CEPHALOMETRICS
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INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalaca...
INTRODUCTION
• A Scientific approach to the scrutiny of human
craniofacial patterns was first initiated by
anthropologists...
• The measurement of the head of a living subject
from the bony landmarks located by palpation or
pressing through the sup...
• Roentegenographic cephalometry- The
measurement of head from the shadows of bony
and soft tissue landmarks on the radiog...
• Hellman used cephalometric techniques
and described their value beginning with
1920’s.
• A teleroentegenographic techniq...
• In 1922 Paul Simon gave the idea of
diagnosing dental deformities by means of
planes and the angles.
• In 1931 Broadbant...
• When Broadbent corrected the
malocclusion of son of Congress women
Bolton, the course of his career changed.
His discuss...
• Broadbent’s single goal was the study of
craniofacial growth. The Broadbent
technique for caphalometric radiography
was ...
The technical aspects
The basic components of the
equipment for producing the lateral
cephalogram are:
1. An X-ray apparat...
The X- ray apparatus
The three basic elements that generate
that xray are:
1. Cathode
2. Anode
3. The electrical power sup...
CATHODE
• Tungsten filament
surrounded by a
molybednum focusing
cup.
• Connected to a low
voltage & high voltage
circuit.
...
Step up transformer
• Supplies the high
voltage circuit with
65-90kV.Differential
potential accelerates
the electrons. The...
ANODE
• Small tungsten block
embedded in the copper
stem, which stops the
accelerated electrons
whose kinetic energy
cause...
• But its thermal resistance is unable to withstand
the heat. Consequently the copper stem acts as
a thermal conductor. Th...
THE IMAGE RECPTOR SYSTEM
It records the final product of X-Rays after
they pass through the subject. The extraoral
project...
THE CEPHALOSTAT
• It is based on the same principles that described
by the Broadbent.
• The patients head is fixed by the ...
• The standardized Frankfurt plane is achieved by
placing the infraorbital pointer at the patients
orbit and then adjustin...
Shortcomings of the Frankfurt
horizontal plane
• Some individuals show a variation of their
FH plane to the true horizonta...
• An alternative to overcome this was to use a
functionally derived NHP.According to Morrees
& Kean, it was obtained by th...
X-Ray Source position
• It is positioned 5 feet(152.4cm) from the
subject’s midsagittal plane.
• The projection is taken w...
Film position
• Magnification factors are affected by the
distance from the film cassette to the midsagittal
plane of the ...
Development of Cephalometric
analysis
• Cephalometric analysis is carried out not
on the radiograph itself, but on a traci...
Tracing of a Cephalogram
• Thorough familiarity with the gross
anatomy is required before the tracing.
• By convention the...
Tracing supplies and equipments
• A lateral cephalogram
• Acetate matte tracing paper(.003 inches
thick, 8×10 inches)
• A ...
• A protractor and tooth symbol tracing
template for drawing the teeth. Also
templates for tracing the outlines of ear
rod...
General considerations for the
tracing
• Start by placing the cephalogram on the
viewbox with the patient’s image facing
t...
• Place the matte acetate film over the
radiographand tape it securely.
• After firmly affixing the acetate film, trace
th...
Stepwise tracing technique
• Tracing the soft tissue profile, external
cranium and the vertebrae,
• Tracing the cranial ba...
Cephalometric landmarks
A landmark is a point which serves as
a guide for measurement or construction
of planes. They are ...
Requisites for a landmark
• Landmark should be easily seen on the
roentegenogram,be uniform in outline, and
easily reprodu...
• Measure points and the measurement
should have significant relation to the
information sought.
• Measurements should be ...
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Lateral cephalograms
HARD TISSUE
LANDMARKS
• A-
point(pt.A,subspinale)
:The most posterior
midline point in the
concavity ...
• Anterior nasal
spine(ANS):The
anteriortip of the sharp
bony process of the
maxilla at the lower
margin of the anterior
n...
• B-
point(Pt.B,Supramentale
): The most posterior
midline point in the
concavity of the
mandible between
infradentale and...
• Bolton point(Bo): The
intersection of the outline
of the occipital condyle
and the Foramen
Magnum at the highest
point o...
• Glabella(G): The most
prominent point of the
anterior contour of the
frontal bone.
• Gnathion(Gn): The
point taken betwe...
• Gonion(Go): A point
on the curvature of
angle of the mandible
located by bisecting
the angle formed by
lines tangent to ...
• Incision superius(Is):The
incisal tip of the most
labialy placed maxillary
incisor.
• Infradentale(Id,Inferior
Prosthion...
• Nasion(Na):
Intersection of the
frontonasal and
internasal sutures in
the midsagittal plane.
• Opisthion(Op): The
most p...
• Pogonion(P,Pg,Pog): The
most anterior point on the
contour of bony chin in
the midsagittal plane.
• Porion(Po): The most...
• Posterior Nasal
Spine(PNS): The
most posterior point
on the bony hard
palate in the
midsagittal plane.
