upper and a lower dental part. •Hamy's line: Galbella to lambda. •Montagus line: Nasion to porion. •His's line:
  117. 117. •Huxley's line: Nasion to basion. •Krogman's Nassion parallel: Sella – nason to Frankfort horizontal. •Martins line: Nasion to the most elevated point on the external occipital protuberance (inion).
  118. 118. •Margolis line: Nasion to top of spheno occipital synchondrosis. •Montagus line: Nasion to porion. •P-O plane: Porion – orbiotale, the Frankfort plane.
  119. 119. •Pterygo maxillary fissure (PTM): The fissure formed by the retromolar tuberosity of the maxilla and the anterior curve of the pterygoid process of the sphenoid. •Pycraft's line: Nasion to centre of bony external meatus of the ear.
  120. 120. •Rickets esthetic line: Tangent to the tip of the nose and the most anterior point on the chin. •Salzmann's basal arch: The basal arch is the area in the jaws which begins at the most constricted point in the body of the maxilla and of the mandible when seen on the profile roentgenogram.
  121. 121. It includes Down's a point (subspinale) and B point (supra mentale), Axel lunds trom's apical base (which is a line around the apices of the fully formed permanent teeth). And extends around the jaws at the most constricted portions of the alveolar processes.
  122. 122. These are the areas to which tweed referred as (basal bone). •Schmidt's plane: Ophryon to inion. •Schwalbe's line: Galbella to ionion. •Spheno ethmoidal junction (S-E): Read as a distance on the S-N line by dropping a perpendicular.
  123. 123. •Super orbital line: A line from the anterior clinoid process a long the roof of the orbits, bounded anteriorly by the frontal bone and posteriorly by the sphenoid bone. •Von Baer's line: Follows the antero posterior axis of the zygomatic arch, tangent to its upper most convexity.
  124. 124. •Von thering's line: Orbitale to the centre of the bony external meatus (Frankfort horizontal). •Cranial base references planes: •1-The Bolton line (Bolton point – nasion). 2- The sella – rasion line. 3- The spheno occipital synchondrosis. 4- The Frankfort horizontal, because of its close relation to the cranial base may also be used.
  125. 125. •Mandibular references planes: •1- A line tangent to the lower border of the mandible especially when the antegonial notch is extremely pronounce when the mandibular border shows a decided downward curvature it makes thisplane highly variable. 2- A line joining gonion and gnathion. 3- A line joining gonion and menton (both points show variability during growth).
  126. 126. •Middle face references planes: •1- The palatal plane (joining ANS and PNS). •2- The occlusal plane which bisects the maxillary first molar cusps and incisor overbite. 3- One of the mandibular planes also may be used, especially in relation to mandibular denture changes.
  127. 127. Cephalometric angles: •Angle of convexity (Downs): Angle between (nasion – subspinale – pogonion) (N- point A- pog). This angle is read in positive or negative degrees from zero. If the line pogonion-point A is extended (see dotted line in Fig.) and located anterior to the N-A line, the angle is read as positive.
  128. 128. A positive angle suggests prominence of the maxillary denture base relative to the mandible. A negative angle of convexity is associated with prognathic profile. The range extends from a minimal of -8.5 degrees to a maximal of+ 10 degrees, with a mean reading of 0 degree.
  129. 129. •Facial angle (Downs): Frankfort plane intersection of nasion – pogonion line (inner lower angle). Facial angle establishes antero posterior relation of the mandible to the upper face, at the Frankfort horizontal. (FH-N-POG).
  130. 130. •FMIA (Tweed): Angle between Frankfort plane and the mandibular incisor plane. This measures the procumbency of the mandibular incisor to Frankfort planer. •I.A: Internal angle of the mandibule. •MIA: Mandibular incisor angle. This is used to measure the procumbency of mandibular incisor to the mandibular plane.
  131. 131. •N-S-Gn: Angle between SN line with the line connects N with the chin point (Gn). It is used in locating the anterior end of Go- Gn line.
  132. 132. •N-S-MP: Projection of line SN with a tangent to the lower border of the mandible (MP).
  133. 133. •N-ANS-PNS: Angle from nasion (N) to the anterior nasal spine (ANS) to posterior nasal spine (PNS).
  134. 134. •S-N-A angle: Angle between points sella – nasion – subspinale (point A). It represents antero posterior relationship of the maxillary basal arch to the anterior cranial base. This shows the degree of maxillary prognathism.
  135. 135. •S.N.B angle: Angle between points sella rasion – supra metnale (point B). It shows the anterior limit of the mandibular basal arch in relation to the anterior cranial base.
  136. 136. •SNA – SNB Angle: The angle formed by subspintale (point A) rasion supramentale (point B). It indicates the antero posterior relationship of maxillary and mandibulary and mandibular basal arches to the anterior cranial base.
  137. 137. •S-N-I: Angle between SN line and the line connects N to tip of _ (tip of the maxillary central incisor). This is used to determine the position of the maxillary incisor to the anterior cranial base.
  138. 138. •B.P – SN (Broad bent): Formed by the lines s (sella) – N (Nasion) and s (sella) – B.P (Bolton point). By connecting the points B.P and N, the Bolton plane (B.P – N) is obtained. And the angles S-B.P-N and S-N-B. P may be ascertained.
  139. 139. •Y-axis angle: It is read at the angle toward the profile of the face below the Frankfort horizontal. It is indicator of the down ward and forward mandibular growth.
  140. 140. •N-S-MI (maxillary first molar): Angle between SN line with S-MI line. (line froms to the notch between the mesial and the distal cusps of the maxillary first permanent molar).
  141. 141. Dawn's analysis •The control materials studied was derived from 20 living individuals ranging in age from 12 to 17 years and equally divied as to sex. •Both the skeletal criteria and the denture criteria will be discussed.
  142. 142. Skeletal criteria :- Facial angle :- ( 1948 ) This angle is an expression of the degree of recession or protrusion of the chine. It is determined by drawing a line from nasion to pogonion, this plane called the facial plane.
  143. 143. •The inferior inside angle of its intersection with the Frankfort horizontal is designated as the facial angle. •The mean value : 87.8O ± 3O . •The range was from 82O ( recessive chin ) to 95O ( protrusive chine ). •Mansoura measurements : •Male : 86.4O ± 5O . •female : 85.7O ± 5O . •Mean : 86.1O ± 5O .
  144. 144. •If angle smaller than normal this indicates : A skeletal class II malocclusion, with a retrognathic mandible. •If facial angle larger than normal this indicates : A skeletal class III malocclusion, with a prognathic mandible. •Age changes:- This angle increases with age, as mandibular growth concides with general growth.
  145. 145. •Angle of convexity : ( Na – point A – pog ). •This is a measure of the protrusion of the maxillary oart of the face in relation • to the total profile. •The angle is formed by • two lines, one form •nasion and the other •from pognoion, both • meeting at point A.
