1. Cephalometric
radiography
Islam Kassem
ikassem@dr.com

2. • Cephalometric radiography is a standardized
and reproducible form of skull radiography
used extensively in orthodontics to assess the
relationships of the teeth to the jaws and the
jaws to the rest of the facial skeleton.
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3. Standardization was essential for
the development of cephalometry
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4. Main indications
1-Orthodontics
2-Orthognathic
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5. 1-Orthodontics
1- Initial diagnosis — confirmation of the
underlying skeletal and/or soft tissue
abnormalities
2-Treatment planning
3- Monitoring treatment progress, e.g. to assess
anchorage requirements and incisor inclination
4- Appraisal of treatment results
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6. 2-Orthognathic surgery
1- Preoperative evaluation of skeletal and soft
tissue patterns
2- To assist in treatment planning
3-Postoperative appraisal of the results of
surgery and long-term follow-up studies.
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7. Equipment
• Cephalostat (or craniostaf)
• Cassette (usually 18 x 24 cm).
• Aluminium wedge filter.
• X-ray generating apparatus.
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9. Main radiographic projections
1-True cephalometric lateral skull
2- Cephalometric postero-anterior of the jaws
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10. 1-True cephalometric lateral skull
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13. Cephalometric tracing /digitizing
• The outline and inclination of the anterior teeth
• The positional relationship of the mandibular
and maxillary dental bases to the cranial base
• The positional relationship of the dental bases
to one another, i.e. the skeletal patterns
• The relationship between the bones of the
skull and the soft tissues of the face.
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One-shot cephalometric imaging
Multiple image format including exclusive 30x30 cm Autotracing

15. Main Cephalometric points
• Sella (S). The centre of the sella turcica,
• (determined by inspection).
• Orbitale (Or). The lowest point on the infraorbital margin.
• Nasion (N). The most anterior point on the frontonasal
suture.
• Anterior nasal spine (ANS). The tip of the anterior nasal
spine.
• Subspinale or point A. The deepest midline point between
the anterior nasal spine and prosthion.
• Prosthion (Pr). The most anterior point of the alveolar crest
in the premaxilla, usually between the upper central
incisors.
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16. • Infradentale (Id). The most anterior point of the alveolar crest,
situated between the lower central incisors.
• Supramentale or point B. The deepest point in the bony outline
between the infradentale and the pogonion.
• Pogonion (Pog). The most anterior point of the bony chin.
• Gnathion (Gn). The most anterior and inferior point on the bony
outline of the chin, situated equidistant from pogonion and
menton.
• Menton (Me). The lowest point on the bony outline of the
mandibular symphysis.
• Gonion (Go). The most lateral external point at the junction of the
horizontal and ascending rami of the mandible.
• Note: The gonion is found by bisecting the angle formed by
tangents to the posterior and inferior borders of the mandible.
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17. Posterior nasal spine (PNS). The tip of the posterior
spine of the palatine bone in the hard palate.
Articulare (Ar). The point of intersection of the
dorsal contours of the posterior border of the
mandible and temporal bone.
Porion (Po). The uppermost point of the
bony external auditory meatus, usually regarded
as coincidental with the uppermost point of the
ear rods of the cephalostat.
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19. Main cephalometric planes and
angles
Frankfort plane. A transverse plane through
the skull represented by the line joining porion and
orbitale.
Mandibular plane. A transverse plane through the skull
representing the lower border of the horizontal ramus of
the mandible.
There are several definitions:
• A tangent to the lower border of the mandible
• A line joining gnathion and gonion
• A line joining menton and gonion.
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20. Maxillary plane. A transverse plane through the skull
represented by a joining of the anterior and posterior nasal
spines.
SNplane. A transverse plane through the skull represented by
the line joining sella and nasion.
SNA. Relates the anteroposterior position of the maxilla, as
represented by the A point, to the cranial base.
SNB. Relates the anteroposterior position of the mandible, as
represented by the B point, to the cranial base.
ANB. Relates the anteroposterior position of the maxilla to
the mandible, i.e. indicates the anteroposterior skeletal
pattern — Class I, II or III.
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21. Maxillary incisal inclination. The angle between
the long axis of the maxillary incisors and the
maxillary plane.
Mandibular incisal inclination. The angle
between the long axis of the mandibular incisors
and the mandibular plane.
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23. CEPHALOMETRIC ANALYSIS