• Prosthion (Pr,
...
• Pterygomaxillary Fissure
(Ptm): A bilateral inverted
teardrop shaped
radiolucency whose
anterior border
represents the p...
• R-Point (Registration
point): A
Cephalometric
reference point for
registration of
superimposed
tracings.
• Sella (S): Th...
Soft tissue landmarks
• Cervical Point (C):
The innermost point
between the
submental area and
the neck. Located at
the in...
• Inferior Labial Sulcus
(Ils): The point of
greatest concavity of
the lower lip between
the labrale inferius
and Menton i...
• Labrale superius (Ls):
The point denoting
the vermillion border
of the upper lip in the
midsagittal plane.
• Pronasale (...
• Soft tissue Menton (Me’):
The most inferior point on
the soft tissue chin.
• Soft tissue Nasion (Na’):
The deepest point...
• Stomion (St): The most
anterior point of contact
between the upper and
lower lip. When the lips
are apart at rest, a
sup...
• Subnasale (Sn): The
point in the
midsagittal plane
where the base of the
columella of the nose
meets the upper lip.
• Tr...
POSTERO-ANTERIOR
CEPHALOGRAMS
1. BILATERAL SKELETAL LANDMARKS
• Greater Wing Superior Orbit (GWSO):
The intersection of th...
• Greater Wing Inferior Orbit (GWIO): The
intersection of the inferior border of the
greater wing of the sphenoid bone and...
• Orbitale (O): The midpoint of inferior
orbital margin.
• Lateral Orbit (LO): The midpoint of the
lateral orbital margin....
• Zygomatic Frontal (ZF): The intersection
of the zygomaticofrontal suture and the
lateral orbital margin.
• Zygomatic (Z)...
• Centre Condyle (CC): The centre of the
condylar head of condyle.
• Mastoid Process (MP): The most inferior
point on the ...
• Mandible/Occiput (MBO): The intersection
of the mandibular ramus and the base of
occiput.
• Gonion (Go): The midpoint of...
Midline skeletal landmarks
• Crista Galli (Cg): The geometric centre of
the crista Galli.
• Sella Turcica (St): The most i...
• Incisor Point Upper (IpU): The crest of the
alveolus between the maxillary central incisors.
• Incisor Point Lower (IPL)...
Bilateral dental landmarks
• Maxillary Cuspid (MX3): the incisal tip of
maxillary cuspid.
• Maxillary molar (MX6): The mid...
Cephalometric planes
Are derived from at least 2 or 3
landmarks and are used for
measurements, separation of anatomic
divi...
• Frankfurt Horizontal
plane: This plane is
drawn from Po to Or.
The name is given in
the conference of
anthropology held ...
• Sella-Nasion plane: It
represents the
anterior cranial base.
Can be accurately
located on the
radiographs. Cranial
base ...
• Basion-Nasion plane:
This plane is used in
the Rickett’s analysis.
• Palatal plane: plane
passing through the
ANS and th...
• Bolton-Nasion plane
• Mandibular plane:
Different definitions are
given in different analysis,
1. Downs analysis – it
ex...
Vertical planes
• Facial plane : It
extends from nasion
to pogonion.
• Y-axis : It is the line
joining sella to
gnathion.
...
HORIZONTAL PLANES
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Vertical planes
• Facial plane : It extends from nasion to
pogonion.
• Y-axis : It is the line joining sella to
gnathion.
...
Vertical planes
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Principle of Cephalometric analysis
• The goal is to compare the patient with a
normal reference group, so that
difference...
• Issue of how to establish the normal reference
standards was difficult.
• Since normal occlusion is not the usual findin...
• The standards developed for the Down’s
analysis are still useful but have been
largely replaced by newer standards
based...
Goal of Cephalometrics
It is the evaluating the relationships, both
horizontally and vertically, of the five major
functio...
• The skeletal mandible (portion of the
mandible that would remain if there were
no teeth and alveolar process).
• The max...
Two basic ways to approach this
goals are:
• Use of selected linear and angular
measurements to establish the
appropriate ...
MEASUREMENT ANALYSIS
1. DOWN’S ANALYSIS
In this analysis FH plane is used as the
reference plane. It was based on the
stud...
Facial angle
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Angle of convexity
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A-B plane angle
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FMA angle
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Y-(growth axis)
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Dental patterns
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Mean values of Down’s analysis
Skeletal Mean Value
1. Facial angle (N.Pog
-FHP)
87.8°
2. Angle of convexity
(N.A - A.Pog)
...
Dentition to skeletal pattern
1. Cant of occlusal
plane
9.3°
2. Inter incisal angle 135.4°
3. Lower incisor to
occlusal pl...
TWEED’ ANALYSIS
Tweed used three planes to establish a
diagnostic triangle, the three planes used
in this analysis are:
1....
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The values of the angles according to
Tweed’s finding are as follows:
1. FMA- Frankfurt Mandibular plane angle
= 25°
2. FM...
STEINER’S ANALYSIS
Developed by Cecil.C.Steiner in the 1950’s
can be considered the first of the modern
cephalometric anal...