  146. 146. •The mean value of the angle is 0O ( the angle of convexity would concide with the facial plane ) and becomes 180O . •Normally, points N, A, pog fall on a straight line. •If point A fell posterior • to the facial plane, •the formed angle was • read in a minus degree • ( - ) .
  147. 147. •If point A anterior, the angle was read in a plus degree ( + ). •The rang was + 10O ( convex ) to – 8.5O ( concave ). •Mansoura measurements : •Male : 4.3O ± 4O . •female : 4.6O ± 2O . •Mean : 4.4O ± 3O .
  148. 148. •This angle reveals the convexity or concavity of the skeletal profile. •If angle larger than normal this indicates : A skeletal class II malocclusion and a convex skeletal profile ( + ). If angle smaller than normal this indicates : A skeletal class III malocclusion and a concave skeletal profile ( - ). Age changes :- The skeletal profile becames more concave with age because the mandibular growth usually surpass growth of the maxilla.
  149. 149. •A-B plane to facial plane angle : ( Down's ) :- •The angle formed by the intersection of the A-B plane with the facial plane ( Na – Pog ). •It is a measure of the • anteroposterior position • of the maxillary •denture base and the •mandibular denture base • to the facial plane.
  150. 150. •Average value : ( - 4.6O ± 3O ) range ( 0 to – 9O ) . •In normal class I skeletal relationship, where point A is anterior to point B ( or anterior to facial plane ) the angle is expressed as a ( - ) number.Large negative value means protrusion of the maxilla and retrusion of the mandible ( class II relationship ).
  151. 151. •If point A is posterior to the facial plane, the angle is expressed as a ( + ) number. •Zero and positive measurements indicates class III skeletal malocclusion. •The location of A-B plane in relation the facial plane is a measure of the relation of the anterior limits of the maxillary and mandibular denture bases to each other and to the profile. •It helps the operator in gaining correct incisal relationships and satisfactory axial inclinations of the incisors and helps to check ANB angle.
  152. 152. •Mandibular plane angle :- ( MP to FH ) •This is a measure of the relationship between the Frankfort horizontal plane and a tangent to the lower border of the mandible. •The mean value : 21.9O with a range from 28O to 17O . •Mansoura measurements : •Male : 23O ± 6O . •female : 26O ± 5O . •Mean : 24O ± 5O .
  153. 153. •If the angle is larger than normal ( as in skeletal class II division I ) it indicates a vertical growth of the mandible. •If the angle is larger than normal ( as in skeletal class II division 1 ) it indicates a vertical growth of the mandible. •If the angle is smaller than normal ( as in class II division 2 ) growth of the mandible will be horizontal in nature.
  154. 154. Y-( Growth) Axis The y-axis is measured as the acute angle formed by the intersection of a line from the sella turcica to gnathion with the Frankfort horizontal plane . This angle is larger in Class II facial patterns than in Class III tendencies.
  155. 155. The y-axis indicates the degree of the downward, rearward, or forward position of the chin in relation to the upper face. A decrease of the y-axis in serial radiographs may be interpreted as a greater horizontal than vertical growth pattern.
  156. 156. An increase in the y-axis is suggestive of vertical growth exceeding horizontal (or forward) growth of the mandible. The range extends from a minimal of 53 degrees to a maximal of 66 degrees with a mean reading of 59.4 degrees.
  157. 157. ( In the appraisal of severe malocclusions, where the incisors in extreme positions of supra or infra occlusion, molars and premolars are used instead of incisors ). •The angular relation between the Occlusal plane and the Frankfort plane ranged from 1.5O to 14O with a mean value of 9.3O . •The class II cases have a steep Occlusal plane, the class III cases have Occlusal plane tends to became more horizontal.
  158. 158. •Denture criteria :- •Occlusal plane angle :- ( OP to FH ) •Cant of the Occlusal plane : In order to make angular readings, the Occlusal plane was represented as a straight line. by bisecting the first molar cups height line.
  159. 159. When the anterior part of the plane is lower than the posterior, the angle would be positive. Larger positive angles are found in Class II facial patterns. Long rami tend to decrease this angle. The minimal angular measurement is +1.5 degrees; the maximal, +14 degrees; and the mean, +9.3 degrees.
  160. 160. •Inter incisal angle :- ( T to ⊥ ) •This angle relates the angular position of the long axis of the upper and lower central incisors to each other. •It is a measure of the •degree of procumbency •of the incisor teeth. •The mean value : •135.7O with a range •from 130O to 150.5O .
  161. 161. •Mansoura measurements : •Male : 122.8O ± 12O . •female : 122O ± 8.6O . •Mean : 122O ± 1.8O .
  162. 162. •If angle smaller than normal this indicates :- •Class I bimaxillary protrusion in which fullness of the lips are seen, and both the teeth and alveolar bones are too far forward from the denture bases. In BlacK races, this biprotrusion is normal. •Class II division I malocclusion.
  163. 163. If angle larger than normal this indicates :- Class II division 2 malocclusion which associated with deep anterior over bite because there is no ( incisal stop ) to prevent supra eruption of the incisors.
  164. 164. Therefore, in cases of deep anterior over bite, not only is it important to correct the vertical problem, but it is also important to treat the incisors to a proper inter incisal angle to prevent its relaps. In biretrusion cases, the incisors are up right, in those patient dished in faces are seen.
  165. 165. •Lower incisor to Occlusal plane :-( T to OP ) •This angle indicates the inclination of the lower central incisor in relation to the Occlusal plane. •The angle measured is the inferior inside angle ( the complement of the angle formed by the inter section of the long axis of T with the Occlusal plane.
  166. 166. Mean value : 14.5O with a range from 3.5O to 20O . This angle is larger than normal in class II division 1 and smaller than normal in class III malocclusion.
  167. 167. •Lower incisor to mandibular plane :- ( T to MP ) •This angle reveals the inclination of the loser central incisor in relation to the mandibular plane. The mean value : 91.4O or 90O , the difference in the mean is duo to the slightly different methods of locating the mandibular plane. ( 90O ± 5O ).
  168. 168. •All previous studies have located the mandibular plane tangent to the lower border of the mandibular at gonion and the lowest anterior point which usually is found beneath the premolars.
  169. 169. •As the latter point is not in the midline and appositional growth occure in this area, the lowest point of the mandible in the mid sagittal plane (menton) is used as the anterior tangant point ,by down’s .(Go-Me).
  170. 170. As the relationship of the lower incisors to the mandibular plane is a right angle (90) so the labial tip of the incisors is described as plus the number degrees in excess of 90. Mansoura measurements:- Male: 101.6 ±8 Female: 97.7 ±7 Mean 100.1 ± 7.8
  171. 171. Upper incisors to Apo line :- (The protrusion of the maxillary) incisors is measured as the distance between the incisal edge of the maxillary central incisor to the line from point A-pogonion. This distance is positive if the incisal edge is ahead of the point A-pogonion line and indicates the amount of maxillary dental protrusion.
