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Segmented arch technique /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,
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Segmented arch technique /certified fixed orthodontic courses by Indian dental academy

  1. 1. SEGMENTED ARCH TECHNIQUE INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com 1
  2. 2.        Introduction Rationale of SAT Preliminary Bracket Alignment Deep overbite correction Open bite correction Space Closure Root correction www.indiandentalacademy.com 2
  3. 3. Introduction:  Designed to deliver light continuous forces.  “continuous” arch wire.  Segmented arch consists of multiple wire cross sections.  SA does not connect brackets & tubes on adjacent teeth. www.indiandentalacademy.com 3
  4. 4. Rationale Consolidation of teeth into units:  Segmentation allows the treatment to proceed by consolidation of teeth into units.  Few teeth are considered for each segment.  Continuous arch-forces are distributed to the adjacent teeth. www.indiandentalacademy.com 4
  5. 5. www.indiandentalacademy.com 5
  6. 6. Rationale Varying Cross-section of Arch wire:  Active units  Reactive units  Wires used to displace the teeth should have low LDR. www.indiandentalacademy.com 6
  7. 7. Increasing the Inter bracket distance:  Forces used during intersegmental mechanics are applied at large distances.  Continuous arch – Active & Reactive forces occur on the adjacent teeth. www.indiandentalacademy.com 7
  8. 8.  Increases the space available for longer activations. www.indiandentalacademy.com 8
  9. 9. Prefabrication & Precalibration: • Continuous arch –Difficult to determine the forces. • Segmentation allows the use of precalibrated springs to deliver the desired forces. www.indiandentalacademy.com 9
  10. 10. Clinical Efficiency:  No. of arches are made during treatment in continuous arch therapy.  In segmental approach continual replacement of arch wires are not required www.indiandentalacademy.com 10
  11. 11. Preliminary Bracket Alignment • Initial stage of treatment. • Brackets of the teeth are ideally aligned. • Goal : Consolidated segments www.indiandentalacademy.com 11
  12. 12. Attachments & Placement Attachments:- Slot - 0.022 x 0.028 -Hooks, auxiliary tubes, Head gear tubes. -Cuspid bracket- 0.175 X 0.025 vertical/horizontal tube. www.indiandentalacademy.com 12
  13. 13. Molar attachments Lingual hinge cap (0.032 X 0.032) www.indiandentalacademy.com 13
  14. 14. • Attachments with 1st, 2nd, 3rd order angulations are available. • Help clinician to get good occlusion. • Second order angulations can be individualized during banding. www.indiandentalacademy.com 14
  15. 15. Burstone OrthosTM Attachment Prescription www.indiandentalacademy.com 15
  16. 16. www.indiandentalacademy.com 16
  17. 17. Placement of Attachments Objectives:     No 2nd order steps Minimal 1st order bends All slots are parallel to the occlusal plane. Variations in the tooth position & morphology. www.indiandentalacademy.com 17
  18. 18. Second order level:- Criteria: -Occluso-gingival level -Angulation with respect to ‘z’ or faciolingual axis. www.indiandentalacademy.com 18
  19. 19.  Level of attachments is established first for the posteriors. -Maxillary arch: centrals, laterals, canines,1st &2nd molars. -Mandibular arch: centrals, laterals, canines,1st &2nd molars. www.indiandentalacademy.com 19
  20. 20. Second order Angulation: - OPG Objectives:-Proper root dispersion, & occlusion. www.indiandentalacademy.com 20
  21. 21.  Angulations of anterior teeth are assessed  Using PA cephalograms & assessed to the treatment occlusal plane.  All slots should lie in the same line & roots should have proper root dispersion. www.indiandentalacademy.com 21
  22. 22. First order placement: -Attachments are centered mesiodistally on the crown -Parallel to the incisal edges/buccal cusp tip. www.indiandentalacademy.com 22
  23. 23.  Objectives of PBA:-  Normalize the teeth Intrasegmentally. -Rotations, B-L positions -Occlusogingival discrepancies. -Teeth torqued.   Improve the Intersegmental relationship. Improve the Intermaxillary relationship. www.indiandentalacademy.com 23
  24. 24. Basic lingual arches: www.indiandentalacademy.com 24
  25. 25. Upper horse shoe shape www.indiandentalacademy.com 25
  26. 26. Lingual Arch Wires:       Establishing & maintaining the upper and lower arch widths. Correcting intra-arch rotations or inter-segmental rotations. A-P asymmetries. Difference in the occlusal planes. Buccolingual & M-D axial inclinations of the post. teeth. Reducing the undesirable side effects. www.indiandentalacademy.com 26
