Fixed appliances in orthodontics

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Fixed appliances in orthodontics

  1. 1. DEFINITION Fixed Appliances are devices or equipments that are attached to the teeth , cannot be removed by the patient and are capable of causing tooth movement.
  2. 2. INDICATIONS Fixed Appliances are indicated when precise tooth movements are required  Correction of mild to moderate skeletal discrepancies  Intrusion/ Extrusion of teeh  Correction of rotation  Overbite reduction by intrusion of incisors  Multiple tooth movements required in one arch  Active closure of spaces: extraction spaces/hypodontia
  3. 3. Components of fixed appliances Active components Seperators metal Arch wires elastic Passive components Elastics Springs Brackets Bands Lockpins Accessories Molar tube Ligiature wire modules
  4. 4. SEPARTORS  Seperators are used to create space for banding teeth  Tight proximal contacts does not allow proper banding of teeth PRINCIPLE:  It is a device to wedge the teeth in place B/w the teeth TYPES Metal seperators Elastic seperators
  5. 5. ARCHWIRES • Ideal Properties        Springback Stiffness Formability Resilience Biocompatibilty Joinability Frictional characteristics
  6. 6. Materials • • • • • Stainless steel/ Cobalt chromium Precious metal Nickel-Titanium Beta-Titanium Composite Plastics
  7. 7. BANDS Bands are thin strips of stainless steel which are adapted to the contours of the tooth to which attachments are welded or soldered TYPES : 1. Preformed 1. Molar Bands 2. Custom made 2.Premolars 3.Incisors
  8. 8. BRACKETS The force required for orthodontic tooth movement is transmitted from the active components through the bracket.
  9. 9. MOLAR TUBE Accessory Archwire Slot Main Archwire Slot Headgear tube
  10. 10. BANDS FOR ATTACHMENTS. BONDED ATTACHMENTS.
  11. 11. Indications for Banding • Teeth that will receive heavy intermittent forces against the attachments. • Teeth that will require both labial and lingual attachments. • Teeth with short clinical crowns. • Teeth with extensive restorations.
  12. 12. STEPS IN BANDING 1.SEPERATION 2.FITTING BANDS 3. CEMENTATION
  13. 13. BONDED ATTACHMENTS • Mechanical locking of an adhesive to irregularities in the enamel surface of the tooth and to mechanical locks formed in base of the 0rthodontic attachment. COMPONENTS OF THE SYSTEM : 1. Tooth surface and its preperation. 2. The design of the attachment base. 3. Bonding material itself
  14. 14. Armamentarium
  15. 15. Direct Bonding 1. Cleaning 2.Acid etching 3.A small amount of bonding agent is squeezed into the mesh on the back of the bracket , and it is pressed to place on the tooth surface.
  16. 16. 4.Excess bonded material is removed from around the bracket 5.For light cured materials, a cordless light is used to activate the adhesive bonding process 6.The bracket is bonded in place.
  17. 17. Indirect Bonding 1.Brackets are placed precisely on a cast of the teeth and held in place with a fitted resin 2.After the brackets are cured in the ideal position, a transfer tray is formed and placed on the working cast. 3 The trays are removed from the working cast after soaking in warm water and trimmed.
  18. 18. 4. The teeth are isolated , etched, and a chemically cured two paste resin is painted on the etched enamel and brackets. 5. After the resin has completely set , the trays are carefully removed , leaving the brackets bonded to the teeth.
  19. 19. ACCURACY IN PLACEMENT!
  20. 20. Debanding/Debonding
  21. 21. RULES!!!!!!  Bonded attachements are almost always preferred for anterior teeth and premolars .  Bands usually are preferred for first molars , especially if both buccal and lingual attachments are needed.  Second molars are bonded if exposure of crown allows it , banded if not.  There is an increasing trend towards bonded attachments on all the teeth ,however, especially in older patients who have longer clinical crown and tighter contacts .
