ACTIVATOR
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INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy....
INTRODUCTION
 The term functional appliance refers to a variety
of removable appliances designed to alter the
arrangement...
 A variety of different functional appliances
are available. The appliance selected for
treatment is based on type of ano...
HISTORY AND DEVELOPMENT
OF ACTIVATOR
 In the year 1880 Dr. N.W. Kingsley wrote, in his treatise
on oral deformity, that h...
 But then an individual arrived on the scene who took all the various
ideas and theories about using the functional appli...
 He believed in the theories, expounded by
Roux and Wolfe in the 1890s that changes
in biomechanical function bring about...
 Andersen believed that many malocclusions were functional in origin
and that if form followed function”, it followed tha...
ANDRESEN APPLIANCE
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 He was appointed as a professor at the Dental
School at Oslo, Norway. Here he had the good
fortune to strike up an allia...
 To understand the working hypothesis of activator, Haupl
tried to apply the functional adaptation hypothesis of
“William...
 Together they further developed the appliance-induced
mandibular advancement techniques, refined it, and
unlike previous...
 Everyone in Europe disagreed to its effectiveness.
 .One of the controversies raised was the inability of some clinicia...
 Moreover, one of the problems with wearing the
Activator was its size.
 It was a bulky appliance at first; and by virtu...
 With the advent of modern acrylic, a new world of
feasibility was created for the orthodontist using
functional applianc...
PHILOSOPHIES OF MODE OF
ACTION
 According to the mode of action, there are two main
principles. A third approach combines...
 According to the second working hypothesis
the appliance is squeezed the jaws in a
splinting action. The appliance exert...
 The third approach enlists the modes of action of the
preceding two. It can be called a transitional type of
activator a...
MODE OF ACTION
 Andresen stated that this appliance has a stimulating
effect on jaw development. In class II cases when t...
 Opposing to Andresen, Herren based his mode of action
of the activator on the basis of spatial relation between
position...
 The Herren type or L.S.U. type activator and extraoral forward
traction exert their action mainly through the sagittal
r...
 According to Herren, mandible hyoid bone, tongues are
considered to be the components of masticatory organ.
 The moveme...
CLASP KNIFE REFLEX
 The basis for such severe increase in the displacement of mandible is the
clasp knife reflex or autog...
 Rational behind Harvold Wood side hypothesis is that
mandible normally drops open when the patient is sleep.
If it is op...
 The viscoelastic properties of muscle and the
stretching of the soft tissues are decisive for
activator action. During e...
 Stretching of muscles give rise to stretch reflex
contractions.
 Stretch reflex by activator displacing mandible beyond...
 Eschler supported Andersen Haupl‟s concept based in
muscle physiology experiments. He found action
currents in patients ...
Effects on Condyle
 The influence of activator on the condyle is very much controversial.
 The possibility of influencin...
 The activator can, to a limited degree,
control the upper growth vector, supplied
by the sphenoccipital synchondrosis,
w...
Condylar development and mandibular
rotation and displacement during activator
treatment (AJO 1982 Apr)
 An analysis of t...
Effective temporomandibular joint growth
and chin position changes: Activator versus
Herbst treatment. A cephalometric
roe...
changes in activator treatment: A
cephalometric roentgenoraphic study
 The present investigation revealed that
effective ...
Effects on maxilla
 Regarding activator effect on maxilla
authors like Harvold and Vargervik,
Jacobson have observed ante...
A cephalometric analysis of skeletal and dental changes
contributing to Class II correction in activator treatment (AJO
19...
EFFECTS ON MANDIBLE
 The effect of the activator on the mandible can be indirect as a result
of growth of the condyle plu...
Mandibular changes during functional appliance
treatment AJO 1993 Aug.
 The purpose of this prospective trial was to
dete...
Response to activator treatment in Class II
malocclusions
 A clinical study was designed to disclose the effects of
activ...
Effects on Soft Tissues
 Very little study was carried out on effects of
activator on the soft tissues, but however studi...
TIMING OF TREATMENT
 Reey, Eastwood, says that mixed dentition
period was best for activator treatment.
 Experience clin...
INDICATIONS
 Partial or total correction of Cl II Div 1 cases
 Partial or total correction of Cl II Div 2 cases
 Partia...
Advantages
 Treatment may be started during late deciduous or mixed dentition
period.
 Disturbances or suppression of no...
DISADVANTAGES
 Cannot be used inpatient who are un co-
operative.
 Greater selectivity of cases is necessary than
with f...
SELECTION OF CASES
 Following are the empirical criteria for
case selection.
A. Skeletal
 A mild skeletal Cl II facial p...
B. Dental
 No crowding in the upper and lower arches.
 A good integral mandible with no rotations and
no displacement of...
C. Soft tissue
 Competent or potentially competent lips in which
the lip well as capable of stabilizing the upper
anterio...
TREATMENT PLANNING
PRETREATMENT CONSIDERATIONS
 Before activator treatment is started –
forward movement of mandible is c...
DIAGNOSTIC PREPARATIONS
 A. Patient compliance: It is very essential. It is
very important to assess clinically patient‟s...
Study model Analysis
 Following information can be derived form
the study model.
 First molar relationship in habitual o...
Functional Analysis
 Precise registration of postural rest position is
done as vertical opening of construction bite
depe...
Cephalometric Analysis
 It is done to establish the nature of craniofacial
morphogenetic pattern to be treated.
 It also...
CONSTRUCTION BITE
 The construction bite is an intermaxillary wax record
used to relate the mandible to the maxilla in th...
 In taking a construction bite one should
look at the bite in three different planes of
space
 Sagital
 Vertical
 Fron...
A. Sagittal or anterior positioning of
mandible should not exceed 7-8 mm or ¾
mesiodistal dimension of first permanent
mol...
B. Vertical or Opening the bite:
 The vertical and sagittal relationship are
intimately linked.
Guiding Principles
 Mand...
 C. Frontal or Midline establishment
 midlines of the maxilla and mandible
should coincide when the construction bite
is...
Sequential steps for construction bite
 Amount of horizontal and vertical displacement of the mandible is
determined. Mar...
 Transfer the wax to the patients mouth fitting it on the lower arch,
in the same manner.
 Ask the patient to move the m...
LOW CONSTRUCTION BITE WITH MARKED
MANDIBULAR FORWARD POSITIONING:
 This kind of construction bite is characterized by
mar...
High construction bite with slight anterior
mandibular positioning:
 The mandible is positioned anteriorly by 3-5 mm
only...
Construction bite without forward positioning
of the mandible:
 Sometimes a construction bite without
forward positioning...
Construction bite with opening and posterior
positioning of the mandible:
 In Class III malocclusion, bite is taken
after...
FABRICATION
 After the construction bite is taken and checked on the patient and
rechecked on stone working models, the w...
Fabrication of the Acrylic portion
 The appliance consists of upper, lower and
interocclusal parts.
 In the upper and lo...
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STEPWISE PROCESS FOR ACRYLISATION
 Before acrylic portion are made the casts are put
in a water bath for 20 min.
Then iso...
TRIMMING OF THE ACTIVATOR
 After fabrication of the activator it is usually found to
fit tightly as acrylic is interposed...
TRIMMING OF ACTIVATOR FOR VERTICAL
CONTROL
 Selective trimming of the activator can be
done to intrude or extrude the tee...
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 . In case intrusion
posteriors is needed
then only the cusp
tips are loaded with
acrylic. The fossae
and fissures are fr...