  172. 172. The reading is negative if the incisal edge lies behind the point A-pogonion line and suggests a retruded position of maxillary incisors. The minimal reading is —1.0 mm; the maximal, +5 mm; and the mean, +2.7 mm.
  173. 173. Tweed's analysis :- •In order to study the human dentition, Tweed selected one hundred patients of both sexes and various age groups with normal, healthy occlusions of the permanent dentition which are esthetically pleasing.
  174. 174. Tweed's triangle :- •It is formed by the Frankfort horizontal plane, mandibular plane and a line drawn through the long axis of the most protrusive lower incisor.
  175. 175. •The Frankfort mandibular incisor angle ( FMIA ) : is formed by the Frankfort plane and the line drawn through the long axis of the mandibular incisor. •Tweed's belief that the ideal relationship of the lower to the Frankfort plane should give an angle of 65O .
  176. 176. •Any reading below 65O indicates a procumbency of the lower incisors to basal bone. •Any reading above 65O indicates a lingual axial relationship of the mandibular incisors to basal bone. •The mandibular incisor plane angle ( IMPA ) : is formed by mandibular plane and line drawn through the long axis of the loser incisor. According to Tweed this angle should measure 90O ± 5O , depending on the Frankfort mandibular angle.
  177. 177. •With a short ramus and an obtuse gonialongle the IMPA may read below 90O . •While in squared jaw individuals, the angle may read above 90O . •Tweed's triangle :- ( The requirements ) harmonious face with normal occlusion requires :- •ANB angle : not exceeds 4.5O . •FMIA : 65O . •IMPA : 90O ( 5O . •FMA : 20O – 30O .
  178. 178. •By using the Tweed's triangle, Tweed assessed the linear arch length. To determine if extraction of teeth is needed or not during treatment of the malocclusion. •Eacth tooth anterior to the first molar is measured with a caliper. This called the required space. •The linear measurement of the arch from the mesial surface of the first molar of one side to the missal surface of the first molar of the other side is called the available space.
  179. 179. The incisal reduction ( IR ) :- •A line drawn from the apex of the most procumbent lower incisor to a point 65O on the Frankfort plane is Known as the incisal Reduction ( IR ).This designates the true position of the basal bone.
  180. 180. •When the line falls lingual to the mandibular incisor, the reading is a minus and indicates the lower teeth are in procumbent relationship to the basal bone.
  181. 181. •Conversely, when the IR line lies labial to the lower incisors, the reading is a plus and indicates : the mandibular incisors are in a lingual axial relationship to basal bone. •The IR number must be multiplied by 2 because the mandible is eliptical in shape. and must be considered geometrically.
  182. 182. •The mass tooth discrepancy : is determined from the figures which represents the available space, Required space, and the incisal reduction. •Any minus reading indicates the need for extraction. The prognosis for the facial balance and harmony is depend on the FMA. •Any reading 35O is considered favorable, while any reading above 35O presents a poor profile with an unfavorable prognosis.
  183. 183. Tweed's objectives :- •The best balance and harmony of facial lines ( facial esthetics ). •Stability of the denture after treatment ( permanency of result ). •Healthy mouth tissues ( longevity of dentition ). •An efficient chewing mechanism.
  184. 184. Tweed's formula for treatment :- •Non. Extraction – FMIA 65O or greater with sufficient arch length. •Border line – FMIA 62O to 65O and sufficient arch length. •Extraction –FMIA 62O or less. •The lower incisor should be oriented to give a pleasing face and this determines whether or not extraction is to be made.
  185. 185. •Harmony of Tweed's clinical findings : ( balanced and harmony ) :- •FMA : from 16O to 28O progonosis from excellent to good. •FMA : from 28O to 32O progonosis from good to fair. •FMA : from 32O to 35O progonosis from fair to favorable. •FMA : from 35O to anything upward progonosis gets lees favorable. FMA : of 45O and above progonosis is nill.
  186. 186. •Determining the tooth mass discrepancy :- ( All measurements are made in the mandible ) :- •1- Available space :- The linear measurement from the mesial of the first molar on one side to the mesial of the first molar on the opposite side is measured with a brass wire.
  187. 187. The wire is easy contoured so that it runs along the buccal cusps of the premolars and the incisal edges of the anterior teeth as far labially as the most protrusive incisor. This wire is laid along a millimeter ruler and the measurement is recorded.
  188. 188. •2 - The IR or incisal reduction :- This is determined cephalometrically by dropping a line from the FH at a 65O angle to the apex of the lower central incisor. It is done to establish the true position of the basal bone as it is related to the linear measurement of the available space.
  189. 189. •If the line falls lingual to the lower incisor, or if FMIA less than 65O , the IR must be a minus reading. •If the IR line lies labial to the lower incisor, or if FMIA greater than 65O , IR must be plus. •IR measurement must be multiplied by 2 duo to the elliptical shape of the mandible. ( either + or - ). 3- Correcting the available space :- The IR measurement is either add or subtracted from the previous available space obtained with the brass wire. This will correct any labial or lingual deviation of the lower incisors from the true basal bone.
  190. 190. •4- The required space :- The sum total of the mesio-distal widths of each tooth mesial to the first molars. This will include the four premolars, two cuspids, two laterals and two centrals. It can be done with the aid of caliper using the patient's models to measure the erupted permanent teeth and intra oral xrays can be used to measure the un erupted permanent teeth.
  191. 191. •5- If the required space is lees than the corrected available space :- The tooth mass discrepancy is recorded as a plus figure. •When the required space is greater than the corrected available space: the tooth mass discrepancy is recorded as a minus figure. A minus tooth mass discrepancy indicates a lack of the clinical linear measurement.
  192. 192. •Tweed analysis :- N.B : •A cephalometric evaluation can not be considered complete without including the soft-tissue facial contours, and racial differences. •A patient's profile may affect the decision to need to extract or not. •When one has a well developed nose or chine, the extraction may be contra indicated, because he was wind up with a dished in appearance if teeth would be extracted. •Person that is fleshy and round faced may look well with a bimaxillary protrusion.
  193. 193. Ricketts analysis •Ricketts established live minimum cephalometric measurements :- •1-Facial angle :- As established by Down's the superior border of the extranal auditory canal is used in constructing the FH.
  194. 194. The mean is 85.4O ± 3.7O . One degree represents 1.5 mm of difference in position of the chine. Relative to the nasion point. •Facial angle 80O are retrognathic. •Facial angle 85O are orthognathic •Facial angle 90O are prognathic
  195. 195. •2- X – Y axis :- ( Facial axis ) •A line from sella to gnathion. •X – y axis is an indicator of the facial height. •This is measured where the x – y axis crosses the nasion – basion line.
  196. 196. •A differenc of one degree represents a lmost 2 mm of height relative to depth. •The average angle is 93O or plus 3O . •The rang of variation is from – 12O to 29O with a standard deviation of 3O .
