Myofunctional Appliance 2j1n11

MYOFUNCTIONAL APPLIANCES

CONTENTS

• • • • • • • •

DEFINITION HISTORY CLASSIFICATION MECHANISM OF CRANIO FACIAL GROWTH ADVANTAGES AND DISADVANTAGES CRITERIA FOR CASE SELECTION PRINCIPLES OF MYOFUNCTIONAL APPLIANCE ACCORDING TO TOM GRABERS CLASSIFICATION

• • • •

BITE PLANE INCLINED PLANE ORAL SCREEN VESTIBULAR SCREEN

DEFINITION

•    Functional or myofunctional appliances are defined as loose fitting or ive appliances, which harness natural forces of the oro-facial musculature, that are transmitted to the teeth and alveolar bone through the medium of the appliance.  

HISTORY…………………THE PAST

History …………..the past

• ROUX 1883-Reported the influence of natural forces and the functional stimulation on form of tissues. • This hypothesis “shaking of bone” became the background of both general and functional dental orthopedic procedures.

HISTORY ……………the past

• History traced back to 1879 • Norman .w. kingsley:introduced the term “jumping the bite”for patients with mandibular retrusion-1880.

HISTORY…………………….The past

• He used a vulcanite palatal plate with an anterior inclined plane, which guided the mandible to a forward position when patient closed on it.

• His ideas influenced the development of

HISTORY………………….THE PAST

• Pierre robin, -1902- developed the monobloc appliance, used to influence muscular activity by change in spatial relationship of jaws.

• Fore runner of all functional appliance.

HISTORY………………..The past

• Alfred p.rogers • Sometimes called “father of myofunctinal therapy”

• Recognized the importance of whole oro facialsystem in the problem of orthodontic treatment.

HISTORY ……………..The past

• Viggo andresen1920-ACTIVATOR • Not initially well received . • Karl haupl:- became enthusiastic, and they together called this the “norwegian system”.

• VIGGO ANDRESEN

HISTORY-----THE PAST KARL HAUPL • HAUPL –Applied roux concepts to the correction of jaw and dental arch deformities. • Explained how functional appliances worked through the activity of orofacial muscles. •

the principle and their application lead to development of orthodontics in Europe. “Crisis in orthodontics”-Oppenheim showed potential tissue damaging effect of heavy orthodontic force.

HISTORY……………………….The past

• First functional appliance to be widely accepted. universal appliance

HISTORY-----------THE PAST

• schwarz, reitan and other investigators proved that any force applied causes hyalinization changes in bone.

A. MARTIN SCHWARZ

HISTORY OF DEVELOPMENT OF FUNCTIONAL APPLIANCE

• ROBIN 1902-MONOBLOC • ANDRESEN 1920-ACTIVATOR • HERBST 1934-HERBST • BALTERS 1960-BIONATOR • BIMLER 1964-BIMLER • FRANKEL 1967-FRANKEL • CLARK 1977-TWIN BLOCK

CLASSIFICATION

1.

Stockfish

MYOTONIC APPLIANCES • Muscle mass • Activator, oral screen

MYODYNAMIC APPLIANCES • Muscle activity • Bimlers appliance

2. when functional appliances where still removable

TOM GRABER

GROUP A

TOOTH ED

GROUP B

TOOTH/TISSUE ED

GROUP C

TISSUE ED

ORAL SCREEN INCLINED PLANES

ACTIVATOR BIONATOR

FRANKEL APPLIANCE VESTIBULAR SCREEN

3. WITH THE ADVENT OF FIXED FUNCTIONALS

REMOVABLE APPLIANCE • ACTIVATOR • BIONATOR

SEMI FIXED APPLIANCE • DEN HOLTZ • BASS APPLIANCE

FIXED APPLIANCE • HERBST JASPER JUMBER • MARS

WITH THE AWARENESS AND ACCEPTENCE OF CONCEPT OF HYBRIDISATION

PETER VIGI

CLASSIC FUNCTIONAL APPLIANCE

ACTIVATOR CATLANS APPLIANCE FRANKELS APPLIANCE

HYBRID APPLIANCES

PROPULSOR DOUBLE ORAL SCREEN HYBRID BIONATORS

PROFITT

TOOTH BORNE IVE ACTIVATOR BIONATOR HERBST

TOOTH BORNE ACTIVE Modification of activator $ bionator . ACTIVATOR AND EXPANSION SCREWS. ELASTIC OPEN ACTIVATOR

TISSUE BORNE IVE FRANKLES FUNCTIONAL REGULATOR

FORCE ANALYSIS

TYPES OF FORCE

• PRIMARY FORCE force applied by functional appliance • SECONDARY FORCE reaction of tissues to primary force

Types of forces

compressive tensile shearing

Force application and force elimination Force application

Compressive stress and strain act on the structures involved

Primary alteration in form with secondary adaptation in function

eg

All active fixed or removable appliance

Force elimination

Abnormal and restrictive influences eliminated

viscoelastic displacement of periosteum and bone forming response

Tensile strain

Optimal development

changes

• Functional appliance can bring about ORTHOPEDIC CHANGES DENTAL CHANGES MUSCULAR CHANGES

• 1 orthopedic changes  Accelerating growth in condylar region.  Remodeling of glenoid fossa  Restrictive influences and changing direction of growth of jaws

DENTAL CHANGES sagittal direction • upper anterior tip palatally. • lower anterior tip labially

Transverse direction • Shielding the buccal muscles away from dental arch. • Bring about expansion by screws

Vertical direction • Selective eruption of teeth

• Muscular change: functional appliance can induce sensory stimulation to trigger a neuromuscular response.  Children with neuromuscular disease such as poliomyelities and cerebral palsy cannot be treated successfully with functional appliance therapy.