 Extrusion of the
incisors, the lingual
surface is loaded above
the area of greatest
convexity in the maxilla
and below t...
 In case of molars,
extrusion is brought
about by loading the
lingual surface above
the area of greatest
convexity in max...
TRIMMING OF THE
ACTIVATOR FOR
SAGITTAL CONTROL
 Protrusion of incisors: In
case the incisors be
protruded, lingual surfac...
 Retrusion of incisors:
The acrylic is trimmed
away form the lingual
surface and an active
labial bow is used to
bring ab...
 Movement of posterior teeth in sagittal
plane: The teeth in the buccal segment
can be moved mesially and distally to hel...
MESIAL MOVEMENT OFMOLARS
DISTAL MOVEMENT OF MOLARS
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Movement Of Teeth In
Transverse Plane
 It is possible to trim
the activator to stimulate
expansion of buccal
segment This...
MODIFICATIONS OF ACTIVATOR
 The original Andresen appliance made of
vulcanite or acrylic fabrication consisted of
maxilla...
PROPULSOR
 Designed by Muhlemann
 Refined by Hotz
 It is a hybrid appliance with features of both he monobloc
and the s...
PROPULSAR
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ELASTIC OPEN ACTIVATOR (EOA)
 Designed by G. Klammt of Gorlitz of GERMANY (1955)
Design
 acrylic is reduced from anterio...
ELASTIC OPEN
ACTIVATOR
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WUNDERER‟S MODIFICATION
 Designed by Wunderer
 Indicated C1 III malocclusion
Design
 Activator split horizontally into ...
WUNDERERS MODIFICATION
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BOW ACTIVATOR OF A.M. SCHWARZ
 Designed by A.M. Schwarz
Design
 Consists of an upper half and lower half connected with ...
BOW ACTIVATOR
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THE KARWETZKY MODIFICATION
 Design by Karwetzky
Design : Similar to Bow activator of Schwarz but with improved
technique
...
KARWETZKY MODIFICATION
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Advantages
 Exerts a delicate force on dentition and tempero
mandibular joint
 Mobility of parts allows various mandibul...
REDUCED ACTIVATOR OR CYBERNATOR OF
SCHMUTH
 Design by Prof. G.P.F. Schmuth
 Design : Major portion of acrylic is trimmed...
REDUCED ACTIVATOR
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THE KINETOR
Designed by Hugo Stockfish (1951)
 It was an elastic activator which is easier for patient
to wear during the...
KINETOR
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HERREN’S ACTIVATOR
 Designed by Paul Herren
 He proposed that the posture of mandible during the
night, changes and alte...
LSU ACTIVATOR
 Robert Shaye follows the same principle and
design as Herren Activator. Lower incisors bite
on a plane for...
BIONATOR
Designed by Balters
Design
 Less bulky than activator
 Takes tongue as an essential factor in development of de...
BIONATOR
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HARVOLD-WOODSIDE ACTIVATOR
 Designed by Dr. Egie Harvold
 Differs from the classical activator in the following aspects....
ACTIVATOR HEADGEAR APPLIANCES
 Pfeiffer and Groberty in 1972 studied the
simultaneous use of cervical appliance and activ...
INITIAL EFFECTS OF TREATMENT OF CLASS II
MALOCCLUSION WITH THE HERREN ACTIVATOR-
HEADGEAR COMBINATION, AND JASPER JUMPER
A...
DENTAL AND SKELETAL CONTRIBUTIONS TO
OCCLUSAL CORRECTION IN PATIENTS
TREATED WITH THE HIGH-PULL HEADGEAR –
ACTIVATOR COMBI...
MAGNETIC ACTIVATOR DEVICE (MAD) AJO 1993 MARCH
Designed by Dr. Ali Darendilier in 1993
Design
 The conventional activator...
MAGNETIC ACTIVATOR DEVICE
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For more details please visit
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Activator slide/certified fixed orthodontic courses by Indian dental academy

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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.


Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
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Activator slide/certified fixed orthodontic courses by Indian dental academy

  1. 1. ACTIVATOR www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. INTRODUCTION  The term functional appliance refers to a variety of removable appliances designed to alter the arrangement of various muscle groups that influence the function and position of mandible in order to transmit forces to dentition and basal bone.  These muscular forces are generated by altering mandibular position sagitally and vertically resulting in orthodontic and orthopedic changes. www.indiandentalacademy.com
  3. 3.  A variety of different functional appliances are available. The appliance selected for treatment is based on type of anomaly, growth direction, growth prediction and presence or absence of functional disturbances.  Each proponent of different functional appliance, has conceived his own concept and working hypothesis www.indiandentalacademy.com
  4. 4. HISTORY AND DEVELOPMENT OF ACTIVATOR  In the year 1880 Dr. N.W. Kingsley wrote, in his treatise on oral deformity, that he had developed a maxillary plate with an inclined plane for the purpose of “Jumping the bite” forward in cases of extreme mandibular retrusion.  . The idea was further evolved by French dentist Dr. Pierre Robin, who published a paper in 1902 describing his “monobloc” appliance to be used for bimaxillary expansion. Incidentally, he also advocated the use of this appliance for the treatment of “glossoptosis”. But his concept of moving the mandible and the tongue forward to correct mandibular retrusion and free up the esophageal and tracheal passages survives down to this day. www.indiandentalacademy.com
  5. 5.  But then an individual arrived on the scene who took all the various ideas and theories about using the functional appliances to treat dental malocclusions, coordinated the appropriate information, and after some initial trial and error, devised an appliance that reflected the true genius that he was.  His name was VIGGO ANDRESEN, and his appliance was the Activator.  Andresen was originally Dane, But he eventually become Director of the orthodontic department in the Dental School at Oslo, Norway.  He developed an appliance similar to monobloc, except that in monobloc expansion screw was incorporated. Andresen was not aware of the monobloc appliance and its influence on the bone shape, size, and position leading to correction of sagittal malrelation in the growing child. He used the appliance to prevent relapse of the fixed appliance treated case. The appliance he developed was a modified Hawely type retainer on the maxillary arch and horseshoe shaped flange in the lower arch. After the period of 3 months he was surprised to see the complete sagittal correction and improved profile. www.indiandentalacademy.com
  6. 6.  He believed in the theories, expounded by Roux and Wolfe in the 1890s that changes in biomechanical function bring about corresponding changes in both internal structures of bone as well as external shape www.indiandentalacademy.com
  7. 7.  Andersen believed that many malocclusions were functional in origin and that if form followed function”, it followed that correct function would eventually lead to correct from.  The activator he constructed transmit the tissue-forming functional stimuli of the perioral and masticatory muscles, tongue, and teeth to the periodontal tissues, alveolar bone, and temporomandibular joint bringing about the eventual resolution of the structural Class II deformity.  Its use was confined to Class II, Division 1; Class II, Division2; and pseudo-Class III malocclusions.  The appliance consisted of an upper maxillary plate with an anterior flange extending into the lingual area of the mandibular arch that on closing held the lower jaw in a forward position relative to the maxilla with a bite opening of approximately 5mm between the posterior teeth. The appliance also had a labial bow or labial archwire across the maxillary anterior teeth for the purposes of stabilizing the appliance and retracting overly protruded maxillary anterior teeth. The appliance was meant to be worn by the patient only at night, and its projected treatment time consisted of 18 to 24 months. The life of appliance was about 9 months. They were initially made of Vulcanite. Therefore, several appliances were required to be fabricated in order to complete a case. www.indiandentalacademy.com
  8. 8. ANDRESEN APPLIANCE www.indiandentalacademy.com
  9. 9.  He was appointed as a professor at the Dental School at Oslo, Norway. Here he had the good fortune to strike up an alliance with a fellow staff member at the same institution, the Austrian- born periodontist and pathologist Karl Haupl.  A Physician by training, Haupl was a superb scientist of considerable international reputation. Haupl was extremely excited, for Andersen‟s findings coincide exactly with results he had already seen independently relative to tooth migration and tissue and bone reaction. www.indiandentalacademy.com