  197. 197. •This suggests that x-y measurement less than zero tend towards greater length in facial from as opposed to depth. •The x-y axis is considerd plus if it is more than 90O and minus if it is less than 90O those with less than 90O are retrognathic.
  198. 198. •3- Maxillary incisors to A.point – pogonion line :- •The A point – pogonion line is an indicator of denture position in relation to the facial line. •This is 5.7 mm with arrange • from -8 mm to 15 mm. •One standard deviation is • the equivalent of 3 mm.
  199. 199. •4-Mandibular incisors to A. point – pogonion line :- •The average mandibular • incisor tip is located •approximately 0.5mm •arterior to the A. pog line • one standard deviation is • 2.7 mm. •The rang of variation is •between + 10 mm and – 10 mm. •The mandibular incisors •inclines on an average 20.5O •to the line A- pog.
  200. 200. •One standard deviation of inclination is 6.4O . •The range of angulations is from -11O to + 53O the range of standard deviation is 15O to 27O . •Mansoura measurements :- •Male : 4.35 ± 3 mm. •Female : 4.06 ± 2 mm. •Total : 4.24 ± 3 mm.
  201. 201. Facial contour :- •This is A. point related to the facial line. •It is used to determine the relationship of the maxilla to the mandible as seen in the bony profile. •At the usual distance from nasion to A.point 1 degree of difference from the line N.A to the facial line equals about 1 mm on an arc from A. point to the facial line.
  202. 202. •There fore direct measurement from A.point to the facial line is used to measure variation of the profile a straight line. •A reading of 10 mm distance from A.point to the facial line is about 20O of convexity as measured by Downs, or about half that of the angular value in millimeters. •There is an average of 4.1 mm • and a standard deviation of 2.8 •mm.
  203. 203. •Faces with a convexity or concavity of not more than 2 mm are regarded as being orthognathic. •Those with up to 5 or 6 mm convexity or concavity are classified as moderately • convex or concave. •At, 10 mm or over, the faces • are severely convex or • concave.
  204. 204. •Facial esthetic line ( E- line ) :- •The facial esthetic line extends from the tip of the nose to the end of the chin. •These measurements indicate the antero-posterior position of the lips with reference to the line between the most anterior point of the soft-tissue chine ( pogonion ) and the most anterior point of the nose ( pro nasale ) .
  205. 205. •The lower lip is on an average 0.3 forward to this line with a standard of 3 mm. •The upper lip is on an average 1 mm posterior to the lower lip when related to the facial esthetic line. •The mean is – 7 mm. At age of 11 to 14 years there is an average practically no variation of the lower lip to the facial esthetic line. In adults the difference is -4 mm.
  206. 206. •Mansoura measurements :- •Male : upper lip : -2.23 ± 1.96 mm. Lower lip : -0.12 ± 2.7 mm. •Female: upper lip : -5.2 ± 2.1 mm. Lower lip : -1.44 ± 2.8 mm. •Total : upper lip : -3.4 ± 2.45 mm. Lower lip : -0.62 ± 2.75 mm.
  207. 207. •This reference line describes facial esthetics and lip position. •Dentures that are forward ( class I bimaxillary protrusion and, class II division 1 malocclusion ) produce a convex profile with the lips ahead of the E-line. •Straight or concave profiles ( class II division 2, and class III ) are associated with returned lips.
  208. 208. •Larger noses or large chin buttons or combination of the two cases produce erroneous measurements of the lips to the E- lone. •In such cases, a rhino plasty or genioplasty may be necessary in order to arrive at a pleasing profile.
  209. 209. Sassouni's analysis •In order to study the stracture of the skull for the purpose of growth analysis and treatment, Sassouni constructed planes, arcs and axes on the lateral cephalogram.
  210. 210. •From these planes he determines the centre, and then he uses the reference 0, after analysis of these planes, the problem becaomes obvious to you. This analysis is individual in nature and is not proportional but translates the anomaly in millimeter. .
  211. 211. •Steps of the analysis :- •1- Construction of the planes. •2- Locate the centre O. •3- Construction of the arcs. •4- Construction of the axes. •5- Evaluation of the profile.
  212. 212. A- Construction of the planes. 1- Anterior cranial base planer or Basal plane ( OS ) :- Two parts, first draw a tangent from the anterior clinoid to the superior part of the roof of the orbit which called the : cranial base plane and second draw a plane parallet to the first one and tangent to the inferior border of the sella turcica and called : the supra orbital plane.
  213. 213. •2- Palatal plane ( ON ) :- It is perpendicular to the midsagittal plane, going through the anterior nasal spine ( ANS ) and the posterior nasal spine ( PNS ) and extended posteriorly as you can. •3- Occlusal plane ( OP ) :- Similar to Downs. ( Midpoint of incisor over bite through the incisal edges of the upper and the lower central incisors, and cusp height through the mesial cusps of the permanent upper and lower first molars. In open bite ignare the incisors and use the posterior teeth only. In deep over bite ( deep curve of spee ) take the occlusal surfaces of the molars and premolars do not use the incisors.
  214. 214. • In deep over bite ( deep curve of spee ) take the occlusal surfaces of the molars and premolars do not use the incisors. •4- Mandibular plane ( OG ) :- Of Down's, from ME-tangent to the lower border of the mandibular body. •5- Ramus plane ( RX ) :- The plane runs tangent to the posterior border of the ascending ramus.
  215. 215. B- Locate the centre O. To locate the centre O make sure when you put the tracing paper on the film that you are taking the lesser amount of soft tissue profile and extend the planes posteriorly as you can. Also look at the posterior area, if you have any doubt to find this area, locate the two extreme planes i.e take the most divergent two planes and draw a vertical lines, the lines will decrease in length and the increase gradually.
  216. 216. O is the centre or the midpoint of the shortest vertical line beyond which the planes will diverage. O will located up in cases of : (1)Skeletal open bite. (2)Deep bite. Ignore any bizarre plane, in this case take the other three planes.
  217. 217. C- Construction of the arcs. a - For the antero-posterior dimension :- 1- Anterior arc. 2- Basal arc. 3 - Mid facial arc. 4 - Posterior arc.
  218. 218. 1- Anterior arc. The anterior arc is the arc of a circle, between the anterior cranial base plane and the mandibular plane, with O as centre and O-ANS as radius. Use the centre O, as the one end of the compass, and open it until the N and draw an arc that pog and ANS posterior to this arc draw another arc because N may be too forward. If you find pog and ANS too forward to this arc draw another arc with ANS as radius i.e spinal arc.
  219. 219. •2- Basal arc :- Using the centre O to point A as a radius and draw another arc but if ANS is closer to the anterior arc than the pog, take the ANS as a radius from the centre O. •3- Mid facial arc :- Using the centre O to temporali, draw an arc down to the occlusal plane. Temporali (Te ) is the intersection of the shadows of the ethmoid and anterior wall of the infratemporal fossa.
