Headgear

Question 1

Define headgear

Answer 1

• Applying posterior directed forces to teeth and skeletal structures from extra oral force

Question 2

History of headgear

Answer 2

• Introduced in 1800’s but later abandoned as they thought Intra oral elastics would effect same
• 1940 introduced again after Cephalometric radiographs demonstrated that potentially adverse effect of elastics ( Extrusion of molars, Proclination of lower incisors)

Question 3

Headgear use

Answer 3

• Anchorage
• Traction

Question 4

Classification of headgear

Answer 4

• Distalising HG -
• Reverse (Protraction) HG

Question 5

Distalising HG

Answer 5

• Direction of elastic traction has distal component.
  -Most often used in crowded class 2 cases.

Question 6

Type of Distalising HG

Answer 6

• Occipital directed High pull
• Combination directed Pull
• Cervical directed low pull

Question 7

Reverse Protraction HG and component

Answer 7

• Means of applying ANTERIOR directed forces to the teeth and skeletal structures from an extra oral source.
• Chin up : Restrain forward growth of mandible by changing direction of force to downward and backward
• Forehead cap - Support
• Framework
• Intra oral splint/ device : for RME
• Elastics - Traction force to maxilla

Question 8

Components of HG

Answer 8

• Head cap/ neck strap
• Elastics
• Facebow e.g Kloehn bow ( Distalising HG)
• Face mask e.g Delaire type (Protraction HG)
• Removable / FA
• Chin cap
• Safety straps / mechanism

Question 9

Reverse pull headgear / Facemask
Type of Facemask

Answer 9

• Hickman
• Delaire
• Petit
• Turbinger

Question 10

Uses of Distalising HG
Dental and skeletal

Answer 10

Dental 70% - Reinforce Anchorage
- Distalise single or block of teeth
- To Extrude single or blocks of teeth ( low pull / cervical HG)
- To intrude single or blocks of teeth (High pull HG).
- Skeletal- small effect 30%
- Maxilla - Suppression of anterior growth 1-2mm over 10 yrs which is permanent even after treatment has been ceased.
- Mandible - Suppression of anterior growth - Retrusion of chin during chin cap treatment, but catch up mandibular growth may occur during pubertal growth .

Question 11

Which HG bring favourable outcome achieve Dento skeletal ?

Answer 11

• cervical HG

Question 12

Uses of Reverse protraction HG
Dental and skeletal

Answer 12

Dental - Protraction of single or block of teeth
Skeletal -
Maxilla - Enhancement due to accelerated growth. 2mm advancement of maxilla if rapid maxillary expansion (RME) and protraction HG is used in primary dentition.
Mandible - Suppression- effect is relevant than max

Question 13

Treatment timing

Answer 13

• before age of 8-10years after this age orthodontic movement overwhelms any SK changes
• Early use skeletally and dentally can be effective

Question 14

Factor influencing effect :Duration of force and duration for Head Gear

Answer 14

Duration:
- 10 - 12 hours Anchorage
- 12-14 hours for traction
- Magnitude force:
Anchorage -250- 300g per side
Traction - 400-500g per side Sk effect

Question 15

Factor influences effect
Centre of rotation

Answer 15

• Single rooted teeth - Centroid
• U6 - trifurcation ( split in root)
• Max - between roots of U45

Question 16

Centre of resistance

Answer 16

• This is point in body at which resistance to movement .
• The centre of resistance is on long axis of tooth between one third and half of the root length apical to alveolar crest.

Question 17

Resolution of forces

Answer 17

Horizontally-
- Force through centre of resistance - bodily movement
- Force above centre of resistance - distal root tipping
- Force below centre of resistance- Mesial root tipping

Vertically-
- above occlusal plane - Intrudes teeth
- below occlusal plane- Extrudes teeth

Question 18

Problems with HG

Answer 18

• Tooth related
• Patient related

Question 19

Problem with HG - Tooth related

Answer 19

• Unwanted tooth movement ( tipping, extrusion may cause clockwise rotation of mandible- Pt becomes more sk 2)
• lingual tipping of lower incisors can cause a clockwise rotation of mandible increasing LAFH and with chin up therapy.
• Forward movement of maxilla

Question 20

Problem with HG - Pt related

Answer 20

• Pt compliance - Many pt over estimated wear. HG calendar has been shown increase wear of 2.6hours/day
• Biological variability
• Extra/ Intra oral soft tissue injuries
• Pain
• Difficulty with insertion
• Nickel allergy

Question 21

Safety feature in HG

Answer 21

-BOS recommends 2 safety features together to use
- Safety face bow and release mechanism ( Snap away elastics mechanism) together.
E.g. Masel safety strap, snap release system ( to prevent recoil injuries)
- Written instructions must be given to pt advising them not to wear it if it’s not fitting, removing or of it disengages while they are asleep.
- Seek medical advice if injury should occur.
- Infraorbital injuries may be asymptomatic initially but may exacerbated later can even lead to Cavernous sinus thrombosis.

Question 22

Alternative

Answer 22

• TAD
  Less anterior tooth retraction and more Anchorage loss with HG compared to TAD’s