Activator

1. ACTIVATOR
PRESENTED BY:
Dr. Hema Taragi (JRI)
Dept. of orthodontics
GUIDED BY:
Dr. Anil Chandna
Dr. Preeti Bhattacharya
Dr. Ankur Gupta
Dr. Ravi Bhandari
Dr. Shivani Singh
Dr. Dhruv Tiwari

2. CONTENTS
• INTRODUCTION
• HISTORY
• MODE OF ACTION
• SKELETAL AND DENTO ALVEOLAR
EFFECTS OF ACTIVATOR
• INDICATIONS
• SELECTION OF CASES
• CLINICAL MANAGEMENT
• TRIMMING OF THE ACTIVATOR
• ADVANTAGES
• DISADVANTAGE

3. INTRODUCTION
• MYO FUNCTIONAL
Muscles functioning
• Myofunctional / functional appliances are defined as loose fitting or passive
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.

4. • An activator is a functional appliance that positions the mandible
forward. Since it activates the muscle, it was called an activator.
ACTIVATOR
Ability to activate muscle forces

5. HISTORY
• Earlier in 1879, Kingsley introduced the term & concept of “ jumping the bite” for
mandibular retrusion patients.
• Hotz used modified kingsley plate or “Vorbissplate” in cases of deep bite
retrognathism.
• Pierre Robin (1902) –Monobloc – used in glossoptosis patients.
• The activator was originally used by Andresen (1908) with vertical extensions to
contact the contiguous lingual surface of mandibular teeth.

6. • In many cases a forward jumping of the bite has resulted in a dual bite after
appliance removal.
• Impressed by Kingsley’s ideas Viggo Andersen developed a mobile loose-fitting
appliance that transferred functioning muscle stimuli to the jaws, tooth &
supporting structures.
• Used as a retainer for his daughter to wear while at summer camp. Over the
summer Andersen was surprised to see improvement in the sagittal jaw
relationship.

7. • Called it ‘Biomechanic Working Retainer’.
• When Andresen moved from Denmark to Norway, he became associated with
Haupl at the University of Oslo.
• He was impressed with the results obtained by Andresen’s Functioning Retainer.
• By the time Andresen and Haupl teamed up to write about their appliance, they
called it an Activator because of its ability to activate the muscle forces.
• All the original appliances had a basic Vulcanite or Acrylic fabrication consisting
of joined Maxillary and Mandibular components.

8. • Haupl became convinced that the appliance induced growth changes in a
physiologic manner and stimulated or transformed the natural forces with an
intermittent functional action transmitted to the jaw, teeth & investing tissues.
• They called it an ACTIVATOR, because of its ability to activate the muscle forces.

9. MODE OF ACTION
• Myotactic reflex
• Condylar adaptation
• Viscoelastic property

10. MODE OF ACTION
ACTIVATOR - A loose-fitting appliance
The Pt. have to move the mandible forward to engage the appliance
Streching of elevator muscles of mastication
As muscles stretch they will start contracting
Myotactic reflex

11. WHAT IS MYOTACTIC REFLEX
• It is a neural mechanism that responds to changes in muscle length ( stretching) by
attempting to resist the changes in length.
• The change in length is detected by proprioceptors called muscle spindles.
• Condylar adaptation
• Viscoelastic property

12. COMPONENTS
• wire component
• Active labial bow:- it is made using 0.9mm:
• Passive labial bow:-made with 0.8mm thick ss wire : When only orthopaedic
change is desirable.

13. • Acrylic components ;
1. Maxillary part
2. Mandibular part
3. Interocclusal part

14. • Flanges for upper cast are usually 8-12 mm high in gingival area covering the
alveolar crest.
• Lower acrylic plate is 5-12 mm high.

15. Construction bite
PURPOSE
to advance the mandible into an acceptable forward position.

16. GENERAL CONSIDERATIONS FOR CONSTRUCTION
BITE
In cases of forward positioning of the mandible by 7-8 mm, the vertical opening
should be slight to moderate i.e 2-4 mm.
If the forward positioning is not more than 3-5 mm, then the vertical opening can
be 4-6 mm.