  220. 220. 4- Posterior arc :- Between the anterior cranial base plane and the mandibular plane, of a circle with its centre at O and OSA as ( SA is the most posterior point on the rear margin of sella turcica ) posterior arc from O to the centre of the contour of sella as a radius.
  221. 221. b -Arcs for the vertical dimensions :- •1- From as a centre to supra orbitale ( eye brow ) as a radius make a small arc and then rotate the compass downward and draw another arc down. In adult patient draw a second small arc 10 mm below the first one, both are below the chin. •2- Posteriorly from PNS as a centre and the point of inter section of the parallel to plane (1) and posterior arc draw (2) arcs up and down.
  222. 222. •In deep bite : you will find parallel planes and centre O will shift away from the profile. •In open bite : steeper planes and centre O is very close to the profile. •In class II skeletal cases, centre O is lower. •In class III cases, it is higher relative to foramen magnum.
  223. 223. •Evaluation of the profile :- •1- From the anterior arc :- Evaluate the labial surface the maxillary incisors pogonion and ANS. •A- In well balanced face all these points are on the anterior arc. If you find ANS and pogonion are anterior to this arc by equal amount this situation considers normal. •B- If you find ANS and pog equal distance too forward or too backward this is normal.
  224. 224. •C- ANS on the arc and pogonion is not on the arc : •1- ANS on the arc and pog anterior to the arc this means chin protusion. •2- ANS on the arc and pogonion posterior to the arc this means mandibular retrusion. •D- Combination if pog is on the arc, ANS could be anterior or posterior.
  225. 225. •2- From the basal arc :- Normally from A will pass through point B or approximating this area. •3- From mid facial arc :- Evaluate the maxillary first molar, the mesial contour of the first molar should be tangent to this arc. In the mixed dentition the first mnolar will be 2 mm distal to the arc because of the lee way space.
  226. 226. •4- Posterior arc :- Normally it passes through the gonion and indicates either the chin is protrusive or retrusive. In well balanced face the corpus size is equal to the cranial size i.e from the anterior are the posterior arc.
  227. 227. •The vertical balance :- The outer upper and lower facial height should be equal in adult male, the lower face height is larger 6-7 mm than the upper. The distance from N to the inter section of the anterior arc with the first plane should be added to the lower face height from menton.
  228. 228. In posterior vertical height the upper posterior and lower posterior heights should be equal i.e the upper posterior and lower posterior parts of the arc should be equal. •Limitation :- With this analysis you have to dissociate between the soft-tissue and the skeletal reading in class II skeletal with open bite on the other hand it correlates well with class III.
  229. 229. •Axes :- •M, M', M Axis of – 6 •m, m' Axis of – 6 •I, I', I Axis of ⊥ •I, I' Axis of T
  230. 230. •The Sassouni norm :- In a well-proportioned face the four planes :- •1- that tangent to the sella and parallel with anterior cranial base, (2) the palatal plane, (3) the occlusal plane, and (4) the mandibular plane, meet at O. •2- while an arc from O to the anterior nasal spine ( ANS ) as a radius, will pass also through the pogonion, the incisal edge of the maxillary central incisor, the nasion, and the frontoethmoid junction.
  231. 231. •3- If a circle has centre O, an arc that passes through the posterior wall of the sella turcica will pass also through the gonion. •A dysplasia in any one part of the face is reflected in the face as a whole. •4- The relation of the four planes to the commen point, O, permits the classification of four facial types :- Type1: anterior cranial base plane does not pass through O. TypeII: palatal plane does not pass through O. Type III: Occlusal plane does not pass through O. Type IIII: Mandibu for base plane does not pass through O.
  232. 232. •The axial relation of the maxillary and mandibular teeth to the maxillary and mandibular teeth to the palatal plane and mandibular plane such that: •Angle M = angle I + 10. •Angle M = angle I + 5. •The angle formed by the ramal plane with the occlusal plane ® is equal to the angle formed by the inc lination of the mandibular centralincisor and the occlusal plane (I) (angle R = angle I).
  233. 233. •Since the norm concept can not be accepted as absolute for the individual, Sassouni advocales measure ment of proportionality in the individual as a base for growth study, diagnosis, and treatment planning. •N.B: discrepancy within 1 – 2 mm by archival analysis considers normal.
  234. 234. •Steiner's analysis (1953) •1- SNA angle: •Used by riedel in 1950 and •then Steiner in 1953. •It provides in formation • of the anteroposterior •position of the apical •base of the maxilla •either protruded or • retruded to the anterior • cranial base. •Mean value is 81 sd 3.
  235. 235. •If it greater than 80, it indicates protrusion of the maxilla (skeletal class II mal occlusion). •If lt less than 80, it indicates retrusion of the maxilla (skeletal class III malocclusion). •This is describing the position nothing regarding the size.
  236. 236. •This angle influenced by antero postemrior position and also bertical position of nasion. •If nasion is more forward, higher, lower or backward, this will influence the value of the angle.
  237. 237. Age change: •This angle imdergpesminor age changes, there is proportional growth between the maxilla and anterior cranial base, it has to stay constant. •Mansoura measurements: Male: 82.15 + 2.8 female: 80.69 + 2.5. Mean: 81.6 + 2.8.
  238. 238. 2- SNB angle: •It provide information of the antero posterior position of the apical base of the mandible either protruded or retruded to anterior cranial base. The mean value is 78 with sd ± 3
  239. 239. •If the angle is smaller than normal (class II) malocclusion that is caused by a retrognathic mandible). •If the angle is greater than normal (class III malocclusion duo to a prognathic mandible). •It is influenced by antero posterior and vertical position of the nasion.
  240. 240. Age changes: •This angle increase with age, because the mand ible grows more than the maxilla, and the growth is in horizontal direction. •Mansoura measurements: Male: 79.69 + 2.4. female: 77.8 + 3.29. Mean: 78.9 + 3..
  241. 241. 3- ANB angle :- •It is the difference between SNA and SNB agles. •It indicates the antero- posterior position of the maxillary apical base relative to the mandibular apical base. •The mean value is 6 + 3.
  242. 242. If the value is larger than the mean, this means that maxillary protrusion or mandibular retrusion, but it will not tell you where the maxilla is forward and where the mandible is back ward. (class II skeletal malooclusion).
  243. 243. •If the value is smaller than the mean, this means that maxillary retrusion or mandibular protrusion (class III skeletal malocclusion). But it does not tell you which one is wrong. Mansoura measurements: Male:205 + 1.8. female: 2.88 + 1.09. Mean: 2.46 + 1.53.