Angle SNA
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Angle SNB
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Angle ANB
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The mean values for Steiner’s
analysis are as follows:
SNA 82°
SNB 80°
ANB 2°
SND 76°
Upper incisor to NA 22°
Upper inciso...
TEMPLATE ANALYSIS
• In the early years of cephalometric
analysis, it was recognized that
representing the norm in graphica...
One of the objectives of any analytic
approach is to reduce the practically
infinite set of possible cephalometric
measure...
1. The measurements should be useful
clinically in differentiating patients with
skeletal and dental characteristics of
ma...
What is a template?
Any individual cephalometric tracing can
be represented as a series of coordinate
points (x,y) on an g...
At present two forms of the
templates are currently available:
• Schematic template (Michigan, Burlington):
These show the...
Selecting of a template for analysis
The first step in template analysis is to
pick the correct template from the set of
a...
The best thing to do is to select the
reference template considering the length
of the anterior cranial base, which should...
Doing analysis using a template
It is based on a series of
superimpositions of the template over a
tracing of the patient ...
Superimposition being done on SN-
plane, registering the patient’s tracing at
nasion rather than sella if there is a
diffe...
2. The second superimposition is on the
maximum contour of the maxilla to
evaluate the relationship of the maxillary
denti...
Advantages of the template
analysis
• It allows the easy use of the age related
samples,
• It quickly provides an overall ...
Errors of the cephalometric
measurements
These are grossly divided into three
heads :
1. Radiographic projection errors
2....
Application of cephalometrics
• For gross inspection
• To describe morphology and growth
• To diagnose anomalies
• To fore...
Limitation of cephalometrics
• It gives two dimensional view of a three
dimensional object.
• It gives a static picture wh...
Thank you
For more details please visit
www.indiandentalacademy.com
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Cephalometrics (3) /certified fixed orthodontic courses by Indian dental academy

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Cephalometrics (3) /certified fixed orthodontic courses by Indian dental academy

  1. 1. CEPHALOMETRICS www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. INTRODUCTION • A Scientific approach to the scrutiny of human craniofacial patterns was first initiated by anthropologists and anatomists who recorded the various dimensions of ancient dry skulls. • The measurement of the dry skull from osteological landmarks, called CRANIOMETRY, was then applied to living subjects as a tool for ‘longitudinal growth studies’ www.indiandentalacademy.com
  3. 3. • The measurement of the head of a living subject from the bony landmarks located by palpation or pressing through the supra-adjacent tissues is called-CEPHALOMETRY. • The discovery of X-rays by Roentgen in 1895 revolutionized the dental profession. A radiographic head image could be measured in two dimensions, thereby making possible the accurate study of craniofacial growth and development. www.indiandentalacademy.com
  4. 4. • Roentegenographic cephalometry- The measurement of head from the shadows of bony and soft tissue landmarks on the radiographic image.(Krogman & Sassouni,1957). • Von loon was probably the first to introduce cephalometrics to orthodontics.For analyzing facial growth he made plaster casts of face in which he inserted oriented casts of dentition. www.indiandentalacademy.com
  5. 5. • Hellman used cephalometric techniques and described their value beginning with 1920’s. • A teleroentegenographic technique for producing the lateral head film was introduced by Paccini in 1922.He identified the following landmarks on the roentegenogram: Gonion,Pogonion,Nasion and ANS. www.indiandentalacademy.com
  6. 6. • In 1922 Paul Simon gave the idea of diagnosing dental deformities by means of planes and the angles. • In 1931 Broadbant in USA and Hofrath in Germany simultaneously presented a standardized cephalometrics technique using the high powered X-ray machine and a head holder called a Cephalostat or the Cephalometer. www.indiandentalacademy.com
  7. 7. • When Broadbent corrected the malocclusion of son of Congress women Bolton, the course of his career changed. His discussion of facial growth with congress women led to the addition of Bolton study of facial growth. • Cephalometrics was neither developed as a technique looking for any application nor was it developed as a diagnostic tool. www.indiandentalacademy.com
  8. 8. • Broadbent’s single goal was the study of craniofacial growth. The Broadbent technique for caphalometric radiography was one of the tools that he developed for the implementation of that study. • The technique used by him eliminated practicaly all the technical difficulties encountered in previous methods of recording the dentofacial changes. www.indiandentalacademy.com
  9. 9. The technical aspects The basic components of the equipment for producing the lateral cephalogram are: 1. An X-ray apparatus 2. An image receptor system 3. A cephalostat www.indiandentalacademy.com
  10. 10. The X- ray apparatus The three basic elements that generate that xray are: 1. Cathode 2. Anode 3. The electrical power supply. www.indiandentalacademy.com
