Myofunctional appliances

1. Basic Concepts

2. Definition
 Functional appliances are loose removable appliances
designed to alter the neuromuscular environment of
the orofacial region to improve occlusal development
and/or craniofacial skeletal growth.
 -Moyers

3.  Functional appliances are appliances which alter the
the posture of the mandible ,holding it open or closed
and forward or backward.
 -Proffit

4. Basis of functional appliance
treatment
 A ‘ new pattern of function ’ dictated by the appliance
leads to the corresponding ‘new morphologic pattern’.

5. Functional jaw orthopedics
 Forces generated from the muscles when the mandible
is held forward (functional forces) indirectly produce
growth modulation and bring about changes in jaw
bones and hence the term ‘functional jaw orthopedics’.

6. Treatment principles
 Force application-Compressive stress and strain act on
the structures involved and result in a primary
alteration in form with a secondary adaptation in
function.

7.  Force elimination-This principle involves the
elimination of abnormal and restrictive environmental
influences on the dentition thereby allowing optimal
development thus function is rehabilitated with a
secondary change in form

8.  All functional appliances are assemblies of a few
simple components. These components produce
skeletal and dentoalveolar changes by acting on the
following;
 Eruption (bite planes)
 Linguofacial muscle balance (shields or screen)
 Mandibular repositioning (Construction or working
bite).

9. Action of functional appliaces
 Orthopaedic changes
 -Accelerating the growth in the condylar region
 -Remodelling of the glenoid fossa
 -They can change the direction of the growth of the
jaws
 -They can be designed to have a restrictive influence
on the growth of the jaws.

10.  Dentoalveolar changes-They can bring about
dentoalveolar changes in the saggital,transverse and
the vertical directions.
 -Most functional appliances allow the upper anteriors
to tip palatally and lower anteriors to tip labially.
 -Transerverse plane- Expansion-shielding buccal
musculatures away or by incorporating screws in
them.

11.  Vertical plane- Allow selective eruption of teeth.
 Muscular changes-Improve the tonocity of the
orofacial musculature.

12. Classification
 I-Tooth borne active appliances
 - Tooth borne passive appliances
 II-Myotonic appliances
 - Myodynamic appliances
 III-Removable functional appliances
 -Fixed functional appliances.

13.  Group I appliances
 Group II appliances
 Group III appliances

14.  Tooth borne passive appliances-They have no intrinsic
force generating components such as springs or
screws.They depend on the soft tissue stretch and
muscular activity to produce the desired treatment
result.
 Activator,bionator

15.  Tooth borne active appliances.They include
modifications of activator and bionator that include
expansion screw and other springs to provide intrinsic
force for transvese or antero-posterior changes.

16.  Myotonic appliances;They depend on the muscle mass
for their action.
 Myodynamic appliances;They depend on muscle
activity for their function.

17.  Group I :They consist of appliances that transmit the
muscle force directly to the teeth for the purpose of
correction of the malocclusion.
 Oral screen,inclined planes.
 Group II:They reposiotion the mandible and the
resultant force is transmitted to the teeth and other
structures.
 Activator,bionator

18.  Group III appliances :They also reposition the
mandible but their area of operation is the
vestibule,outside the dental arch.
 Frankel appliance,vestibular screen.

19. Case selection
 Age: The growth modification therapy using
functional appliances is possible only in a growing
patient.
 Dental considerations;Well aligned upper and lower
arches.

20.  Skeletal consideration: Skeletal class II malocclusions
with horizontal growth pattern. Mild class III
malocclusions.

21. Visual treatment Objective
 This is an important diagnostic test undertaken before
making a decision to use a functional appliance.
 This test enables us to know visualize how the patient’s
profile would be after functional appliance therapy.
 It is performed by asking the patient to bring the
mandible forward.

22.  An improvement in facial profile is considered a
positive indication for the use of a functional
appliance.
 In case the profile worsens,the other treatment
modalities heve to be considered.
 Photographs of the patient taken with forward
mandibular posture are a valuable aid in motivatiing
the patient and parents.

23. Thank you