Endodontic instruments

A well pictured presentation on Endodontic Instrumentation for UG students. Best for getting a good grip on the topic as a whole. Meant to supplement not substitute standard texts.

1. ENDODONTIC INSTRUMENTS Aaron Sarwal MDS 2 nd Prof Batch 2017

2. INDEX Introduction Classification of Endodontic Instruments Standardization of Endodontic Instruments Make of Endodontic Instruments Terms used with Endodontic Instruments Hand Instruments Rotary Devices Clinical Considerations References

3. INTRODUCTION Instruments play a very important role in the success of a root canal treatment therefore a basic knowledge of endodontic instruments is essential. General guidelines exist for root canal preparation, but due to the complex and varied canal anatomy each case presents unique challenges. A variety of instruments are thus available for this purpose.

4. CLASSIFICATION OF ENDODONTIC INSTRUMENTS

5. CLASSIFICATION OF CLEANING AND SHAPING INSTRUMENTS

6. CLINICAL CLASSIFICATION INSTRUMENTS USED FOR DIAGNOSIS Endodontic Explorers Tooth Slooth Dental Transilluminator Pulp Vitality Tester

7. CLINICAL CLASSIFICATION INSTRUMENTS USED FOR ACCESS OPENING Diamond Rose Head Burs Tapered Fissure Carbide Burs Safe End Long Burs Endo Z Bur

8. CLINICAL CLASSIFICATION INSTRUMENTS USED FOR CANAL PREPARATION: INSTRUMENTS USED TO REMOVE PULP TISSUE: Barbed Broaches Endodontic Excavators INSTRUMENTS USED FOR ROOT CANAL PREPARATION Reamers Files

9. CLINICAL CLASSIFICATION INSTRUMENTS USED FOR ROOT CANAL OBTURATION: Lentulo spirals Spreaders Pluggers Condensors Heat carriers Thermomechanical compactors

10. STANDARDIZATION OF ENDODONTIC INSTRUMENTS Before 1958, endodontic instruments were manufactured without benefit of any established criteria. The numbering (1 to 6) was entirely arbitrary . An instrument of one company rarely coincided with a comparable instrument of another company .

11. STANDARDIZATION OF ENDODONTIC INSTRUMENTS Cutting blades 16 mm in length 2 % Taper. The diameter of the instrument at tip (D1) is determined by size in hundredths of millimetres. Diameter 2 (D2) is uniformly 0.32 mm greater than D1. Length- 21, 25, 31 mm. Ingle’s Original Recommendation

12. STANDARDIZATION OF ENDODONTIC INSTRUMENTS Two modifications were made in Ingle’s original proposed recommendation: Additional measurement at D3 , 3 mm from tip / D1 Specification for shapes of the tip : 75 degrees, ± 15 degrees . Modification of Ingle’s Original Recommendation

13. STANDARDIZATION OF ENDODONTIC INSTRUMENTS #06 PINK ONLY AVAILABLE IN #06 #08 GRAY ONLY AVAILBLE IN #08 #10 PURPLE ONLY AVAILBLE IN #10 #15 #45 #90 #20 #50 #100 #25 #55 #110 #30 #60 #120 #35 #70 #130 #40 #80 #140 ISO-COLOR CODING With the exception of Pink, Gray and Purple, all the colors are repeated every six instruments

14. STANDARDIZATION OF ENDODONTIC INSTRUMENTS GEOMETRIC SHAPE CODING

15. MAKE OF ENDODONTIC INSTRUMENTS METALLURGY

16. Alloys Used for Manufacturing Endodontic Instruments

17. METALLURGY OF ENDODONTIC INSTRUMENTS CARBON STEEL e.g. Barbed Broach

18. METALLURGY OF ENDODONTIC INSTRUMENTS STAINLESS STEEL Example: K-file,

19. METALLURGY OF ENDODONTIC INSTRUMENTS NICKLE-TITANIUM HyFlex CM NiTi Files

20. MAKE OF ENDODONTIC INSTRUMENTS MANUFACTURING AND DESIGN

21. MANUFACTURING OF ENDODONTIC INSTRUMENTS A hand operated instrument reamer or file begins as a round wire which is modified to form a tapered instrument with cutting edges. These are manufactured by two techniques:

22. DESIGN OF ENDODONTIC INSTRUMENTS COMPONENTS OF A FILE: TAPER CORE FLUTE CUTTING EDGE LAND HELIX ANGLE PITCH RAKE ANGLE CUTTING ANGLE TIP DESIGN

23. DESIGN OF ENDODONTIC INSTRUMENTS TAPER It is expressed as the amount of file diameter increases each millimetre along its working surface from the tip towards the file handle.