  244. 244. Factors affecting the values of SNA, SNB and ANB.Angles: (a) Size of the anterior crania base if it is large or small this will change the angulation. (b) Position of nasion, higher or lower. (c) Maxilla and mandible in relation to position are bar word or back word or rotated in a slight
  245. 245. The method of Richard reidal: (1)Because the points S and N are both located in hard, nonyielding tissue, are directly and easily visible in a profile x- ray picture, and particularly because they one located in the midsagittal plane and there for are displaced to a minimum degree by movement of the head, the SN line was chosen as a reference line for all of the assessment measurements.
  246. 246. 4- SND angle: (1)Point d: the middle of the symphysis. It is used to represent the anterior aspect of the mandible in a sagittal plane. (2)Point D can be established on the mandible to serve as equivalent purpose.
  247. 247. (3) The cross section of the body of the mandible is only considered. (1)Alveolar process is ignored because it is influenced by the positions of the teeth and is changeable. Either visually or with instrument, establish a poing at the centre of the mass of this cross section. It is called point D, like point sin in the cranium.
  248. 248. It is well surrounded by sturdy done, it is protected from outside influences and is well isolated from the area where movement of the teeth and normal grow the changes occur. The SND angle is used to esprss and evaluate the antero posterior location of the anterior portion of the mandible in relation to the head as whole. SND will record the changes more accurately than when using the angles SNB or SNB og.
  249. 249. Point D can also be used to determine chnges, in the position of the mandibular teeth within the mandible. To do so, erect a line through D perpendicular to the line Go – Gn. To a position even with the incisal edge of the lower incisor (d- line). Generally D – line will pass through the lower central incisor but the varied relationship of this totth to this D- line will be a surprise.
  250. 250. D point is sued as a reference point, and is transferred to subsequent tracings by coping it directly from the first. Copy the line go – gn and the point D from the first to the subsequent tracing. The line go – gn and poing D will serve the same purposes for the moving mandible, as does the line SN and the poing N for the rest of the skull. When the mandible moves, line go-gn and point D move with it.
  251. 251. Denture criteria: Upper incisor to NA: (linear). •The upper incisor should lie on the line NA in such a way that the most mesially placed point on its crown is 4 mm in front of the line NA. This measurement indicates the interpose.
  252. 252. •Rior position of the incisal edge ot he upper central incisor, with reference to the NA line. •The clinician can decide whether the incisor has to be protruded or retruded by tipping mechanics, bodily movement, or by a combination of the two procedures.
  253. 253. •This angle indicates the inclination of the upper central incisor. •The axial inclination of to NA line is 22. •It is preferred to use NA line instead of facial plane because NA is established by two fixed points plane because NA is established by two fixed pints one of them on the maxilla and in juxta position to the tooth in question. Upper incisor to NA:
  254. 254. •It is preferred to use NA line instead of facial plane because NA is established by two fixed points plane because NA is established by two fixed pints one of them on the maxilla and in juxta position to the tooth in question. In contrast the facial plane is depedent on a changeable moving part. •The chin point pogonion). •A larger than normal angel, is seen in class II division I mal occlusion.
  255. 255. •Clinically, this angle is important in torgue control when retracting or advancing upper incisors. Mansoura measurements: (1)to NA (linear): male: 5.81 mm + 3.77 mm. female: 5.31 mm + 0.59 mm. mean: 5.26 mm + 2.95 mm. (1)to NA (angle(: male: 24.69 + 7.72. femal: 24.88 + 2.84. mean: 24.78 + 6.21.
  256. 256. Lower incisor to NB: (angle): •This angle reveals the •inclination of the lower • central incisor. •The axial inclination of •the I to the NB line is 25. •This angle is larger than • normal in a class II •division I malocclusion. •This angle is smaller than • normal in skeletal class III malocclusion. •Mansoura measurements: •Male: 29.45 + 6.35. Mean: 29.62 + 6.1.
  257. 257. Lower incisor to NB (linear): •This measurement gives an idivation of the antero- posterior linear measurement of the lower central incisor with refrence to the NB line. •The most mesial point on the crown of the t is 4 mm in front of the line NB.
  258. 258. •This measurement is larger than normal, (protrusive or in positive direction) in malocclusions associated with a convex profile. (class I bimaxillary protrusion and class II division 1). •And larger in a negative direction (retrusive) in mal occlusions associated with a straight or concave profile (class II division 2 or class III). •Male: 7.35 + 2.69 mm. •Female: 6.91 + 1.44 mm. •Mean: 6.90 + 2.25 mm.
  259. 259. Pogonion to NB (linear): •The degree of prominence of the chin should contribute to a determination of the placement of the lower. There fore, the method of holdaway is followed and the distance is measured from pogonion (pog) the line NB.
  260. 260. •This distance will vary so wide by among individuals that an average or norm measurement of it would have little diagnostic value. Because the chin point varies according to type in off individuals so the difference between the two measurements T to NB and pog to NB will vary widely among normal individuals. •Holdaways liked this distances to be equal.
  261. 261. •He beleives that the overlying soft tissues one of average thickness and arrangement, acceptable results can be obtained when these measurements vary within a range of 2 mm. he regards a 3mm variance is being tolerated. •The ratio between these two measurements can be greatly influenced by orthodontic therapy and it can be brought within acceptable limits.
  262. 262. •This measurement indicates the amount of bony chin buttons present in the symphysis of the mandible. •Clinically, this measurement dictates the anterior positioning of the lower incisor during treatment. •An in sufficient bony chin contributes to a convex skeletal profile, thereby necessitating retraction of the lower incisor to improve the esthetics.
  263. 263. •A good chin enhances the profile and allows a more labial placement of the lower incisor to prevent a dished in appearance to the lower soft – tissue profile. •Average value is pog 4 mm in front NB line. •Mansoura measurements: •Male 7.35 + 2.65 mm. •Female: 6.81 + 2 mm. •Mean: 7.14 + 2.4 mm. •(t – NB / pong – nb)
  264. 264. Inter incisal angle: This angle was illustrated in the downs analysis. This angle used as a supplementary method of appraisal of the angulations of these teeth (T to ┴ ) to each other and to the face. This measurement indicates the total variation from normal of these teeth to each other. Average value is 131.
  265. 265. Occlusal plane angle (occl – SN): The angle of the occlusal plane to SN (principle of downs) except that this analysis uses the SN line instead of the Frankfort horizontal plane. used by downs.
  266. 266. A cephalometric survey of a case of malocclusion would be incomplete without the appraisal of the location of the teeth in occlusion to the face and to the skull.
  267. 267. SN to mandibular plane agnle (go. Gn To SN)" The angle go-gn to SN is very useful in: (1)Measures the degree of warpage or malformation of the mandible it self or the surfaces with Which it articulates.
  268. 268. (2) As an indication of the growth history. The line Go-Gn has been taken to represent the body of the mandible ( Riesel ). A line which more nearly represents the mass of the body of the mandible rather than its lower border is preferred. ( Mean value is 32O )
  269. 269. •Upper incisor to SN :- •This angle reveals the inclination of the central incisor, as related to the cranial base line ( SN ).