  10. 10.  To understand the working hypothesis of activator, Haupl tried to apply the functional adaptation hypothesis of “William Roux” to the clinical application of activator.  This become a foundation for the theoretical basis of functional jaw orthopedics.  His main focus was on the reaction of alveolar bone on normal and abnormal masticatory muscle function and it‟s influence in periodontium.  He explained that Andresen Activator causes muscle stimuli of adequate influence creating adaptational changes in the periodontal tissue and the alveolar bone.  At the same time there was a discussion regarding the growth stimulation, but Haupl was under the strong belief that growth is guided primarily by hereditary factors and only the extent of the growth changes can be influenced by functional stimuli this statement of opinion has lead to controversy between orthodontists and basic scientists. www.indiandentalacademy.com
  11. 11.  Together they further developed the appliance-induced mandibular advancement techniques, refined it, and unlike previous individuals, were able to support their clinical observations with sound research data.  Haupl was offered the prestigious position of Director of the Dental Clinic at the University of Prague. From such an eminent position, he had great leverage in convincing other European orthodontists that Andersen‟s method as an effective therapeutic method of “functional jaw orthopedics”, a term they coined together  Timely supportive data from men like A.M. Schwarz, whose active plates could move individual teeth and whose methods complimented and enhanced Activator therapy, coupled with the proof of men like A.H. Ketcham from America, that heavy force of fixed appliances caused pathologic root resorption, brought the European orthodontic community to applause for the new biologically superior method of removable appliance therapy. www.indiandentalacademy.com
  12. 12.  Everyone in Europe disagreed to its effectiveness.  .One of the controversies raised was the inability of some clinicians to obtain permanent mandibular repositioning.  This was due to the incorrect nature of construction bites used at that time and the lack of understanding of this important step in the beginning.  The bites were generally, at first, not taken with the mandible in an inferior or protruded enough position. By not gaining enough interocclusal space between the posterior teeth or without enough tension on the muscles of the jaws from proper protrusion of the mandible, the Activator‟s action and efficiency is greatly diminished.  The construction bites were initially taken with the mandible opened just beyond, the physiologic rest position. Generally, this was not enough. Gradually, as more clinicians experimented with the technique, they realized that the construction bite had to be taken with the mandible in a more open and protruded position. But despite these initial difficulties, the Activator was used in many thousands of cases throughout Europe with outstanding results. www.indiandentalacademy.com
  13. 13.  Moreover, one of the problems with wearing the Activator was its size.  It was a bulky appliance at first; and by virtue of the full palatal covering, it made speech very difficult. This was not considered an important drawback as the activator was to be worn only at night.  Another difficulty with this appliance, and with all appliances of that time, was that they had to be made out of vulcanite. When minor tooth movements were desired, gutta-percha melted with chloroform was used and “layered on” in order to make the appliance a little thicker behind the tooth that was to be moved. Another method of individual advocated the drilling of holes in various places in the vulcanite and gluing in small wooden pegs that would put pressure upon the teeth to be moved when the appliance was inserted. www.indiandentalacademy.com
  14. 14.  With the advent of modern acrylic, a new world of feasibility was created for the orthodontist using functional appliances. Its lightweight strength, low porosity, and ease of manipulation made this “wonder” material used for creating intraoral orthodontic devices.  The late-model Activators were made out of acrylic, rather than vulcanite, once this material become available. But they were still made in the traditional black color as were the original models in order to facilitate grinding high spots and various other adjustments. Thus, any excessive contact by the teeth on the appliance would cause a shiny spot to appear denoting the place where an adjustment was needed and where acrylic should be reduced.  The other eminent Orthodontists who worked on activator are Wooside, Petrik, Eschler, Herren, Harvold and Ahlgren. www.indiandentalacademy.com
  15. 15. PHILOSOPHIES OF MODE OF ACTION  According to the mode of action, there are two main principles. A third approach combines the two rationales.  According to the original Andresen Haupl concept the forces generated in activator therapy are due to muscle contractions and myotatic reflex activity. There is stimulation of the muscles by a loose appliance, and the moving appliance moves the teeth. The muscles function with kinetic energy, and intermittent forces are of clinical significance. A successful treatment depends on muscle stimulation, the frequency of movements of the mandible, and the duration of the effective forces. Activators with a low vertical dimension construction bite function this way. www.indiandentalacademy.com
  16. 16.  According to the second working hypothesis the appliance is squeezed the jaws in a splinting action. The appliance exerts forces that move the teeth to this rigid position. The stretch reflex is activated, inherent tissue elasticity is operative, and there is strain without functional movement. The appliance works using potential energy. For this mode of action in overcompensation of the construction bite in the sagittal or vertical plane is necessary. An efficient stretch action is achieved by the overcompensation and the viscoelastic properties of the contiguous soft tissues. www.indiandentalacademy.com
  17. 17.  The third approach enlists the modes of action of the preceding two. It can be called a transitional type of activator action, which alternately uses muscle contraction and viscoelastic properties of soft tissue. The appliances in this group have a greater bite opening than recommended by Andersen and Haupl, but they do not over compensates as do Harvold and Woodside. The stretch reflex resulting from activators in this group is seen as a longlasting contraction. The intermittent forces induced by the contractions are not as pronounced as in the original construction. Eschler observed the occurrence of both isometric and isotonic contractions when this appliance construction was used.  All the modes of action are dependent on the direction and degree of opening of the construction bite. By taking into account the individual characteristics of the facial skeleton, the individualized growth processes, and the goal of treatment, the clinician can fabricate the appliance to work according to the desired mode of action. www.indiandentalacademy.com
  18. 18. MODE OF ACTION  Andresen stated that this appliance has a stimulating effect on jaw development. In class II cases when the mandible is brought forward into Class I relationship, there is stimulation of protractors and elevators with stretching of retractors resulting in the change in functional pattern of muscle and the bone structures as they adopt to the new functional environment,  For stimulating these muscles, the appliance should be loosely fitting and as the patient every time tries to occlude, or swallow, upper and lower teeth contact resulting in jolts to the periodontal membrane. This acts as a stimuli for tissue rebuilding.  They were of the opinion that myotatic reflex activity and isometric muscle contraction induce musculo skeletal adaptation by inducing new mandibular closing pattern.www.indiandentalacademy.com