  11. 11. CATHODE • Tungsten filament surrounded by a molybednum focusing cup. • Connected to a low voltage & high voltage circuit. • A step down transfprmer supplies the low voltage circuit with 10V and a high current to heat the filament untill the electrons are emitted. www.indiandentalacademy.com
  12. 12. Step up transformer • Supplies the high voltage circuit with 65-90kV.Differential potential accelerates the electrons. The beams are directed by the focusing cup to strike a small target in the anode called focal spot. www.indiandentalacademy.com
  13. 13. ANODE • Small tungsten block embedded in the copper stem, which stops the accelerated electrons whose kinetic energy causes the production of photons. • Less then 1% is converted to photons, rest is converted to heat. • Although tungsten is a high molecular substance.. www.indiandentalacademy.com
  14. 14. • But its thermal resistance is unable to withstand the heat. Consequently the copper stem acts as a thermal conductor. This is an integral part of the cooling system & it dissipates the heat into the oil surrounding the X-Ray tube. • The size of the focal spot follows the Benson line focus principle. Therefore the target face in the X-Ray tube is oriented at an angle of 15-20˚to the cathode. www.indiandentalacademy.com
  15. 15. THE IMAGE RECPTOR SYSTEM It records the final product of X-Rays after they pass through the subject. The extraoral projection like the lateral cephalometric technique, requires a complex image receptor system that consists of : 1. Extraoral film 2. Intensifying screen 3. A cassette 4. A grid & a soft tissue shield www.indiandentalacademy.com
  16. 16. THE CEPHALOSTAT • It is based on the same principles that described by the Broadbent. • The patients head is fixed by the two ear rods that are inserted into the ear holes so that the upper borders of the ear holes rest on the upper border of the ear rods. • The head which is centered in the cephalostat, is oriented with the Frankfurt plane parallel to the floor & the midsagittal plane vertical & parallel to the cassette. www.indiandentalacademy.com
  17. 17. • The standardized Frankfurt plane is achieved by placing the infraorbital pointer at the patients orbit and then adjusting the head vertically until the infraorbital pointer & the two ear rods are at the same levels. • The upper part of the face is supported by the forehead clamp, positioned at the nasion,to eliminate rotation around the ear rods in the sagittal plane and for future references in subsequent exposures. www.indiandentalacademy.com
  18. 18. Shortcomings of the Frankfurt horizontal plane • Some individuals show a variation of their FH plane to the true horizontal to an extent of 10°. • The landmarks to locate the Fh plane on a cephalogram, orbitale & porion, are difficult to locate accurately on the radiographs. www.indiandentalacademy.com
  19. 19. • An alternative to overcome this was to use a functionally derived NHP.According to Morrees & Kean, it was obtained by the patient standing up & looking directly into the reflection of his/her eyes in a mirror directly ahead in the middle of the cephalostat. • To record the NHP,the ear rods are not used for locking the patient head into a fixed position but serve to place the midsagittal plane at a fixed distance from the film plane. www.indiandentalacademy.com
  20. 20. X-Ray Source position • It is positioned 5 feet(152.4cm) from the subject’s midsagittal plane. • The projection is taken when the teeth are in centric occlusion &the lips in the repose, unless other specifications have been recommended ( e.g. with the mouth open or with a specific interocclusal registration used as orientation. www.indiandentalacademy.com
  21. 21. Film position • Magnification factors are affected by the distance from the film cassette to the midsagittal plane of the patient. • To minimize variations in magnification from patient to patient& to obtain consistent measurements on the patient over time, a distance of 15cm is often used. • However, to place the film cassette as close to the patient head as possible is also in practice. www.indiandentalacademy.com
  22. 22. Development of Cephalometric analysis • Cephalometric analysis is carried out not on the radiograph itself, but on a tracing or digital model that emphasizes the relationship of selected points. • Tracing or the model is used to reduce the amount of information to a manageable level. www.indiandentalacademy.com
  23. 23. Tracing of a Cephalogram • Thorough familiarity with the gross anatomy is required before the tracing. • By convention the bilateral structures (eg, the rami and inferior borders of the mandible) are first traced independently. An average is then drawn by visual approximation, which is represented by a broken line. www.indiandentalacademy.com
  24. 24. Tracing supplies and equipments • A lateral cephalogram • Acetate matte tracing paper(.003 inches thick, 8×10 inches) • A sharp 3H drawing pencil or a very fine tipped pen • Masking tape • A few sheets of cardboard (preferably black) and a hollow cardboard tube. www.indiandentalacademy.com
  25. 25. • A protractor and tooth symbol tracing template for drawing the teeth. Also templates for tracing the outlines of ear rods. • Dental casts trimmed to maximum intercuspation of the teeth in occlusion. • Viewbox (variable rheostat desirable but not essential). • Pencil sharpener and a eraser. www.indiandentalacademy.com
