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Activators/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 …

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 ,or call

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  • 1. ACTIVATOR INDIAN DENTAL ACADEMY Leader in continuing dental education
  • 2. HISTORY  Kingsley in 1880 introduced the term- jumping the bite for patients with mandible retrusion. He inserted a vulcanite palatal plate consisting of an anterior incline that guided the mandible in a forward position when the pt closed on it. This corrected the sagittal relationship without tipping the lower incisors forward.  Hotz Vorbissplate was a modification of Kingsley plate. He used it in case of deep bite retrognathism, when the overbite was likely to cause a functional retrusion and the lower incisors were lingually inclined by the hyperactivity of the mentalis muscle and lower lip.
  • 3.  The activator was originally used by Andresen with vertical extensions to contact the lingual surfaces of mandibular teeth. He developed a mobile loose-fitting appliance that transferred functioning muscle stimuli to the jaws, teeth and supporting tissues.  The progenitor of the appliance was a modified Kingsley plate that Andersen used as a retainer over summer vacation for his daughter after he removed fixed appliance used to correct distocclusion. Seeing the improvement with this retainer, he called it biomechanical working retainer.
  • 4.  Pierre Robin – developed monobloc prior to Andersen appliance.  Andersen became associated with Haupl at the university of Oslo. Both termed the appliance as Activator because of its ability to stimulate muscle forces.  Haulp concept of individual optimum. The limitation of the appliance is that it cannot create a large mandible from a small one, but can help pt achieve optimal size consistent with morphogenetic pattern.  The original appliance combined an upper and a lower plate at the occlusal plane. Only one wire element was used- a labial arch for the upper ant. teeth. To achieve expansion, the appliance was split in the centre and a flexible coffin spring was incorporated.
  • 5. DRAWBACK OF ACTIVATOR THERAPY 1. Dual bite can be a late consequence of activator treatment with a false indication. Indicated in retroposition of the condyle in the fossa as a result of dominant retrusive activity of the posterior temporalis, deep masseter and the hyoid musculature associated with deep bite. 2. Jumping the bite should be performed without proclination of the lower incisors. Failure of activator therapy occurred as a result of overjet reduction due to proclination of teeth instead of bodily anterior positioning of the mandible.
  • 6. EVOLUTION OF APPLIANCE  Eschler – developed modification of the labial bow that improved intermaxillary effectiveness. One part was active, moving the teeth, the other was passive, holding the soft tissue of the lower lip away and thus enhancing the tooth movement desired.
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  • 8.  The initial appliance was worn at night and hence its bulk was not critical. Subsequent modifications made to reduce the bulk allowed an increase in wearing time. They were two types of modifications- 1. Some appliance consist of one rigid acrylic mass for the maxillary and mandibular arches but with reduced volume/bulk. a. Appliance were reduced in the anterior palatal region- open activator. Their goal is to restore exteroceptive contact between the tongue and palate, which is prevented in the classical activator. Pt prefer it as they are reduced in the linguoincisal area and do not obstruct the oral cavity.
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  • 10. disadvantages- construction bite cannot be opened too far vertically because it impairs the tongue function. The tongue may thrust into the anterior interincisal gap, creating a postural and functional abnormality. elastic open activator ( Klammt)- lack of support in the cutaway area of the appliance, especially if guidance of erupting teeth or expansion is necessary. b. Appliance with reduced alveolar region and with cross palatal wires instead of full acrylic plate. They are supported/anchored dentally. Hence due to their tooth borne anchorage their use is limited and management can be difficult. The labial bow eliminates abnormal muscle pressure by extending into the buccal vestibule area.
  • 11. 2. Appliance consist of two parts joined with wire bows. The muscle impulse are reinforced by the wire elements incorporated in the design. The flexibility of the appliance permits mandibular movements in all directions. a. Schwartz double plate b. Stockfish- elastic activator Difference in the mode of action of rigid one piece activator (long lasting tonic phase reflex contraction) and flexible two piece joined by intermaxillary wiring (transient phase reflex contraction)
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  • 14. FORCE ANALYSIS  When activator activates the muscles, various types of forces are created- a. Static force- permanent and vary in magnitude and direction. They do not appear simultaneously with the movement of mandible. Eg- forces of gravity, posture and elasticity of soft tissue and muscle. a. Dynamic force- interrupted, appear simultaneously with the movements of the head and body and have a higher magnitude than static force. Eg- swallowing a. Rhythmic force- associated with respiration and circulation. They are synchronous with breathing and their amplitude varies with the pulse. Imp. In stimulating cellular activity. Mandible transmits rhythmic vibrations to the maxilla. The applied forces are intermittent and interrupted. Force application to the teeth are intermittent. Removal of activator from mouth interrupts these forces.