  27. 27. Lingual Hinge Cap -0.032 X 0.032 -Ligation of the lingual arch www.indiandentalacademy.com 27
  28. 28.  Buccal Stabilizing Segment: -To connect the individual teeth into one unit - For Alignment -To act as stop anteriorly. -Point of connection. -0.018 TMA welded to the molar. www.indiandentalacademy.com 28
  29. 29. Deep Overbite Correction Differential diagnosis & Treatment plan. 3 basic ways - Intrusion of Ant. teeth Extrusion of post. teeth www.indiandentalacademy.com 29
  30. 30.  Intermaxillary growth space  Skeletal vertical dimension  AB Relationship  Occlusal plane cant  Esthetics www.indiandentalacademy.com 30
  31. 31. Intermaxillary Growth Space: www.indiandentalacademy.com 31
  32. 32. www.indiandentalacademy.com 32
  33. 33.  Skeletal Vertical Dimension www.indiandentalacademy.com 33
  34. 34.   Occlusal Plane cant desired after the treatment Esthetics www.indiandentalacademy.com 34
  35. 35. Principles of Anterior Intrusion -Controlling force magnitude & constancy -Anterior single point contact -Point of force application -Selective Intrusion -Control of reactive units -Avoiding Extrusive mechanics  www.indiandentalacademy.com 35
  36. 36. Controlling force Magnitude: -Magnitude of forces used for intrusion should as low as possible. -Side Effects: Root resorption  Extrusion of buccal segments www.indiandentalacademy.com 36
  37. 37. FORCE VALUES FOR INTRUSION TOOTH MOVEMENT FORCE (gm) INTRUSION PER SIDE 2 UPPER CENTRAL INCISORS 15 – 20 30 –40 4 UPPER INCISORS 30 – 40 60 – 80 6 UPPER ANTERIORS 60 120 2 LOWER CENTRAL INCISORS 12.5 25 4 LOWER INCISORS 25 50 6 LOWER ANTERIORS 50 100 2 UPPER CANINES 25 - 2 LOWER CANINES 25 - MOLAR EXTRUSION 60 – 100 120 – 200 www.indiandentalacademy.com TOTAL IN MIDLINE 37
  38. 38.   Force constancy is obtained by using low LDR springs. Intrusive Arch-0.018 x 0.025 with 3mm helix www.indiandentalacademy.com 38
  39. 39. Anterior Single Point Contact: -Intrusion arch is not placed in the anterior brackets. -Torque -Allows the clinician to know the force systems involved. (Statically Determinant) -Anterior alignment arch wires can be placed.  www.indiandentalacademy.com 39
  40. 40.   Point of Force Application: Force applied to the Cres will not produce any labial /lingual rotation. Intrusion arch is placed anterior to the labial surface. www.indiandentalacademy.com 40
  41. 41.  Selective Intrusion: www.indiandentalacademy.com 41
  42. 42. Control of the Reactive Units: -Minimization of force magnitudes. Side Effects: Plane of occlusion in the buccal segments is altered.  • Forces of intrusion should be kept low. • More no.of teeth should be incorporated. • Retraction is done initially. • Occipital HG www.indiandentalacademy.com 42
  43. 43. www.indiandentalacademy.com 43
  44. 44. • Equal & opposite extrusive effect www.indiandentalacademy.com 44
  45. 45.  Avoiding Extrusive Mechanics: -CL-II elastics -CL-III elastics -Cervical HG Pts requiring true intrusion. www.indiandentalacademy.com 45
  46. 46. Principles of Anterior Intrusion  Use of optimal magnitudes of force  Point contact in the anterior region  Selection of the point of force application with respect to the Cres.  Selective intrusion  Control over the reactive units  Avoidance of undesirable eruptive mechanics. www.indiandentalacademy.com 46
  47. 47. Continuous Intrusion Arch • • •  Post.Anchorage unit Ant.segment Intrusion arch(0.017x0.025 TMA). 0.018 round TMA stops are welded – to serve as tie backs. www.indiandentalacademy.com 47
  48. 48. Three-Piece Intrusion Arch  Intrude the flared incisors, control their axial inclinations & retract with good anchorage control.  Point contact of force application.  Pt’s with proclined incisors have to be treated differently. www.indiandentalacademy.com 48
  49. 49. www.indiandentalacademy.com 49
  50. 50.     Post-Anchorage unit Ant.segment with a posterior extension Intrusion cantilevers Chain elastic. www.indiandentalacademy.com 50
  51. 51.   Distal extensions end 2-3mm distal to the Cres of he anterior segment. Design of the appliance -low friction. www.indiandentalacademy.com 51
  52. 52.  Anterior Segment & Direction of Intrusive force www.indiandentalacademy.com 52
  53. 53. www.indiandentalacademy.com 53
  54. 54. CANINE INTRUSION:   A cantilever from the auxiliary tube of the molar tied to the canine bracket. The cantilever is bent to the lingual to give a lingual force. www.indiandentalacademy.com 54
