Retention Flashcards
What is retention?
Holding of teeth following orthodontic treatment in treated position for a period of time necessary for maintenance of the result
Why do we need to retain?
Widening of the periodontal ligament
Disruption of the collagen fibres
Takes time to reorganise and reset the periodontal ligament
How long does it take periodontal ligament fibres to reorganise after orthodontic treatment?
3-4 months
How long does it take collagen fibres to reorganise after orthodontic treatment?
4-6 months
How long does it take for elastic supracrestal fibres to reorganise after orthodontic treatment?
1 year
How long should we retain?
Standard retention protocol-
- 0-3 months full time
- 9-12 months part time
- lifetime wear to maintain occlusion achieved at deboned/titrate retention
What are the ideal properties of a retainer?
Keep each tooth in its new position Should be strong enough Good aesthetics Facilitate plaque control Allow settling to occur Be removable
What cases don’t require retention?
Correction of anterior crossbite if adequate overbite at end of treatment
Correction of posterior crossbites if adequate positive contact and no excessive tipping
Interceptive orthodontics
What are the types of removable retainers?
Hawley Vacuum formed Wraparound Barrer-type Activators
What are the types of fixed/permanent retainers?
Coaxial wire (round) Coaxial wire (rectangular) Thick SS wire bounded to canines only
What are in the indications for a removable Hawley retainer?
Historical To carry Pontic teeth (hypodontia cases) To allow settling To maintain transverse dimensions To carry a biteplanes Can allow for tooth eruption
What are the indications for vacuum formed retainers?
Default choice for most orthodontic retention
To retain all types of irregularity
It’s suitable if there’s concerns
As an adjunct to a fixed retainer
What is the protocol for VFRs?
1-3 months full time wear
9-12 months part time wear (every night)
After 12 months, continue with regular night time wear on a indefinite basis
Replace if problems
What’s the process for providing VFRs?
Debond as required (removing all composite)
Record an impression in the clinic and write a prescription
Fabrication in the lab
Fit in the clinic (usually the same day)
What is the fabrication process of VFRs?
Impression/lab prescription
Cast model
Name model
Block out any undercuts as appropriate
Turn on heating element of vacuum forming machine
Select blank- copolyester resin and place jig on machine
Heat the blank until it drops by approx 10mm/turn on vacuum/drop jig with blank into model
Allow to cool
Trim blank using bench-top trimmer and cutting disc 2-3mm past gingival margin/leave more palatally and lingually
Tidy flash from margins using stone