Biomechanics of molar distalization /certified fixed orthodontic courses by Indian dental academy

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Biomechanics of molar distalization /certified fixed orthodontic courses by Indian dental academy

  1. 1. BIOMECHANICS OF MOLAR DISTALIZATION APPLIANCE www.indiandentalacademy.com INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com
  2. 2. CONTENTS • INTRODUCTION • INDICATIONS AND CONTRAINDICATIONS • BIOMECHANICS • TYPES OF APPLIANCES -EXTRAORAL -INTRA ORAL • APPLIANCE SELECTION CRITERIA • CONCLUSION • REFERENCES www.indiandentalacademy.com
  3. 3. INTRODUCTION Correction of class II malocclusion without extractions requires maxillary molar distalization by means intraoral or extra- oral forces. www.indiandentalacademy.com
  4. 4. • William Kingsley (1892) described for the first time headgear apparatus with which class I molar relationship could be achieved successfully. www.indiandentalacademy.com
  5. 5. • Oppenheim advocated that position of mandibular teeth as being the most correct for individual and use of occipital anchorage for moving maxillary teeth distally into correct relationship without disturbing mandibular teeth. • In 1944, he treated a case with extra-oral anchorage for distalizing maxillary molar. www.indiandentalacademy.com
  6. 6. • Kloehn in 1947 started a long and beneficial series of investigations and clinical applications of cervical anchorage to the maxillary dentition. www.indiandentalacademy.com
  7. 7. • The headgears over the years have shown to be effective in maxillary molar distalization with movements in all planes of space. With the recent trend more towards non extraction treatment, several inter/intra arch devices have been advocated to distalize molars in the upper arch. www.indiandentalacademy.com
  8. 8. • Researchers have focused on the simplicity and efficiency of these intra arch devices, which improves the continuity and constancy of forces. Oral hygiene is easier to maintain and the need for patient compliance is eliminated. www.indiandentalacademy.com
  9. 9. • Molar distalization is a technique that has added a new column in the practice of every orthodontist to produce consistent, predictable and high quality results. The goals of practicing with efficiency and profitability are positively affected. www.indiandentalacademy.com
  10. 10. • Since space is easier to gain in the maxillary arch than in the mandible because of increased trabecular structure of supporting bone and increased anchorage afforded by palatal vault, the distalization of maxillary molar becomes of significant value for the treatment of cases with mild to moderate arch discrepancy and class II molar relationship associated with a normal mandible. www.indiandentalacademy.com
  11. 11. INDICATIONS • Profile - should be acceptable with minimal facial change or straight profile www.indiandentalacademy.com
  12. 12. • Functional – Normal TMJ www.indiandentalacademy.com
  13. 13. • Skeletal - Class I skeletal pattern - Normal, short lower face height - Skeletal closed bite www.indiandentalacademy.com
  14. 14. Dental • class II / End-on molar relationship www.indiandentalacademy.com
  15. 15. • Deep overbite • Maxillary first molar mesially inclined • Maxillary cuspids labially displaced www.indiandentalacademy.com
  16. 16. • Loss of arch length due to premature loss of second deciduous molar • Mild to moderate arch perimeter discrepancy www.indiandentalacademy.com
  17. 17. www.indiandentalacademy.com
  18. 18. UPPER MOLAR POSITION • This is a linear measurement between the distal surface of the maxillary first permanent molar and the pterygoid vertical line (PTV). • It is an indication of the forward position of the upper molar and illustrates to the clinician whether or not sufficient space is present for the second and third molars. www.indiandentalacademy.com
  19. 19. • This measurement indicates or contraindicates molar distalization. • An interesting aspect of this measurement is that its mean value is the patient's age in years plus 3mm until growth is complete. Therefore the mean • measurement for nine - year old child is l2mm. www.indiandentalacademy.com
  20. 20. www.indiandentalacademy.com
  21. 21. TIMING • A favorable time to move molars distally appears to be in mixed dentition, before the eruption of the second molars, and an efficient force system to move molars distally is a continuously acting force. www.indiandentalacademy.com
