MEDIUM OPENING ACTIVATOR(Removable Functional

Appliance)

Mobina SohaibRoll # 93Group D

• Functional Appliances• Indications & Contraindications• Types Of Functional Appliances• Medium Opening Activator• Components• Mechanism• Uses• Advantages & Disadvantages

ORTHODONTIC FUNCTIONAL APPLIANCE

“A functional appliance is an appliance that produces all or part of its effect by

altering the position of the mandible”

• It is one that changes the posture of the mandible, holding it open or open and forward.

Indications For Functional Appliances

• Well aligned dental arches• Posterior positioned mandible

• Non severe skeletal discrepancy• Lingual tipping of mandibular incisors• Proper patient selection (growing age)

Contraindications

• Crowding• Labial tipping of lower incisors• Class ll skeletal by maxillary prognathism

Types Of Functional Appliances

–Removable • (activator, bionator

& Frankel II)–Fixed • (Herbst appliance)

– Passive Tooth-borneActivatorBionatorHerbst appliance

– Active Tooth-borneModifications of

activator & bionator

– Tissue-borneFrankel appliance

Types Of Functional Appliances

– TOOTH BORNE PASSIVE:–No intrinsic force generating component such as

springs or screws– Depend on soft tissue stretch & muscular activity

– TOOTH BORNE ACTIVE:– Include expansion screws or other active components

like springs to provides intrinsic force for transvers or AP changes

Types Of Functional Appliances

– TISSUE BORNE PASSIVE:–Mostly located in vestibule– Little or no contact with dentition

History Of Development Of Functional Appliances

• Robin 1902- Monoblock• Andresen 1908- Activator• Herbst 1934- Herbst• Balters 1960- Bionator• Bimler 1964 – Bimler• Frankel 1967- Frankel• Clark 1977-Twin Block

History Of Development Of Functional Appliances

• Origin of activator• Class II deep bite tendency• Biomechanical Workng

Retainer• Norwegian Appliance• ACTVATOR

Hawley Retainer

Activators

Loose-fitting removable orthodontic appliances

redirect the pressures of the facial and masticatory muscles onto the teeth and their

supporting structures to produce improvements in tooth arrangements and occlusal relations

Medium Opening Activators(Monoblock)

• Removable, tooth-borne functional appliance• One-piece functional appliance• Made up of heat cured acrylic (minimal acrylic to

improve patient’s comfort)• Consists of upper and lower acrylic plates• Lower plate extends only in the lingual portion• Upper and lower plates are joined by two stout

acrylic posts• Breathing hole is left between them anteriorly

Medium Opening Activator with upper and lower models 

Medium Opening Activator with upper model removed

Medium Opening Activator with lower removed

MEDIUM OPENING

ACTIVATOR

Components

Lower incisal capping 33-43 Anterior Palatal wire 13-23 Labial Bow 13-23 Adams clasps 15-16/25-26 (in upper buccal

segment) Occlusal rests 15-16/25-26 Acrylic connecting 'struts' / ‘posts’

Labial bow 13-23

Lower incisal capping 33-43

Labial bow 13-23

Lower incisal capping 33-43

Double Adams Clasp 15-16/25-26

Anterior Palatal Wire 13-23

Double Adams Clasp 15-16/25-26

Occlusal Rest 15-16/25-26

Lower incisal capping 33-43

2 Rigid Acrylic Posts

Rigid Acrylic Post – upper n lower parts are joined by these posts

Anterior breathing hole

Mechanism

• When the patient bites the mandibular incisors contact the bite plane, thus disoccluding the posteriors that are free to erupt

• Adam’s clasps on the molars help in retaining the appliance

• Labial bow is also incorporated to counter any forward component of force on the upper anteriors

• The interocclusal acrylic is trimmed gradually to encourage the eruption of posterior teeth

Effects on Teeth in General

• Tipping of mandibular incisors facially• Retract maxillary incisors• Allow eruption and mesial movements of

mandibular molars• This result in increase lower facial height

Use

• Designed to translate a Class II division I incisor relationship into a Class I with a reduced overjet and overbite.

• Most effective treatment approaches available for the management of Class II deep bite malocclusion in growing subjects

• Deep bite cases diagnosed to be due to infraocclusion of molars can also be treated

Advantages• Breathing hole present anteriorly• No molar capping; these teeth can erupt

freely• Less bulky and more comfortable• Can be modified to fit around fixed braces

Disadvantages• Could not speak or eat when appliance is

worn

Patients Compliance

• Excellent rapport with the patient• Convincing the patient about temporary

inconveniences• Compliant or non compliant appliances must

be weighed and composed, keeping in mind the optional result.

PATIENCE

References

• An introduction to orthodontics – Laura Mtchell• http://www.columbia.edu/itc/hs/dental/D5300/

Functional%20Appliances%20Slide%20Show%20with%20sounds_Mod6_04.ppt%206-1_BW.pdf

• http://www.toteeth.com/html/y2010-297-what-is-a-functional-appliance.html

• http://faculty.ksu.edu.sa/Alkhadra/PublishingImages/Functional%20Appliances%20(2nd%20round)%20-%20Dr%20Khadra.pdf

• http://www.dentalcompare.com/litupdate.asp?ArticleID=6903

• http://www.ncbi.nlm.nih.gov/pubmed/19641758

• file:///F:/Medium_Opening_Activator.html• http://www.learn-ortho.com/docs/intro%20to%

20ortho.pdf

THANK YOU!