  26. 26. General considerations for the tracing • Start by placing the cephalogram on the viewbox with the patient’s image facing towards the right. • Tape the four corners of the radiograph to the viewbox. • Draw three crosses on the radiographs, two within the cranium and one over the area of the cervical vertebrae. www.indiandentalacademy.com
  27. 27. • Place the matte acetate film over the radiographand tape it securely. • After firmly affixing the acetate film, trace the three registration crosses. • Print the pt name, record number, age in years and months, the date on which the cephalogram was taken and your name on the bottom left corner of the acetate film. • Begin tracing using smooth continuous pressure. www.indiandentalacademy.com
  28. 28. Stepwise tracing technique • Tracing the soft tissue profile, external cranium and the vertebrae, • Tracing the cranial base, internal border of the cranium, frontal sinus and the ear rods, • Maxilla and related structures including the nasal bone and pterygomaxillary fissure, • The mandible. www.indiandentalacademy.com
  29. 29. Cephalometric landmarks A landmark is a point which serves as a guide for measurement or construction of planes. They are divided into two types: 1. Anatomic: These represent actual anatomic structure of the skull. 2. Constructed: These have been constructed or obtained secondarily from anatomic structures in the cephalogram. www.indiandentalacademy.com
  30. 30. Requisites for a landmark • Landmark should be easily seen on the roentegenogram,be uniform in outline, and easily reproducible. • Lines and planes should have significant relationship to the vectors of growth of specific areas. • Landmark should permit valid quantitative measurement of lines and angles. www.indiandentalacademy.com
  31. 31. • Measure points and the measurement should have significant relation to the information sought. • Measurements should be amenable to statistical analysis but should preferably not require extensive specialized training in statistical methods. • Following is the list of most commonly used Cephalometric landmarks. www.indiandentalacademy.com
  32. 32. www.indiandentalacademy.com
  33. 33. Lateral cephalograms HARD TISSUE LANDMARKS • A- point(pt.A,subspinale) :The most posterior midline point in the concavity between the ANS and the Prosthion www.indiandentalacademy.com
  34. 34. • Anterior nasal spine(ANS):The anteriortip of the sharp bony process of the maxilla at the lower margin of the anterior nasal opening. • Articulare(Ar):A point at the junction of the posterior border of the ramus and the inferior border of the posterior cranial base(occipital bone). www.indiandentalacademy.com
  35. 35. • B- point(Pt.B,Supramentale ): The most posterior midline point in the concavity of the mandible between infradentale and Pogonion • Basion – The most anterior inferior point on the anterior margin of Foramen magnum. www.indiandentalacademy.com
  36. 36. • Bolton point(Bo): The intersection of the outline of the occipital condyle and the Foramen Magnum at the highest point on the notch posterior to the occipital condyle. • Condylion(Co): The most superior point on the head of mandibular condyle. www.indiandentalacademy.com
  37. 37. • Glabella(G): The most prominent point of the anterior contour of the frontal bone. • Gnathion(Gn): The point taken between the anterior(Pogonion) and inferior point(Menton) on the bony chin. www.indiandentalacademy.com
  38. 38. • Gonion(Go): A point on the curvature of angle of the mandible located by bisecting the angle formed by lines tangent to the posterior ramus and inferior border of the mandible. • Incision inferius(Ii):The incisal tip of the most labialy placed mandibular incisor www.indiandentalacademy.com
  39. 39. • Incision superius(Is):The incisal tip of the most labialy placed maxillary incisor. • Infradentale(Id,Inferior Prosthion): The most superior anterior point on mandibular alveolar process between the central incisors. • Menton(Me): The most inferior point of the mandibular symphysis in the midsagittal plane www.indiandentalacademy.com
  40. 40. • Nasion(Na): Intersection of the frontonasal and internasal sutures in the midsagittal plane. • Opisthion(Op): The most posterior inferior point on the margin of the foramen Magnum in the midsagittal plane. • Orbitale(Or): The lowest point on the inferior orbital margin. www.indiandentalacademy.com
  41. 41. • Pogonion(P,Pg,Pog): The most anterior point on the contour of bony chin in the midsagittal plane. • Porion(Po): The most superior point of the outline of the external auditory meatus (anatomic porion). When the anatomic porion cannot be readily located,the superiormost point of the image of the ear rods (machine porion) is used www.indiandentalacademy.com
  42. 42. • Posterior Nasal Spine(PNS): The most posterior point on the bony hard palate in the midsagittal plane. • Prosthion (Pr, Superior Prosthion, Supradentale): The most inferior anterior point on the maxillary alveolar process between the central incisors. www.indiandentalacademy.com
  43. 43. • Pterygomaxillary Fissure (Ptm): A bilateral inverted teardrop shaped radiolucency whose anterior border represents the posterior surface of maxillary tuberosities. • Ptm landmark is taken at the most inferior point of the fissure, where the anterior and the posterior outlines of the inverted teardrop merge with each other www.indiandentalacademy.com
