Functional Appliance

Question 1

What are the types of functional appliances?

Answer 1

Myotonic: bulky appliance placed in mouth to posture mandible forward, stretching soft tissues after which growth and development take over, will result in increased lower anterior facial height and will reduce patient’s function (can’t talk or eat)

Myodynamic: fit into buccal/lingual vestibule and posture mandible forward, forcing patient to function in a protruded position, require a lip seal (can talk but can’t eat with them in)

Hybrid devices (Clark twin block): take components from both (can achieve normal function)
-Upper part over maxillary teeth, lower over lower anteriors
-70 degree Ramp causes posture forward
Herst appliance is another hybrid that is a rod and piston system (pt can open but can’t go side to side)–>efficient as non removable

Question 2

What is the main purpose of functional appliances?

Answer 2

Generate a class I relationship

Question 3

T/F functional appliances make mandible grow?

Answer 3

F

They make maxilla grow less, and may alter position of glenoid fossa

Question 4

What changes can functional appliances cause in teh mandible?

Answer 4

• Change direction of growth
• Neuromuscular adaptation can change form
• May increase the RATE of growth while wearing appliance but growth slows down after and will not increase beyond genetic potential

Question 5

What can you do to acrylic to further facilitate class II correction?

Answer 5

-Remove some over lower molars to selectively erupt them–>mesial inclination of eruption path helps forward movement

Question 6

What can you do to determine whether functional appliance would be effective on a patient?

Answer 6

Check if appearance improved by posturing md forward

Question 7

What are some controversies regarding functional appliances?

Answer 7

• No evidence of mandibular growth
• 70% affect dental, only 30% impact on bone growth (may as well use fixed)
• Early treatment sometimes shown to have no impact on later treatment
• 30% of cases improve spontaneously without treatment
• Good response only in the correct facial types

Question 8

What uncertanties are induced by studies re. effectiveness of functional appliances?

Answer 8

• No long term studies
• Can not get adequate control
• Often small sample sizes
• Landmark identification and tracing errors
• Practitioner’s skill
• Animal studies may not extrapolate to humans

Question 9

What characteristics does the ideal patient have for functional appliances?

Answer 9

• Short lower anterior facial height
• Slightly proclined upper centrals
• Retroclined lower centrals
• Deep overbite
• Under erupted lower molars
• Compliant
• Still growing