24. INSTRUMENT DESIGN : TAPER INSTRUMENT TAPER PROFILE 2%, 4%, 6% HERO 642 2%, 4%, 6% K3 2%, 4%, 6% FLEXMASTER 2%, 4%, 6%, INTRO FILE-11% RACE 2%, 4%, 6%, 8%,10% QUANTEC SC 2%,3%, 4%, 5%,6%, 8%,10%,12% M-TWO 4%,5%,6%,7% GT FILE 4%, 6%, 8%, 10%, 12% LIGHTSPEED NO TAPER PROTAPER VARIABLE TAPER

25. DESIGN OF ENDODONTIC INSTRUMENTS CORE It is the cylindrical centre part of the file having its circumference outlined and bordered by the depth of the flutes.

26. DESIGN OF ENDODONTIC INSTRUMENTS F LUTE It is the groove in the working surface used to collect soft tissue and dentin chips removed from the walls of the canal. The effectiveness of the flute depends on its depth, width, configuration, and surface finish.

27. DESIGN OF ENDODONTIC INSTRUMENTS CUTTING EDGE The surface with the greatest diameter that follows the groove (where the flute and land intersect) as it rotates, forms the leading (cutting) edge, or the blade of the file .

28. DESIGN OF ENDODONTIC INSTRUMENTS LAND/MARGINAL WIDTH The surface that projects axially from the central axis as far as the cutting edge between the flutes

29. DESIGN OF ENDODONTIC INSTRUMENTS HELIX ANGLE The angle formed by the cutting edge with the long axis of the file. Helps in removing debris collected in the flute from the canal.

30. DESIGN OF ENDODONTIC INSTRUMENTS PITCH The pitch of the file is the distance between a point on the leading edge and the corresponding point on the adjacent leading edge. OR It may be the distance between corresponding points within which the pattern is not repeated.

31. DESIGN OF ENDODONTIC INSTRUMENTS RAKE ANGLE The angle formed by the leading edge and the radius of the file when the file is sectioned perpendicular to its long axis.

32. DESIGN OF ENDODONTIC INSTRUMENTS CUTTING ANGLE The cutting angle or effective rake angle is a better indication of the cutting ability of a file and is obtained by measuring the angle formed by the cutting (leading) edge and the radius when the file is sectioned perpendicular to its cutting edge.

33. TIP DESIGN It can affect file control, efficiency, and outcome in the shaping of root canal systems. The tip of the original K-file resembled a pyramid. Instrument tips have been described as cutting, non-cutting, and partially cutting, although no clear distinction exists among the three types DESIGN OF ENDODONTIC INSTRUMENTS

34. TIP DESIGN Powell et al pointed out that when this tip “ angle” is reduced, the file stays centred within the original canal and cuts all sides (circumference) more evenly. This modified-tip file has been marketed as the Flex-R-file. DESIGN OF ENDODONTIC INSTRUMENTS

35. TERMS USED WITH ENDODONTIC INSTRUMENTS

36. ELASTIC LIMIT It is the maximum stress that can be applied to a metal without producing permanent deformation. Application of external forces causes internal stresses that cause deformation. If the stresses are not too much, the metal will return to its original dimensions on removal of the stress. TERMS USED WITH ENDODONTIC INSTRUMENTS

37. STRESS The force acting across a unit area in a solid material . Stress is a quotient of force divided by area. TERMS USED WITH ENDODONTIC INSTRUMENTS

38. STRAIN The amount of deformation a metal undergoes. It is the change in length divided by original length. Strain has no units. TERMS USED WITH ENDODONTIC INSTRUMENTS

39. ELASTIC DEFORMATION Reversible deformation that does not exceed the elastic limit. TERMS USED WITH ENDODONTIC INSTRUMENTS