  44. 44. • R-Point (Registration point): A Cephalometric reference point for registration of superimposed tracings. • Sella (S): The geometric centre of the pituitary fossa (sella turcica), determined by inspection. www.indiandentalacademy.com
  45. 45. Soft tissue landmarks • Cervical Point (C): The innermost point between the submental area and the neck. Located at the intersection of lines drawn tangent to the neck and submental area www.indiandentalacademy.com
  46. 46. • Inferior Labial Sulcus (Ils): The point of greatest concavity of the lower lip between the labrale inferius and Menton in the midsagittal plane. • Labrale inferius (Li): The point denoting the vermillion border of the lower lip in the midsagittal plane. www.indiandentalacademy.com
  47. 47. • Labrale superius (Ls): The point denoting the vermillion border of the upper lip in the midsagittal plane. • Pronasale (Pn): The most prominent point on the tip of the nose. • Soft tissue Glabellla (G’): The most prominent point on the soft tissue drape of the forehead. www.indiandentalacademy.com
  48. 48. • Soft tissue Menton (Me’): The most inferior point on the soft tissue chin. • Soft tissue Nasion (Na’): The deepest point of the concavity between the forehead and soft tissue contour of the nose. • Soft tissue Pogonion (Pog’): The most prominent point on the soft tissue contour of the chin in the midsagittal plane. www.indiandentalacademy.com
  49. 49. • Stomion (St): The most anterior point of contact between the upper and lower lip. When the lips are apart at rest, a supreior and inferior stomion points can be distinguished. • Stomion Superius (Sts): The lowest midline point of the upper lip. • Stomion Inferius (Sti): The highest midline point of the upper lip. www.indiandentalacademy.com
  50. 50. • Subnasale (Sn): The point in the midsagittal plane where the base of the columella of the nose meets the upper lip. • Trichion (Tr): Demarcation point of the hairline in the midline of the forehead. www.indiandentalacademy.com
  51. 51. POSTERO-ANTERIOR CEPHALOGRAMS 1. BILATERAL SKELETAL LANDMARKS • Greater Wing Superior Orbit (GWSO): The intersection of the superior border of the greater wing of the sphenoid bone and lateral orbital margin. www.indiandentalacademy.com
  52. 52. • Greater Wing Inferior Orbit (GWIO): The intersection of the inferior border of the greater wing of the sphenoid bone and the lateral orbital margin. • Lesser Wing Orbit (LWO): The intersection of the superior border of the lesser wing of the sphenoid bone and the medial aspect of the orbital margin. www.indiandentalacademy.com
  53. 53. • Orbitale (O): The midpoint of inferior orbital margin. • Lateral Orbit (LO): The midpoint of the lateral orbital margin. • Medial Orbit (MO): The midpoint of the medial orbital margin. • Superior Orbit (SO): The midpoint of the superior orbital margin. www.indiandentalacademy.com
  54. 54. • Zygomatic Frontal (ZF): The intersection of the zygomaticofrontal suture and the lateral orbital margin. • Zygomatic (Z): The most lateral aspect of the zygomatic arch. • Foramen Rotundum (FR): The centre of the foramen rotundum. • Condyle superius (CS): The most superior aspect of the condyle. www.indiandentalacademy.com
  55. 55. • Centre Condyle (CC): The centre of the condylar head of condyle. • Mastoid Process (MP): The most inferior point on the mastoid process. • Malar (M): The deepest point on the curvature of the malar process of the maxilla. • Nasal Capsule (NC): The most lateral point on the nasl cavity. www.indiandentalacademy.com
  56. 56. • Mandible/Occiput (MBO): The intersection of the mandibular ramus and the base of occiput. • Gonion (Go): The midpoint of the curvature of the angle of the mandible. • Antegonion (Ag): The deepest point on the curvature of the antegonial notch. www.indiandentalacademy.com
  57. 57. Midline skeletal landmarks • Crista Galli (Cg): The geometric centre of the crista Galli. • Sella Turcica (St): The most inferior point on the floor of sella turcica. • Nasal Septum (NSM): The approximated midpoint of the nasal septum and the palate. www.indiandentalacademy.com
  58. 58. • Incisor Point Upper (IpU): The crest of the alveolus between the maxillary central incisors. • Incisor Point Lower (IPL): The crest of the alveolus between the lower central incisors. • Genial tubercles (Gt): Centre of the genial tubercles. • Menton (M): Midpoint on inferior border of mental protuberance. www.indiandentalacademy.com
  59. 59. Bilateral dental landmarks • Maxillary Cuspid (MX3): the incisal tip of maxillary cuspid. • Maxillary molar (MX6): The midpoint on the buccal surface of the first molar. • Mandibular Cuspid (MD3): The incisal tip of the mandibular cuspid. • Mandibular Molar (MD6): The midpoint on the buccal surface of the mandibular first molar. www.indiandentalacademy.com
  60. 60. Cephalometric planes Are derived from at least 2 or 3 landmarks and are used for measurements, separation of anatomic divisions, definition of anatomic structures of relating parts of the face to one another.The various cephalometric planes used are: www.indiandentalacademy.com
  61. 61. • Frankfurt Horizontal plane: This plane is drawn from Po to Or. The name is given in the conference of anthropology held at Frankfurt in1985. www.indiandentalacademy.com
