FUNCTIONAL APPLIANCES prepared by :

Hana f.abdullah

Introduction Are appliances that utilize natural forces of

orofacial and masticatory musculature for their action

Functional appliances are conceptually based on Moss’ functional matrix theory

Functional matrix theory proposes that functional matrices, tissues like muscles and glands influence skeletal units such as jaw bones and ultimately control their growth

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

FORCE ELIMINATION The principle involves the elimination of abnormal

and restrictive environmental influences on the dentition thereby allowing optimum development thus function is rehabilitated with a secondary change in form. these components produce skeletal and dentoalveolar changes by acting on the following

1. eruption 2. linguofacial muscle balance 3. mandibular repositioning

Action of functional appliance

Functional appliance can produce following changes

1. Orthopedic changes

2. dentoalveolar changes

3. muscular changes

1.Orthopedic changes Myofunctional appl are capable of accelerating

growth in condylar region

They bring about remodelling of glenoid fossa

They can change direction of growth of the jaws

Action of functional appliance

2 - Dentoalveolar changes

They can bring about changes in sagittal ,transverse, and vertical directions most MFA allow upper anterior to tip labially

In transverse direction they can bring about expansion of the dental arches by incorporating screws in them

In vertical plane they allow selective eruption of teeth

3 - muscular changes

Functional appliance can improve tonicity of the orofacial musculature

Classifications of functional appliances:

1. removable functional appliance A)removable tooth borne applianceB)removable tissue borne appliance

2. fixed functional appliance

Functional appliance types

Orthodontic functional appliances may be active or passive: Active appliances reposition the mandible so

that the condyle is forced out of the glenoid fossa and this in turn is thought to stimulate the posterior/superior growth of the condyle

Passive appliances act by repositioning the musculature associated with the mandible so that the jaw bone itself responds by growing to the new equilibrium position

Active functional appliances

Bionator

Active functional appliances

Woodside activator

Active functional appliances

Twin-block appliance

Passive functional appliances

Frankel

Active functional appliances

Herbst

Mode of action

Most of functional appliances act by utilizing one or more the following

1. a forced mandible. Posture which transmits forces to the teeth and jaws.

2. bite planes which produce deferential eruption

Advantage of functional appliances

1. Functional appliances are effective in vertical control of increased over bite

2. Patient on growth

3. Can be used in mixed dention

4. Minimal chair side adjustment

Disadvantage

1.succes of functional appliances depend on patient cooperation.

2.there is no precise tooth movement 3.treatment duration is often prolonged. 4.need to faces treatment to complete

treatment

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

These appliances should be worn at nighttime as this is when growth takes place

Frankel functional appliance Developed by Rolf Frankel Also called oral gymnastic appliance

It has two main treatment effects

1. It serves as a template against which the cranio

facial muscle function

2. The appliance removes muscle forces in labial

and buccal areas that restricts skeletal growth

thereby providing an environment which

enables skeletal growth

MODE OF ACTION

The following are effects of frankel appliance

1. Increase in saggital and transverse intra oral space

2. Increase in vertical space where appliance is kept free from posterior teeth

3. Mandibular protraction

4. Muscle function adaptation the pads and shield massage the blood vessels increase circulation

5. Shields loosen up the tight muscles and improve muscle tone

Frankels exercises or oral gymnastics1. lips closed at all times 2. swallowing speaking etc becomes exercise while using

the appliance

Types of frankel appliance

FR 1 : Class 1, class2 division 1 malocclusion

FR2 : Class2 division 1&2 FR3 : Class3 FR4 : Open bite and bimaxillary protrusion FR5 : They are functional regulator which

incorporate head gear indicated in long face patients having a high mandibular plane angle and vertical maxillary excess

ACTIVATOR

Activators induces musculo skeletal adaptation by

introducing a new pattern of mandibular closure

The appliance loosely fits in the mouth the pt has to

move the mandible forward to engage the appliance

this result in stretching of elevator muscles of

mastication which starts contracting thereby setting

up a myotactic reflex

ACTIVATOR

This generates kinetic energy that cause

1. Prevention of further forward growth of the maxillary dento alveolar process

2. Movement of maxillary dento alveolar process distally

3. Reciprocal forward force on the mandible

4. force is generated while sleeping and swallowing

ACTIVATOR Indications: In actively growing individuals with favorable

growth patterns.

