Limitations and current uses of removable appliances

Question 1

3 problems of just tipping teeth

Answer 1

• aesthetic
• dental health
• occlusal fit

Question 2

why should removable appliances not be used in lower arch 3

Answer 2

• less undercut for retention
• less buccal sulcus
• tongue limits lingual space for springs

Question 3

what type of movement do removable appliances do to teeth

Answer 3

tipping

Question 4

4 directions tooth movement can be attained using removable appliances.. what does this depend on

Answer 4

mesio-distal (buccal segments)
labio-lingual (class II)
labio-lingual (class III)
mesio-distal (labial segments)
teeth must be angled a lot in the other direction to begin with

Question 5

how does movement produced by a fixed appliance differ t a removable appliance

Answer 5

moves whole tooth, eg by moving centre of resistance

Question 6

7 limitations of removable appliances

Answer 6

• tipping (not rotation/whole tooth movement)
• upper arch only
• cannot use inter-arch elastics
• imprecise
• cannot correct rotations
• no multiple tooth movements (impractical)

Question 7

7 current uses of removable appliances

Answer 7

• space maintenance (keeps space open eg after extractions)
• retainers
• tooth crosses over the bite
• bite opening
• expansion
• other simple tooth movements
• functional appliances

Question 8

6 advantages of removable retainers

Answer 8

• all teeth can be retained
• partial withdrawal possible
• less dental health hazard
• OH
• missing teeth can be replaced
• responsibility of the pt –> less appointments etc

Question 9

4 disadvantages of removable retainers

Answer 9

• cannot rotate teeth
• cannot fix anterior diastemas
• cannot alter vertical tooth position (move tooth up/down)
• need to be worn (pt dependent)

Question 10

other name for vacuum formed retainers

Answer 10

pressure formed retainers

Question 11

where are Z/T springs used

Answer 11

Z springs: push anterior teeth forward, fits in cingulum

T spring: push premolars buccally

Question 12

how is bite opening achieved using removable appliances

Answer 12

anterior/posterior bite planes (bits of plastic attached to baseplate to stop opposing teeth coming together)

Question 13

3 advantages of the acrylic baseplate

Answer 13

• can provide anterior and posterior biteplanes
• can accommodate a screw
• gives anchorage from palate

Question 14

3 functions of screws

Answer 14

• distal movement (unilateral/bilateral)
• arch expansion
• anterior crossbite correction

Question 15

name a type of removable appliance that attaches to both upper and lower arches

Answer 15

twin-block functional appliance

Question 16

function of functional appliances

Answer 16

reduce overet

Question 17

5 ways to tell if pt is wearing appliance

Answer 17

• good speech (if they have bad speech, they obv don’t wear it much)
• palatal gingivitis
• wear facets on acrylic
• springs passive
• confident removal and insertion

Question 18

define anchorage

Answer 18

resistance to unwanted reciprocal forces