  62. 62. • Sella-Nasion plane: It represents the anterior cranial base. Can be accurately located on the radiographs. Cranial base undergoes little change after the age of 6-7 years but the N-point can drift either forwards or vertically giving rise to an error. www.indiandentalacademy.com
  63. 63. • Basion-Nasion plane: This plane is used in the Rickett’s analysis. • Palatal plane: plane passing through the ANS and the PNS. • Occlusion plane: It is the plane passing through the cusp tips of the upper and lower first molars and a point bisecting the overbite. www.indiandentalacademy.com
  64. 64. • Bolton-Nasion plane • Mandibular plane: Different definitions are given in different analysis, 1. Downs analysis – it extends from Go to Me. 2. Steiner’s anlysis – it extends from Go to Gn. 3. Salzmann took lower border of the mandible as the mandibular plane. www.indiandentalacademy.com
  65. 65. Vertical planes • Facial plane : It extends from nasion to pogonion. • Y-axis : It is the line joining sella to gnathion. • Ramal plane : It is drawn tangent to the posterior border of the ramus and the condyles. www.indiandentalacademy.com
  66. 66. HORIZONTAL PLANES www.indiandentalacademy.com
  67. 67. Vertical planes • Facial plane : It extends from nasion to pogonion. • Y-axis : It is the line joining sella to gnathion. • Ramal plane : It is drawn tangent to the posterior border of the ramus and the condyles. www.indiandentalacademy.com
  68. 68. Vertical planes www.indiandentalacademy.com
  69. 69. Principle of Cephalometric analysis • The goal is to compare the patient with a normal reference group, so that differences between the patient’s actual dentofacial relationships and those expected for his/her racial or ethnic groups are revealed. • First popularized after world warII in the form of Down’s analysis. www.indiandentalacademy.com
  70. 70. • Issue of how to establish the normal reference standards was difficult. • Since normal occlusion is not the usual finding in a randomly selected population group,one must make a further choice in establishing the references group,either excluding only obviously deformed individuals while including most of the malocclusions, or excluding essentialy all those with malocclusion to obtain ideal sample. www.indiandentalacademy.com
  71. 71. • The standards developed for the Down’s analysis are still useful but have been largely replaced by newer standards based on less rigidly selected groups. • Major database for contemporary studies: Michigan growth studies, Burlington growth studies and the Bolton’s growth studies. www.indiandentalacademy.com
  72. 72. Goal of Cephalometrics It is the evaluating the relationships, both horizontally and vertically, of the five major functional components of the face: • The cranium and the cranial base, • The skeletal maxilla (described as the portions of the maxilla that would remain if there were no teeth and the alveolar process) www.indiandentalacademy.com
  73. 73. • The skeletal mandible (portion of the mandible that would remain if there were no teeth and alveolar process). • The maxillary dentition and the alveolar process. • The mandibular dentition and the alveolar process. www.indiandentalacademy.com
  74. 74. Two basic ways to approach this goals are: • Use of selected linear and angular measurements to establish the appropriate comparisons. Like in the case of Down’s analysis. • Template method: Express the normative data graphically and to compare the patient’s dentofacial form directly. www.indiandentalacademy.com
  75. 75. MEASUREMENT ANALYSIS 1. DOWN’S ANALYSIS In this analysis FH plane is used as the reference plane. It was based on the study of 25 white subjects who had good occlusion and proportional facial skeleton. This analysis indicates whether the dysplasia is in the facial skeleton or in the dentition or both. www.indiandentalacademy.com
  76. 76. Facial angle www.indiandentalacademy.com
  77. 77. Angle of convexity www.indiandentalacademy.com
  78. 78. A-B plane angle www.indiandentalacademy.com
  79. 79. FMA angle www.indiandentalacademy.com
  80. 80. Y-(growth axis) www.indiandentalacademy.com
  81. 81. Dental patterns www.indiandentalacademy.com
  82. 82. Mean values of Down’s analysis Skeletal Mean Value 1. Facial angle (N.Pog -FHP) 87.8° 2. Angle of convexity (N.A - A.Pog) 0° 3. A – B plane angle -4.6° 4. Mandibular plane angle (FHP – MP) 21.9° 5. Y axis (S.Gn-FHP) 59.4° www.indiandentalacademy.com
  83. 83. Dentition to skeletal pattern 1. Cant of occlusal plane 9.3° 2. Inter incisal angle 135.4° 3. Lower incisor to occlusal plane 14.5° 4. Lower incisor to mandibular plane 91.4° 5. Upper incisor to 2.7mmwww.indiandentalacademy.com
  84. 84. TWEED’ ANALYSIS Tweed used three planes to establish a diagnostic triangle, the three planes used in this analysis are: 1. Frankfurt horizontal plane 2. Mandibular plane 3. Long axis of lower incisor www.indiandentalacademy.com
  85. 85. www.indiandentalacademy.com
  86. 86. The values of the angles according to Tweed’s finding are as follows: 1. FMA- Frankfurt Mandibular plane angle = 25° 2. FMIA- Frankfurt Mandibular incisor plane angle = 65° 3. IMPA- Incisor Mandibular angle = 90° www.indiandentalacademy.com
  87. 87. STEINER’S ANALYSIS Developed by Cecil.C.Steiner in the 1950’s can be considered the first of the modern cephalometric analysis for two reasons: 1. It displayed measurements in a way that emphasized not just the individual measurements but their interrelationship into a pattern. 2. Specific guide for use of cephalometric measurements in treatment planning. www.indiandentalacademy.com
