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3. INTRODUCTION
described a method of cephalometric analysis which is
used in the evaluation and treatment planning of
orthodontic and orthognathic surgery patients
The analysis represents an effort to relate…
Teeth to teeth
Teeth to jaws
Each jaw to the other
Jaws to the cranial www.indiandentalacademy.com
base
4. Composite Normative Standards
Are Based On..
Bolton's
Standards
Burlington
Ann
Orthodontic Research Centre
Arbor sample of 111 young adults
(Female – 26 yrs 8 mon, Male – 30 yrs 9 mon )
The analysis method is derived in part from the
principles of cephalometric analyses of Ricketts
and Harvold
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5. Why Another Analysis ?
1940 – 1970 : Significant alteration in the craniofacial
relationship were thought impossible
In the decade from 1970 - 1980
Advent
of numerous Orthognathic surgery procedures
which allow three dimensional repositioning of almost
every bony structure in the facial region
Functional
appliance therapy which present new
possibilities in the treatment of skeletal discrepancies
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6. Landmarks And Planes :
Nasion- Most anterior point
on Nasofrontal Suture
Porion- Superior aspect of
the external auditory meatus
N
s
po
Co
Ptm
Or
Ba
A
Orbital- lowermost point on
the orbit
Basion- lowest point on the
foramen magnum in the
median plane
ANS
Go
Ptmwww.indiandentalacademy.com
Pog
Me Gn
7. Landmarks And Planes :
ANS- Tip of the bony
anterior nasal spine
Point A- Deepest point on the
curved bony outline
( subspinale )
Pogonion- Most anterior point
on the bony chin
Menton- Lowest point on the
outline of the symphysis
N
s
po
Co
Ptm
Or
Ba
A
ANS
Go
Gonion- Constructed by
intersection of the lines
tangent to the posterior
margin of the ascending ramus
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Pog
Me Gn
8. Landmarks And Planes :
Gnathion- Constructed by
intersecting a line drawn
perpendicularly to the line
connecting Me and Pog
N
s
po
Condylion- Most
posterosuperior point on the
outline of the condyle
Co
Ptm
Or
Ba
A
ANS
Mandibular plane – Go – Me
Go
Pog
Facial axis – Ptm – Gn
Me Gn
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9. Craniofacial Skeletal Complex Is
Divided Into Five Major Sections…
Maxilla to Cranial base
Maxilla to Mandible
Mandible to Cranial base
Dentition
Airway
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10. Relating Maxilla To The Cranial
Base
N
Hard tissue evaluation:
po
Linear distance is measured
FH
or
1 mm
Between nasion
perpendicular to point A
0 mm – in mixed dentition
1 mm – in adults
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12. Relating Maxilla To The Cranial
Base
Soft Tissue Evaluation:
Nasolabial Angle:
Formed by line drawn tangent
to the base of the nose and a
line tangent to the upper lip
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13. Relating Maxilla To The Cranial
Base
Soft Tissue Evaluation:
N Perpendicular
Cant Of Upper Lip :
Female – 14 degree
Male – 8 degree
( SD 8 0 )
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14. Relating Maxilla To The Mandible:
Anteroposterior Relationship:
Effective Midfacial Length :
Measured from Condylion to
point A
Effective mandibular length :
Measured from Condylion to
gnathion
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15. Effective lengths are not age or sex related
but are related to size of component parts
Small - Mixed dentition
Medium - Adult female
Large - Adult male
Any given effective midfacial length corresponds to a
given effective mandibular length
Mandibular length – Midfacial length =
Maxillomandibular differential
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16. Small : 20 mm
Medium : 25 to 27 mm
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Large : 30 to 33 mm
17. CLASS II DIV 1
Mandible 12 mm deficient
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18. Relating Maxilla To The Mandible:
Vertical Relationship :
Lower Anterior Face Height :
Measured
from ANS to Menton
Increases
with age and is correlated
With effective midfacial length
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19. 66 – 68 mm
60 – 62 mm
70 – 74 mm
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20. Vertical
maxillary excess can cause a downward
and backward rotation of mandible resulting in an
increase in lower anterior face height and vice –
versa
An
increase or decrease in the lower anterior face
height can have a profound effect on the horizontal
relationship of the maxilla and mandible
If
the lower anterior face height is increased then
the mandible will appear to be more retrognathic
and vice - versa
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22. Mandibular Plane Angle :
Angle between FH plane and
the Mandibular plane
( Gonion – Menton )
220 + 40
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23. Facial Axis Angle :
Angle between a line from
basion to nasion and the
facial axis i.e. PTM to Gn
900
< 900 – ( -ve value ) excessive
vertical development
> 900 – ( +ve value ) deficient
vertical development
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24. Relating Mandible To The Cranial
Base
Distance from Pog to the nasion
Perpendicular
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25. - 8 mm to – 6 mm
- 4 mm to 0 mm
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- 2 mm to 2 mm
27. Dentition :
In
cases of malrelationship between the maxillary
and mandibular skeletal structures, errors may result if
the position of the upper incisor is determined by any
measurement that uses mandible as a reference point
e.g. A – pogonion line
A
measurement of upper incisor to the N – A line is
valid only if the maxilla is in neutral position
anteroposteriorly relative to the cranial base
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29. Relating upper Incisor to Maxilla :
Anteroposterior position
Position of the upper incisor can be located by
using measurement that relate dental portion of
maxilla to the skeletal portion
Line parallel to nasion
perpendicular through
point A
Distance from point A er
To the facial surface of
upper incisor is measured
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30. Vertical position :
The incisal edge of the upper incisor lies 2 –
3 mm below the upper lip at rest
Vertical position of the upper lip is best
determined at the time of clinical
examination
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31. Relating Lower Incisor To
Mandible :
Anteroposterior position :
Measurement of the facial
surface of the lower
incisor to the A – Pog line
Normal : 1 mm to 3 mm
anterior
A
Pog
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32. If
there is a discrepancy in Anteroposterior or
vertical positioning of the maxilla and the
mandible then modifications in this measurement
procedure is necessary
To
predict Anteroposterior position of the incisor
after functional or surgical intervention
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33. A second tracing of the mandible
and the incisor is made
The tracing is moved so that the
mandible is in the desired
position relative to the maxilla
A new A – Pog line is drawn
The incisor is expected to lie 1 – 2
mm anterior to the constructed
line
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34. Estimate the number of mm that the
mandible will be brought forward
relative to the maxilla at the end of the
treatment
Then a new point A is constructed the
same number of mm in the opposite
direction
Post treatment A – Pog line
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35. Vertical Position Of The Lower
Incisor :
Relating the lower incisor tip to the functional
occlusal plane
Evaluated on the basis of existing lower anterior
facial height
Excessive Curve of Spee…
LAFH is normal or excess – Intruded
LAFH is inadequate – Eruption of the
Molars
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36. Airway :
Upper pharynx
Width is measured from a point on the
posterior outline of the soft palate to the
closest point on the posterior pharyngeal
wall
Average : 15 - 20 mm
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38. Airway :
Lower pharynx
Width is measured from intersection of
the posterior border of tongue and the
inferior border of the mandible to the
closest point on the posterior pharyngeal
wall
Average : 10 – 12 mm
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40. Advantages :
Linear measurements rather than angles
Provides guidelines with respect to normally
occurring growth increments
The method is more sensitive to the vertical
changes
Easily explained to non specialist and lay
persons such as patients and parents
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