  19. 19.  Opposing to Andresen, Herren based his mode of action of the activator on the basis of spatial relation between position of mandible and postural rest position. He observed in sleeping patients that the activator showed no significant influence on the general behaviour of the wearer. Frequency of movements of mandible remained same with and without activator, neither there was increase in secretion of saliva, nor increase in swallowing movements. The muscles were in relaxed and tension less condition. Thus concluding that activator does not work in the way stated by Andresen.  As the activator does not have any anchorage except maxillary and lingual extension of acrylic, he was under the impression that at night appliance will not retain its position. A slight unconscious lowering of mandible will detach activator from maxilla. Therefore Herren activator is fixed by clasps to maxillary dentition and he also recommended a high vertical and sagittal displacement of mandible to prevent detachment of appliance. www.indiandentalacademy.com
  20. 20.  The Herren type or L.S.U. type activator and extraoral forward traction exert their action mainly through the sagittal repositioning of the mandible.  This kind of functional appliance seems to have a two step effect: during the time of wearing the appliance, the more forward positioning of the mandible is the cause of reduced growth of the lateral pterygoid muscle; simultaneously a new sensory engram is formed for the new positioning of the lower jaw.  During the time that the activator is not worn, the mandible is functioning in the more forward position in such a way that the retrodiscal pad will be much more stimulated than in the controls. The increased repetitive activity of the retrodiscal pad produces an earlier beginning of the condylar chondroblast hypertrophy and an increased growth rate of condylar cartilage. In other wards, the lateral pterygoid muscle does mediate the action of the activator but the stimulating effect on condylar growth appears to be produced during the time when the appliance is not worn www.indiandentalacademy.com
  21. 21.  According to Herren, mandible hyoid bone, tongues are considered to be the components of masticatory organ.  The movements of mandible can be active or passive. The active movements results from contraction of musculature. The passive movement resulting indirectly due to active influence of neighbouring structures.  Rest position of mandible can be active resulting from the active muscular contraction or passive where in the mandible is placed in rest position responding to equilibrium of acting forces.  As the activator is inserted, mandible is prevented from moving in all directions of space except caudally. Thus it is unable to assume most of the rest position that occur during nighttime wear. Forces which pull the mandible towards these rest positions are absorbed by the appliance and transmitted to the teeth and alveolar process. www.indiandentalacademy.com
  22. 22. CLASP KNIFE REFLEX  The basis for such severe increase in the displacement of mandible is the clasp knife reflex or autogenic inhibition or lengthening reaction.  When a spastic limb is flexed forcibly resistance is encountered. If the flexion forcibly carried further, the resistance to the flexion was found to disappear and previously rigid limb collapses readily. This phenomenon is called clasp knife reaction that is, muscle first resists, then relaxes.  The excessive stretch of the muscle brings into play some new influence which inhibits the stretch reflex and allows the muscle to be lengthened with little or no resistance  The receptors for clasp knife reflex are golgi tendon organs located in the tendon of the muscle and the stimulus for the reflex is excessive stretch, impulses conducted from the sensory nerve fibres of golgi tendon organ act on the motor neuron supplying the stretched muscle.  The output of motor neuron depend on the balance between 2 antagonistic inputs. One from golgi tendon organ inhibiting the muscle contraction, other from the nuclear bag of the muscle facilitating muscle contraction. The functional significance of the clasp knife reflex, is to protect the overload by preventing damaging contraction against stretching forces www.indiandentalacademy.com
  23. 23.  Rational behind Harvold Wood side hypothesis is that mandible normally drops open when the patient is sleep. If it is opened 3 to 4 mm by the appliance one of the two things happen, either appliance may fall out or it may be ineffective because the wider open sleep position  Harvold and Woodside doubted the actual contractions taking place when the patient is sleeping. They recommended wide open construction bite so that appliance does not fall off. They open the mandible with construction bite as much as 15mm beyond postural rest position. Muscle tension arises as a consequence of stretching of tissues and the over extended activator stretches the soft tissues like a splint. The appliance induces no myotatic reflex activity but instead a rigid stretch and builds up potential energy. www.indiandentalacademy.com
  24. 24.  The viscoelastic properties of muscle and the stretching of the soft tissues are decisive for activator action. During each force application, secondary forces arise in the tissues, introducing a bioelastic process. Thus not only the muscle contractions but also the viscoelastic properties of the soft tissue are important in stimulating the skeletal adaptation. Depending on the magnitude and duration of the applied force, the viscoelastic reaction can be divided into the following stages:  Emptying of vessels  Pressing out interstitial fluid  Stretching of fibres  Elastic deformation of bone  Bioplastic adaption www.indiandentalacademy.com
  25. 25.  Stretching of muscles give rise to stretch reflex contractions.  Stretch reflex by activator displacing mandible beyond rest position is tonic type. The tonic activity of the muscles varies with the level of wakefulness or sleep. In waking state, tonic activity is increased. In sleeping state, tonic activity is depressed and in deep sleep it is completely abolished.  When worn during day the activator elicits increased frequency of swallowing movements. Also as the activator is squeezed between the teeth, it elicits passive tension in the stretched muscles thus it transfers continuous force from the muscle to the teeth. During sleep when muscles are tonic, myoclonic twitches of tongue push the activator against the teeth. These intermittent forces are transmitted through the appliance to the teeth www.indiandentalacademy.com
  26. 26.  Eschler supported Andersen Haupl‟s concept based in muscle physiology experiments. He found action currents in patients wearing activator as compared to patients not wearing.  Eschler denies activators potential to activation of the muscle directly. Its effect depends on the stretch reflex. Without stretching of muscles, there will be no effect of the appliance and the effect is proportional to the degree of mandibular displacement. He recommends an inter occlusal clearance 4-6mm. He agrees with Andresen that increased frequency of mandibular movements occur when an activator is worn.  On insertion of the appliance, the mandible is elevated by isotonic muscle contractions succeeded by isometric contractions which is tonic in nature. Mandible assumes static position in contact with the appliance and is prevented from reaching the occlusion. The elevators and retractors remain contracted, fatigue of the muscle occurs. Muscle relax and the mandible drops down. When the muscles have recovered the cycle starts againwww.indiandentalacademy.com
  27. 27. Effects on Condyle  The influence of activator on the condyle is very much controversial.  The possibility of influencing condylar growth with functional orthodontic appliances is conditioned by psychogenetic and ontogenetic peculiarities of the condylar cartilage. In contrast to primary cartilages (epiphyses, sphenoccipital synchrondroses) growth is regulated to a high degree by local exogenous factors.  According to Moss and Petrovic condylar growth is an expression of a locally based homeostasis for the establishment and maintenance of a functionally coordinated stomatognathic system.  Petrovic has shown, the lateral pterygoid muscle has a decisive role in this growth. Forward posturing of the condyle activates the superior head of the lateral pterygoid. In young individuals this induces a cell proliferation in the condyle and a growth response.  Bireback and Melsen in 1984 laminographic study observed increased amount of condylar growth and remodellingof glaenoid fossa EJO-1984 EFFECT OF ACTIVATOR ON CONDYLAR GROWTH  Luder in 1981-82 observed two types of results with the activator treatment which may be sex related. In boys there was marked increase of mandibular relocation due to stimulated condylar growth. and it is possible to alter amount and direction of condylar growth to a clinically relevant extent by activator treatment .EJO 1981www.indiandentalacademy.com
