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INDIAN DENTAL ACADEMY
Leader in continuing dental education
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2. PG Retraction Spring
• Poul Gjessing- 1985
• Controlled tipping- uprighting-
over long periods of activation
• Net result- bodily movement
• Preformed-0.016 x 0.022 SS
• Double ovoid apical helix- 10mm
• Smaller occlusally placed helix-
activation further closes the loops
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3. o Segment of circle in distal leg- eliminate undesirable
moments acting on 2nd
premolar
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4. PG Retraction Spring
• For canine retraction- 160gms
• Double helix separated by 1mm
• Resist tipping & rotational tendencies
-not correct rotation or extreme
inclination
• Leveling of buccal segment –must
• Activation- every 4 wks
• Each activation- 1.5mm of controlled
movement www.indiandentalacademy.com

5. PG Retraction Spring
• Controlled incisor retraction
• Auxiliary molar tube- lateral incisor
bracket
• Twist anterior leg 90˚ - 3mm in front
of vertical helix- fit in vertical tube of
lateral bracket
• Intrusive force- 12-25gms each side
• Estimated treatment time- 5-6
months on an avgwww.indiandentalacademy.com

6. • Used for retraction of both canine and
incisors
• Incisor segment intrusion- 20-25gms/side
• Mesial and distal extensions angulated to
build in residual moments
• Vertical forces in the posterior segment
counteracted by forces of occlusion
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7. Opus loop
• Described by Raymond E. Siatkowski
• M/F for translation
– Individual teeth: 7.1-10.2 mm
– Groups of teeth: 8.0-9.1 mm
• Most closing loops M/F 4-5 mm
• To achieve net translation, add
residual moment
– Gable bends anterior & posterior
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8. Opus loop
Disadvantage of gable bend
• Tipping- translation- uprighting
• Correct magnitude of residual moments
are difficult to achieve
• Changing areas of stress distribution in
the pdl may not yield most rapid, least
traumatic method of space closure
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9. Opus loop
• Study: design and verify loop design
capable of delivering M/F inherently
without adding residual moments.
• Castigliano’s Theorem: to derive of M/F
ratio in terms of loop geometry.
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10. Standard Opus 70 loop
M/F ratio on both the ends is equal
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