  55. 55. CANINE INTRUSION: www.indiandentalacademy.com 55
  56. 56. Extrusion of Posterior Segments  Higher forces promote posterior eruption.  Canting of the occlusal plane should be avoided.  Extrusion arch is similar to the intrusion arch.  Eruptive appliances should be used in growing children.  Extrusion occurs rapidly than intrusion. www.indiandentalacademy.com 56
  57. 57.  2 types of extrusion can be achieved with extrusion arch. Type-I Combines extrusion with rotation of the buccal segment. Applied in the lower arch. Type-II Used in the upper arch when parallel eruption of buccal segments is required www.indiandentalacademy.com 57
  58. 58. www.indiandentalacademy.com 58
  59. 59. Types of extrusive mechanics • • • Tip-back mechanism Base arch mechanism Parallel eruption of buccal segments www.indiandentalacademy.com 59
  60. 60. Tip back mechanism:Indications:  Growing pt with a forward rotation. Deep curve of spee in the lower arch. Arch length inadequacy. www.indiandentalacademy.com 60
  61. 61. Tip back mechanism consists:     0.036 inch lingual arch 0.018x0.025 anterior segment Buccal stabilizing segment of 0.018x0.025. 0.018x0.025 tip back spring www.indiandentalacademy.com 61
  62. 62.    CRot is placed around the root of the 2nd molar. Eruption & rotation of buccal segments. Increase in the arch length www.indiandentalacademy.com 62
  63. 63. Base Arch Mechanism:  Also called as Intrusive arch.  Buccal and anterior arch wires are identical. 0.018x0.025 SS www.indiandentalacademy.com 63
  64. 64. Ligature is tied to the helices to prevent flaring of anterior teeth. • Effects: -Eruption & rotation of the buccal segments. -Roots of the buccal segments move forward. -No increase in the arch length. • www.indiandentalacademy.com 64
  65. 65. Parallel Eruption of the Buccal Segment:   Used in the upper jaw Cervical HG with long outer bow . www.indiandentalacademy.com 65
  66. 66. www.indiandentalacademy.com 66
  67. 67.   Natural plane of occlusion must be monitored 0.018x0.025 wire is placed as an indicator wire. www.indiandentalacademy.com 67
  68. 68. Closing Anterior Open Bite : Extrusion Arch  Open bites occur less frequently.  Treatment involves a wide variety of approaches.  Dental compensations – Vertical elastics. Extrusion Arch: reverse action of the intrusion arch.  Effective way to close the open bite without Pt compliance  Choice of dental compensation is based on lip-tooth distance. www.indiandentalacademy.com 68
  69. 69. Extrusion Arch  Action at the Molar:- www.indiandentalacademy.com 69
  70. 70. Extrusion Arch  Timing: Undesirable actions at the molars will be insignificant if the EA is kept only for a minimum time. (Isaacson)  Segment of SS wire has to be placed in the posterior segment. www.indiandentalacademy.com 70
  71. 71. Extrusion Arch  Action at the Incisor:- Extrusion -Single tooth -Groups of teeth. • Magnitude of extrusive forces used are100gms for 4 incisors • 0.016X0.022 SS wire is used www.indiandentalacademy.com 71
  72. 72. Space Closure Biomechanical Basis of extraction space closure  2 methods to close extraction sites -Segmental springs -Loops in the continuous wire www.indiandentalacademy.com 72
  73. 73.  Anchorage classification:- www.indiandentalacademy.com 73
  74. 74. Single cuspid retraction Vs En-mass retraction    Adequately designed appliances based on the desired biomechanics. En-mass space closure reduces the treatment time. Separate canine retraction is done in anterior crowding cases. www.indiandentalacademy.com 74
  75. 75. Space closure –A Biomechanical Perspective www.indiandentalacademy.com 75
  76. 76.   Force systems for Grp B space Closure. M/F-10/1 is needed for Translation. www.indiandentalacademy.com 76
  77. 77. Space closure –A Biomechanical Perspective Grp-A anchorage: Mesial force on the posterior teeth should be minimized. -Forces & moments acting on the posterior teeth can be minimized by using extraoral force. www.indiandentalacademy.com 77
  78. 78. Space closure –A Biomechanical Perspective  Differential tooth movement: www.indiandentalacademy.com 78
  79. 79. Grp-A anchorage: Space closure with differential moments.   Increasing the posterior M/F ratio encourages root movement & decreasing the M/F ratio causes tipping type of tooth movement. Magnitude of the vertical force – difference between anterior & posterior moments. www.indiandentalacademy.com 79
  80. 80. Determinants of space closure:     Amount of crowding Anchorage Axial inclination of canines & incisors. Midline discrepancies & Lft/Rht symmetry Vertical dimension www.indiandentalacademy.com 80
