TWEED’S ANALYSIS

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

www.indiandenta...
Background
• In 1930, with the death of Dr. Angle
• the introduction of the cephalometric
headplate by Dr. Broadbent,

www...
Charles H Tweed (1895~1970)
• Dr. Tweed
established the
diagnostic facial
triangle
• Based primarily on
deflection of
mand...
Planes Used for Tweeds Facial Triangle

Frankfort Horizontal Plane

Long Axis of
Lower Incisor

Mandibular plane

www.indi...
Frankfort Horizontal Plane
• Adopted at 13th German Congress of
Anthropologists – the Frankfort Agreement
at Frankfort am ...
Frankfort Horizontal Plane
• A horizontal plane represented in the
profile by a line between the lowest point
on the margi...
Mandibular plane
• Tangent to the lower border of the
mandible

www.indiandentalacademy.com
Angles of Tweeds Facial Triangle

www.indiandentalacademy.com
Angles of Tweeds Facial Triangle
Variable

Mean
Value

Range

Frankfort Mandibular
plane Angle (FMA)

250

160-350

Inciso...
Objectives
• Determines the position the lower incisor
should occupy at the end of treatment
– Useful information for trea...
• People agreed that extraction was often
necessary.
• Tweed’s reasons for extraction seem to
have prevailed

www.indiande...
When extraction is done, one is
inevitably reminded of Newton’s
third law
Newton’s third law
“For every action,
there is a...
Newton’s Law in Orthodontics
• In orthodontics this means that when
retracting front teeth, one will be faced
with the pro...
Anchorage & Anchorage
Preparation
• The minimization of such force is called
“Anchorage”
• Dr. Tweed introduced en-masse
a...
Determining Growth Pattern
• When FMA<25
– Horizontal Growth Pattern

• When FMA>25
– Vertical Growth Pattern

www.indiand...
Prognosis???
 If FMA 160 to 280

PROGNOSIS IS GOOD
at 160 IMPA should BE 900+50 = 950
0
0
at 25 IMPA should be 90
at 280 ...
Prognosis???
• If FMA 280 to 350

PROGNOSIS IS FAIR
at 28 0 IMPA should be 90 0-95 0
at 35 0 Extraction necessary in major...
Prognosis???
• If FMA above 350

PROGNOSIS IS BAD
• Extraction usually complicates the
problem
• Tweed stressed the import...
Thank You
Qu
Any
•

ns??
estio

www.indiandentalacademy.com
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Tweed’s analysis /certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in

continuing dental education , training dentists

in all aspects of dentistry and offering a wide

range of dental certified courses in different

formats.

Indian dental academy provides dental crown &

Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit

www.indiandentalacademy.com ,or call
0091-9248678078

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Tweed’s analysis /certified fixed orthodontic courses by Indian dental academy

  1. 1. TWEED’S ANALYSIS INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Background • In 1930, with the death of Dr. Angle • the introduction of the cephalometric headplate by Dr. Broadbent, www.indiandentalacademy.com
  3. 3. Charles H Tweed (1895~1970) • Dr. Tweed established the diagnostic facial triangle • Based primarily on deflection of mandible as measured by FMA and position of the lower incisors www.indiandentalacademy.com
  4. 4. Planes Used for Tweeds Facial Triangle Frankfort Horizontal Plane Long Axis of Lower Incisor Mandibular plane www.indiandentalacademy.com
  5. 5. Frankfort Horizontal Plane • Adopted at 13th German Congress of Anthropologists – the Frankfort Agreement at Frankfort am Main , 1882 • Finally accepted by the International Agreement for the Unification of Craniometric and cephalometric Measurements in Monaco, 1906 www.indiandentalacademy.com
  6. 6. Frankfort Horizontal Plane • A horizontal plane represented in the profile by a line between the lowest point on the margin of the orbit to the highest point on the margin of the auditory meatus • Tweed took the Porion as a point 4.5 mm above the geometric center of the mechanical ear rods www.indiandentalacademy.com
  7. 7. Mandibular plane • Tangent to the lower border of the mandible www.indiandentalacademy.com
  8. 8. Angles of Tweeds Facial Triangle www.indiandentalacademy.com
  9. 9. Angles of Tweeds Facial Triangle Variable Mean Value Range Frankfort Mandibular plane Angle (FMA) 250 160-350 Incisor Mandibular Plane Angle (IMPA) 900 850-950 Frankfort Mandibular Incisor Angle (FMIA) 650 600-750 www.indiandentalacademy.com
  10. 10. Objectives • Determines the position the lower incisor should occupy at the end of treatment – Useful information for treatment planning – Planning of Extraction • Prognosis of treatment result www.indiandentalacademy.com
  11. 11. • People agreed that extraction was often necessary. • Tweed’s reasons for extraction seem to have prevailed www.indiandentalacademy.com
  12. 12. When extraction is done, one is inevitably reminded of Newton’s third law Newton’s third law “For every action, there is an equal and opposite reaction.” www.indiandentalacademy.com
  13. 13. Newton’s Law in Orthodontics • In orthodontics this means that when retracting front teeth, one will be faced with the problem of having to minimize the tendency of the posterior teeth to move forward www.indiandentalacademy.com
  14. 14. Anchorage & Anchorage Preparation • The minimization of such force is called “Anchorage” • Dr. Tweed introduced en-masse anchorage preparation www.indiandentalacademy.com
  15. 15. Determining Growth Pattern • When FMA<25 – Horizontal Growth Pattern • When FMA>25 – Vertical Growth Pattern www.indiandentalacademy.com
  16. 16. Prognosis???  If FMA 160 to 280 PROGNOSIS IS GOOD at 160 IMPA should BE 900+50 = 950 0 0 at 25 IMPA should be 90 at 280 IMPA should be 900-50 =850 www.indiandentalacademy.com  Approximately 60% of malocclusion have 0 0
  17. 17. Prognosis??? • If FMA 280 to 350 PROGNOSIS IS FAIR at 28 0 IMPA should be 90 0-95 0 at 35 0 Extraction necessary in majority of cases IMPA should be 80 0 -85 0 www.indiandentalacademy.com
  18. 18. Prognosis??? • If FMA above 350 PROGNOSIS IS BAD • Extraction usually complicates the problem • Tweed stressed the importance of the FMIA angle recommending that it be maintained at 65° to 70° www.indiandentalacademy.com
  19. 19. Thank You Qu Any • ns?? estio www.indiandentalacademy.com

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