  22. 22. CONTRAINDICATIONS • Profile:- Retrognathic profile www.indiandentalacademy.com
  23. 23. • Functional:-abnormal temporomandibular Joint www.indiandentalacademy.com
  24. 24. • Skeletal:- Class II skeletal - Skeletal open bite - Excess lower face height www.indiandentalacademy.com
  25. 25. • Dental:-Class I or III molar relation. - Dental open bite/shallow bite www.indiandentalacademy.com
  26. 26. BIOMECHANICS MD www.indiandentalacademy.com
  27. 27. MD www.indiandentalacademy.com
  28. 28. MD www.indiandentalacademy.com
  29. 29. www.indiandentalacademy.com
  30. 30. www.indiandentalacademy.com
  31. 31. www.indiandentalacademy.com
  32. 32. BP BP www.indiandentalacademy.com
  33. 33. P B www.indiandentalacademy.com
  34. 34. P B www.indiandentalacademy.com
  35. 35. P B www.indiandentalacademy.com
  36. 36. B P MD www.indiandentalacademy.com
  37. 37. B P MD www.indiandentalacademy.com
  38. 38. TYPES OF APPLIANCES • EXTRAORAL • INTRA ORAL www.indiandentalacademy.com
  39. 39. EXTRA ORAL • Bilateral molar distalization a) Cervical pull head gear. b) Combi pull head gear. • Unilateral molar distalization with unilateral face bows a) power-arm face bow b) soldered offset face bow c) swivel-offset face bow d) spring-attachment face bow. www.indiandentalacademy.com
  40. 40. INTRA ORAL • INTER ARCH • INTRA ARCH www.indiandentalacademy.com
  41. 41. INTER ARCH  Atkinson buccal bar  Tandem yoke  3d biometric distalizing arch  Modified herbst appliance for distalization of molars  Jasper jumper  Sliding jig Crickett appliance www.indiandentalacademy.com
  42. 42. INTRA ARCH Sagittal appliance Magnets Modified lingual and Nance holding arches Jones jig NiTi coil springs www.indiandentalacademy.com
  43. 43.  Pendulum appliance  Super elastic NiTi wires  Molar distalizing bow  Space regainers  K-Loop  Fixed piston appliance  Distal jet www.indiandentalacademy.com
  44. 44. C-Space Regainer  Palatal orthodontic implants  First class appliance  Fixed palatal expander  Lokar molar distalisation  Transpalatal arch www.indiandentalacademy.com
  45. 45. Acrylic cervical occipital appliance Rremovable molar distalization splint Compressed springs Mini distalization appliance IBMD www.indiandentalacademy.com
  46. 46. SPACE REGAINERS  Sling Shot Appliance  Modified Kings Appliance  Removable or fixed lingual arch with spring  Clasp ring www.indiandentalacademy.com
  47. 47. MOLAR DISTALIZATION IN LOWER ARCH : • Lip bumper • Modified lingual appliance • Distal jet for lower molar • Franzulum appliance www.indiandentalacademy.com
  48. 48. EXTAORAL FORCES www.indiandentalacademy.com
  49. 49. LOW-PULL HEADGEAR www.indiandentalacademy.com
  50. 50. MEDIUM-PULL HEADGEAR www.indiandentalacademy.com
  51. 51. HIGH-PULL HEADGEAR www.indiandentalacademy.com
  52. 52. ASYMMETRIC HEADGEAR www.indiandentalacademy.com
  53. 53. www.indiandentalacademy.com
  54. 54. www.indiandentalacademy.com
  55. 55. EXTRA ORAL • Bilateral molar distalization a) Cervical pull head gear. b) Combi pull head gear. www.indiandentalacademy.com
  56. 56. Cervical pull head gear. www.indiandentalacademy.com
  57. 57. Cervical Anchorage with low-pull Headgear Anti-clockwise Rotation Clockwise Rotation Translation www.indiandentalacademy.com
  58. 58. COMBI PULL HEAD GEAR www.indiandentalacademy.com
  59. 59. combi-pull Headgear Anti-clockwise Rotation Clockwise Rotation Translation www.indiandentalacademy.com
  60. 60. Unilateral molar distalization with unilateral face bows power-arm face bow www.indiandentalacademy.com
  61. 61. soldered offset face bow www.indiandentalacademy.com
  62. 62. swivel-offset face bow Swivel union www.indiandentalacademy.com
  63. 63. spring-attachment face bow www.indiandentalacademy.com
  64. 64. INTRA ORAL www.indiandentalacademy.com
  65. 65. STANDARD PENDULUM APPLIANCE • In 1992, Hilgers • made of 0.032 TMA wire, • Springs deliver approximately 230 gms of force per side. • Springs have adjustment loop that can be manipulated to increase molar expansion, rotation and distal root tip. www.indiandentalacademy.com
  66. 66. www.indiandentalacademy.com
  67. 67. www.indiandentalacademy.com
  68. 68. www.indiandentalacademy.com
  69. 69. www.indiandentalacademy.com
  70. 70. www.indiandentalacademy.com
  71. 71. www.indiandentalacademy.com
  72. 72. www.indiandentalacademy.com
  73. 73. MODIFIED PENDULUM APPLIANCE • M- pendulum • Inverted loop • Activation - 40-450 • Springs deliver approximately 125 gms of force per side. • Springs have adjustment loop www.indiandentalacademy.com
  74. 74. www.indiandentalacademy.com