  • 15.  Two principles are applied in modern activator therapy- force application- muscle force elimination- the dentition is shielded away from normal and abnormal functional and tissue pressure by pads, shields and wire configuration.
  • 16.  Types of forces employed in activator therapy- a. Natural force- growth potential, eruption and migration of teeth. These can be guided, promoted or inhibited by the activator. a. Artificially functioning forces- muscle contraction and stretching of soft tissues initiate forces when the mandible is relocated from its postural rest position by the appliance. The activator stimulates and transforms the contractions. Whereas the forces may be muscular in origin, their activation is artificial. sagittal plane- effect on the condyle vertical plane- teeth and the alveolar process are loaded with or relieved of normal forces. If the construction bite is high it will inhibit the growth of maxilla and influence the inclination of the maxillary base. transverse plane- midline correction c. Various active elements (springs, screws) can be built into the activator to produce an active biomechanical type of force application.
  • 17. CONSTRUCTION BITE Horizontal H activator- low construction bite with marked forward mandibular positioning a. Class II functional retrusion b. Class II Div 1 malocclusion with sufficient overjet c. Class II Div 1 malocclusion with posterior positioning of the mandible caused by growth deficiency but with the likelihood of a future horizontal growth pattern
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  • 19.  Vertical V activator- high construction bite with slightly anterior mandibular positioning a. Class II Div 1 malocclusion with vertical growth direction
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  • 27. TRIMMING OF ACTIVATOR  PRINCIPLES- The movement and eruption of selected teeth can be achieved by grinding away areas of acrylic that contact the tooth surface. Carefully planned grinding and trimming of the activator in the tooth contact area improves its effectiveness in the dentoalveolar region by stimulating or restricting selective eruption and movement of anterior and posterior teeth.
  • 28.  The principles of force application in the trimming process are determined by the typa, direction and magnitude of force created by the loosely fitting appliance a. Intermittent force- isotonic and isometric muscle contractions enabling the appliance to work by utilizing kinetic energy. b. The direction of the desired force is determined by selective grinding of the acrylic surface that contact the u & l teeth. After proper grinding the desired force acts on predetermined areas of the teeth and applies pressure in the direction of needed tooth movement. .
  • 29. c. The magnitude of force can be estimated by determining the amount of acrylic contact with the tooth surface. If the force is delivered to smaller portion of tooth surface, it is greater than if broader contact occurs between the acrylic and broader tooth surface. Acrylic surface that transmit the desired force and contact the teeth are called guide planes. d. Approximate trimming can be done on the plaster cast but the final trimming is done in the mouth. Any undercut acrylic surface that might interfere with planned tooth guidance must be removed. Need for trimming can be assessed by- explorer observing the shadows created on the acrylic by the undercut
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  • 31. TRIMMING OF ACTIVATOR FOR VERTICAL CONTROL  Intrusion  Prevention of teeth from eruption  Teeth are free to erupt and are stimulated to do so by acrylic planes
  • 32. INTRUSION OF TEETH  Incisors- Performed by loading the incisor edges Indicated in deep overbite case
  • 33.  Molars- Performed by loading the cusps of teeth Acrylic detail is ground away from the fissures and fossas to eliminate any possible inclined plane stimulation to molar movement Indicated in open bite cases
  • 34. EXTRUSION OF TEETH  Incisor- Loading the lingual surfaces above the area of greatest concavity in the maxilla and below this area in the mandible Enhanced by placing the labial bow above the area of greatest convexity Indicated for open bite cases
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  • 36.  Molars- Loading the lingual surfaces of teeth above the area of greatest convexity in the maxilla or below this area in the mandible Indicated in deep bite cases
  • 37. SELECTIVE TRIMMING OF THE ACTIVATOR  By this only the u & l molars are extruded  Path of eruption of molars should be considered  In case of Class II malocclusion- eruption of maxillary molar is inhibited while that of the mandibular molars is stimulated  In case of Class III malocclusion- eruption of mandibular molar is inhibited while that of the maxillary molars is stimulated
  • 38. TRIMMING OF ACTIVATOR FOR SAGITTAL CONTROL  By this protrusion or retrusion of incisors and change in molar sagittal relationship mesially or distally can be achieved.
  • 39. Thank you For more details please visit