HEAD GEAR

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HEAD GEAR

• DR. ABDUL JABBAR

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• Means of applying posterior directed forces to
  teeth and skeletal structures from an extra oral
  source

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• Headgear
• Introduced in late 1800s
• Abandoned as it was thought that intra- oral
  elastics would be as effective
• Reintroduced in 1940s after cephalometric
  developed

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Mechanism of action

• Growth modification by changing the pattern of
  bone apposition at the sutures
• CL II correction is obtained as the mandible
  grows forward normally while maxillary growth is
  restrained
• Favorable mandibular growth is a must for CL II
  correction with HG use

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• Force is generated by head cap or neck strap
  through
• springs
• Elastic bands

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• Force is delivered to the teeth by
• Face bow
• J Hooks

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classification

• Distalising HG direction of elastic traction
  has a distal component
• Types Occipital directed ( high) pull
• Combination pull
• Cervical directed (low) pull
• J-hook HG
• Asymmetric HG
• HG to mandible

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• High Pull Headgear
• Skeletal Class II with prognathic maxilla
• High Angle case
• Growing ages
• Straight Pull Headgear
• Skeletal Class II with prognathic maxilla
• normal Angle case
• Growing ages
• Cervical Pull Headgear
• Skeletal Class II with prognathic maxilla
• Low Angle case
• Growing ages

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High pull HG
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Combination pull HG
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Low pull HG
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J Hook HG
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1. Single pull to maxillary dentition
2. Attachment of the J hooks to both maxillary and
   mandibular dental arches.

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Asymmetric HG
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Components

• Head cap / neck strap
• Elastics
• Face bow (Inner bow, outer bow and U loop)

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Uses dental

• Anchorage
• Distalisation single or blocks of teeth
• Intrusion -- single or blocks of teeth
• Extrusion
• Asymmetric movement

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Uses skeletal

• growth modification
• maxilla --- suppression which is permanent even
  after treatment has ceased
• mandible --- suppression, retrusion of the chin
  during chin cap treatment.however catch-up
  mandibular growth may occur during or after
  pubertal growth period

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Factors influencing effect

• Direction of force
• Duration of force
• Magnitude of force
• Centers of rotation

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Duration and magnitude of force

• Orthopedic effect
• Principle higher forces for comparatively
  smaller duration
• 12 ---16 oz or 350-----450 gm / side
• 10 ---12 hrs

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Duration and magnitude of force

• Tooth movement
• Principle smaller forces for longer duration
• 100 --- 200 gm / side
• 14 --- 16 hrs
• Anchorage
• 250 --- 300 gm / side
• 10 hrs min.

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• Magnitude of force is determined by a
  Strain-gauge
• Spring loaded assembly comes with a built-in
  force indicator

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FORCE MEASURING DEVICE
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Centers of rotation

• Single rooted teeth ----- centroid
• 6_ ----- trifurcation
• Maxilla ----- b/w roots of 45

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Resolution of forceshorizontally

• Force thru center of resistance ----- bodily
  movement
• Force above center of resistance ----- distal
  root tipping
• Force below center of resistance ----- mesial
  root tipping

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Resolution of forcesVertically

• Above occlusal plane ----- intrudes teeth
• Below occlusal plane ----- extrudes teeth

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Problems with HGTooth- related

• Unwanted tooth movement
• Tipping
• Extrusion of 6_ may cause clockwise rotation of
  mand. Pt. Becomes more CLII
• Buccal rolling of 6_ with high pull HG
• Cross bite on side of movement with asymmetric HG
• Lingual tipping of lower incisors, clockwise
  rotation of mand. increased LAFH with chin cup
  therapy
• Root resorption possibly with J hook HG

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Problems with HGPatient related

• Co-operation
• biological variability
• growth may be unfavorable
• Extra / intra-oral injuries
• Pain
• Difficulty with insertion

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• Assessment of patient compliance at every visit
• Check for signs of use intra orally as well as
  extra orally
• Hand out Time-sheets for record of wear
• Offer reward

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• Extra oral injuries include injuries to eyes ,
  eyelids, nose etc.
• Most common are eye injuries
• Catapult type of injury very common while playing
• Disengagement of face bow during sleep

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Safety

• No single safety HG is best
• Should use safety face bow and release mechanism
  together
• Written instructions must be given to patient
• Risks involved should be explained
• told to seek medical advice if any problem arises

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• THANK YOU