CEPHALOMETRY II.pptx_20250823_114235_0000.pdf

Ortho

1. ANALYSES
Cephalometrics- II

2. LEARNING
OBJECTIVES
DOWNS, STEINERS AND TWEEDS ANALYSES
QUIZ
WITS
APRAISAL

4. HI! MY NAME IS NOAH.

5. HI! MY NAME IS NOAH.

6. Point A revisited – Jacobson
Point A cannot be accurately identified in all cephalometric
radiographs.. In instances where this landmark is not clearly
discernible, an alternative means of estimating the anterior
extremity of the maxillary base is shown.
Procedure;
A point plotted 3.0 mm. labial to a point between the upper
third and lower two thirds of the long axis of the root of the
maxillary central incisor was found to be a suitable point -
(estimated point A) through which to draw the NAE line and
one which most closely approximates the true NA plane.

7. 3m
m

8. 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.
CEPHALOMETRIC ANALYSIS
Evaluates the relationship both horizontally and vertically.
Cranium and cranial base
Skeletal maxilla
Maxillary dentition and alveolar process
Skeletal mandible
Mandibular dentition and alveolar process

9. DOWNS ANALYSIS
Considers Frankfort horizontal plane as reference plane.
20 white subjects( 12-17 yrs)
Boys and Girls are 1:1 ratio.
All individuals having excellent occlusion.
Down redused his observation to the following four basic facial types:

10. 2. ANGLE OF CONVEXITY
3. A-B PLANE ANGLE

11. FACIAL ANGLE
To measure , the degree
of retrusion or protrusion
of lower jaw.
Facial line (N-Pog)
intersect the F-H Plane.
Mean – 87.8⁰
Range – 82-95⁰
Angle – Prominent chin
Angle– Retrusive chin

12. ANGLE OF FACIAL CONVEXITY:
By the intersection of line from
Nasion to Point A and line from
Point A to Pogonion.
Revels the convexity or
concavity of the skeletal
profile.
Positive Angle – Convex profile
– Class II
Negative Angle – Concave
profile – Class III
Mean – 0⁰
Range – -8.5⁰ to +10⁰

13. A-B PLANE ANGLE:
Formed by line joining Point
A to Point B AND line joining
Nasion to Pogonion.
Indicative of Maxillo-
Mandibular relationship in
relation to Facial plane.
Mean - -4.6⁰
Range – 0 to -9⁰.
Large –ve angle – Class II
Positive angle – Class III

14. MANDIBULAR PLANE ANGLE:
Formed by the line
joining tangent to lower
border of mandible to F-
H Plane.
Mean – 21.9⁰
Range – 17 to 28⁰
Increased angle-
Unfavorable growth
pattern which
complicates the
treatment and prognosis.

15. Y (GROWTH) AXIS:
Formed by the line joining
Sella to Gnathion and F-H
Plane.
Larger angle- ClassII
tendency and vertical
growth pattern.
Smaller angle- ClassIII
tendency and horizontal
growth pattern.
Mean – 59.4⁰
Range – 53-66⁰

16. DENTAL PATTERN:
1. CANT OF OCCLUSAL PLANE
2. INTERINCISAL ANGLE
3. INCISOR OCCLUSAL PLANE ANGLE
4. INCISOR MANDIBULAR PLANE ANGLE
5. PROTRUSION OF INCISORS

17. CANT OF OCCLUSAL PLANE:
Here Occlusal plane is the
line bisecting overlapping
cusps of first molar and
incisal overbite.
Angle between Occlusal
plane and F-H Plane.
Mean - +9.3⁰
Range - +1.5⁰ to +14⁰

18. INTERINCISAL ANGLE:
Line passing through incisal
edge and apex of root of
maxillary and mandibular
incisors.
Mean – 135.4⁰
Range – 130 to 150⁰
Small angle- Proclined
incisors
Large angle- Retroclined
incisors.

19. INCISOR-OCCLUSAL
PLANEANGLE:
Relates lower incisor to
their functioning occlusal
plane.
Mean – +14.5⁰
Range - +3.5 to +20⁰
Positive angle-proclined
incisors.
Negetive angle-
Retroclined incisors

20. INCISOR MANDIBULAR
PLANEANGLE:
Formed by the
intersection of
Mandibular Plane to
Long axis of lower
incisor.
Mean – 1.4⁰
Range - -8.5 to +7⁰
Positive angle- Proclined
incisor
Negetive angle-
Retroclined incisor

21. PROTRUSION OF
MAXILLARYINCISORS:
It is the linear measurement
between the incisal edge of the
maxillary central incisor and line
joining Point A and Pogonion.
Mean – +2.7mm
Range – -1.0 to +5mm
Reading is negative if incisal
edge lies behind line and
positive if it is front.

