Download - Functional Appliances Mode and Action I & R
Functional Appliance
and
The Mode of Action
By :
Islam Yehia
Raghed Michael
Functional appliances
• They do not act primarily on teeth like
conventional appliances (springs, elastics)
• They transmits, eliminate or guide natural
Forces
• Natural forces that can be controlled by
functional appliances are: muscle activity
from the tongue and check, tooth eruption,
and growth and development
• The most favorable age for therapy
– 8-11 years for girls
– 10-13 years for boys
Why treat malocclusion?
• Possible pre-disposition to disease
• May lead to jaw dysfunction
(TMD, Speech, Mastication)
• Facial esthetics with psychological effects
• Single or multiple tooth damage
Indications for functional
Appliances
• Well aligned dental arches
• Posterior positioned mandible
• Non severe skeletal discrepancy
• Lingual tipping of mand. incisors
• Proper patient selection
History of development of
functional appliances
• Robin 1902- monobloc
• Andresen 1908- Activator
• Herbst 1934- Herbst
• Balters 1960- Bionator
• Bimler 1964 – Bimler
• Frankel 1967- Frankel
• Clark 1977-Twin Block
Historical biases of Europe and
America on functional appliances
European
• Functional approach most
biocompatible
• Mechanical force deemed
unbiologic
American
• European social system
excluded extensive fixed
appliance therapy
• Question of precision of results
Duration and timing of wear
• Functional appliance treatment
should be started before the
pubertal growth spurt.
• This is the time when the
mandible may exhibit increased
growth which may be influenced.
• Functional appliances should be
worn for at least 10-12 hours a
day.
Night Time
VS
Day Time
Growth
Theories
Scott’s
Cartilaginous
Growth Theory
Sitcher’s
Sutural Growth
Theory
Moss’s Functional Matrix Theory
Form
follows
function
Polyvinyle sialoxane bite registration material
Polyvinyle sialoxane bite
registration material
Wax bite material
preformed to arch shape
Activator
Woodside & harvold
activator
Herbst
Bionator
Activator facts
• Tooth borne passive appliance • Original design worn at night
• Large one piece of acrylic
• Teeth could be redirected during eruption
• Large vertical opening construction bite
• Could not speak or eat when worn
• Advances mandibular jaw
• The original andersen activator was designed with
angled flutes to guide the eruption of the molars for the
upper molars distally and the lower molars mesially as
they erupt
• New design
• Lingual flanges contribute to its action
• Upper cant erupt
• Lower free to erupt
• Rotation of occlusion and correction of class II cases
Displacement
springs
Bionater
•
Twin block
Frankel
Herbst Appliance ( a.k.a. the “shock absorber” or "Bite Jumper")
•correction of ant-post relationships of upper and lower jaws.
• encourages mandibular growth, eliminate extractions and surgical corrections with
headgears.
•The appliance is formed from a rod and tube (called the “shock absorber”) and actually
connects the upper and lower jaws.
• fully intraoraly and doesn’t interfere with function.
Herbst facts • Fixed to teeth
• Patient compliance not required
• Works 24 hours
• Less airway blockage
• Most popular type at present time in U.S.
Arms guide the lower jaw
forward to the ideal jaw
position
Upper Molars : Distalization
/Intrusion / Expansion
Upper Incisors : Retrusion /
Uprighting / Extrusion
Lower Molars : Mesialization /
Extrusion
Lower Incisors : Protrusion /
Intsusion
Reposition the Mandible
Jasper Jumper
MARA Appliance (mandibular anterior
repositioning appliance)
Correction of anteroposterior relationships of
upper and lower jaws.
Works by guiding the mandible forward with
occlusion.
Completely intraorally so
better compliance
and aesthetics.
Indications for the MARA
Ø The upper jaw is in good position and you
want to advance the mandible.
Ø It is desirable to inhibit maxillary anterior
growth and produce an increase in
mandibular length.
Ø You want to recapture a prolapsed disc.
Ø Adult cases, when lower jaw surgery is not
an option, needing a good compromise
Class II correction. While the result is
mostly dental, some mesial migration of the
fossa may occur.
THE END
Special thanks for
Assisst. Prof.
Amjad Al-Taki