  28. 28.  The activator can, to a limited degree, control the upper growth vector, supplied by the sphenoccipital synchondrosis, which moves the maxillary base in a forward direction. If the mandible cannot be positioned anteriorly, then maxillary growth can be inhibited and redirected. The growth and translation of the nasomaxillary complex can be influenced, particularly by activators of a special construction. www.indiandentalacademy.com
  29. 29. Condylar development and mandibular rotation and displacement during activator treatment (AJO 1982 Apr)  An analysis of the effects of activator treatment on the spatial development of the mandible over 11 months was performed via the metal implant method for a group of nineteen patients. A posteriorly directed condylar development, in conjunction with an anterior rotational pattern, was found to be optimal if a basal class II malocclusion is to be treated by means of a forward developmental displacement of the mandible www.indiandentalacademy.com
  30. 30. Effective temporomandibular joint growth and chin position changes: Activator versus Herbst treatment. A cephalometric roentgenographic study.EJO -2002  The comparison between the activator and the Herbst group revealed larger effective TMJ and chin changes during Activator therapy  The treatment effects showed marked group differences for both the amount and direction of effective TMJ changes. The changes were vertical and slightly anterior in the Activator group, and predominantly posterior in the Herbst group.  The chin changes, the treatment effects for the Herbst group exceeded those for the Activator group in both directions, caudally and anteriorly. The Activator group showed anterior rotation and the Herbst group a slight posterior rotation of the mandible. www.indiandentalacademy.com
  31. 31. changes in activator treatment: A cephalometric roentgenoraphic study  The present investigation revealed that effective condylar growth can be increased and the chin position can be changed by activator treatment. Thus activator treatment induces skeletal changes, although not always in the desired (sagittal) therapeutic direction. (Angle Ortod 2001: 71: 4 – 11). www.indiandentalacademy.com
  32. 32. Effects on maxilla  Regarding activator effect on maxilla authors like Harvold and Vargervik, Jacobson have observed anterior downward rotation of maxilla.  Studies by Harvold and Vargervik (1971) indicated that forward development of maxilla was retarded.  Vargeroik and Harvold (1985) found that activator inhibited the horizontal growth of maxilla by 2mm.AJO 1985 NOV www.indiandentalacademy.com
  33. 33. A cephalometric analysis of skeletal and dental changes contributing to Class II correction in activator treatment (AJO 1984 Feb)]  The purpose of this investigation was to evaluate cephalometrically the mechanism of antero-posterior occlusal changes in activator treatment.  The following results were found (1) The improvement in occlusal relationships in the molar and incisor segments was about equally a result of skeletal and dental changes. (2) Overjet correction averaging a 2.4 mm more mandibular growth than maxillary growth, a 2.5 mm distal movement of the maxillary incisors, and a 0.1 mm mesial movement of the mandibular incisors (3) Class II molar correction averaging 5.1 mm was a result of 2.4 mm more mandibular growth than maxillary growth, a 0.4 mm distal movement of the maxillary molars, and a 2.3 mm mesial movement of the mandibular molars. (4) When the findings were compared with longitudinal records of persons with normal occlusion (Bolton Standards), activator treatment seemed to inhibit maxillary growth, move the maxillary incisors and molars distally, and move the mandibular incisors and molars mesially. www.indiandentalacademy.com
  34. 34. EFFECTS ON MANDIBLE  The effect of the activator on the mandible can be indirect as a result of growth of the condyle plus the rotation of the mandible anteriorly leading to increase in the mandibular length  studies by Williams and Melson showed that the improvement of skeletal class II was because of posterior superior direction of condylar growth combined with an anterior rotation of the mandible, and also they concluded that the forward positioning of the mandible aided the correction of the skeletal discrepancy, it was found to be positively correlated to the vertical development of the posterior part of the mandible.  Dr. Remmer in his study on the cephalometric changes associated with treatment using the activator, Frankerl appliance, and fixed appliance observed that the activator was found to be more effective in correcting the sagittal discrepancy than Frankel appliance.  Studies by Freunthaller on cephalometric observation in Class II division I malocclusion treated with the activator, there was significant movement of the entire mandible anteriorly leading to correction of Class II malocclusion.  Studies by Dr. Luder has also supported that activator treatment has a positive influence on the mandible. www.indiandentalacademy.com
  35. 35. Mandibular changes during functional appliance treatment AJO 1993 Aug.  The purpose of this prospective trial was to determine the changes in position and size of the mandible in children treated with either the Frankel function regular or Harvold activator.  The main effects of both appliances were to allow vertical development of the mandibular molars and increase the height of the face. The Harvold appliance proclined the lower incisors and increased mandibular arch length. We could find no evidence to support the view that either appliance was capable of altering the size of the mandible. www.indiandentalacademy.com
  36. 36. Response to activator treatment in Class II malocclusions  A clinical study was designed to disclose the effects of activator treatment in the correction of Class II malocclusions.  Treatment results shows (1) inhibition of forward growth of the maxilla, (2) inhibition of mesial migration of maxillary teeth, (3) inhibition of maxillary alveolar height increase and extrusion of mandibular molars, (4) increased growth of the mandible, (5) anterior relocation of the glenoid fossa, (6) mesial movement of mandibular teeth www.indiandentalacademy.com
  37. 37. Effects on Soft Tissues  Very little study was carried out on effects of activator on the soft tissues, but however studies by Forsberg and Odenrick 1981 observed that upper lip retrusion was significantly more prevalent in treated Class II group than in control group. Nose showed equal forward growth in both the groups. Soft tissue pogonion is further anterior in treated group. Further more it was found that in the treated group lip balance was not achieved in patients with relatively retrognathic profiles or those with steep mandibular planes. www.indiandentalacademy.com
  38. 38. TIMING OF TREATMENT  Reey, Eastwood, says that mixed dentition period was best for activator treatment.  Experience clinicians like Bjork concluded that activator was Most effective in decidous dentition Less effective in mixed dentition and Limited effect in permanent dentition  It is also effective in neonatal and Juvenile period. As prechondroblastic and condroblastic activity is increased in condyle according to Carlson et al. www.indiandentalacademy.com
  39. 39. INDICATIONS  Partial or total correction of Cl II Div 1 cases  Partial or total correction of Cl II Div 2 cases  Partial or total correction of Cl II cases.  Correction of Cl I open bite (Dental not skeletal).  Correction of Cl I deep bite case  As a preliminary treatment before major fixed appliance therapy  As post treatment retention in children with deep bite caused by overclosure.  Children with lack of vertical development in lower facial height. www.indiandentalacademy.com
  40. 40. Advantages  Treatment may be started during late deciduous or mixed dentition period.  Disturbances or suppression of normal stomatognathic functions, which occur usually with conventional fixed appliances is avoided with activators.  finger sucking, abnormal tongue posture and function, mouth breathing can be easily corrected.  Activators maintain the beneficial therapeutic effect for long periods of time without requiring the usual office visits which is needed in fixed appliances.  Repairs are seldom needed, and they are simple to perform and the cost factor is low, chair side time is minimal.  For the post treatment retention the same appliance can be used.  Activators make possible the combination of prosthodontic and orthodontic treatment at the same time with built in space control.  No impairment of esthetics during the day since the appliance is used most during nighttime.  The forces employed are physiological and produce no damage either to teeth or supporting tissue and also injury to the soft tissue is negligible.  The teeth are not banded there is no risk of decalcification from cement less conducive to carious incidence and good hygienewww.indiandentalacademy.com