22. Variable mean value range
1. FACIAL ANGLE 87.8 82-95
2. ANGLE OF
CONVEXITY
0 -8.5- 10
3. A-B PLANE
ANGLE
-4.6 -9-0
4. MANDIBULAR
PLANEANGLE
21.9 17-28
5. Y AXIS 59.4 53-66
SKELETAL PARAMETERS

23. Variable mean value range
1. CANT OF OCCLSUAL
PLANE
9.3 1.5-14
2. LOWER INCISOR TO
OCCLUSAL PLANE
14.5 3.5-20
3.LOWER INCISOR TO
MANDIBULAR PLANE
1.4 -8.7-7
4. INTERINCISAL ANGLE 130-150.5
5. UPPER INCISOR TO A-
Pog
2.7mm -1-5mm
DENTAL PARAMETERS

24. Steiner analysis
Cecil C. Steiner
Max. clinical information with least no. of
measurement

25. S-N plane
REFERENC
E PLANE

26. Skeletal analysis

Dental analysis
Soft tissue analysis

27. SNA
Angle
Mean value =
82°

28. SNB
Angle
Mean value =
80°

29. ANB
Angle
Mean value
= 2°

30. Occlusal plane
angle
Mean value =
14°

31. Dental analysis
Maxillary incisor
position
Relating teeth to N-
A line
Mandibular incisor
position
Relating teeth to N-
B line

32. Mx. C.I. to N.A.
line angle
Mean value =
22°
Distance b/w most ant
point of crown to N.A.
line is normally 4 mm.

33. Mb. C.I. to N.B.
line angle
Mean value =
25°
Distance b/w
most antr point
of crown to N.B.
line is normally 4
mm.

34. Inter-incisal
angle
Mean value =
130°

35. Lower incisor to chin
According to Holdway
distance b/w labial
surface of Mb incisor to
N-B line should be equal
(i.e. 4mm)
Discrepancy
b/w 2 mm is acceptable
3 mm is less desirable,
but tolerable
>4 mm then corrective
measures are indicated

36. Soft tissue
analysis
S
line

37. SNA 82°
SNB 80°
ANB 2°
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°

38. TWEED ANALYSIS:
FMA – 25⁰ (FH Plane to
Mandibular Plane).
FMIA – 65⁰ (FH Plane to
Long axis of lower incisor).
IMPA – 90⁰ (Mandibular
Plane to Long axis of lower
incisor).

40. WITTS APPRAISAL:
In the Witts appraisal, Points
A and B are projected to the
functional occlusal plane,
which is drawn through the
posterior teeth. Then A-B
difference is measured. In well
proportioned faces, the A-B
difference is -1mm for men
and is 0mm for women.

41. WHAT’S HAPPENING HERE ?

42. Method of superimposing radiographs
Superimposing on a stable
plane or structure
Registration on a stable
landmark

43. Methods of assessing Dentofacial
changes
Color coding of
consecutive
cephalograms
suggested by ABO:
Pretreatment – black
Progress – blue
End of treatment – red
Retention - green

44. Need for Cephalometric superimposition
Evaluate a patient’s growth pattern at different
ages
To evaluate changes in basal and dentoalveolar
relationships after treatment
To quantify growth and treatment changes in
dento-alveolar and basal relationships.

45. LIMITATIONS OF RADIOGRAPHIC
CEPHALOMETRY
1.It gives two dimensional view of a three dimensional object.
2.The reliability of cephalometrics is not always accurate.
3.Standardization of analytical procedures are difficult.
4.Growth pattern not taken into consideration
5.Mean values are based on different population
6.Form and functions not taken into consideration

46. Angle between FH plane and SN plane is
A. 2 degrees
B. 5 degrees
C. 7 degrees
D. 10 degrees

47. Average angle of convexity in Down’s analysis
A. 0 degrees
B. 25 degrees
C. 82 degrees
D. 84 degrees

48. The highest point of the concavity behind the
occipital condyle
A. Basion
B. Glabella
C. Articulare
D. Bolton point

49. ZYGOMA/ KEY RIDGE CORRESPONDS TO
A. MB root of first molar
B. MB root of second molar
C. DB root of first molar
D. DB root ofsecond molar