  270. 270. •Mean value is ( 104O ) . •A larger than normal angle indicates class II division 1 and class III malocclusion. •A smaller than normal angle indicates class II division 2 malocclusion. •Clinically this angle is important torque control when retracting or advancing upper incisors.
  271. 271. •Modification of Tweed- Holdaway and Steiner :- Dr. Tweed selected 100 people of both sexes and different age groups whom he considered to have excellent facial profiles and who did not need any orthodontic regulation. Their occlusions were considered to be normal and healthy in every respect.
  272. 272. He then proceded to make a comprehensive cephalometric analysis of these patients using the statistical data as the normal objective to be attained in evaluating a malocclusion. In this manner he advised his 90O ( ± ) 5 formula. It is his contention that the lower incisor must be upright on basal bone. This theory has been criticized in many quarters because it is a cut and dry method in dealing with numerous complex situations which are not accounted for.
  273. 273. Dr. Holdaway, who feels that Dr. Tweed's estimate has some merit, none the less claims that the relationship of the mandible to the maxilla can not be ignored when making any sort of evaluation as to the proper axial inclination of the anterior teeth. •1- To prove this point, he took Dr. Tweed's data of the same 100 patients and found that the ANB varied from minus 1O to plus 5O .
  274. 274. •2- He then put the patients into specific groupings and found that the median normal for ANB was ( 2O ) Further study showed that long axis of the upper central to the NA line formed an angle of ( 22O ) with the incisal edge 4 mm. distant from the NA line along the occlusal plane. 3- Like wise, he found that the long axis of the lower incisor to the NB line formed an angle of ( 25O ) with the incisal edge 4 mm. from the NB line along the occlusal plane.
  275. 275. •4- These findings challenged D. Tweed's formula. •There is no doubt that the angle ANB definitely influences the axial inclination of the upper and lower anteriors. 5- The fact is, as the ANB increases, the axial inclination of the maxillary incisors decreases, while the axial inclination of the mandibular incisors increases.
  276. 276. •6- Proportionately, as the procumbency of the uppers diminishes, the incisal edge of the maxillary incisors lies closer to the NA line. •7- In the lower arch, as the procumbency of the incisors increases, the distance from the incisal edge to the NB line increases. 8- If the ANB reading falls beyond minus 1O to plus 5O , it can be certain that an aesthetic or stable result can hardly be expected.
  277. 277. Dr. Steiner, has formulated what he refers to as ( the ideal acceptable Arrangements ) Rather than be committed to a statistical median normal, it is his contention that man must have several normal arrangements which may be considered aesthetically acceptable and stable. In other words, all people do not fall into a rigid pattern, as Dr. Tweed contends, nor do people necessarily have to conform to any sort of a median norm since the normal range varies to such a great degree. All this reasoning was brought forth from the data accumulated from Tweed's 100 cases.
  278. 278. •The lower line: symbolizes the long axis of the lower central as it relates to the NB line in mm. and degrees. At an ANB of 2O , the readings are 4 mm and 25O . •As the ANB increases, the figures representing the upper central decrease while the figures representing the lower central increase. •The reverse is true when the ANB goes below 2O . •
  279. 279. •A patient with an FMA between 15O to 35O and an ANB of -1O to +5O may be considered one that falls within a normal range. With an ANB above 9O or below -3O , the prognosis is poor. Should such patient have a 40O FMA or above, the prognosis is hopeless. •When ANB increases, by 1O , ⊥ to NA decreases by 1 ( millimetric or angular ) and T to NB increases by 0.25 mm and 1O . •When ANB decreases, by 1O , ⊥ to NA increases by 1 ( millimetric or angular ) and T to NB increases by 0.25 mm and 1O .
  280. 280. •Michigan analysis. •SNA. ( Steiner 1953 ) •SNB. ( Steiner 1953 ) •ANB. ( Steiner 1953 ) •Facial angle : ( Down's 1948 ) •It is determined by drawing a line from nasion to pogonion, this plane is called the facial plane. The inferior inside angle of its intersection with the FH is the facial angle.
  281. 281. •Downs used FH as a reference plane because it gives him the natural position of the head in determining this angle. •There is one factor which affect this angle which is the morphology of the symphysis :- •(1) Long and narrow, in this condition there is no difference between B point and pogonion.
  282. 282. 2- Button like chin, and in assessing SNB in a case you may find its value indicates a class II but facial angle tells you it is class III duo to the button like symphysis. 3- Short and broad chin. •Age changes :- If you have a child syears old and shows some tendency toward larger Facial angle, it will becomes larger and, the larger. So if you have a class II at syears, the profile of this patient is improving because of the growth of the mandible. This angle tests the SNB. And gives some verification.
  283. 283. •Angle of convexity ( Down's ) :- •A-B to facial plane angle ( Down's ) . •A-B to occlusal plane : ( Bushra 1974 ) •It measures the relative position of point A and B to occlusal plane. •If B point is forward the inferior posterior angle formed by A-B line and occlusal plane is increased than 90O which is the mean. •If point B more backward, the angle is decreased.
  284. 284. •Mansoura measurements :- •Male : 0.96 ( ± ) 2.25 mm. •Female : 0.94 3 ( ± ) 3.22 mm. •Mean : 0.24 ( ± ) 2.75 mm. There are two types the occlusal plane :- •(1) Functional occlusal plane :- Which is formed by bisecting cusp heights of molars and bicuspids, but not the incisors. Because in open bite and deep over bite cases the anatomical occlusal plane is distorted. (2) Anatomical occlusal plane :- Formed by bisecting the incisor overbite and cusp height of the molars.
  285. 285. •Wits appraisal ( Jacobson 1975 ) :- The wits appraisal of jaw disharmony is a measure of the extend to which the jaws are related to each other antero posteriorly . •It entails drawing perpendiculars on a lateral tracing from points A and B on the maxilla and mandible respectively onto the occlusal plane which is the functional occlusal plane.
  286. 286. •The points of contact on the occlusal plane are labeled Ao and Bo. •The normal value : for Female, is 0 i.e Ao and Bo concided ( ± ) 2. : for male, -1 to -2 point b forward. If Bo is anterior to Ao, the value will be negative. If Bo is posterior to Ao, the value will be positive. Wits eliminates the problem of SN either too forward or too backward so it assess points A and B.
  287. 287. •SN. To Mandibular plane :- ( Steiner ) It is formed by intersection of the SN line with the mandibular plane. •There are two basic mandibular plane :- •(1) From menton to just behind the antegonial notch tangent to the lower border of the mandible. • ( Down's and Tweed ).
  288. 288. •From Go-Gn ( Steiner ) :- •The angle formed by SN and mandibular plane provides information in vertical and antero posterior dimensions. i.e the lower half of the face and position of the chine. •In flat mandibular plane angle ( smaller angle ) :- oPNS could be normal or tipped up ward. oThe gonial angle is acute. oThe condyle is lower in position.