  41. 41. DISADVANTAGES  Cannot be used inpatient who are un co- operative.  Greater selectivity of cases is necessary than with fixed appliance.  Age is a factor in some types of treatment which will prevent the use of activator.  If crowding is of marked degree the use of the activator is limited.  No detailed precise finishing of occlusion. www.indiandentalacademy.com
  42. 42. SELECTION OF CASES  Following are the empirical criteria for case selection. A. Skeletal  A mild skeletal Cl II facial pattern.  A decreased lower face height which is based on a profile assessment from the nostril to chin point.  Proportionate balance between upper and midface heights www.indiandentalacademy.com
  43. 43. B. Dental  No crowding in the upper and lower arches.  A good integral mandible with no rotations and no displacement of the teeth.  A relatively flat mandibular occlusal plane.  No labial tipping of the mandibular incisors relative to the mandibular plane.  A moderate deep anterior over bite, either closed or slightly open, with a 50% to 70 vertical anterior overlap.  A maxillary labial segment that is proclined with or without spacing  no mid line asymmetry. www.indiandentalacademy.com
  44. 44. C. Soft tissue  Competent or potentially competent lips in which the lip well as capable of stabilizing the upper anterior teeth after correction has taken place.  Preferably a muscular pattern that does not exhibit undue tightness of lips and cheeks.  D. Respiratory  No nasal obstruction or chronic respiratory disorder  C. Emotional  1. Keen patient interest and desire and potential co-operation form both patient and parent www.indiandentalacademy.com
  45. 45. TREATMENT PLANNING PRETREATMENT CONSIDERATIONS  Before activator treatment is started – forward movement of mandible is checked to see that it is not blocked by occlusal interferences that makes the correction of disto occlusion impossible.  For example buccal crossbite of upper 1st premolar impedes the forward movement of the mandible www.indiandentalacademy.com
  46. 46. DIAGNOSTIC PREPARATIONS  A. Patient compliance: It is very essential. It is very important to assess clinically patient‟s somatic, psychological aspect and motivation potential. Objective  Motivation potential can be enhanced by visual treatment. Visual treatment objective is creating an “instant correction” in a Cl II malocclusion by moving the mandible forward into an anterior more normal sagital relationship so that the patients sees the potential and objective of correction and is more likely to work towards the goal. It also helps the clinician to diagnose and anticipate whether therapeutic goal is an improvement. www.indiandentalacademy.com
  47. 47. Study model Analysis  Following information can be derived form the study model.  First molar relationship in habitual occlusion.  Nature of midline discrepancy, if any (dentoalveolar non coincidental midlines cannot be corrected by activator).  Symmetry of dental arches  Curve of spee is checked to diagnose whether it can be leveled.  Degree of crowding and dental discrepancies are checked. www.indiandentalacademy.com
  48. 48. Functional Analysis  Precise registration of postural rest position is done as vertical opening of construction bite depends on this.  Path of closure from postural rest to habitual occlusion is checked and sagital / transverse deviations are recorded.  TMJ is palpated. It is also auscultated for clicking and crepitus.  Interocclusal clearance and freeway space is checked.  Mode of respiration is checked (oral, nasal, oronasal). www.indiandentalacademy.com
  49. 49. Cephalometric Analysis  It is done to establish the nature of craniofacial morphogenetic pattern to be treated.  It also provides most important information for planning the construction bite.  The direction of growth whether average, horizontal or vertical can be predicted.  Differentiation between position and size of jaw bases is observed.  Morphologic characteristics are also observed.  The axial inclinations and positions of maxillary and mandibular incisors are recorded.  Hand wrist x-rays are taken to assess growth status www.indiandentalacademy.com
  50. 50. CONSTRUCTION BITE  The construction bite is an intermaxillary wax record used to relate the mandible to the maxilla in the three dimensions of space. They are used to reposition the mandible in order to improve the skeletal inter-jaw relationship. The bite registration involves repositioning the mandible in a forward direction as well as opening the bite vertically. GENERAL CONSIDERATIONS FOR CONSTRUCTION BITE  In case the overjet is too large, the forward positioning is done step wise in 2-3 phases.  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.www.indiandentalacademy.com
  51. 51.  In taking a construction bite one should look at the bite in three different planes of space  Sagital  Vertical  Frontal www.indiandentalacademy.com
  52. 52. A. Sagittal or anterior positioning of mandible should not exceed 7-8 mm or ¾ mesiodistal dimension of first permanent molar.  For example in class II cases anterior positioning to this magnitude is contraindicated when:  The overjet is too large.  There is severe labial tipping of maxillary incisors  When there are lingually erupted incisors www.indiandentalacademy.com
  53. 53. B. Vertical or Opening the bite:  The vertical and sagittal relationship are intimately linked. Guiding Principles  Mandible must be dislocated in atleast one direction from postural rest position. This is essential to activate musculature and induce a strain in the tissues.  If magnitude of forward positioning is great 7-8 mm then vertical opening should be minimal, so that muscles are not overstreched.  If extensive vertical opening is required the mandible must not be positioned anteriorly www.indiandentalacademy.com
  54. 54.  C. Frontal or Midline establishment  midlines of the maxilla and mandible should coincide when the construction bite is taken regardless of shifting of teeth in one or both the jaws www.indiandentalacademy.com
  55. 55. Sequential steps for construction bite  Amount of horizontal and vertical displacement of the mandible is determined. Mark the amount of horizontal shift on the buccal surfaces of first molars.  Show the patients on the cast and a mirror the direction in which the mandible should move. Now practice the movement by guiding the mandible in the desired direction. Advise the patient to move according to verbal direction and stop when asked to do so.  Soften a sheet of wax and make a roll 1 cm in diameter. The shape of the roll should be conformed to the lower dental cast. Now press the roll so that only buccal teeth are covered, in front the wax lies lingual to the incisors. Make grooves to indicate midline.  Remove excess wax on the distal ½ of the last molar and retromolar region www.indiandentalacademy.com
  56. 56.  Transfer the wax to the patients mouth fitting it on the lower arch, in the same manner.  Ask the patient to move the mandible forward as practiced and bite till the proper amount of vertical opening is achieved.  Remove wax from the mouth and chill it. Remove excess wax till the occlusal surface of the molars are visible. All excess wax contacting the soft tissues, interproximal papilla and palate are removed.  Place the wax bite between the casts. Check whether the mandible has moved in the desired amount in the three planes of space. If incorrect, wax is added on the superior surface and repeated.  Replace hard wax bite in the patient‟s mouth to check for a proper fit.  Construction bite should be taken on the patient and not on articulated models. Construction bite prepared on casts have the following disadvantages:  Appliance does not fit and these are frequent disturbances during sleep  Asymetrical biting on the appliance  Greater stress on lower incisors which can cause unwanted procumbancy www.indiandentalacademy.com
  57. 57. LOW CONSTRUCTION BITE WITH MARKED MANDIBULAR FORWARD POSITIONING:  This kind of construction bite is characterized by marked forward positioning of the mandible but minimal vertical opening.  As a rule of thumb the anterior advancement should not exceed more than 3 mm posterior to the most protrusive position. Vertically the opening is minimal and is within the limits of the inter-occlusal clearance. This kind of activator constructed with marked sagittal advancement but minimal vertical opening is called an “H activator”. The H activator is indicated in a patient with class II, division 1 malocclusion having a horizontal growth pattern www.indiandentalacademy.com