  75. 75. www.indiandentalacademy.com
  76. 76. www.indiandentalacademy.com
  77. 77. www.indiandentalacademy.com
  78. 78. www.indiandentalacademy.com
  79. 79. MD www.indiandentalacademy.com
  80. 80. MD www.indiandentalacademy.com
  81. 81. MD www.indiandentalacademy.com
  82. 82. MD www.indiandentalacademy.com
  83. 83. MD www.indiandentalacademy.com
  84. 84. K -LOOP • By Kalra in 1995 • The appliance consists of a K-loop to provide the forces and moments and Nance button to resist anchorage www.indiandentalacademy.com
  85. 85. K-loop made of .017”x.025”TMA wire with each loop 8mm long and 1.5mm wide www.indiandentalacademy.com
  86. 86. Legs of appliance bent down 200 www.indiandentalacademy.com
  87. 87. Wire marked at mesial of molar tube distal of premolar bracket www.indiandentalacademy.com
  88. 88. Bend placed 1 mm distal to distal1 mm distal to distal mark and 1 mm mesial to mesialmark and 1 mm mesial to mesial mark.mark. Stop should be well defined and about 1.5mm long www.indiandentalacademy.com
  89. 89. K-loop in place with 2mm activation www.indiandentalacademy.com
  90. 90. Moments and forces produced by K-loop www.indiandentalacademy.com
  91. 91. Reactivation sequence Open loop 1mm at (1); Open loop 1mm at (2); Open at (3) to regain the 200 bent of mesial and distal legs www.indiandentalacademy.com
  92. 92. www.indiandentalacademy.com
  93. 93. www.indiandentalacademy.com
  94. 94. COMPRESSED SPRINGS • Gianelly and co-workers. • Springs made from compressed stainless steel or NiTi. www.indiandentalacademy.com
  95. 95. • NiTi coil is activated to about 10 mm o produce 100 gm. • First premolars are anchored by Nance holding arch. • Coil springs can also be compressed by placing a sliding Gurin lock. www.indiandentalacademy.com
  96. 96. www.indiandentalacademy.com
  97. 97. www.indiandentalacademy.com
  98. 98. www.indiandentalacademy.com
  99. 99. REPELLING MAGNETIC APPLIANCE • First and second premolar are banded and an impression is made. A palatal stabilizing plate is fabricated and cemented in place. First molars are also banded. www.indiandentalacademy.com
  100. 100. • An assembly containing repelling magnets is placed into the molar tubes on maxillary first molar and magnets are placed in a repelling portion facing by ligating a sliding yoke to an eyelet as premolar. www.indiandentalacademy.com
  101. 101. • Activation every two or four weeks. • Not gained wide acceptance because the magnets tend to be expensive and bulky. www.indiandentalacademy.com
  102. 102. www.indiandentalacademy.com
  103. 103. www.indiandentalacademy.com
  104. 104. www.indiandentalacademy.com
  105. 105. SLIDING JIG • Auxillary sectional arch wires used to tip or move one or a group of teeth in buccal segments distally without disturbing anteriors. • Have bent in eyelets on each side. • To avoid friction or binding they should be made of 0.022 inch round wire and can also be made of rectangular wire. www.indiandentalacademy.com
  106. 106. • Location of intermaxillary hook on the jig, soldered or bent-in, is on the occlusal area of anterior eyelet of jig. • To move maxillary molar distally, eyelet on distal end of jig must but against molar tube, mesial eyelet is located between cuspid and first premolar bracket at least 2 mm anterior to premolar bracket. www.indiandentalacademy.com
  107. 107. www.indiandentalacademy.com
  108. 108. www.indiandentalacademy.com
  109. 109. BIMETRIC DISTALIZING ARCH • Developed by Wilson and Wilson. • components www.indiandentalacademy.com
  110. 110. • Distalizing force on the molars is produced by compression of push coil spring anchored by pull of class II elastics. The force of the elastics counteracts the forces of the push coil springs so that the anterior segment of the Wilson arch approximates the incisor brackets before ligation to the anterior teeth www.indiandentalacademy.com
  111. 111. • Posterior ends of Omega loop should contact the face bow tubes on maxillary first molar, and anterior section of arch should approximate brackets on maxillary anterior teeth. 5 mm section of 0.010 x 0.045” open wound coil is placed over end of William’s arch bilaterally. www.indiandentalacademy.com
  112. 112. • Advocated sequential use of elastics with decreasing force values i.e. 5/16” 6-oz in first week, similar size 4-oz in second and and similar size 2-oz in third and subsequent weeks of treatment. www.indiandentalacademy.com
