ACTIVATOR.pptx

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 ; Maxillary part Mandibular part 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. 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 Correction of Cl II Div 1 cases Correction of Cl II Div 2 cases Correction of open bite (Dental not skeletal). 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 ; By overcompensating the forward positioning of the mandible in construction wax bite almost reaches a feasible maximum. By seating appliance firmly against maxillary dental arch by means of clasps. REDUCED ACTIVATOR ( C YBERNATOR ) – Schmuth Resembles the B ionator . 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 Upper & lower labial wires 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.