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Orthodontic Retention Not Letting Go Padhraig Fleming. Episode 43. IOC 2020

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Hosted by
Farooq Ahmed

Padhraig takes us through the evidence of retention, his hierarchy  of stability and his technique of placing a bonded retainer

Classic paper of Little 1999

  • After treatment
    1. Post treatment relapse – greater in non-extraction cases
    2. Maturation changes
  • Little recommended indefinite retention

Overbite stability

  • Schutz-Fransson 2006 – less than 1mm of change long term
  • Padhraig argued vertical changes are due to loss of alignment of the lower anterior teeth, slipped contact points, lingually displaced incisor, free to overerupt.

 

Interdigitation

  • Pancherz 1982 – theorised stability with interdigitation
  • Oliver 2020 – only 10% of patients had relapse

Retention wear

  • Part time wear as effective as full time – possibly advantageous as less wear

Type of appliance

  • Littlewood Cochrane RV supports VFR over Hawley, but only assessed over 6 months

Retention regime long term

  • Al Moghrabi 4 year follow up study
    • Fixed Vs VFR
    • Irregularity fixed 0.8mm, VFR 2.4mm statistically significant
    • Wear – usually 5 hours less then prescribed
    • Long term wear: At 2 years less than 33% complaint

Periodontal outcomes

  • No difference in fixed Vs VFRs

Compliance app

  • No difference using App Vs no App – increase in 1 hour of wear.
  • When recommended full time wear: average patient 6-7 hours

Compliance has not been tested for the average patient – 60-70 years.

Complications

  • VFRs – reduce fracture by increasing to 0.9-1.5mm thick retainer
  • Fixed retainer – 30% breakage in 3 years
    • Tip to reduce fractures of bonded retainers change to flex tech
      • Twist flex: rigid wire – unlikely to fracture but force can propagates and creates tooth movement / fracture.
      • Flex tech: Less rigid, wont generate force, but can fracture. Padhraig places a large composite pad to reduce wire exposure.
      • Composite broad and shallow

 

Placement of retainer

  • Etch bond
  • Flowable on central
  • Use bond brush to adapt flex tech – place more composite
  • Continue from central outwards
  • Transbond flowable composite

 

Flemings hierarchy of stability

  1. AP correction stable
  2. Vertical: deep bite some relapse but minimal
  3. Transverse: relapse does occur, require use of more rigid retention
  4. Vertical: AOB biggest risk fo relapse: require active retention

Conclusion

Padhraig Fleming has increased the number of bonded retainers, and reduced the reliance of VFRs, focusing on interdigitation.

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