  81. 81. Space closure Considerations for anchorage control & Differential tooth movement  Size of the Anchorage units No. of teeth .  Differential force systems-Variable moments & Forces -Forces act in 3 planes of space. www.indiandentalacademy.com 81
  82. 82. Segmental En-mass Extraction space closure • • • • T-loop space closure springs are used Principle of SA-Ant & Post units are considered as one large tooth. Rt & Lft buccal segments are connected by TPA. Design uses 0.0175x0.025 TMA wire. www.indiandentalacademy.com 82
  83. 83. www.indiandentalacademy.com 83
  84. 84. General Concepts for Segmented T-loop use  Passive form of a spring  Activation of the spring requires application of forces & moments.  Neutral position –Only moments are applied. www.indiandentalacademy.com 84
  85. 85. General Concepts for Segmented T-loop use  Differential Anchorage: Unequal α & β moments.  Higher moment is applied to the anchor teeth.  Differential moments –Off-centered V-bend.  Centering the T-loop -produces equal & opposite moments. www.indiandentalacademy.com 85
  86. 86. Symmetric Space Closure – Grp B Anchorage  Simplest form of space closure.  Equal translation of Ant & Post segments.  T-loop centered  Distance =Interbracket Distance - Activation 2 www.indiandentalacademy.com 86
  87. 87.  Space closure is monitored periodically. -amount of remaining space -axial inclinations www.indiandentalacademy.com 87
  88. 88. Space Closure – Grp A Anchorage • T-loop is positioned closer to the post. Attachment. www.indiandentalacademy.com 88
  89. 89. Space Closure – Grp C Anchorage  Post. Protraction is the difficult space closure.  Extrusive effect on the anterior teeth.  CL-III elastics – to augment the protraction www.indiandentalacademy.com 89
  90. 90. Separate Canine & Incisor Retraction    Anterior crowding Midline disrepancies Moment is produced on the canine during separate canine retraction. www.indiandentalacademy.com 90
  91. 91.  3 ways to counteract this moment: www.indiandentalacademy.com 91
  92. 92. www.indiandentalacademy.com 92
  93. 93. www.indiandentalacademy.com 93
  94. 94. www.indiandentalacademy.com 94
  95. 95. Cuspid-Cuspid Bypass wire: Prevent Rotation  Alter arch width  Eliminate side effects from vertical forces. 0.017 X 0.025SS www.indiandentalacademy.com 95
  96. 96. www.indiandentalacademy.com 96
  97. 97. Incisor Retraction www.indiandentalacademy.com 97
  98. 98. Canine & Incisor Root Movement  Control of axial inclinations of teeth is important.  Good axial inclination & root parallelism-stable result.  Root correction involves-Individual/Groups of teeth.  Enmass root movement  Separate canine root following separate canine retraction.  Separate incisor root correction www.indiandentalacademy.com 98
  99. 99. Diagnosis & Evaluation of root correction  Clinically-Inclination of canine & incisor brackets.  Lateral films-Axial inclinations www.indiandentalacademy.com 99
  100. 100. Enmass Root Movement  Second phase of space closure after tipping movement.  Moments are delivered by Root springs.  Moments generated cause the crowns to flare and roots to retract.  Ligature tie –to prevent the space from opening. www.indiandentalacademy.com 100
  101. 101. Selection of wire in the anterior segment: • •  Rigid wire placed in the 6 anterior teeth. Undersized wire – rotation of the incisors. 3 major root springs for enmass root movement www.indiandentalacademy.com 101
  102. 102. www.indiandentalacademy.com 102
  103. 103.  Root springs: www.indiandentalacademy.com 103
  104. 104.  Cuspid root movement: www.indiandentalacademy.com 104
  105. 105.  Incisor root movement: 0.021 x 0.025 TMA root spring www.indiandentalacademy.com 105
  106. 106. References:Biomechanics In Orthodontics – Marcotte. Biomechanics In Clinical Orthodontics-Ravindra Nanda.  Rationale of the Segmented arch –Burstone AJO (1962). Deep overbite correction by intrusion – Burstone AJO(1977).   Biomechanics of Deep Overbite Correction-Burstone (Semin Orthod 2001). www.indiandentalacademy.com 106
  107. 107.  Segmented approach to simultaneous intrusion and space closure: Biomechanics of the three-piece base arch appliance-Bhavna Shroff AJODO-1995.  Closing Anterior Open bite :The Extrusion Arch – Isaacson & Lindau Semin Orthod 2001.  The Segmented arch approach to space closure – Burstone 1982 AJO www.indiandentalacademy.com 107
  108. 108. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com 108

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