Edgewise technique 2 /certified fixed orthodontic courses by Indian dental academy


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Edgewise technique 2 /certified fixed orthodontic courses by Indian dental academy

  1. 1. Tweed Mechanics www.indiandentalacademy.com
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  3. 3. Graduated from an Angle course given by George Hahn in 1928 Tweed diagnosed & treated cases under Angle’s guidance He held to Angle’s firm conviction that one must never extract for 3 yrs. High frequency of relapse – discouraging Important observation1) facial balance & post treatment success related to upright mandibular incisors 2) to get lower incisors upright, one must prepare anchorage & extract teeth www.indiandentalacademy.com Dr. Tweed
  4. 4. His technique can be summarized as an anchorage technique. While most operators were concentrating on how best to move teeth, he focused himself on how not to move teeth. To a great extent “cart has been placed before the horse”, Dr.Tweed placed the horse where it belongs, in front of the cart. Angle gave orthodontics the edgewise bracket, but Tweed gave the specialty the appliance www.indiandentalacademy.com
  5. 5. Among his other contributions:a) Emphasized the four objectives of orthodontic treatment with emphasis & concern for facial esthetics b) Developed the concept of uprighting teeth over basal bone esp. lower incisors c) Made the extraction of teeth for treatment acceptable d) Enhanced the clinical application of cephalometrics www.indiandentalacademy.com
  6. 6. e) Developed the diagnostic facial triangle to make cephalometrics a diagnostic tool & a guide in treatment & evaluation of results f) He developed the concepts of orderly treatment procedures & introduced anchorage preparation as a major step in treatment g) He developed a fundamentally sound & consistent pre orthodontic guidance program using & popularizing serial extraction of primary & permanent teeth www.indiandentalacademy.com
  7. 7. Over the years several modifications have taken place in the appliance, however the concepts remain the same. Basic concepts which are cornerstones of modern edgewise orthodontics:1)Ability to obtain tooth movement in all 3 planes of space with a single archwire 2)The philosophy of treating to an ideal arch or to Angle’s concept of ‘Line of Occlusion’ The line with which, in form and position according to type,the teeth must be in harmony if in normal occlusion 3)The use of rectangular or square edgewise arches which if properly employed can control arch width, arch form, B-L crown inclinations, axial root inclinations & incisor crownroot torque www.indiandentalacademy.com
  8. 8. Tweed’s philosophy Based on the following :a) Practically all malocclusions are characterized by a forward adjustment of teeth in relation to their basal bones --- this is due to deficiency between the basal bone & tooth material b) The establishment & maintenance of a stable anchorage should be the initial concern of the operator & is a fundamental factor in successful orthodontic treatment c) Teeth like inanimate objects, best resist the force of displacement when tipped to the angulation that offers the most advantageous mechanics against the pull of dislodging forces, they are best stabilized when they overlie the basal bone www.indiandentalacademy.com
  9. 9. d)Teeth are most readily moved when their property & power of mechanical resistance has been primarily reduced e) All forces emanating from an orthodontic appliance must be synchronized if they are to be most effective in the mass stabilization or the mass movement of teeth f) Nature being an expert mechanic herself, offers biologic compensations & adjustments when teeth are placed in position of mechanical advantage for force resistance g) The dental units will best resist forward displacement when the buccal teeth are in mild distal axial position & the incisor teeth are in mild lingual axial inclination & overlying a substantial bony foundation “placing the incisors on the ridge” www.indiandentalacademy.com
  10. 10. Every malocclusion exemplifies a denture that is stabilized by balanced muscular forces & this muscular balance must be preserved in treatment if stability in the end result is to be accomplished ( Strang & Thompson ) www.indiandentalacademy.com
  11. 11. Facial types Tweed divided the facial types into following types:TYPE A :-Maxilla & mandible show forward & downward growth -ANB angle remains the same -Prognosis is good -Treatment not indicated during mixed dentition if ANB angle does not exceed 4.5 TYPE A Subdivision:-ANB angle greater than 4.5 www.indiandentalacademy.com
  12. 12. TYBE B :- Maxilla & mandible grow downward & forward with maxilla growing more rapidly than mandible - When ANB angle is 4.5 or less prognosis is favorable - Extraoral appliances should be used immediately after extraction TYBE B Subdivision :-ANB is large & found to be increasing -Undesirable growth trend, treatment long & difficult www.indiandentalacademy.com
