Edgewise technique 3 /certified fixed orthodontic courses by Indian dental academy

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Edgewise technique 3 /certified fixed orthodontic courses by Indian dental academy

  1. 1. Merrifield’s modification INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. Merrifield’s modification Based on five concepts:1) Sequential appliance placement 2) Sequential &/ individual tooth movement 3) Sequential mandibular anchorage preparation 4) Directional forces including control of the vertical dimension to enhance mandibular response 5) Proper timing of treatment www.indiandentalacademy.com
  3. 3. Sequential appliance placement Advantages : a) Less traumatic to the patient b) Easier, less time consuming c) Greater efficiency, increased interbracket span www.indiandentalacademy.com
  4. 4. Sequential anchorage preparation Tipping two teeth at a time Use of high pull headgear instead of cl.III elastics Controlled, sequential & precise anchorage preparation- Merrifield’s 10-2 system www.indiandentalacademy.com
  5. 5. Directional force concept Hallmark of modern Tweed – Merrifield system - controlled forces that place the teeth in the most harmonious relationship with their environment - resultant of all the forces should be upward & forward for a favourable skeletal change www.indiandentalacademy.com
  6. 6. Steps of treatment Denture preparation Denture correction Denture completion Denture recovery www.indiandentalacademy.com
  7. 7. Denture preparation objectives:-leveling -individual tooth movement &rotation correction -retraction of both maxillary & mandibular canine -preparation of terminal molars for stress resistance time: approx. 6 mths wires :   0.018X .025 in. mand. 0.017x .022 in. max with loop stops flush with the second molar tubes www.indiandentalacademy.com
  8. 8.        Mandibular second molar effective distal tip 15° Maxillary second molar -5° 2nd premolar offset bends -to keep canines from expanding out of alveolar trough passive third order bends high pull J hook headgear used to retract max. & mand. Canines 1st molars are banded canine retraction continued using power chains & headgear force www.indiandentalacademy.com
  9. 9. Denture correction objectives: - complete space closure in both the arches -sequential anchorage preparation in the mand. Arch -enhanced curve of occlusion in the maxillary arch -cl.I intercuspation of canines & premolars Wires:   019 X .025 in.mand. .020X .025 in.max. With vertical loops distal to lateral incisors both the arches are coordinated each mon. until all max. space is closed www.indiandentalacademy.com
  10. 10.    At the end of space closure: the curve of occlusion should be maintained mandibular arch should be completely level dentition is ready for mand. arch prep www.indiandentalacademy.com
  11. 11.     .019X .025 in. wire loop stops flush against molar tubes ideal 1st & 2nd order bends hooks for high pull headgear distal to central incisors 10° distal tip1mm mesial to 1st molar bracket, compensating bend which maintains 15° terminal molar tip www.indiandentalacademy.com
  12. 12. After 1 mon 5° to 8° distal inclination of 1st molar Next 5° distal tip 1 mm mesial to 2nd premolar bracket, which manifests 20 to 30 distal tipping of the premolar. www.indiandentalacademy.com
  13. 13. Cl. II force system It should be based on: -ANB relationship -maxillary posterior space analysis -patient cooperation Guidelines to be followed:   ANB 5° or less max. 3rd molars missing patient is cooperative distalisation best option www.indiandentalacademy.com
  14. 14.    mild cl.II (ANB =5°to 8° ) average skeletal pattern (FMA =28° /less) normally erupting max. 3rd molars extract 2nd molar, distalise    ANB more than 10° max. 3rd molars present patient motivation questionable remove 1st molars, consider surgical correction www.indiandentalacademy.com
  15. 15. Correction of cl. II relation     mandibular .021X .028 stabilization wires with ideal 1st, 2nd, 3rd order bends loop stops should be placed slightly short of molar tube & wire passive in all brackets gingival spurs distal to mand, lateral incisors max. .020 X .025 in. wire with closed helical bulbous arch loops bent flush against 2nd molar tube is fabricated www.indiandentalacademy.com
  16. 16.        progressive 7° lingual crown torque in molar segment gingival spur attached to wire distal to max. 2nd premolar bracket gingival hooks for headgear distal to central incisors Closed loops are activated 1mm /side 8oz cl.II elastics anterior vertical elastics & high pull headgear Continued till second molars occlude in class I relation. www.indiandentalacademy.com
  17. 17.       Once second molar is distalized, closed coil spring placed in the space b/w 2nd premolar & 1st molar elastic chain from 2nd molar to 1st molar - spring & elastic force distalize the molar Cl.II elastics worn anterior vertical elastic-- 12 hrs /day high pull headgear --14hrs/day www.indiandentalacademy.com
  18. 18.   Followed by distalisation of 2nd premolars & canines with Echains & headgear total time - 4 mths www.indiandentalacademy.com
  19. 19.      closing loops distal to the lateral incisors ideal 1st ,2nd , 3rd order bends closing loops are opened 1mm /visit cl.II -- 4 to 8 oz anterior vertical elastics & maxillary high pull headgear are used along with cl.II www.indiandentalacademy.com
  20. 20. Denture completion    finishing archwires -.021x.028 U/L mand. archwire with same tip back bends as used previously max.arch with artistic positioning bends & hook for elastics & headgear www.indiandentalacademy.com
  21. 21. At the end of this stage: 1) incisors aligned 2) occlusion overcorrected to a cl .I relation 3) anteriors in an edge-edge 4) max.canines &2nd premolars in a cl.I relation 5) distal cusp of 1st &2nd molars- out of occlusion 6) all spaces must be closed tightly from the 2nd premolar forward www.indiandentalacademy.com
  22. 22. Denture recovery  When all appliances are removed, retainers are placed  Most crucial phase as muscular forces & periodontal forces are involved  Recovery based on the concept of overcorrection  Posterior disclusion –characteristic feature also known as Tweed occlusion or transitional occlusion www.indiandentalacademy.com
  23. 23.  Edge -edge relation of incisors develop into normal overjet & overbite as occlusion settles down  Muscles of swallowing, expression & mastication are actively involved in determining the final stable, esthetic relationship of teeth referred to as Functional occlusion www.indiandentalacademy.com
  24. 24.  The edgewise mechanism with conventional, static archwire slots is the most popular appliance in the world today. Yet, there are no provisions in the edgewise slot to facilitate the following  Anteroposterior movements in the buccal segments (weakness in mechanism for opening or closing spaces)  Anteroposterior interarch corrections  Anterior bite opening  Also torque from rectangular archwires often “round trips” adjacent teeth www.indiandentalacademy.com
  25. 25. www.indiandentalacademy.com Leader in continuing dental education www.indiandentalacademy.com

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