The document discusses William B. Downs' analysis of variations in facial relationships and their significance in orthodontic treatment and prognosis, published in 1948. It outlines his study involving 20 individuals with clinically excellent occlusion, highlighting key cephalometric measurements and their implications for facial balance. The analysis includes advantages of graphical representations of cephalometric data, but notes limitations due to the study's focus on a homogenous racial group.

1. DOWNS
ANALYSIS
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2. Introduction
• “Variations in Facial Relationship: Their
Significance in Treatment and Prognosis”
• William B. Downs ( Aurora, Illinois)
• At the Graduate Department of Orthodontia,
University of Illinois, Chicago.
• First prize winner, Essay Contest of the
American Association of Orthodontia,1948.
• Published in American Journal of
Orthodontia, Oct., 1948 & reprinted in 1949
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3. Basic facial types
• Downs noted that the position of the
mandible could be used in
determining whether or not faces
were balanced.
• He recognized that facial profiles
could be retrusive or protrusive yet
still be harmonious in proportion.
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5. Variations in Facial Relationship: Their
Significance in Treatment and
Prognosis
W. B. Downs
1948www.indiandentalacademy.
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6. Purpose Of Study
• To determine the range of dental and
skeletal pattern within which one
might expect to find the normal.
• To discover whether any usable
correlation existed in such normals.
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7. Materials and Methods
• 20 individuals with clinically
excellent occlusion (12-17yrs)
• Equally divided in male and female
• Models
• Photographs
• Cephalometric &
• Intraoral roentgenogramwww.indiandentalacademy.
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9. • For the purpose of the study the head
is divided into cranium and face
• The face is further divided into upper
face
• Teeth & alveolar area
• Lower face or mandible
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10. Observations
• Skeletal pattern:-
1. Facial angle
2. Angle of convexity
3. Anterio posterior relationship of the
denture base
4. Mandibular plane angle
5. Y – axis
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11. Facial angle (82-950
)
Mean = 87.80
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12. Angle of Convexity (-8.5 to +100
)
Mean - 00
-
+
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13. A-B Plane (0 to -9)
Mean = -4.6
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14. Mandibular Plane angle
(17-280
)
Mean = 21.90
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15. Y-axis (53-660
)
Mean = 59.4www.indiandentalacademy.
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16. The teeth and alveolar
process
1. Cant of occlusion plane
2. Axial inclination of the upper and lower
incisor to each other.
3. Axial inclination of the lower incisor to
the mandibular plane.
4. Axial inclination of the lower incisor to
the occlusal plane.
5. The amount of protrusion of maxillary
incisor.
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17. Cant of Occlusal plane
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18. Axial inclination of the upper
and lower incisor to each other
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19. Axial inclination of the lower
incisor to the mandibular plane.
+7 to -8.5
Mean =+1.4
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20. Axial inclination of the lower
incisor to the occlusal plane.
+3.5 to +20
Mean = 14.50
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21. Protrusion of maxillary
incisors
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22. Polygonic interpretation of
cephalometric findings3
• “Wiggle” by Hellman in 1937.
• He used anthropometric measurements
of 62 males with normal occlusion
• It was developed by Vorhies & Adams
in 1951 which is also called as
“wiggle” that represents the large
group of cephalometric readings
graphically
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25. Advantages
1. Graphs offer effective means of comparing
values & expressing mathematical
relations.
2. Much time is lost arbitrating the angular
readings from a mathematical standard.
3. The value of serial study & interpretation
is more apparent.
4. Great aid in case presentation because the
parents may more adequately understand a
graphical description.
5. More comprehensive & impressive than
verbal description.www.indiandentalacademy.
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26. Shortcomings5
• Comparisons were made only with
patients with excellent occlusion &
facial proportions.
• Facial types are known to differ
racially and the study is limited to
white race.
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27. Indian cephalometric
norms 6
• By Dr. D. N. kapoor
• Sample size = 50
• 25 males 25 females
• 17- 25 yrs
• Lucknow Hindus
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28. Downs
82to 95o
-8.5 +10
0 to -90
17to 280
53 to660
1.5 to14
7 to -8.5
3.5to 20
130-150.5
-1 to +5
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29. Summary
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30. References
1. Downs, W. B , The Role of Cephalometrics in
Orthodontic Case analysis. Am. J. of Ortho. 38:162-
182.
2. Downs, W. B.: Variations in Facial Relationship:
Their Significance in Treatment and Prognosis, AM.
J. ORTHODONTICS 34: 812, 1948.
3. Jack. M. Vorhies, William Adams. Polygonic
interpretation of cephalometric findings Angle
Orthodontist 1951 : 194-197.
4.Downs, W. B. Analysis of Dentofacila profile. Angle
Orthodontist 1956 : 191-212.
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31. 5. William R Proffit. Contemporary
Orthodontics 4th edition; Mosby Elsevier
publication pg 174-176.
6. Indian Cephalometric Norms. Indian
orthodontic Society, Dental department
CMC Hospital Vellore.
7. Alexander Jacobson; Radiography
Cephalometry ;Quintessence Co,1995
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