Functional Appliances

Question 1

Often used in

Answer 1

Class II (–> Class I)

Question 2

FAs change the skeletal pattern by adjusting…

Answer 2

Position of the mandible
Open
Forwards
Encourage condyles to move out of glenoid fosse to promote growth

Question 3

FAs stretch … by …

Answer 3

stretch muscles by applying forces to bones and teeth

Question 4

How does the position of mandible change

Answer 4

Bite is opened and jaw brought forward

Question 5

Used on who? - twin blocks

What kind of growth

Answer 5

Class II Div I incisors with increased overjet
Class II molars
Actively growing

Question 6

Aetiology of need for FA

Answer 6

86% mandibular retrusion

Question 7

Assessment of skeletal pattern - methods

Answer 7

Clinical

Cephalometric analysis

Question 8

Clinical assessment

Answer 8

Patient sitting upright
Look at profile
Bring mandible forward for posture test - instant improvement?

Question 9

Cephalometric analysis involves measurement of?

ANB > 2 ?

Answer 9

Involves MMPA measurement

ANB > 2 means lower jaw is set back

Question 10

Successful treatment requires

Answer 10

Patient motivation
Dentist enthusiasm and experience
Full time wear - overjet can be reduced in 9 months

Question 11

Avoid FAs for

Answer 11

unmotivated patients
class I molar relationship
high MMPA - suggests open bite

Question 12

Ideal timing depends on…

Answer 12

Stage of development
Dental - need at least first premolars through for fitting
Emotional status
Physical status

Question 13

Measurement of standing height is plotted on

Answer 13

Height curve

Velocity curve

Question 14

Peak growth occurs at ages

Answer 14

10-12 girls

11-13 boys

Question 15

Which appliance to use?

Answer 15

Twin block - easier to get used to
Activators
Frankel

Question 16

Twin block function and indication

Answer 16

Separate upper and lower
Midline screw to draw mandible forwards
Blocks fit together

Question 17

Advantages of twin block

Answer 17

Aesthetic
Full time wear
Patient can move mandible 
Can expand upper arch and widen
Integrate with fixed appliances at same time

Question 18

Medium opening activator function and placement

Answer 18

Covers anterior lower teeth
Means lower posterior teeth are free to erupt which can help correct increased overbite
Cribs are fitted 64/46

Question 19

Fixed functional appliance

Answer 19

Herbst

Fragile

Question 20

Frankel appliance features

Answer 20

Soft tissue borne

Hold soft tissues away and shields alter soft tissue balance

Question 21

Mode of action of FAs - different systems affected

Answer 21

Dental
Skeletal - movement exerts forces on soft and hard tissues
Soft tissues
Muscular

Question 22

Dental mode of action of FAs

Answer 22

Opening bite so mandible moves downs and forwards
Some retroclination of upper incisors
Some proclamation of lower labial segment
Controlled eruption of lowers into class I

Question 23

Skeletal mode of action of FAs

Answer 23

Forward movement of mandible
Headgear inhibits normal forward growth of maxilla
Mainly dento-alveolar
Maximises mandibular growth and encourage dente-alveolar changes to camouflage the malocclusion

Question 24

Further reading

Answer 24

Introduction to orthodontics 4th ed
chapter 9 - class II div I
Chapter 19 - functional appliances