Orthodontic Appliances

• Removable appliances = orthodontic appliances that can be removed by the patient

  
• Advantages of removable appliances:

  • Can be removed for cleaning
  • Relatively cheap
  • Very useful for limited applications
• Disadvantages of/contradictions for removable appliances:

  • Removable (compliance)
  • Poor oral hygiene - will harbour plaque and cause caries
  • Limited tooth movements
  • Difficult/impossible
  • Bodily movement
  • Intrusion/extrusion
  • Rotations
  • Lower appliances poorly tolerated
• Most removable orthodontic appliances can only achieve a simple tipping movement; wire only contacts tooth in 1 place, therefore can only apply pressure in one place.

  
• Patient selection for removable appliances:

  • Well-motivated
  • Good oral hygiene
  • No active caries
  • Good cooperation - wear 24 hours a day including eating
• Coverplate:

  • Post open surgical exposure in attached gingivae
  • Design = palatal coverage, retention, space over exposure
  • Function = maintains dressing (Coe-Pak), aids pt comfort, and aids healing (stops gingivae growing back over area)
  • Maintained 10-14 days - not removed!
  • Removed and oral hygiene commenced
• Space maintainer:

  • Maintains space after early tooth loss - prosthesis/successor
  • Simple upper removable appliance
  • Retention - Adams clasps
  • Maintain space - stops
  • Possible replacement tooth
  • Fixed - band and loop
  • Contraindications = poor oral hygiene or want space closure

  
• Retainers maintain tooth position following orthodontic treatment (prevent relapse).

  
• Essix retainers/vacuum formed retainers:

  • Advantages:
  • Quick and cheap to produce
  • Good aesthetics
  • Less impact on speech
  • Effective - good for rotations
  • Disadvantages:
  • Not durable
  • Oral hygiene critical
  • Must not eat/drink whilst in situ
  • Easily lost
  • All GDPs should be happy to produce and fix Essix retainers

  
• Hawley retainers:

  • Acrylic baseplate, Adams Clasps, labial bow
  • Advantages:
  • More durable than Essix retainers
  • Allow settling
  • Good for maintaining expansion
  • Disadvantages:
  • Compliance
  • Not as well fitting (may allow relapse)
  • More expensive

  
• Fixed/bonded retainers:

  • Multistrand stainless steel wire or braided chain
  • Advantages:
  • Full time
  • Compliance
  • Good for rotations/movement of lower incisors
  • Disadvantages:
  • Breakage
  • Repair difficult
  • Overbite in upper
  • Oral hygiene difficult
  • May be used in addition to Essix retainer

  
• Retainers - patient instructions:

  • Must be worn indefinitely (consent)
  • If stopped, may need retreatement
  • Rotations/spacing/lower incisor crowding
  • Wear - dependent on malocclusion
  • Essix: nights only wear - more if tooth movement suspected (tight on insertion) - remove for eating/drinking
  • Hawley: full time wear 3/12 then nights
  • Diet/oral hygiene
  • Cleaning
  • Essix - soap/water/soft toothbrush
  • Problems with speech/saliva
• GDPs' role - retainers:

  • REALLY IMPORTANT
  • Impact of restorative work
  • Maintenance
  • Part of routine review
  • Long term 2-3 nights/week
  • Replacement - charge/fee - income
  • Bonded
  • Breakages - repair/remove/replace
• Active appliances:

  • Flat anterior bite plave - used in overbite reduction
  • Expansion appliance - used to "widen" maxilla

  
• Functional appliances = removable or fixed orthodontic appliances which use forces generated by the stretching of muscles, fascia and/or periodontium to alter skeletal and dental relationships
• When to use functional appliances:

  • Usually pts with Class II malocclusions
  • Posture mandible forwards
  • Rarely used for pts with Class III malocclusions
  • Hard to posture mandible back
  • Work by altering forces from soft tissues
• A twin block uses forces from facial muscles to:

  • Retrocline upper incisors
  • Procline lower incisors (unwanted)
  • Move upper teeth distally
  • Move lower teeth mesially
  • Capture favourable growth
  • Increase mandibular growth
  • Restrict maxillary growth
  • Condylar remodelling
  • Soft tissue effects

  
• GDP's role - functional appliances:

  • Prevention - need good oral hygiene/caries free dentition
  • Motivation
  • Difficult to wear
  • Better with 24 hr wear including eating
  • Appropriate referral
  • Requires active growth (Female 11-13 years, Male 12-14 years)
  • Class II skeleton
  • Overjet >6mm

  
• Fixed appliances = appliances which are attached to the teeth and so are capable of a greater range of tooth movements than a removable appliance

  
• Fixed appliances:

  • Advantages
  • Complex cases
  • Bodily movement of teeth - high standard
  • Compliance less of an issue
  • Doesn't affect speech
  • Well-accepted by pts
  • Disadvantages
  • Need very good oral hygiene
  • Diet restrictions (hard/sticky)
  • Cause root resorption
  • Distance
  • Existing resorption
  • Pipette-shaped roots
  • Need skill/training
• Components of fixed appliances = brackets, archwires, ligatures, and auxiliaries.