MECHANISM OF CRANIO FACIAL GROWTH

Muscular hypothesis

Andersen-Haupl

MECHANISM OF CRANIO FACIAL GROWTH

Petrovic and McNamara

MECHANISM OF CRANIO FACIAL GROWTH

Viscoelastic hypothesis

Selmer-oslen Harold Woodside Herren

• ive tension caused by stretching of muscles, soft tissues, e.t.c applies a rigid stretch and create a build up of potential energy. • Depending on the magnitude and direction, viscoelastic reaction can be divided into 1 Emptying of vessels 2 Pressing out of interstitial fluid 3 Stretching of fibers 4 Elastic deformation of bone 5 Bioplastic adaptation

Divide $ synthesize matrix Chondroblasts matures $matrix undergo endochondral ossification Susceptable to gen extrensic factors (STH,thyroxin,sex hormones) Cartilagenous matrix isolates them from local factors Functional appliance can only mod direction of growth.

Growth zone Skeletoblasts$prechondrobla st

Secondary cartilage

Primary cartilage

Growth zone Functional chondroblast

Divide $do not synthesize matrix Once the prechondroblasts matures and become chondroblasts they become surrounded by matrix and they stop dividing General $local factors influence the growth

Amount of growth can be modulated using appliances

MODUS OPERANDI OF FUNCTIONAL APPLIANCE FUNCTIONAL APPLIANCE

INCREASED CONTRACTILE ACTIVITY OF LATERAL PTERYGOID MUSCLE

INTENSIFICATION OF RETRODISCAL PAD

INCREASE INGROWTH STIMULATING FACTORS ENHANCEMENT OF LOCAL MEDIATORS

REDUCTION OF LOCAL REGULATORS

ADDITIONAL GROWTH OF CONDYLAR CARTILAGE

ADDITIONAL SUB PERIOSTEAL OSSIFICATION OF POSTERIOR BORDERTOF MANDIBLE

SUPPLEMENTARY LENGTHENING OF MANDIBLE

ADVANTAGES DISADVANTAGES

AND

ADVANTAGES • Helps in elimination of abnormal muscle function– aiding in normal development. • Less chair side time with less frequent adjustments. • Treatment can be started as early as mixed dentition period, avoid psychological disturbance associated with malocclusion • Worn during night, patient acceptance is good. • Do not interfere with oral hygiene maintenance.

LIMITATIONS

•

patients whose growth has ceased (adults)

• Cannot bring about individual tooth movement. • Un cooperative patient • Fixed appliance therapy may be required at the termination of treatment. • May require prefunctinal orthodontic treatment for correction of minor local irregularities. • Severe crowding • Moth breathers

Criteria for case selection

• Well aligned lower/upper arch. • Class I, mild class II skeletal pattern. • Forward posture of mandible will give a satisfactory soft tissue profile. • Person undergoing active treatment(8-12yrs)

PRINCIPLE OF FUNTIONAL APPLIANCE

1. 2. 3. 4. 5. 6. 7. 8. 9.

Growth utilization Correct diagnosis Ideal and responsive type of malocclusion Construction bite Eruptive bite platform Linguo facial screening Force delivery/elimination Patient cooperation Patience

APPLIANCES

ORAL SCREEN/ VESTIBULAR SCREEN - Introduction

• 1912 – Newell –Introduced vestibular screen. • Before world war II it was used frequently in England. • Recently, it is widely advocated by Kraus, Hotz, Nord and Fingeroth. • Simple appliance in early interceptive treatment of dental arch deformities.

• According to Kraus • Vestibular screen –Appliances that extent into the vestibule in with alveolar process, but did not tooth at all.

• Oral screen – Appliance with primary objective of controlling tongue function.

PRINCIPLE • Force application as well as elimination. • Anterior segment – influenced –directly by appliance -through muscle pressure. • Posterior segment – influenced by –keeping away of cheek muscle – allowing tongue posture and function to expand posterior areas.

Oral screen…………principle $ indication

• INDICATION:1.

Intercept habits:Mouth breathing [when airways

are open] thumb sucking tongue thrusting lip and cheek biting

2, Mild disto occlusion with premaxillary protrusion.

3, Perform muscle exercise-hypotonic lip and cheek.