  113. 113. • Appliance is activated by placing loop forming pliers into Omega loop, forcing posterior leg distally. Elastic sequence begins again when reactivated. • Lower arch should have a stiffer rectangular arch wire or lingual arc. www.indiandentalacademy.com
  114. 114. www.indiandentalacademy.com
  115. 115. www.indiandentalacademy.com
  116. 116. www.indiandentalacademy.com
  117. 117. HERBST APPLIANCE • Emil Herbst in 1905. • Original design consisted of placement of bands on maxillary first premolar and molar and mandibular first premolar, which were connected with lingual bar to support anterior teeth. www.indiandentalacademy.com
  118. 118. • The arches are connected with a telescopic adjustable piston mechanism to produce a protrusive force on mandible. www.indiandentalacademy.com
  119. 119. • Class II correction is by equal amounts of dental and skeletal changes. • Dental changes include distalization of maxillary molar and mesial movement of mandibular molar and incisors. www.indiandentalacademy.com
  120. 120. • Skeletal changes include inhibition of maxillary antero-posterior growth and to produce an increase in mandibular length and lower face height. www.indiandentalacademy.com
  121. 121. www.indiandentalacademy.com
  122. 122. www.indiandentalacademy.com
  123. 123. MOLAR DISTALIZATION IN LOWER ARCH www.indiandentalacademy.com
  124. 124. LIP BUMPER • used for molar anchorage, prevention of poor lip habits and creation of increased space for mandibular arch. • Made of 0.045” stainless steel that spans the facial structures of mandibular arch without contacting teeth and inserted into molar tubes. www.indiandentalacademy.com
  125. 125. • Anteriorly wire is covered by plastic tubing or acrylic shield to hold lip away from incisors. • Force from mentalis muscle is transmitted to molar, enabling them to move to an upright and distal position www.indiandentalacademy.com
  126. 126. www.indiandentalacademy.com
  127. 127. www.indiandentalacademy.com
  128. 128. APPLIANCE SELECTION CRITERIA • Regardless of approach, one should ponder several issues before considering any of these appliances for use Side effects Case types Arch length Treatment timing Co-operation www.indiandentalacademy.com
  129. 129. Side Effects • Did incisors flare? • If mandible is used as an anchor unit, did anything occur in that arch? www.indiandentalacademy.com
  130. 130. • Side effects are a fact of life, especially in orthodontics. • There are some side effects that would be favorable in certain cases, while the same effects may be detrimental in others. www.indiandentalacademy.com
  131. 131. • The key to correct appliance selection is to know, and be able to predict these effects. • For this a sound and thorough knowledge of biomechanics is essential. www.indiandentalacademy.com
  132. 132. Case types • Consider an individual case at hand and his/her needs. • If mandibular dentition can be slightly mesialized, if this in the case then Herbst or BDA may be appliance of choice. • If not pendulum and other intra-arch appliances can be used. • If you may not afford flaring of incisors then headgear would be treatment of choice. www.indiandentalacademy.com
  133. 133. Arch length How much distalization is required. TPA has limited application of 2-3 mm, if in need of greater amount of correction then Herbst and headgear are of choice followed by pendulum, Wilson BDA etc. www.indiandentalacademy.com
  134. 134. Treatment timing Perhaps best time to initiate distalization is late mixed dentition and it may be too late after eruption of second molar. Some synergistic effect as dentition transits from primary to permanent as canines and premolars follow molars as they moved distally. Thus appliances that requires some anterior anchorage like pendulum may dilute these results. www.indiandentalacademy.com
  135. 135. Co-operation • Invariably appliances that require least co-operation come with side effects that have to be considered. www.indiandentalacademy.com
  136. 136. CONCLUSION • There are many advantages and disadvantages of both the intra-oral and extra-oral methods. • It should be remembered that patient selection for a particular method of distalization is of utmost importance and should not be overlooked . www.indiandentalacademy.com
  137. 137. • Right appliance should be selected for the right patient and one should not select the patient for the appliance rather the appliance should be for the patient www.indiandentalacademy.com
  138. 138. Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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