six keys to optimal occlusion /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.

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six keys to optimal occlusion /certified fixed orthodontic courses by Indian dental academy

  1. 1. Six keys to Optimal Occlusion
  2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education
  3. 3. Introduction Classic guideline in ortho diagnosis – ‘Sine qua non’ of proper occlusion – “cusp of upper first perm molar must occlude in the groove btw the mesial & middle buccal cusps of the lower first perm molar” Angle (1899) Angle did not contend that this factor alone enough Acceptable molar relationships with obvious inadequacies seen 120 casts of Naturally occuring optimal occlusions studied from 1960 – 64 to ascertain which characteristics would be found consistently in all the models.
  4. 4. Six keys – optimal = most desirable or satisfactory – Webster’s dictionary Interdependent elements of the structural system of optimal occlusion. Serve as base for evaluating occlusion Can be used as treatment objectives in most patients Make it possible to assess the occlusion form the facial & occlusal sites without using measuring devices or articulating paper.
  5. 5. Key I : Molar Relationship 
  6. 6.
  7. 7.
  8. 8. Key II : Crown Angulation (Tip)
  9. 9. Crown Angulation (Tip)
  10. 10. Key III : Crown Inclination 
  11. 11. Crown Inclination
  12. 12.
  13. 13. Key IV : Absence of Rotations 
  14. 14. Key V : Tight Contacts
  15. 15. Key VI : Occlusal Plane Flat to slight curve of Spee 
  16. 16. Terminologies  Andrew’s Planemid transverse plane of every crown  Clinical crown – visible intraorally/on cast anatomic crown – 1.8mm (Orban)  FACC – LACC in earlier writings all teeth except molars – most prominent portion of the central lobe on each crown’s facial surface for molars – buccal groove
  17. 17. Terminologies FA point- point on the FACC that separates the gingival half of clinical crown from the occusal half Facial plane – tangent to FA point eqidistant from gingival and occlusal extremities. Embrasure line –at level of mid transverse plane – connecting most facial portions of the contact areas of the teeth
  18. 18. Andrews classified brackets into three types1. Non programmed appliance-a set of brackets designed the same for all tooth types ,relying totally on wire bending. 2. Partly programmed appliance- a set of brackets designed with some in built features ,but always require some wire bending 3. Fully programmed appliance- a set of brackets designed to guide teeth directly to their goal positions with unbent wires. – Straight wire Appliance.
  19. 19. The Straight Wire Appliance • Fully programmed appliance- Slot-siting feature - Convenience feature - Auxiliary feature
  20. 20. The Straight Wire Appliance • Slot siting featureMid Transverse plane: Feature 1- mid transverse planes of the slot stem and crown must be the same. Feature 2-base of the bracket for each tooth type must have same inclination as the facial plane of the crown.
  21. 21. Feature 3-each bracket inclined base must be contoured occluso- gingivally
  22. 22. Mid sagittal plane Feature 4- mid sagittal plane of the slot stem and crown must be same. Feature 5 -the plane of the bracket base at its base point must be identical to the facial plane of the crown at the FA point.
  23. 23. Feature 6 - Base should match the m-d contour of the tooth. •Feature 7 - the vertical component should be parallel to one another.
  24. 24. Mid frontal plane • Feature 8 – all slots point must have same distance between them and the crown embrasure line.
  25. 25. The Straight Wire Appliance • Convenience feature-. 1. The gingival tie wings of the post Brackets extend farther laterally . Base are inclined . 2.
  26. 26. 3) 4) 5) Facial surface of the incisor and canine brackets are designed to parallel their bases. In mandibular brackets the tie wings are designed with least amount occlusofacial prominence Bracket identification.
  27. 27. Convenience feature-
  28. 28. The Straight Wire Appliance • - Auxiliary feature – Power arms Hooks Face bow tubes Utility tubes Rotational wings
  29. 29. Leader in continuing dental education