Oral screen ………………..construction 1 - Casts • Working casts that reproduce the depths of sulcus is made. 2- Construction bite • Sagittal relationship normal-Casts are sealed in occlusion using plaster. • Disto-occlusion case –it is taken by moving mandible forward by 1-3 mm and bite opened by 2mm. After wax construction bite, it is transferred on the models and articulated on a straight line articulator.

construction 3 Extension - Into the sulcus to the point where mucosal tissue reflects outwards. Care not to impinge on frenum and muscle attachment. Posteriorly - up to distal margin of last erupted molar. 4 , Models covered with 2-3mm wax over labial surface of tooth and alveolar process.

•

Case of proclined teeth that is to retract, wax is removed from incisal 1/3rd of tooth

construction • Ensure that screen s maxillary incisors only and stands away 3mm on each side from buccal segment. • Open bite case – no need expansion –appliance allowed to rest on tissue.

5 Appliance fabricated using either self cure or heat cure .

MANAGEMENT • Patient should be asked to wear the appliance at night and 2-3 hours during day time. • Instructed to maintain lip seal. • First few days certain areas of inflammation seen that should be trimmed .  Best time for treatment is 3 ½ - 4 years of age.  Duration 3-6 months

MODIFICATION OF ORAL SCREEN

• HOTZ MODIFICATION - Oral screen with a Metal ring projecting between lips .The ring used to carry out various exercise.

MODIFICATION OF ORAL SCREEN VESTIBULAR SCREEN WITH BREATHING HOLES:Fingeroth and Kraus. Mouth breathers

3 small holes at the inter incisal angle . Holes can be gradually reduced as the patient become accustomed to the appliance, which will stimulate nasal breathing.

COMBINED VESTIBULAR SCREEN AND TONGUE CRIB:-

• KRAUS • A crib of wire or acrylic can be placed in the area of open bite and attached to screen by a wire that extends around the last molar tooth or ed through inter occlusal space in the region of canine and first premolar. • In both cases it should not touch teeth even in occlusion.

BITE PLANES

BITE PLANE • These are simple functional appliances that  bring about minor  corrections of the anteroposterior relationship of the jaws.

They can be:• Anterior or Posterior • Inclined or flat

Bite Plate.flv

ANTERIOR BITE PLANE • Thickened platform of acrylic palatal to upper incisors on which the lower incisor occlude leaving the posterior tooth out of occlusion. • DESIGN • Canine to canine

• consists of Adam’s clasps on the molars retaining the appliance. • A labial bow is incorporated to counter any forward

• INDICATION – • Class I deep bite with low facial height

• CONTRAINDICATION – • High facial height • Skeletal deep bite

• Class II div II • Severely protruded/ retruded lower anteriors

CONSTRUCTION AND ADJUSTMENT • Correction of height • Adjustment of bite plane during treatment Bite plane should be – high enough, so that posteriors are Appliance should be separated by 2-3 mm worn full time, If bite opening requires again bite is increased . • Horizontal adjustment – Before the upper Surface of bite plane incisors can be should be parallel to retracted to reduce the occlusal plane and overjet acrylic is horizontal. The trimmed from lingual posterior limit of bite surface but should be plane should extent just careful that lower sufficiently to engage incisors maintain lower incisor with it until

• POSTERIOR BITE PLANE Indications : • To give occlusal clearance for the correction of  the cross  bite of either the anterior or posterior teeth. • For diagnosis of occlusal prematurities

 

• CONSTRUCTION : 

 cover  the  occlusal  surface of posterior teet h ,  extending  anteriorly   from first premolar to t he last  erupted  tooth  posteriorly.  • The thickness should be kept as minimum as possible. • It is constructed as an extension of the

CLINICAL MANAGEMENT • When the appliance is delivered , care is take n to see  that the bite plane should  the buccal  and  lingual cusps of the posterior teeth of the opp osing arch uniformly on both the sides.  • The bite plane should be sufficiently thick to r elieve the occlusal interference. 

• If an anterior cross bite is being correct ed, the  bite plane needs only to be sufficiently  thick to  disengage occlusion on anterior teeth.  • Once the cross bite is corrected, the mo

INCLINED PLANE/CATALANS APPLIANCE  Lower anterior inclined plane.  • Introduced by Catalan more than 150years ago  This appliance guides erupting tooth in to normal position.   All inclined planes have characteristic of opening the bite by allowing posterior teeth to erupt .So inclined plane is contraindicated unless there is appreciable amount of overbite.

INDICATION -  • Where anterior cross bite(single tooth or a segment of upper arch) is developing with a good degree of overbite and there is sufficient space for the erupting teeth.

DESIGN – Fabricated using self cure acrylic, designed to have a 45° angulation, which forces teeth in crossbite to more labial position

• MANAGEMENT OF APPLIANCE – Must be worn continuously, If appliance is removed during eating the tooth will be forced back towards original malposition.

Correction will occur within 6 weeks.

After correction advise patient to wear appliance during sleep to guard against the tendency to move mandible forward .

• DISADVANTAGES 1- Speech problem during therapy. 2- Anterior open bite if used for more than 6 weeks. 3-May need frequent recementation.

Thank you !