  289. 289. •In higher or steep mandibular plane angle ( larger angle ) :- oRamus is short, corpus is short i.e oral size of the mandible is short. oThe gonial angle is obtuse. oThe condyle is very high relative to the sella turcica.
  290. 290. •Clinically :- •(1) Patients with higher or steep mandibular plane angle : have – Large lower face height – Retrusive chin. •Steep mandibular plane is usually associated with class II open bite. •Higher steep mandibular plane is not related to the prognosis of the case because you many find a case nice looking and has only steep mandibular plane.
  291. 291. 2- Patients with flat mandibular plane angle : have – The posterior facial height is smaller than the anterior lower face height or equal to it – forward position of the chine. •There is a negative correlation between the facial angle and mandibular plane. If the facial angle is large, the mandibular plane will be flat. If it is small, the plane will be steep. Mansoura measurements :- Male : 29O ( ± ) 6.07O . Female : 33.75O ( ± ) 4.3O . Mean : 30.81O ( ± ) 5.84O .
  292. 292. •SN to palatal plane angle •It gives information regarding position of ANS, PNS or rotation of the plate. PNS may be tipped up or down relative to ANS. i.e in clockwise or counter clock wise direction.
  293. 293. •If you have smaller angle : this means that there is no displacement of PNS down ward in counter clock wise direction. •This will decrease the anterior lower face height.
  294. 294. •If the angle is greater than 8O : this means that the ANS tipped down ward and this is associated with large anterior facial height. •In normal subjects palatal plane will pass through the odontoid process and basion this gives a very good clue regarding the displacement of PNS. •Mansoura measurements :- •Male : 9.19O ( ± ) 3.4O . •Female : 11.25O ( ± ) 5.12O . •Mean : 9.98O ( ± ) 4.15O .
  295. 295. •Palatal plane to Mandibular plane :- ( used in 1936 by Schwarz and picked up by Sassouni ). •It can figures if there is something wrong regarding SN or palatal plane. •Large angle indicates : Steep mandibular plane. or PNS tipped down ward or both.
  296. 296. •It is usually associated with large anterior facial height, and small posterior facial height. •Large angle suggest open bite or class II. •Mansoura measurements :- •Male : 20.27O ( ± ) 6.37O . •Female : 22.88O ( ± ) 5.4O . •Mean : 21.26O ( ± ) 6.03O .
  297. 297. •Cranial base angle :- ( used by Pjork 1947 and Ricketts ) •It is formed by 2 lines SN and SBa. •It denotes the of glenoid fossa and TMj and some information regarding malocclusion.
  298. 298. You are measuring the angle in midsagittal plane but the glenoid fossa is bilaterally positioned so it may implied for the synchronized growth in the midsagittal and lateral directions. In obtuse angle cases : The mandible is carried backward which reflects chin backward.
  299. 299. •In acute angle cases : TMJ will be forward and the mandible is carried forward creating class III or protrusive mandible. •Even if the mandible has normal shape and size it may has different position if cranial base angle is large or small. •Mansoura measurements :- •Male : 147.12O ( ± ) 9.6O . •Female : 148.5O ( ± ) 6.2O . •Mean : 147.6O ( ± ) 8.5O .
  300. 300. •Frankfort horizontal to mandible Plane angle :- ( Tweed 1946 and Down ). •It is very similar in information gained by SN to mandibular plane.
  301. 301. •Facial axis ( Ricketts ) :- •It is constructed of Na – Ba and gnathion – foramen – rotundum. •It is an expression of growth in the horizontal and vertical direction of the • face. •Large values will have • more or less skeletal • problems.
  302. 302. •If the chin is too forward, you will have large value, if it is too posterior, you will have small value. It is very similar to Down's Y axis. •It gives information regarding the downward and forward growth direction during development. •If you have equal horizontal growth to vertical growth, the angle will be 90O . If the vertical growth exceeds the horizontal growth, the angle is decreased.
  303. 303. If the angle is larger, this denotes that the growth is in horizontal direction. •Try to relate facial axis with the facial angle, facial axis alone gives the position of the chine only.
  304. 304. •Posterior facial height to anterior facial height :- •The mean value is 65 % ( it is the percentage of S- Go to Na-Me ). •Smaller values, are associated with skeletal open bite, this denotes that anterior facial height is large and posterior facial height is smaller. •You can use SN palatal plane or Mand. plane to palatal plane because the latter angle give the same things.
  305. 305. •Lower anterior face height to total pace height :- •The mean value of ( ANS - Me to Na - Me ) is 54.6 % . •Larger values tends to reflects skeletal open bite. You have to correlate with the bizygomatic width to see either it matches or exceptible wide face with large lower facial height and the face looks good so this is compatible.
  306. 306. Aging reduced lower facial height and persons with low anterior facial height aged early. •At 6 years in males and females th upper face height and lower anterior face height are equal in length. •At 12 years, in females the 2 dimensions are equal, but in males the lower anterior face height is 3 mm longer than the upper anterior one. •In adult age, lower anterior face height in female is 3 mm longer than the upper one and in males 7.10 mm longer than the upper.
  307. 307. •T to Mandibular plane ( IMPA ) :- ( Tweed ) •It relates the axial inclination of the most labial incisor to the mandibular plane. •It depends on the morphology of the mandible and the mandibular plane. •If the mandibular plane is small or flat, the angle will be small. If the mandibular plane is steep, the angle will be large.
  308. 308. •In class III the lower incisors are lingually inclined and the mandibular plane is small and mandibular plane is flat, and IMPA smaller than 90O , this is very important in performing surgery for the mandible, the cause of the lingual inclination of the incisors in class III is the pressure of the lower lip because in this case there is no toughie pressure on these teeth. •Mansoura measurements :- •Male : 101.65O ( ± ) 8.1O . •Female : 97.75O ( ± ) 7.2O . Mean : 100.17O ( ± ) 7.8O .
  309. 309. •T to FH ( FMIA ) :- ( Tweed ) •It express lower incisor to bony profile, the average is 65O . •If IMPA is large, FMIA will be smaller and vise versa. IMPA, FMIA and MPA form the Tweed triangle. •Lower incisors upright with age, IMPA will decrease, FMIA will increase.
  310. 310. •So when we see crowding the reason may be either duo to improper angulation by orthodontic treatment or duo to late growth changes. •Mansoura measurements :- •Male : 55.15O ( ± ) 5.8O . •Female : 55.3O ( ± ) 5.75O . •Mean : 55.21O ( ± ) 5.66O .
  311. 311. •T to ⊥ ( Down's ) •T to NA ( Steiner ) •It relates the ⊥ to denture base either angular or linear. •T to NB ( Steiner ) :- •This angle checks the procumbency of T relative to the denture base. •The average is 25O and 4 mm. •The distance in mm will decrease with age duo to righting of the incisors from 6 – 12 years of age. The angle will increase from 6 – 12 years duo to labial eruption of permanent incisors.

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