  58. 58. High construction bite with slight anterior mandibular positioning:  The mandible is positioned anteriorly by 3-5 mm only and the bite is opened vertically by 4-6 mm or a maximum of 4 mm beyond the resting position. This kind of activator constructed with minimal sagittal advancement but marked vertical opening is called a “V activator”. The V type of activator is indicated in a Class II, Division 1 malocclusion having a vertical growth pattern. www.indiandentalacademy.com
  59. 59. Construction bite without forward positioning of the mandible:  Sometimes a construction bite without forward positioning of the mandible is made in cases such as deep bite and open bite www.indiandentalacademy.com
  60. 60. Construction bite with opening and posterior positioning of the mandible:  In Class III malocclusion, bite is taken after retruding the mandible to a more posterior position. In addition, the bite is opened sufficiently to clear the bite. In general a vertical opening of 5 mm and a posterior positioning of about 2 mm is required. www.indiandentalacademy.com
  61. 61. FABRICATION  After the construction bite is taken and checked on the patient and rechecked on stone working models, the working models are mounted on the fixator.  The FIXATOR allows upper and lower parts to be made separately and both parts are united in the correct construction bite on the fixator.  The extensions of acrylic body and flanges are drawn on the upper and lower working models. The wire elements can also be drawn  Each labial bow consist of a horizontal middle section, two vertical loops, and wire extensions through the canine or deciduous first molars and they are embedded din the acrylic body.  The horizontal portions crosses above convexity in deep bite and below convexity in open bite.  The bow is active or passive and influences soft tissue without touching teeth.  The wire usually used is 0.8 mm round stainless steel.. www.indiandentalacademy.com
  62. 62. Fabrication of the Acrylic portion  The appliance consists of upper, lower and interocclusal parts.  In the upper and lower, the dental and gingival portions can be differentiated.  In the lower cast, the gingival portion can be extended posteriorly.  Flanges for upper cast are usually 8-12 mm high in gingival area covering the alveolar crest. Lower acrylic plate is 5-10 mm high but in molar region it is as great as 10-15 mm. www.indiandentalacademy.com
  63. 63. www.indiandentalacademy.com
  64. 64. STEPWISE PROCESS FOR ACRYLISATION  Before acrylic portion are made the casts are put in a water bath for 20 min. Then isolated and dried.  Fixation of wire elements and acrylic free areas are covered with wax.  Upper and lower portions are moulded from self curing acrylic.  The upper and lower parts are joined with acrylic in interdental areas.  After polymerization of the appliance it is ground and polished. However it is not ground for specific tooth guidance. This is done with the patients on the chair. www.indiandentalacademy.com
  65. 65. TRIMMING OF THE ACTIVATOR  After fabrication of the activator it is usually found to fit tightly as acrylic is interposed between the upper and lower occlusal surfaces. 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.  Selective trimming of acrylic is done in the direction of tooth movement  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 become polished.  Approximate trimming can be done on the plaster casts. However, final trimming should be done at the chair side. www.indiandentalacademy.com
  66. 66. 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 below the area of greatest convexity i.e incisally, to aid in the intrusion. www.indiandentalacademy.com
  67. 67. www.indiandentalacademy.com
  68. 68.  . In case intrusion posteriors is needed then only the cusp tips are loaded with acrylic. The fossae and fissures are free of acrylic. This applies a vertical intrusive force on the molars. www.indiandentalacademy.com
  69. 69.  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 above the area of greatest convexity i.e in the gingival 1/3 of the labial surface www.indiandentalacademy.com
  70. 70.  In case of molars, extrusion is brought about by loading the lingual surface above the area of greatest convexity in maxilla and below the area of greatest convexity in mandible www.indiandentalacademy.com
  71. 71. TRIMMING OF THE ACTIVATOR FOR SAGITTAL CONTROL  Protrusion of incisors: In case the incisors be protruded, 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 contacting the teeth www.indiandentalacademy.com
  72. 72.  Retrusion of incisors: The acrylic is trimmed away form the lingual surface and an active labial bow is used to bring about retrusion of the incisors www.indiandentalacademy.com
  73. 73.  Movement of posterior teeth in sagittal plane: The teeth in the buccal segment can be moved mesially and distally to help in treating Class II and Class III malocclusion. 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 surfacewww.indiandentalacademy.com
  74. 74. MESIAL MOVEMENT OFMOLARS DISTAL MOVEMENT OF MOLARS www.indiandentalacademy.com
  75. 75. 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 www.indiandentalacademy.com
  76. 76. MODIFICATIONS OF ACTIVATOR  The original Andresen appliance made of vulcanite or acrylic fabrication consisted of maxillary and mandibular components joined together. Since appliance is worn at night during sleep due to the slackening of the mandible the appliance is rendered ineffective and there is frequent loss of appliance during sleep. Hence to overcome the above drive backs, modifications were made. www.indiandentalacademy.com
  77. 77. PROPULSOR  Designed by Muhlemann  Refined by Hotz  It is a hybrid appliance with features of both he monobloc and the simple oral screen. Construction bite is smaller compared to activator with the mode of action same as that of activator. Design  Has no wire components and made completely with acrylic. The acrylic between occlusal surface of the 1st molar stabilizes appliance, with improvement in intermaxillary relations. The appliance is reactivated by adding acrylic in the upper anterior segment. Indication  In cases of maxillary dentoalveolar protrusion Advantage  Light weight – minimum bulk of appliance  It effects changes in alveolar process and teeth in maxillary anterior segment.www.indiandentalacademy.com
  78. 78. PROPULSAR www.indiandentalacademy.com
  79. 79. ELASTIC OPEN ACTIVATOR (EOA)  Designed by G. Klammt of Gorlitz of GERMANY (1955) Design  acrylic is reduced from anterior palatal region to restore exteroceptive contact between tongue and palate. Advantages  No obstruction to oral cavity  Reduced size comfortable to the patient  Can be used during day also. Disadvantages  Construction bite cannot be opened too much because vertically the tongue function is not under control and may thrust into interincisal gap.  Lack of support in cutaway area is disadvantageous. www.indiandentalacademy.com
  80. 80. ELASTIC OPEN ACTIVATOR www.indiandentalacademy.com
  81. 81. WUNDERER‟S MODIFICATION  Designed by Wunderer  Indicated C1 III malocclusion Design  Activator split horizontally into an upper half and lower half which are connected with a screw situated in an extension of mandibular portion behind the maxillary incisors. Opening of the screw causes maxillary portion to move anteriorly and a reciprocal back thrust on mandible is effected. Retention is from occlusal surface of buccal segment. The screw was designed by Weise www.indiandentalacademy.com
  82. 82. WUNDERERS MODIFICATION www.indiandentalacademy.com
  83. 83. BOW ACTIVATOR OF A.M. SCHWARZ  Designed by A.M. Schwarz Design  Consists of an upper half and lower half connected with an elastic bow. Advantages  Step by step forward positioning can be done  Transverse mobility can be brought  The bow can be activated only on one side for correction as unilateral distoocclusion  Independent maxillary or mandibular expansions can be effected by incorporation of a screw. Disadvantages  Easily distorted  Difficulty in adapting loops  Breakage of bow portion Indications  Treatment of CI II div I malocclusion in deciduous dentition www.indiandentalacademy.com
  84. 84. BOW ACTIVATOR www.indiandentalacademy.com