24. ANALYSIS UTILIZING THE CEPHALOMETRIC
TRACING
1) Describe the subject’s dento-facial morphology
2) Quantitative description of morphological deviations
3) Make diagnostic and treatment planing decisions
2) Evaluate change over time - treatment induced and
growth process

25. Morphological Description
• Skeletal - horizontal and vertical
• Dental - horizontal and vertical
• Comparing individual subject’s tracing to the
“ideal”

26. Cephalometric Evaluation
• Identification of anatomic landmarks
• Landmarks: stable reference structures and
maxillary and mandibular skeletal and dental
• Graphically relating the dento-facial elements
to these reference structures
• Angular and or linear measurements

27. METHODS OF CEPHALOMETRIC ANALYSIS
• Two basic approaches
• Metric approach - use of selected linear and
angular measures
• Graphic approach - “overlay” of individual’s
tracing on a reference template and visual
inspection of degree of variation

28. Metric Method - Use of selected linear and
angular measures

29. Graphic Method - Use of a Composite
Template

30. GOALS OF CEPHALOMETRIC ANLYSIS
• Evaluating relationships, both horizontal and
vertical of 5 major functional components of
the face:
• the cranial base;
• the maxilla; the mandible,
• the maxillary and mandibular dento-alveolus

31. REFERENCE LINES
• Frankfort’s Horizontal (porion to orbitale)
• Sella - Nasion line
• True horizontal plane
• True vertical plane

32. Reference Lines
sella nasion
porion orbitale

33. SNA 82 ± 2 deg
NA TO FH 90 ± 3
deg
SKELETAL HORIZONTAL - MAXILLA
s n
FH
a

34. SNB 80 ± 2 deg
N-PG TO FH
88 ± 6 deg SKELETAL HORIZONTAL - MANDIBLE
n
s
FH
b
Pg

35. ANB 2 ± 2 deg
SKELETAL HORIZONTAL - MAXILLA TO
MANDIBLE
N
A
B

36. FH TO GOGN 22 ± 5
deg
Y AXIS 59 ± 6 deg
SKELETAL VERTICAL
LFH 55% OF TFH
S
FH
GO
ME GN

37. INTERINCISAL 130
± 5 deg
DENTAL - UPPER TO LOWER INCISOR

38. U1 TO FH 110 ± 5
deg
U1 TO NA 22deg
DENTAL - MAXILLARY INCISOR
U1 TO NA 4mm
N
FH
A

39. L1 TO NB 25deg
L1 TO NB 4mm
L1 TO GOGN 91 ± DENTAL - MANDIBULAR ANTERIOR
6deg
N
GO B
GN

40. NASOLABIAL
ANGLE 102 ± 8 deg
L.LIP TO E PLANE -2
±2mm
SOFT TISSUE

41. Limitations of the Metric Method
• Stable reference structures are only relatively
stable
• Validity of landmarks
• Error in landmark identification

42. Graphic Method
• Template
• Changes between 2 time points

43. Superimposition Method - on the cranial
base

44. Maxillary and mandibular
superimposition

45. Limitations of Cephalometric Analysis
• Individual variability
• Ethnic variability
• Gender variability

46. 2-Cephalometric postero-anterior of
the jaws
• This projection is identical to the P view except
that it is standardized and reproducible. This
makes it suitable for the assessment of facial
asymmetries and for preoperative and
postoperative comparisons in orthognathic
surgery involving the mandible.
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48. Thank you
• You can get the lecture on
• http://www.slideshare.net/islamkassem
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