Functional Appliances Flashcards
Functional Appliances
Variety of appliances which alter the saggital and vertical position of the mandible
This repositioning generates muscular forces which result in orthodontic and possible orthopaedic changes
Classification
Fixed functional appliances
Removable functional appliances
Fixed appliances
Herbst appliance
Fixed twin block
Herbst Appliance
Piston mechanism each side
Attached to fixed appliance
Advantages:
+ Less cooperation required
+ More effective
+ Use simultaneously with FA
Disadvantages:
- complex design
- time consuming to fit
- more frequent breakage
removable appliance
CTB
Andresen activator
Medium opening activator
bionators (balters)
dynamax (bass)
functional regulator (frankel)
Theoretical adv of functional appliances
improve facial aesthetics
correct dental relationship
reduce the need for extractions
reduce the time needed for fixed appliance therapy
reduce chairside time
reduce incidence of trauma
reduce need for headgear
removable - facilitates plaque control
proven advantages of functional appliances
do produce a significant correct in the A-P dental relationship
do provide efficient anchorage reinforcement prior to FA treatment
allows for FT wear - thereby more effective than HG at correcting molar relationship
can be used during mixed dentition phase
can attach auxiliaries/expand upper arch etc
disadvantages of functional appliances
cannot produce detailed tooth movement
do not produce a clinically significant effect on skeletal bases
can cause excessive proclination of lower incisors
may cause AOB in patients with increased LAFH
demand high level of patient cooperation
advantages of CTB
well tolerated
full time wear possible
eating possible
versatile appliance e.g., elastics/sectional functional appliance
expansion of upper arch possible
can add headgear
can add fixed appliance
possible to secure CTB to FA
How do CTB work?
Forces arising from the facial soft tissues are source of main tooth movements.
Class I occlusion is achieved by…
Upper arch –> retrocline upper incisors/distal movement of upper molars
lower arch –> mesial movement of lower teeth/vertical movement of posterior teeth
What patients are suitable for functional appliances?
mild, uncrowded class II
first phase in more severe class II’s, second phase FA
anchorage reinforcement in Class II cases
interceptive tx –> early tx to reduce very large OJ
limitations and contraindications of functional appliances
poor cooperation
non-growing pts
timing of tx
individual tooth movements
high angle cases
variability of response
timing of tx - growth
age
height
hand-wrist radiographs
secondary sex characteristics
timing of tx - dental factors
can start functional tx in mixed dentition
time start of functional phase to allow progression straight into FAs
Aim in general to start functional treatment at 11/12 yers of age
Stages of tx ctb
assessment
imps and bite pres
fit appliance to take baseline measurements
review visits to review measurements
retention via night time wear and plan FA
Bite registration for Functional Appliances (CTB)
Estimate the amount of saggital advancement of mandible needed.
Select and try in ProJet jig.
Soften wax into horseshoe shape –> wax bite should be 2-3mm thicker than planned vertical opening
The softened wax bite and jig are placed against upper teeth
Wax bite removed from the mouth
The cooled wax bite is tried in again –> critical to ensure accurate fit against upper and lower teeth
Prescription – designing an appliance
Upper
clasp 4s and 6s
split baseplate and screw
labial bow
acrylic plates
Lower
lower incisor capping or ball clasps
clasp lower 4s +/- 6s
Acrylic blocks
Review visits
Assess co-operation
Measure overjet
Record molar relationship
adjust clasps as necessary
check/start expansion
update patient on progress
