Functional appliances

Question 1

What do functional appliances do?

Answer 1

Change position of mandible - open and forwards
Stretch muscles - apply forces to bone and teeth
Use growth

Question 2

How do functional appliances work? What does this mean?

Answer 2

Open the bite up
Bring mandible forwards and downwards to exert forces on the hard and soft tissues = maximises mandibular growth and encourages dento-alveolar changes to camouflage the malocclusion
Applies forces to teeth and bones - condyle out of glenoid fossa
= cannot use for class III pts as jaw cannot move any further back

Question 3

When are functional appliances used?

Answer 3

Class II div 1 incisors with increased overjet
Class II molars
Actively growing

Question 4

Skeletal pattern assessment consists of?

Answer 4

Clinical assessment - assess visually, posture test
- Pt sitting upright, look at profile
- Posture test - bring mandible forwards
Cephalometric analysis

Question 5

What is needed for functional appliances to be successful?

Answer 5

Pt keen, motivated

Dentist enthusiastic and experienced

Question 6

When to avoid functional appliances?

Answer 6

Non-motivated pt
Class I molar relationship
High MMPA (maxillary mandibular plane angle)

Question 7

When is the ideal time for a functional appliance?

Answer 7

Depends on stage of development;
- Dental - late mixed/permanent dentition
- Emotional - motivation
- Physical - height (growing)
= Rapid pubertal growth is the most ideal time (10-12 yrs girls, 11-13 yrs boys)

Question 8

How to measure growth?

Answer 8

Height curve - standing height - skeletal growth

Velocity curve - rate of growth per yr

Question 9

List the types of functional appliances

Answer 9

Twin blocks
Activators;
- Medium-opening activator
- Andresen
- Harvold
- Bionator
Frankel

Question 10

Twin block appliance features?

Answer 10

Separate upper and lower appliance - blocks fit together which pushes the mandible forwards
Removable functional appliances
Worn 24hrs except sports and cleaning
Midline screw in upper

Question 11

Advantages of twin block appliances?

Answer 11

Aesthetic
Pt can move mandible
Robust
Can expand upper arch/reactivate
Integrate with fixed appliances - at same time, following twin blocks

Question 12

Advantages of opening activator?

Answer 12

Lower posterior teeth free to erupt (can help correct increased OB)
One block

Question 13

Frankel appliance features?

Answer 13

Soft tissue borne - wires hold the plastic in place that holds the soft tissues
Shields alter the soft tissue balance
Difficult to repair - not as robust
Difficult to wear

Question 14

What are the effects of functional appliances?

Answer 14

Dental effects;
- Upper labial segment retroclines
- Lower labial segment proclines
Skeletal effects
- Controlled eruption of lowers into class I

Skeletal effects;

• Forward movement of mandible
• Inhibit normal forward growth of maxilla

3/4 of func applaince effects due to dento-alveolar
1/4 skeletal effects