Extraoral appliances

Question 1

Extraoral appliances

What are extraoral appliances?

Answer 1

• Mechanical orthodontic appliances w/ extraorally located anchorage=>
• Exert orthopedic forces on the teeth, dental arches, and jaws

Question 2

Extraoral appliances

What is orthodontic therapy?

Answer 2

• Correction of dentoalveolar malocclusion without any skeletal deviation=>
• Tooth movement alone

Question 3

Extraoral appliances

What is orthopedic therapy?

Answer 3

• Correction of skeletal imbalance=>
• Little or no tooth movement is desired

Correction of dentoalveolar malocclusion is of less importance

Question 4

Extraoral appliances

Orthopedic and orthodontic forces ranges

Answer 4

Orthopedic forces are heavier (1000-1300 g per side), while orthodontic forces range from 100-500 g.

Question 5

Extraoral appliances

Three approaches to managing a skeletal problem

Answer 5

1. Growth modification
2. Camouflage treatment
3. Surgical correction

Question 6

Extraoral appliances

Recommended force magnitude for orthopedic movement

Answer 6

• 400-600 g per side=>
• w/ maximum total of 2kg

Question 7

Extraoral appliances

What effect does high force have on tooth movement?

Answer 7

High forces produce hyalinization leading to undermining resorption, preventing tooth movement and allowing only orthopedic movement.

Question 8

Extraoral appliances

Effect of intermittent vs. continuous forces

Answer 8

• Intermittent forces produce skeletal change
• Continuous forces produce dental movement

Question 9

Extraoral appliances

How long should extraoral appliances be worn daily?

Answer 9

About 12-14 hours/day

Question 10

Extraoral appliances

What happens if the duration of force exceeds the optimum range?

Answer 10

It increases dental effects.

Question 11

Extraoral appliances

Which is less harmful to teeth and periodontium: intermittent heavy force or continuous heavy force?

Answer 11

Intermittent heavy force is less harmful.

Question 12

Extraoral appliances

When orthopedic appliances most effective

Answer 12

• Mixed dentition period=>
• Take advantage of prepubertal growth spurt

Question 13

Extraoral appliances

What should be done after the growth is complete?

Answer 13

• Treatment should be maintained
• Extraoral appliances only change expression of growth, not the underlying growth pattern.

Question 14

What are orthopedic appliances?

Answer 14

Appliances whose anchor is outside the oral cavity.

Question 15

What are the types of orthopedic appliances?

Answer 15

1. Headgear
2. Facemask

Question 16

Orthopaedic appliance classifications

Answer 16

1. According to direction of force
2. According to location of anchor unit:
3. According to jaw affected

Question 17

How are orthopedic appliances classified according to the direction of force?

Answer 17

1. Distal force
2. Mesial force

Question 18

How are orthopedic appliances classified according to the location of the anchor unit?

Answer 18

1. Cervical pull
2. Occipital pull
3. High pull (Parietal)
4. Combination pull

Question 19

How are orthopedic appliances classified according to the jaw affected?

Answer 19

1. Effects on the upper jaw
2. Effects on the lower jaw
3. Effects on both jaws together

Question 20

What is the most frequent orthopedic appliance for the upper jaw?

Answer 20

Headgears are the most frequent appliance among all the orthopedic appliances.

Question 21

What are the indications for using headgear?

Answer 21

1. In patients with excessive horizontal growth of the maxilla with or without vertical changes along with some protrusion of the maxillary teeth, reasonably good mandibular dental and skeletal morphology.
2. They are most effective in the prepubertal period.
3. Can also be used to distalize the maxillary dentition along with the maxilla.
4. Provide good anchorage.

Question 22

What are the components of headgear?

Answer 22

1. Face bow that redistributes the applied force
2. Force generating unit
3. Extraoral anchorage - head cap, neck strap
4. Intraoral support unit