1. CLASS 2 division 1&2

2. Class 3 malocclusion

3. Class 1 open bite

4. Class1 deep bite

5. Before major fixed appliance therapy

6. For post treatment retention

7. Children with lack of vertical height

Contraindications

-correction of class I cases with crowded teeth caused by

disharmony b/w tooth size & jaw size.

-in children with excess lower facial height.

-in children whose lower incisors are severely procumbent.

-in children with nasal stenosis caused by structural

problems w/in the nose or chronic untreated allergy.

-in non-growing individuals.

Advantages

-uses existing growth of the jaws

-minimal oral hygiene problems

-intervals b/w appointments is long

-appoints are short,minimal adjustments required

-hence, more economical

Disadvantages

- requires very good patient cooperation- cannot produce a precise detailing & finishing of occlusion.- may produce moderate mandibular rotation(hence contraindicated in excess lower facial height cases)

Modifications:

BOW ACTIVATOR By A.M.Schwarz

Wunderer’s modificaiton for Class III

BIONATOR

Modified activator less bulky & more elastic

3 types-

> Standard type-class II div I having narrow

dental arches

> Class III Appliance

>Open bite appliance

Types of bionator

Standard type

Class III Appliance Open Bite Appliance

TWIN BLOCK APPLIANCE

The Twin Block appliance is a removable, orthodontic

functional appliance that is used to help correct jaw

alignment, particularly an underdeveloped lower jaw. 

Effectively combines inclined planes with intermaxillary &

extraoral traction.

TWIN BLOCK APPLIANCE

The removable twin block is a tooth-born functional appliance that is

worn fulltime. It helps in the advancement of the mandible. It is a two-

piece appliance composed of an upper and lower bite block. Orthopedic

traction can be added in cases of severe skeletal discrepancies. This

includes the use of a Concord Facebow (or headgear) at nighttime.

Upper & lower bite blocks interlock at 700 angle.

TWIN BLOCK APPLIANCE

The fixed twin block is similar to the removable twin block, but

can be used in non-compliant patients. It is similar in design to

the Herbst appliance, however the telescopic tubes of the Herbst

appliance are replaced with two bite blocks.

Advantages

-very good patient acceptance.

-bite planes offer greater freedom of

movement & lateral excursion.

-less interference with normal function.

-significant changes in patient’s

appearance within 2-3 months.

HERBST APPLIANCE

Fixed functional appliance developed by Emil Herbst in early 1900’s.

Indications:

-correction of class II MO due to retrognathic

mandible.

-can be used as anterior repositioning splint in

patients having TMJ disorders.

Specific indications

-Post adolescent patients: T/t completed w/in 6-8

months,hence possible to use the residual growth in

these patients.

-Mouth breathers

-Uncooperative patients

2 types:

-Banded Herbst

-Bonded Herbst

Types of herbs appliance

Banded Herbst Appliance

Bonded Herbst Appliance

Advantages and disadvantages

Advantages:- continuous action- T/t duration is short- less pt cooperation needed- can be used in pts who are at the end of their growth- can be used in pts with mouth breathing habit.

Disadvantages:- cause minor functional disturbances.- increased risk of development of dual bit,with TMJ dysfunction symptoms as a possible consequence.- repeated breakage & loosening of appliance occurs,esp. in lower premolar area.- plaque accumulation & enamel decalcification can occur- tendency for posterior open bite.

JASPER JUMPER A relatively new flexible,fixed ,tooth borne FA.

Introduced by J.J.Jasper ,1980

Actions similar to Herbst appliance but lack rigidity.

Basically indicated in skeletal class II mo with max. excess & mandibular deficiency.

Advantages

- produce continuous force

- does not require patient compliance

- allows greater degree of mandibular

freedom than Herbst appliance

- oral hygiene is easier to manage.

POST DELIVERY INSTRUCTION 1. Teach the patient to wear and remove the

appliance in front of mirror

2. Should be worn 2-3 hours daily initially

3. When not in use keep in water

4. Any pain ,soreness etc report to the clinic

5. If no pain also report the clinic after 2 wks

6. Pt advised to maintain lip seal by conscious effort

7. Time charts should be given to record duration of wearing the appliance

Discomfort, as both upper & lower teeth are joined together.

Mainly depends on patient’s compliance Can be used only if a favorable horizontal growth

pattern is present in cases of Class II correction. It has to be removed during mastication ,

particularly when strongest forces are applied. May interfere with speech. Treatment duration is often long

Limitations & complications