  22. 22. E-Arch (Angles first appliance) Pin and tube appliance Edge wise appliance by Angle Preadjusted edgewise appliance by lawrence Andrews Ribbon arch appliance by Angle Modified Ribbon arch by Raymond begg Tip edge appliances by peter Kesling
  23. 23. E-Arch Pin and tube Ribbon Arch Edgewise
  24. 24. 3.Ribbon Arch 1.E-Arch  Only heavy interrupted forces  Only tipping movements achieved  Unable to precisely position any individual tooth 2.Pin and Tube  Overcome the drawbacks of E-Arch  Incredible degree of craftsmanship was involved in constructing and adjusting the pin and tube appliance  Impractical clinically  Only Angle’s and one of his students ever mastered this appliance  Heavy base arch meant that the spring qualities were poor  Many small adjustments needed  Archwire was small enough to have good spring qualities and efficiently aligned malposed teeth  Major weakness of the appliance was that it provided relatively poor control of root position  Resiliency of the ribbon archwire did not allow generation of moments necessary to torque roots to a new position  Incisogingival and buccolingual tooth movements were possible but mesiodistal tooth movements could not be achieved 4.Edgewise     Ability to move teeth in all 3 planes of space Good control over tooth movement Bodily movement possible Precise finishing possible
  25. 25. Bends 1st order 2nd order 3rd order
  26. 26. Disadvantages of Angle’s edgewise appliance • Heavy forces required Complex wire bending • Increased friction • Extraoral forces for anchorage required • Difficulty in opening deep bites
  27. 27. TWEED’S MODIFICATION OF EDGEWISE • Advocated extraction of teeth in selected cases for better stability • Tweed moved the teeth bodily and used the subdivision approach for anchorage control, first sliding the canines distally the arch wire and then retracting the incisors
  28. 28. BEGG’S APPLIANCE • Modified ribbon arch technique and introduced the Begg’s light wire differential force technique • Concluded extraction of teeth was necessary and set out to adapt ribbon arch appliance so that it could be used for better root positioning control.
  29. 29. • Begg’s adaptation took 3 forms: 1. Replaced precious metal wire with high strength 16 mil stainless steel 2. Retained the original ribbon arch bracket but turned it upside down so that the bracket slot pointed gingivally rather than occlusally 3. He added auxillary springs to the appliance for the control of root position • Resulting in reduced friction as the area of contact between the narrow ribbon arch bracket and the archwire was very small and the force of the wire was also small • Begg’s strategy for anchorage control was tipping/uprighting
  30. 30. LABIOLINGUAL, TWIN WIRE • First half of the 20th century, Labiolingual appliance & Twinwire appliance were major competing appliances for repositioning teeth • Bands on first molars and a combination of heavy lingual and labial archwires to which fingersprings were soldered to move individual teeth  Labiolingual appliance
  31. 31. • Twin wire appliance used bands on incisors as well as molars and featured twin 10mil steel archwires for alignment of the incisor teeth. • Delicate wires were protected with long tubes that extended forward from the molars to the vicinity of canines. • None of these appliances were capable of more than tipping
  32. 32. CONTEMPORARY EDGEWISE • Major steps in evolution of edgewise include :  Automatic rotational control  Alteration in Bracket Slot Dimensions  Straight Wire Prescriptions
  33. 33. EDGEWISE TECHNIQUE IN WIRE BENDING PURPOSE COMPENSATION First Order/In and Out bends To compensate for difference in thickness of labial surfaces of individual teeth Compensated by built-in variation in thickness of bracket base Second Order/ Tip back bends Required for mesiodistal root positioning Compensated by angulating bracket base or bracket slot Third Order/ Torque bends Required to compensate for the difference in inclination of facial surface to the true vertical Bracket slots are inclined to preadjusted appliances to compensate for third order bends
  34. 34. Bends 1st order 2nd order 3rd order
  35. 35. SELF LIGATING BRACKETS ‘’A bracket which utilizes a permanently installed , movable component to entrap the arch wire.’’
  36. 36. INDIVIDUALLY CUSTOMIZED BRACKETS  Offer the prospect of eliminating almost all archwire wire bending.  3D scan is taken of a dental cast  The information is used to precisely cut each bracket using CAD/CAM technology , so that slot for each bracket has the appropriate thickness, inclination and torque needed for ideal positioning of the tooth and archwires with an arch form established for that patient are supplied.
  37. 37. ARCH FORM AND ARCH WIRE FABRICATION
  38. 38. WIRE BENDING ROBOTS
  39. 39. ANY QUESTIONS???
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