17. 1. Construction bite with marked mandibular forward position
H – Activator –
• More horizontal advancement.
• Given in severely retruded mandibular case.
2. Construction bite with slight mandibular forward positioning
V Activator –
• Slight mandibular forward positioning and extreme vertical opening.
• Deep bite case

18. 3. Construction bite with opening and posterior positioning of the mandible
• In class 3 cases.
• Position mandible posteriorly.
• Sufficient vertical opening should be done to correct anterior cross bite.

19. SKELETAL EFFECTS
 The activator is more effective in controlling downward and forward growth of
the mandible.
Upward and backward growth of the condyle is capable of moving the mandible
anteriorly
So The effect of the activator on the mandible can be
a) indirect as a result of growthe th of the condyle
 b) rotation of the mandible anteriorly
 Downward displacement of the maxillary base allows the maxilla is insignificant

20. DENTOALVEOLAR EFFECT
The dentoalveolar effect of the activator is to control tooth eruption and alveolar
bone apposition.
 For this reason, the activator is most effective if used in the early mixed dentition.
With proper trimming of the appliance, different movements can be performed
and the eruption of the teeth can be guided.

21. INDICATION
I. Correction of Cl II Div 1 cases
II. Correction of Cl II Div 2 cases
III. Correction of open bite (Dental not skeletal).
IV. Correction deep bite case

22. Response to activator treatment in Class II malocclusions
Increased growth of the mandible
Anterior relocation of the glenoid fossa
Inhibition of forward growth of the maxilla
Inhibition of mesial migration of maxillary teeth
Inhibition of maxillary alveolar height increase and extrusion of mandibular
molars

23. SELECTION OF CASES
 SKELETAL
• A mild skeletal Cl-II facial pattern.
• A decreased lower face height
DENTAL
• No crowding in the upper and lower arches& or should be corrected by fixed
orthdontic treatment.
• No rotations and no displacement of the teeth.
• A relatively flat mandibular occlusal plane.

24. SOFT TISSUE
• Preferably a muscular pattern that does not exhibit undue tightness of lips and
cheeks.
 RESPIRATORY
• No nasal obstruction or chronic respiratory disorder

25. CLINICAL MANAGEMENT
• Patient compliance: It is very essential. It is very important to assess clinically
the patient’s psychological aspect and motivation potential. Motivation potential
can be enhanced by visual treatment objectives.
• Construction bite: The construction bite is an intermaxillary wax record used to
relate the mandible to the maxilla in a desirable position.

26. TIMING OF WEAR
• The appliance is usually worn for 2 or 3 hours during the day for the first week.
• During the second week, the patient sleep with the appliance in place and wears it
for 1 to 3 hours in the daytime.
• The appliance is checked by the clinician after 3 weeks to evaluate whether the
trimming is accurate and the activator is working as desired.

27. Guide plane contact areas are usually shiny if they are functioning properly; they
can be reshaped and corrected as needed.
If the patient is wearing the activator without difficulty and instruction, checkup
appointments should be scheduled every 6 weeks.

28. TRIMMING OF THE ACTIVATOR
• Planned trimming of the appliance in tooth contact area is carried out to bring
about dento-alveolar changes so as to guide the teeth into good relation in all the 3
planes of space.:
• Vertical
• Sagittal
• Transverse
• The acrylic surfaces that transmits the desired force by contact with the teeth are
called guiding planes. The areas of acrylic that contact the teeth are polished.

29. TRIMMING OF
ACTIVATOR FOR
VERTICAL CONTROL
• Selective trimming of the activator can be
done to intrude or extrude the teeth.
• INTRUSION OF TEETH:
• Intrusion of the incisors are achieved by
loading the incisal edge of these teeth with
acrylic. In case labial bows are used, they
should be placed incisal to the area of greatest
convexity to aid in the intrusion.

30. In case intrusion of posteriors is needed then only the cusp tips are loaded with
acrylic.
The fossae and fissures are free of acrylic.

31. EXTRUSION OF
THE INCISORS: • the lingual surface is loaded above the area of
greatest convexity in the maxilla and below the
area of greatest convexity in the mandible.
• The extrusive movement can be enhanced by
placing a labial bow gingival to area of
greatest convexity.

32. IN CASE OF MOLARS,
EXTRUSION:
• It is brought about by loading the lingual
surface above the area of greatest convexity in
the maxilla and below the area of greatest
convexity in the mandible.