  88. 88. Angle SNA www.indiandentalacademy.com
  89. 89. Angle SNB www.indiandentalacademy.com
  90. 90. Angle ANB www.indiandentalacademy.com
  91. 91. The mean values for Steiner’s analysis are as follows: SNA 82° SNB 80° ANB 2° SND 76° Upper incisor to NA 22° Upper incisor to NA 4mm Lower incisor to NB 25° Lower incisor to NB 4mm interincisal angle 130° MP to SN 32° www.indiandentalacademy.com
  92. 92. TEMPLATE ANALYSIS • In the early years of cephalometric analysis, it was recognized that representing the norm in graphical form might make it easier to recognize a pattern of relationship. • In recent years, direct comparisons of patients with templates derived from the various growth studies has become a reliable method of analysis. www.indiandentalacademy.com
  93. 93. One of the objectives of any analytic approach is to reduce the practically infinite set of possible cephalometric measurement to a manageably small group that can be compared to the norms and thereby provide useful information. From the beginning it was recognized that the measurements for comparison with the norms should have several characteristics. The following were specifically desired: www.indiandentalacademy.com
  94. 94. 1. The measurements should be useful clinically in differentiating patients with skeletal and dental characteristics of malocclusion; 2. The measurement should not be affected by the size of patient: 3. The measurement should be affected minimally by the age of the patient. www.indiandentalacademy.com
  95. 95. What is a template? Any individual cephalometric tracing can be represented as a series of coordinate points (x,y) on an grid. Similarly the cephalometric data from any group also could be represented graphically by calculating the average coordinates of each landmark point, and then connecting the points. The resultant average or composite tracing often is referred to as a template. www.indiandentalacademy.com
  96. 96. At present two forms of the templates are currently available: • Schematic template (Michigan, Burlington): These show the changing position of selected landmarks with age on a single template. • Anatomically complete template (Broadbent-Bolton, Alabama): These are a different ones for each age. www.indiandentalacademy.com
  97. 97. Selecting of a template for analysis The first step in template analysis is to pick the correct template from the set of age different ones that represent the reference data. Two things that have to be kept in mind are: • The patient’s physical size • Developmental age. www.indiandentalacademy.com
  98. 98. The best thing to do is to select the reference template considering the length of the anterior cranial base, which should be same for the patient and the template. After this we move forward or backwards in the template age if the patient is developmentally quite advanced or retarded. www.indiandentalacademy.com
  99. 99. Doing analysis using a template It is based on a series of superimpositions of the template over a tracing of the patient being analyzed. The sequence of superimpositions follows: 1. Cranial base superimpositions: This allows the relationship of the maxilla and mandible to the cranium to be calculated. www.indiandentalacademy.com
  100. 100. Superimposition being done on SN- plane, registering the patient’s tracing at nasion rather than sella if there is a difference in the anterior cranial base length. With the cranial base registered, the anteroposterior and vertical position of the maxilla and mandible can be observed. ANS, ptA for the anterior maxilla, PNS for the posterior maxilla; PtB, Pog and Gn for the anterior mandible and Go for the posterior mandible are looked for. www.indiandentalacademy.com
  101. 101. 2. The second superimposition is on the maximum contour of the maxilla to evaluate the relationship of the maxillary dentition to the maxilla. Template makes the vertical evaluation of the teeth possible which is not possible with the measurement approach. 3. The third superimposition is on the symphysis of the mandible www.indiandentalacademy.com
  102. 102. Advantages of the template analysis • It allows the easy use of the age related samples, • It quickly provides an overall appraisal of the way in which the patient’s dentofacial structures are related unlike the measurement approach in which the focus sometimes shifts to acquiring the numbers themselves. www.indiandentalacademy.com
  103. 103. Errors of the cephalometric measurements These are grossly divided into three heads : 1. Radiographic projection errors 2. Errors within the measuring system 3. Errors in landmark identification. www.indiandentalacademy.com
  104. 104. Application of cephalometrics • For gross inspection • To describe morphology and growth • To diagnose anomalies • To forecast future relationships • To plan treatment • To evaluate treament results www.indiandentalacademy.com
  105. 105. Limitation of cephalometrics • It gives two dimensional view of a three dimensional object. • It gives a static picture which does not takes time into consideration. • The reliability of cephalometrics is not always accurate. • Standardization of analytical procedures are difficult. www.indiandentalacademy.com
  106. 106. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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