  13. 13. TYPE C :- -Maxilla & mandible grow downward & forward with mandible growing more than maxilla -ANB decreasing -Growth is favourable & treatment is facilitated by growth TYPE C Subdivision :-mandible grows more than maxilla but only to a little extent www.indiandentalacademy.com
  14. 14. Tweed’s Diagnostic facial triangle Basis for diagnosis & treatment planning Consists of the following :1) FMA –the Frankfort mandibular plane angle 2) IMPA –the incisor mandibular plane angle 3) FMIA – the Frankfort mandibular incisor angle www.indiandentalacademy.com
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  16. 16. Angle FMA Visual 25 cephalometric 24.57 Range 15 – 36 IMPA 90 86.93 76 – 99 FMIA 65 68.20 56 – 80 For successful treatment triangle should be attainable Aim should be to obtain:FMIA of 70° – 75° ( when FMA = 20 ) FMIA of 65° ( when FMA = 30) When FMA is less than 20° FMIA should be more than 70° & IMPA should not exceed 94° He showed that in well balanced faces – IMPA was 90°±5° For every degree that FMA was in excess of 25° .the incisor mandibular angle IMPA would have to be decreased by 1° www.indiandentalacademy.com
  17. 17. Cephalogram or Headplate Correction      Based on the requirements of diagnostic facial triangle Consists of constructing the triangle on a tracing of the patients lateral ceph and measuring the 3 angles. According to the FMA measured the required IMPA and FMIA are then constructed on the tracing, involving relocating the axial inclinations of the mandibbular incisors. This new hypothetical position is considered and the change in arch length is calculated, which is the cephalogram correction This is added to the arch length discrepancy measured on the cast to give us the total discrepancy. www.indiandentalacademy.com
  18. 18. Tweed summarized his philosophy on which his appliance therapy is based:i) Normal occlusion is best maintained with the mandibular incisors in their normal axial inclination when related to the F-H plane approx. 65°(FMIA) ii) The ultimate in balance & harmony of facial esthetics is achieved only when the mandibular incisors are positioned over the basal bone iii) The normal relationship of the mandibular incisors to their basal bone is the most reliable guide in diagnosis & treatment of cl. I ,cl. II & bimaxillary protrusion cases and also in attainment of balance & harmony of facial profile & permanence of tooth position www.indiandentalacademy.com
  19. 19. Treatment objectives :- Facial balance & harmony Stability of the post treatment dentition Healthy oral tissues Efficient mastication www.indiandentalacademy.com
  20. 20. Anchorage preparation Stable anchorage – important to prevent forward movement of mandibular denture when cl.II intermaxillary force is applied On histological basis Brodie (1937) believes that the strongest anchorage is provided by stable fixation of teeth – to allow as little movement as possible Tweed – anchor teeth best resist the dislodging forces when their vertical axes are parallel to the direction which offers the most advantageous mechanical resistance against the pull of dislodging forces www.indiandentalacademy.com
  21. 21. Strongest anchorage is provided by tipping back the crowns of the teeth so that they will have a disto-axial inclination that will resist a forward pull therefore, first & most important step in treatment - Anchorage preparation If anchorage preparation is not done the action of intermaxillary elastics causes -elevation of terminal molars & depression of mandibular incisors -canting of occlusal plane, -increase in FMA, -point B drops downward & backward, -entire mandibular denture is tipped & displaced forward into protrusion www.indiandentalacademy.com
  22. 22. Classification of anchorage preparation First degree -minimal anchorage preparation, -applicable to all malocclusion with ANB =0 to 4 , -total discrepancy does not exceed 10 mm, -terminal molars must be uprighted & or maintained in an upright position to prevent their being elongated when cl. II intermaxillary force is used . www.indiandentalacademy.com
  23. 23. Second degree -for malocclusions with ANB more than 0° to 4° -facial esthetics requires to move point B anteriorly & point A posteriorly i,e cl. II cases -usually accompanied by type A, type A subdiv.,type B & type B subdiv. -degree of distal tipping of mandibular molars more severe than first degree anch.prep. –they should be tipped so that their distal marginal ridges are at gum level www.indiandentalacademy.com
  24. 24. Third degree -severe discrepancy cases –14-20mm or more -ANB does not exceed 5° -generally cl.I bimaxillary cases -sliding jigs are necessary -2nd ,1st molars & 2nd premolar must be tipped to such an extent that the distal marginal ridges are below the gum level also called total anchorage preparation www.indiandentalacademy.com
  25. 25. Ideal arch form orthodontic arch is the form which moulds the dental arch with every bend reflected in the position of the teeth Angle “if an archwire is placed in brackets with uniform slot depths,it must take the form of the outline of the buccal & labial surfaces of the teeth” www.indiandentalacademy.com
