03 02 lower special tray construction


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03 02 lower special tray construction

  1. 1. Week 3 Session 2 Anatomy Quiz & Lower Special Tray Construction Unit 6ADT4305
  2. 2. Part 1 A short quiz of upper oral anatomy and terminology PLEASE PUT ALL NOTES AWAY
  3. 3. C D B A E Identify the zones lettered A-E NOT THE STRUCTURES
  4. 4. F G H I Identify the CUSPS lettered F > I MESIAL DISTAL PALATAL
  5. 5. J K L M NIdentify the oral structures lettered J > N
  6. 6. Answers What did you remember?
  7. 7. Answers A to G A. Labial B. Buccal C. Palatal D. Lingual E. Buccal F. Mesiobuccal cusp G. Mesiopalatal cusp
  8. 8. Answers H to N H. Distobuccal cusp I. Distopalatal cusp J. Upper labial frenum K. Rougae L. Upper right buccal frenum (Just ‘buccal frenum’ does not count) M. Hard palate N. Tuberosity
  9. 9. Part 2 Making an edentulous lower special tray for ZOE (Zinc Oxide Eugenol)
  10. 10. Mark line of the ridges and outline of the sulcus Identify location for rests, in the second premolar/first molar region
  11. 11. Posterior margin to be just above the retromolar pad Identify areas of undercut e.g. below retromolar pad and block out with wax
  12. 12. Carefully adapt a sheet of light cure polymer Do not over thin If the cast shows through add more material Initial adaptation
  13. 13. Initial trimming
  14. 14. Push the material into the sulcus ensuring the material fully extends into it
  15. 15. Using a sharp tool carefully trim the material to the marked extension.
  16. 16. Trim all around the sulcus to the extension identified
  17. 17. Make a handle approximately 20mm long, 15mm wide and 5mm thick taper towards the tip. Flare the base of the handle to ease adaption to the base material. Side view
  18. 18. Position the handle in the midline of the anterior ridge. The handle should be between 22mm and 25 mm from the depth of the sulcus. It should be vertical but a slight anterior tilt may be acceptable. When correctly positioned the flared edges are blended into the base material.
  19. 19. Rests • The rest is made in the same way as the handle although slightly shorter. • The base is flared and the rest positioned centrally on the ridge approximately in the position of the second premolar/first molar. • The rest should be a maximum of 15 mm from the depth of the sulcus. • If the rest is placed too far lingually it will restrict the tongue, too far buccally will distort the cheeks.
  20. 20. Rests • When both rests are completed the tray is checked and then smoothed with petroleum jelly. This smoothes the material and acts to seal the material to reduce surface inhibition of the set by oxygen in the atmosphere. • The tray is placed in a light curing box and cured for 3 minutes. When cured the tray is removed from the cast, the tray is turned over and the fitting surface cured