33. TRIMMING OF THE ACTIVATOR FOR SAGITTAL
CONTROL
Protrusion of incisors:
lingual surface of the teeth is loaded with acrylic and a passive labial bow is given
that is kept away from teeth to prevent perioral soft tissues from contacting the
teeth.

34. RETRUSION OF
INCISORS
 Acrylic is trimmed away form the lingual
surface and an active labial bow is placed on
incisal 1/3rd and it is used to bring about
retrusion of the incisors

35. MOVEMENT OF POSTERIOR TEETH IN SAGITTAL
PLANE:
The teeth in the buccal segment can be moved to help in treating Class II.
In Class II malocclusion, the maxillary molars are allowed to move distally while
the mandibular molars are allowed to move mesially by loading the maxillary
mesioligual surface and mandibular distolingual surface.

36. MOVEMENT OF TEETH IN
TRANSVERSE PLANE
It is possible to trim the activator to stimulate
expansion of buccal segment This is done by
contact of acrylic on the lingual surfaces of the
teeth to be moved transversely. But better
expansion is possible by placing a jack screw
in the activator.

37. ADVANTAGES
Treatment may start in the late mixed dentition period.
Maintain the beneficial therapeutic effect for long periods of time without
requiring the usual office visits which are needed in fixed appliances.
For post-treatment retention, the same appliance can be used.
No esthetics issue during the day because used mostly during the night.

38. DISADVANTAGES
 uncooperative patient.
Age is a factor.
crowding
No detailed precise finishing of occlusion.
 bulky appliance .

39. MODIFICATIONS
BOW ACTIVATOR – A. M. Schwarz
• The maxillary and mandibular portions are
connected together by an elastic bow.
• Can have screw incorporated to allow arch
expansion.
• It allows stepwise sagittal advancement of the
mandible by adjustment of this bow.
KARWETZKY MODIFICATION –
• Maxillary and mandibular plates are joined by u
bow in the region of the first permanent molar.
Also extends over the occlusal aspect of all teeth.
• It allows stepwise advancement of the mandible by
adjustment of the u loop.
Indian Journal of Orthodontics and Dentofacial Research,
April-June, 2019;5(2):41-46

40. WUNDERER’S MODIFICATION –
• horizontally splitted appliance with upper and
lower parts connected by a screw which is
embedded in mandibular portion.
• When the screw is opened it causes maxillary
portion to move forward and reciprocal
posterior movement in the mandibular portion.
• Used for class 3 malocclusion.
HARVOLD-WOODSIDE MODIFICATION –
• Used in class II div1 and class III.
• Construction bite – vertical opening , labial
arch wire – expansion.

41. HERREN – SHAYE MODIFICATION –
• Modified activator in two ways ;
1. By overcompensating the forward positioning of
the mandible in construction wax bite almost
reaches a feasible maximum.
2. By seating appliance firmly against maxillary
dental arch by means of clasps.
REDUCED ACTIVATOR ( CYBERNATOR) –
Schmuth
• Resembles the Bionator.
• The acrylic portion is reduced from the anterior
area leaving a small flange of acrylic on palatal
slopes.
• The 2 halves may be connected by an omega-
shaped palatal wire.

42. PROPULSOR (Muhlemann and Hotz) –
• Hybrid appliance with features of Monobloc & Oral
screen.
• Devoid of any wire components.
• Has acrylic that covers the maxillary buccal portion like
an oral screen.
• Its advantage is its ability to effect changes in the
alveolar process, in addition to the teeth in the maxillary
anterior segment.
• ELASTIC OPEN ACTIVATOR – G Klammt
• Completely lacks occlusal stabilization and thus its
vertical mobility in the mouth is unimpeded
• Has a reduced size and needs to be worn in daytime
only
• Components of bilateral acrylic parts
1. Upper & lower labial wires
2. Palatal arch & guiding wire for upper & lower incisors

43. HEADGEAR
COMBINATION
Pfeiffer & Grobety in 1967
• Used a cervical/occipital pull headgear
attached to bands on maxillary first molars
• Recommended for reducing vertical & sagittal
maxillary displacement, achieving autorotation
& increasing forward displacement of
mandible.