  26. 26. Unique alignment of upper lateral incisor –thinner labiolingually & short crown length Contact points lie on an ellipsoid curve There is a straight line from canine to mesio buccal cusp of first molar, but beyond that it curves inward progressively Bonwill-Hawley diagram is widely used to decide arch form General pattern – decided by studying the original models & of the muscle behavior of the patient rather than based upon widths of teeth themselves www.indiandentalacademy.com
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  28. 28. Three orders of tooth movement Movements necessary to bring the teeth into the line of occlusion are of three kinds –first, second and third order First order bends-horizontal change relative to the line of occlusion -also called in -out bends -do not alter the horizontal plane of the wire -the action & reaction of these bends affect expansion or contraction -used to move individual teeth -the interaction of bends can affect the third order position of the teeth if expansionary forces are used www.indiandentalacademy.com
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  35. 35. Second order bends -represent a vertical change -also called tip/angulation -used to tip posterior teeth mesially or distallymay be tip back or tip forward bends www.indiandentalacademy.com
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  39. 39. Third order bends -torsional change (with the line of occlusion serving as axis) -also called torque or inclination movement -used to obtain axial changes in the bucco-lingual or labio-lingual root & crown axis on one or more teeth -involves twisting of the wire www.indiandentalacademy.com
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  41. 41. Labial and Lingual torque in Wires www.indiandentalacademy.com
  42. 42. Lingual torque Labial torque www.indiandentalacademy.com
  43. 43. Lingual torque with lingual spring pressure by the archwire Lingual torque combined with labial spring action www.indiandentalacademy.com
  44. 44. Labial torque combined with labial spring Labial torque combined with lingual spring www.indiandentalacademy.com
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  46. 46. Incorporation of torque www.indiandentalacademy.com
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  49. 49. Other tooth movements Opening spaces Closing spaces www.indiandentalacademy.com
  50. 50. Effect on teeth mesial and distal to loop www.indiandentalacademy.com
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  53. 53. Activation with ligature traction Distalization of molar + space opening for 2nd premolar www.indiandentalacademy.com
  54. 54. Opening spaces in anterior region www.indiandentalacademy.com
  55. 55. Vertical spring loop used to tip a molar distally and upright www.indiandentalacademy.com
  56. 56. Vertical spring loop used for root paralleling www.indiandentalacademy.com
  57. 57. Double vertical spring loop auxiliary for mass movement of incisors www.indiandentalacademy.com
  58. 58. General plan of treatment Treatment divided into 3 phases:a)Anchorage preparation b)Distal enmasse movement of maxillary buccal segments c)Establishing correct denture form & completing treatment objectives www.indiandentalacademy.com
  59. 59. Cl. II Div I - Extraction treatment Leveling of arches -.018 in. wire with molar stops/tie back spurs at the molar tube -distal tip back bends in posteriors - cl. III elastics & headgear - Working arches U/L .019 X .026 in. with mild second order bends www.indiandentalacademy.com
  60. 60. Uprighting of canines - horizontal loops soldered mesial to second premolars and a staple attached to anterior end of loop -ligature tied from here to distal staple on canine Canine bracket is not engaged in the wire www.indiandentalacademy.com
  61. 61. Anchorage preparation 1) placing mandibular incisors upright 2) changing axial inclinations of the maxillary incisors, to make them less resistant to distal movement 3) changing the axial inclinations of buccal teeth to a more distal axial inclination www.indiandentalacademy.com
  62. 62. .021 X .027 stabilization wire with mild second order bends in upper arch .019 X .026 in working wire in lower arch with tip back bends & sliding jigs to bear pressure on 2nd premolar bracket cl. III elastics are worn Once anchorage preparation in lower arch done – reverse the mechanics cl. II elastics are worn www.indiandentalacademy.com
  63. 63. Distal enmasse movement of maxillary buccal segments Canine retraction U/L .019 X .026 archwires with second order bends & open coil springs compressed mesial to canines are inserted Cl. III elastics aid in distal movement of mandibular canine Headgear applied to upper arch aids in upper canine retraction www.indiandentalacademy.com
  64. 64. Incisor retraction Using .019 X .026 archwire with closed Bull loop distal to canine – activated 1mm every 3 wks. Mandibular incisors are retracted to an FMIA of 65° in cl.I cases & 70° in cl.II cases www.indiandentalacademy.com
  65. 65. Maxillary incisor retraction completed with heavier .021 X .027 in. wire, reduced posterior to lateral incisors & passed free of canine Strong lingual root torque in upper wire for bodily retraction www.indiandentalacademy.com
