Retention of a removable appliance

Question 1

4 elements of a removable appliance

Answer 1

4: - active components -retentive components -anchorage -baseplates

Question 2

what is the active part of a removable appliance?

Answer 2

palatal retractors, baseplate

Question 3

list the retentive components and what they are made from

Answer 3

3: -Adams clasp (posterior. 0.7mm, 0.6mm on deciduous/ premolars) -Southend clasp (anterior, 0.7mm) -Labial bow (reversed loop, anterior, 0.8mm) (baseplate made from acrylic resin)

Question 4

define retention

Answer 4

capacity of appliance to remain fixed in mouth

Question 5

List the component parts of an Adams clasp and what provides retention

Answer 5

Bridge

2 arrowheads (retention)

2 flyovers

2 tags

Question 6

what part of the adams clasp creates retention?

Answer 6

arrowheads

Question 7

what are the points of contact of the Adams clasp with the mouth?

Answer 7

3:

• end of arrowhead (x2)
• toe of tag end (x2)
• possibly in occlusion

Question 8

what is the consequence of
a) bridge too low

b) bridge too short
c) bridge too close to tooth
d) arrowheads too low

Answer 8

a) bridge too low: no room for adjustment
b) bridge too short: arrowheads flare out, not engaging undercuts
c) bridge too close to tooth: arrowheads too small, undercut not engaged
d) arrowheads too low: tissue trauma

Question 9

what is the ideal potition of

a) bridge
b) arrowheads

Answer 9

a) bridge: 2/3 up crown of tooth
b) arrowheads: should be slightly narrower than bridge

Question 10

consequence of flyover too high

Answer 10

interferes with occlusion

Question 11

tag ends too close together

Answer 11

baseplate may fracture

Question 12

size of wire types for different ortho appliances

Answer 12

adams clasp: 0.7mm wire (0.6mm on premolars)

southend wire: 0.7mm (anterior teeth)

labial bow: 0.8mm