  85. 85. THE KARWETZKY MODIFICATION  Design by Karwetzky Design : Similar to Bow activator of Schwarz but with improved technique  Consists of maxillary and mandibular active plates joined by a‟U‟ bow in 1st permanent molar region. Acrylic covers lingual tissue, gingivae, teeth and also occlusal aspects of all teeth.  Construction bite is done with mandible in postural rest position  Forward position of mandible is done in stages  The Labial bow is made from 0.9 mm round stainless steel wire, for retention  Various other elements could be incorporated  Acrylic between upper and lower parts are made flat and joined by a „U‟ bow made of 1.1 mm round stainless steel wire.  Depending upon the placement of ends of the „U‟ bow – three types of Karwetzky activator are created.  Type I - for CI II Div 1 malocclusion  Type II - for CI III malocclusion  Type III - used in facial asymmetry and lateral crossbite www.indiandentalacademy.com
  86. 86. KARWETZKY MODIFICATION www.indiandentalacademy.com
  87. 87. Advantages  Exerts a delicate force on dentition and tempero mandibular joint  Mobility of parts allows various mandibular movements making it more comfortable and reinforces various functional stimuli.  Supplements treatment of certain jaw fractures  Used with certain types of orthognathic surgeries, in adults  Correction may be achieved quickly within 5-8 months making it a versatile appliance  Screws, labial bows, springs can be used to enhance appliance action. www.indiandentalacademy.com
  88. 88. REDUCED ACTIVATOR OR CYBERNATOR OF SCHMUTH  Design by Prof. G.P.F. Schmuth  Design : Major portion of acrylic is trimmed off  Advantage  Easier to construct customary labial bows are used auxillaries also can be used. According to Schmuth “It is not a new method or a new appliance but an adaptation of the activator to use principles of myofunctional appliance in the simplest manner www.indiandentalacademy.com
  89. 89. REDUCED ACTIVATOR www.indiandentalacademy.com
  90. 90. THE KINETOR Designed by Hugo Stockfish (1951)  It was an elastic activator which is easier for patient to wear during the day.  It was a night time wear appliance and required a treatment time of 2 to 4 years.  active operation of various screws and springs added to the appliance.  it is a complicated system and subject to breakage, difficulty of construction, and adjustments.  It does have the capabilities of expanding the arches in all three directions, sagitally, vertically and horizontally with jackscrews, but does violate the principle of simplicity. www.indiandentalacademy.com
  91. 91. KINETOR www.indiandentalacademy.com
  92. 92. HERREN’S ACTIVATOR  Designed by Paul Herren  He proposed that the posture of mandible during the night, changes and alternates with its normal posture in conjunction with orofacial function during the day.  So, Herren modified that activator by  Overcompensating the vertical position in construction bite registration  Seating firmly the appliance against maxillary dental arch with arrowhead clasps. Jackson clasp also can be used. Construction bite:  Differs from Andreson activator in the sagital positioning which is greater than the vertical opening.  Anterior positioning is 3-4 mm beyond neurtroocclusion  Vertical positioning is 2-4 mm apart incisal edge. Uses  To correct CI II malacclusion  To retard forward growth of maxilla  To reposition the mandible  Successful results achieved during transitional as well as early permanent dentition  High rate of stablity and success www.indiandentalacademy.com
  93. 93. LSU ACTIVATOR  Robert Shaye follows the same principle and design as Herren Activator. Lower incisors bite on a plane formed by acrylic so that growth in occlusal direction is restricted.  Acrylic freed from occlusal aspects of posterior teeth enhances eruption of premolars and molars and decreases the curve of spee www.indiandentalacademy.com
  94. 94. BIONATOR Designed by Balters Design  Less bulky than activator  Takes tongue as an essential factor in development of dentition  The Bionator maintains the forward position, preventing the deleterious parafunctional effects at night.  The construction bite is opened slightly with mandible in a forward position and the lower incisors can then be capped. No grinding is done thus when the acrylic is worn, it grasps or leads both uypper and lower buccal segments, guiding the mandible forward during the clenching or bruxing activity.  The Bionator is an effective appliance for treating functional or mild skeletal Class II malocclusions in the mixed and transitional dentitions.  patient compliance is excellent for both day time and night time wear  . A special indication is in the treatment of TMJ patients who have bruxism and clenching, clicking and crepitus. www.indiandentalacademy.com
  95. 95. BIONATOR www.indiandentalacademy.com
  96. 96. HARVOLD-WOODSIDE ACTIVATOR  Designed by Dr. Egie Harvold  Differs from the classical activator in the following aspects.  Degree of opening is greater  Labial arch wire is formed very differently from the conventional activator  The degree of opening is atleast 5 mm more – beyond the freeway space so that an increased effect of myotatic reflex is effected. It also has an added effect of visco elastic properties of connective tissue and muscles of face. The acrylic design is brought about by trimming out in the buccal segments.  In the upper: only the cusp-tips are seen through the wax spacer thus putting a restraining effect on the maxillary buccal segments.  Lower activator acts directly on the mandibular mucopesitosteum and via this to the basal bone.  In contrast to Andersen appliance where untrimmed facets cause forward movement of teeth. This Activator has generous lingual flanges which provide good retention.  Labial arch extends from premolar to premolar, usually passive and rests at the junction of gingival and middle 1/3 of the anteriors – 1.5 to 1 mm away from the canines. 0.8 or 0.9 mm round stainless steel wire are used. www.indiandentalacademy.com
  97. 97. ACTIVATOR HEADGEAR APPLIANCES  Pfeiffer and Groberty in 1972 studied the simultaneous use of cervical appliance and activator. Stockli and Teuscher also conducted studies on the effects of activator headgear therapy.  With activator headgear treatment the dentoalveolar reactions in the upper jaw and skeletal reactions in the lower jaw contribute about equally to the correction of Class II malocclusions.  Cervical appliance  Slows down and interrupts growth of maxilla  It initiates a distal movement of the anchor molars and to some extent adjacent teeth.  Tips anchor teeth if desired  Extrudes the molars and opens the bite  Tips anterior part of the palate down.www.indiandentalacademy.com
  98. 98. INITIAL EFFECTS OF TREATMENT OF CLASS II MALOCCLUSION WITH THE HERREN ACTIVATOR- HEADGEAR COMBINATION, AND JASPER JUMPER AJO 1997 JULY.  The initial effects of treatment of Class II, Division 1 malocclusion with an activator, according to Herren (27 patients), with an activator – deadgear combination (20 patients), or with the jasper jumper appliance (25 patients) were studied on lateral cephalograms from before and after 6 to 8 months of treatment.  Skeletal changes accounted for 42%, 35%, and 48% of the overjet correction by the Herren-type activator, the headgear-activator, and the jasper jumper, respectively.  The correction of the molar relationship occurred to 55%, 46%, and 38% by skeletal changes in the respective groups. www.indiandentalacademy.com
  99. 99. DENTAL AND SKELETAL CONTRIBUTIONS TO OCCLUSAL CORRECTION IN PATIENTS TREATED WITH THE HIGH-PULL HEADGEAR – ACTIVATOR COMBINATION AJO – 1990 JUNE.  The purpose of this study was to examine dental and skeletal changes in patients treated with the high-pull headgear – activator combination. The results showed that class II correction often was achieved by distal repositioning of the maxillary teeth (mean, 0.07mm) and mesial repositioning of the mandibular teeth (mean, 3.3 mm) with a wide range of variation. www.indiandentalacademy.com
  100. 100. MAGNETIC ACTIVATOR DEVICE (MAD) AJO 1993 MARCH Designed by Dr. Ali Darendilier in 1993 Design  The conventional activator is constructed as a two piece, upper and lower activator. Samarium Cobalt magnets are used in attractive or repelling mode to achieve orthodontic and orthopaedic correction.  Modifications  Magnetic Activator Device : MAD I - For Mandibular deviations  Magnetic Activator Device : MAD II - For Class II malocclusion  Magnetic Activator Device : MAD III - For Class III malocclusion  Magnetic Activator Device : MAD IV - For open bite malocclusion Advantages:  Continuous force  Freedom of movement for the mandible www.indiandentalacademy.com
  101. 101. MAGNETIC ACTIVATOR DEVICE www.indiandentalacademy.com
  102. 102. www.indiandentalacademy.com Thank you For more details please visit www.indiandentalacademy.com

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