1. WORKING CASTS AND DIE SYSTEMS
dr shabeel pn

2. WORKING CASTS WITH A SEPARATE DIE
The simplest means
It keeps the relationship with the abutment fixed and immovable

3. Stone is added to the impression in small increments above the preparation

4. TRAY IS TILTED TO FILL THE PREPARATION

5. Stone is added to the impression so that the base of the set stone will be 1 inch

7. The die is first trimmed on a model trimmer

8. A properly trimmed die handle is slightly larger in diameter than the preparation

9. Improperly trimmed die with a handle that meets the preparation at an angle

10. Handle should be 1 inch long

11. The die is trimmed with an acrylic bur

12. Shaping of the handle near the finish line is completed with a scalpel

13. The die is smoothened below the finish line with the discoid end of a tanner carver

14. The preparation finish line on the die should be red pencil outlined with a

15. Die relief agent is painted on the preparation-20 to 40 mm

16. WORKING CAST WITH A REMOVABLE DIE
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WORKING CAST WITH A REMOVABLE DIE

17. Requirements
The die must return to their exact original positions The die must remain stable , even when inverted The cast containing the dies must be easy to mount on the articulator

19. FOUR SYSTEMS
Straight dowel pin Curved dowel pin Pindex system Di-lok trays

20. PINDEX SYSTEM
Reverse drill press is used that can be removed and replaced with great precision Impression poured before positioning dowel pins Drills parellel holes from underside Of the trimmed cast

21. Pour the impression adding 20mm of stone beyond the edge of the tray—allow trimmg Cast set in 60 min Remove the cast -Wet the cast

22. PARTS OF PINDEX MACHINE

23. Cast should be 15mm thick , exclusive the teeth

24. After trimming location of pin holes is marked with a pencil

25. Pencil marks are placed under the illuminated dot

26. Debris is removed from pin holes The holes are refined with a hand reamer

27. Cyanoacrylate cement is placed on the prior to cementing the pin tips

28. Shorter pins are placed before the long pins

29. White sleeves are placed on the long pins and gray sleeves on the short pins

30. The bottom of the cost is lightly coated with petrolactum

31. The ends of the gray sleeves are blocked with wax

32. Utility wax is placed on the ends of the long pins

33. A palatal \tongue filler is made of boxingwax and seated on the cast

34. Boxing wax is applied around the cast

35. The base is poured in microstone

36. Cast is seated in the base former Wax is removed

37. Saw cuts are marked with pencil Cast is removed

38. Dies are sectioned from underside and from occlusal aspect

39. Large condensers are used to loosen the dies

40. Mounted on an articulator

41. DI-LOK TRAY
Snap apart plastic tray with internal orienting grooves and notches to reassemble working casts and dies are used

42. CURVED DOWEL PIN
DOWELS INCORPORATED BEFORE POURING THE IMPRESSINO

43. WORKING CAST VERSES DIAGNOSTIC CASTS
Accuracy of the cast Errors in CRrecord are significant in working casts Kinematic face bow is used Reorganised occlusion by selective grinding and reorganising anterior guidance before tooth preparation

44. REFERENCES FUNDAMENTALS OF FPD ----H.T . SHILLINGBURG
THEORY AND PRACTICE OF FPD --- TYLMAN
CONTEMPARORY FPD----ROSENSTIEL

45. THANK YOU