  66. 66. to facilitate retraction, stops are soldered 3mm mesial to 2nd premolar brackets Coil springs compressed against the stops and tied to the entire posterior segment www.indiandentalacademy.com
  67. 67. Correction of cl. II relationship Now, mand. arch - .021 X .027 in. max.arch -.019 X .026 in. with accentuated tip back bends Mand. arch tied back to receive cl. II elastics while maxillary archwire is not tied back Intermaxillary hooks soldered mesial to maxillary canines Class II elastics worn till normal cusp relation is achieved www.indiandentalacademy.com
  68. 68. Completion procedure Final space closure & detailed tooth positioning -.019 X .026 in. max. & mand. ideal arches, coil springs compressed mesial to 2nd molar tubes until space closure is completed www.indiandentalacademy.com
  69. 69. Vertical elastics are used for seating cusps if bite is open In case of a deepening of bite a biteplate is used along with box elastics to increase the vertical opening to the desired level. Biteplate is retained for 3-4 months to allow for osseous develpoment. www.indiandentalacademy.com
  70. 70. cl. II div.1 –non-extraction treatment     Preparation of anchorage in the lower arch Preparation of anchorage in the upper arch Distal enmasse movement of maxillary arch Detailed positioning of teeth www.indiandentalacademy.com
  71. 71. Anchorage Preparation Anchorage preparation in mandibular arch Initial leveling & alignment - .016 or .018 round wires Working arch wire .019 X .026 in. with coordinated tip back bends cl. III intermaxillary hooks soldered mesial to canine Loop stops are made mesial to molar tubes but the archwire not tied to molar anchor teeth www.indiandentalacademy.com
  72. 72. Upper arch is stabilized -.021 X .027 in.wire with mild tip back bends Intermediate pull headgear mesial to canine is used to augment the anchorage - min. 14 hrs./day Distal pull by headgear – twice as much as mesial pull on the arch by cl. III elastics During day – light cl. III During night – heavy cl. III Distal tip back bends increased slightly every 2-3 wks. www.indiandentalacademy.com
  73. 73. Stabilization arch -.021 X .027 in. wire with same degree of tip back bends as in working archwire Passive in mandibular incisor region Total time required – aprrox. 4 mons. Anchorage preparation in upper arch Excessive inclination of the proclined upper incisors is reduced by using .018 in. round wire Important – this provides unfavorable stationary anchorage & resist distal / lingual movement of the teeth Heavy stabilization wire with mild second order bends is placed www.indiandentalacademy.com
  74. 74. Enmasse distal movement of maxillary arch Upper arch wire -.021 X .027 in. reduced distal to lateral incisors Mild lingual crown torque if incisors are proclined Intermaxillary hooks on archwire – patient put on cl. II elastics Watch out for mandibular anchorage – any signs of mobility, increase the tip back bends After 3 wks. – tip back bends in the maxillary arch are increased, stronger elastic force is applied until normal relation of teeth attained Mild palatal root torque in anteriors Continue till incisors in edge – edge relation & posteriors in good occlusion www.indiandentalacademy.com
  75. 75. Detailed positioning of teeth Proper seating of cusps is obtained by fitting correlated U & L ideal arches carrying vertical spurs for vertical elastics between them www.indiandentalacademy.com
  76. 76. Bimaxillary dentoalveolar protrusion Two types of cases:1)Axial inclinations of all the teeth in the arch inclined abnormally forward (both in cl.I & cl. II cases ), dental arches are more or less well aligned 2) Axial inclinations of teeth in buccal segments fairly upright, irregular & crowded Steps in treatment :     Anchorage preparation in lower arch Anchorage preparation in upper arch Extraction of four premolars Multiple loops .016 in. archwire U/L used for alignment Space closure done using looped archwire www.indiandentalacademy.com
  77. 77. Treatment of cl.III malocclusion Objective:1)To correct abnormal buccolingual inclination of all posterior teeth in both arches 2)Constrict the mandibular arch which is too broad 3)Expand the maxillary arch which is too narrow 4)Move maxillary arch forward enmasse, using mandibular arch as stationary anchorage www.indiandentalacademy.com
  78. 78. Steps in treatment Initial .016 in. round wires After 2 wks. ,.021X .027 in. U/L ideal arches Brass wire hooks mesial to canine Mandibular archwire is bent considerably narrower than the ideal & torque is placed in the buccal segment Step forward 2nd order bends placed in maxillary posterior segment (direct opp. of tip back bends) Intermaxillary elastics from lingual of maxillary molar to hook mesial to mandibular canine When cross bite is corrected –archwires are reshaped to the ideal Treatment continued until the maxillary teeth have moved forward enmasse into occlusion with teeth in mandibular arch. www.indiandentalacademy.com
  79. 79. www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com