1. REMOVABLE ORTHODONTIC APPLIANCES (ROA), THEIR INDICATIONS AND CONTRAINDICATIONS by Dr. Wangui .K.

2. Objectives
Definition of ROA
Brief History of ROA
Mode of Action
Components of ROA
Indications & Contraindications of ROA

3. Definition: Appliances that can be inserted and removed from the mouth at will, by the patient.
History
Victor Hugo early 20th century used vulcanite bases
Crozat used precious metals i.e. gold for arch expansion

4. Action of removable appliances
Act by tipping the tooth around its centre of resistance.
Teeth that have their apex at the correct position are ideally suited for treatment with ROA.

5. Ineffective in bringing about bodily translation, derotation and uprighting due to the single point of contact of these appliances
Incorporation of bite planes enables intrution and extrusion of teeth

6. COMPONENTS OF ROA
retentive components
active components
base plate

7. Retentive Components
Clasps:
Adam’s clasp
Crozat clasp
Circumferential clasp
Jackson’s clasp
South end clasp
Ball end clasp

9. Requirements of clasps
Easy to fabricate & clean
Shouldn't impinge on soft tissues
Provide adequate retention
Deciduous and permanent dentition
No active forces causing unwanted tooth movement

10. Active Components
Bows
Springs
Screws
elastics

11. Bows
*Uses & Examples:
Short & long labial bow
Reverse labial bow
Split labial bow
Roberts retractor-severe overjet
Mills retractor
High labial bow with apron springs

12. Springs
Requirements:
Easy to fabricate and clean
Robust
Should not be easily dislodged
Force in required magnitude and direction
Active over a long period of time
Should fit easily in available space

13. *Uses & Examples:
Finger springs
Z spring
T spring
Coffin Spring
Canine retractors

14. Screws
Used to:
expand arch
Buccal lingual & mesio-distal tooth movement
Activated using a key
Elastics
Rarely used with ROA.
used for anterior teeth retraction
Base Plate

16. Contraindications of ROA
Expansion of narrow arches
Severe skeletal discrepancy
Treatment of Individual arches
Severe rotation
Bite correction
Upper & lower arch correlation treatment
Unilateral Crossbite
Bodily movement
Single malpositioned teeth
Severe crowding
Bad habits
Very dense bone

17. References
Orthodontic Art and Science S.I Bhalajhi
Orthodontic Pearls Eliakim Mizrahi
Adams: Removable Appliances Yesterday and Today American Journal of Orthodontics1969;