functional appliances Flashcards
What is a functional appliance?
Growth modification
Alters muscle forces again teeth and craniofacial skeleton
Ideally during pubertal growth phase- late mixed to permanent (girls 10-12, boys 12-14)
Tissue/tooth borne
Removable/fixed
Often 2 phases of tx (fixed afterwards)
Who is suitable?
Motivated
Good OH
Growing w pubertal growth spurt
Early tx in mixed dentition only eg. Bullying/trauma
Moderate to severe skeletal problems eg class II div 1/2
Pts w low/average angle
What do we want to achieve?
Reduce OJ
Reduce OB
Class I canines
Class I molar
Expand for CB
Eliminate soft tissue causes eg lip trap
Need to overcorrect as there will be relapse
What are the types?
Clarke twin block
Frankel
Other activators
How does the Clarke twin block work?
1. Alter soft tissue environment
2. Stretch the muscles of mastication
3. Cause dentoalveolar changes via tipping (70%)
4. Skeletal change- transient (30%)
What are the dentoalveolar changes?
Maxillary-
Distal tipping of molars
Retroclination of upper incisors (10 degrees)
Mandibular-
Mesial and vertical eruption of molars
Proclination of lower incisors (5 degrees)
What is a Frankel?
Tissue borne
Mono block
Class II/III correction
How does a Frankel work?
Alters soft tissue environment and uses bows and shields for retro/proclination
What are other activators?
Bionator, MOA
Loose fitting mono lock
Posture mandible forward w lingual extension of acrylic
What are the advantages and disadvantages of removable functionals?
Remove for cleaning
Easy to modify/adjust
Allows OB reduction
Relies on compliance
Difficult to tolerate
Can’t eat w monoblocks in
Can get broken/lost when not in mouth
What are types of fixed functionals?
Herbst- custom, telescopic afk from upper molar to lower premolar band
Forsus- spring attaches from upper molar tube to archwire in premolar area
What are the advantages and disadvantages of fixed functionals?
Reduces reliance on pt compliance
Breakages more complicated and common
Breakages more costly
What are the stages of producing a Clarke Twin Block?
Intra/extra oral photos
Alginate impressions
Postures bite w wax w 5-8mm gap between premolar cusps
Fit twin block
Review after month (start expansion if needed)
Review every 8-10 weeks +/- activation
9-12 months overall
Aim to overcorrect
May see lateral OB
Review need for extractions
What are twin block instructions/advice?
Wear 24hrs but take out to clean, for contact sports, playing instrument
Keep teeth together at all times
Will affect speech so practice
More saliva in first week
Can cause ulcers- can give wax
How do you know if the pt has been wearing the TB?
No lisp or drooling
Can place/remove easily
Slight wear and tear
Indentations of block on palate
What is being checked at each session?
OJ
OB
Canine and molar relationship
Reverse OJ
Can reactivate if necessary
Why might there be no improvement?
Issue w compliance
Issue w design/fit
Stopped growing/unfavourable growth
What happens after TB therapy?
Review need for extractions
TRANSITION into fixed appliance- 3 months or so-
Night time wear for 3 months
Clip over bite plane (upper removable, acrylic, plinth clasps on 6s, bite plane 3mm below upper incisors, 70 degrees)
Early use of class II elastics
FIXED- 12-18months
What do twin blocks fail?
20-30% fail
Due to compliance
Avoid by-
-incremental advancement
-good explanation/consent
-motivation
What skeletal patterns are suitable for TB?
Class II moderate to severe
What components retain the TB?
Adam’s cribs on 4s and 6s
Ball ended clasps on lower incisors
4s= 0.6mm SS
6s= 0.7mm SS
How much proclination of lower and upper incisors result from a twin block?
5 degrees lower
10 degrees upper