40. SHAPE MEMORY It is the property of an alloy to return to its original shape when heated. TERMS USED WITH ENDODONTIC INSTRUMENTS

41. HAND-OPERATED INSTRUMENTS BARBED BROACHES, RASPS, K-FILES, K-REAMERS, H-FILES

42. Specification : (ADA no. 63, ISO no. 3630/1) Barbed broaches are short-handled instruments used primarily for vital pulp extirpation. They are also used to loosen debris in necrotic canals or to remove paper points or cotton pellets. These instruments are manufactured by notching a round, tapered wire with a blade to form sharp, projecting barbs that cut or snag tissue BARBED BROACHES

43. Broaches and rasps show some significant differences in taper and barb size. The broach has lesser taper of .007 to .010/mm and the rasp has more taper of .015 to .020/mm. Barb height is much greater in the broach than in the rasp. RASPS BROACH RASP

44. There is also a smooth broach, sometimes used as a pathfinder. The newly released Pathfinder CS ( Sybron Endo /Kerr; Orange, Calif.), made of carbon steel, is less likely to collapse when forced down in a fine canal. SMOOTH BROACH

45. In 1904 Kerr Manufacturing Company designed the, K-style files and reamers . (ADA NO 28 / ISO standard no. 3630-1) Files are instruments that enlarge canals with reciprocal insertion and withdrawal motions . K Files blade angle makes them best suited for cutting dentin in the filing motion. Reamers cut and enlarge canals with rotational motions. K Reamers have a rake angle which makes them most efficient in rotary motion , hence reaming is preferred. K-STYLE FILES AND REAMERS

46. BLANKS OF K-STYLE REAMERS AND FILES K-REAMER K- FILE

47. CROSS SECTION OF K-STYLE REAMERS AND FILES K-REAMER K- FILE

48. K-FLEX FILE The Kerr Manufacturing Company in 1982 introduced a new instrument design that they termed the K-Flex File . The cross-section of the K-Flex is rhombus or diamond shaped. This new cross-section presents significant changes in instrument flexibility and cutting characteristics. MODIFIED K-INSTRUMENTS

49. FLEX-R FILE (MILLED K-FILE) They are made by removing the sharp cutting edges from the tip of the instrument .and the tip is rounded . The flutes are sharper and has less negative rake angle than a traditional twisted K-file. MODIFIED K-INSTRUMENTS

50. C-FILE (MALLIFER) These are made of specially treated stainless steel for stiffness and strength. The result is easier access to challenging, calcified canals. Heat-tempered steel for stiff performance Twisted file design for greater strength Eases penetration of calcified canals Available in 21 mm & 25 mm MODIFIED K-INSTRUMENTS

51. Specification : ADA 58. ISO no. 3630-1. H-type files are made by cutting/grinding the spiraling flutes into the shaft of a piece of round, tapered, stainless steel wire. H-files cuts in only one direction— retraction/ pull motion. H-STYLE INSTRUMENTS

52. Single helix, tear drop shaped cross-section. Deep grinding of the surface of H-file reduces central mass of metal and thereby weakened the structure. hence it should not to be used in a rotational manner. H-FILES

53. McSpadden was the first to modify the traditional Hedstroem file. Marketed as the Unifile and Dynatrak , these files were designed with two spirals for cutting blades, a double-helix design In cross-section, the blades presented an “S” shape rather than the single-helix teardrop cross-sectional shape of the true Hedstroem file. MODIFIED H-STYLE FILES

54. The “S” File (J-S Dental) also appears to be a variant of the Unifile in its double-helix configuration. This instrument can be used with any hand motion (filing or reaming) thus this file can also be classified as hybrid design . S-FILE

55. These are H-Files characterized by short staff bent at and angle of 200 deg, with a long plastic handle. Available in sizes 20 and 30, taper 0.02 The flutes clear away paste, pulpal residues, gutta-percha, and calcification. These instruments also allow additional shaping of the canal. MICRO-DEBRIDERS

56. H-Files with a non-cutting edge to prevent ledging and stripping in curved canals. SAFETY H-FILES

57. ROTARY INSTRUMENTS LOW-SPEED LATCH-TYPE AND ENGINE-DRIVEN INSTRUMENTS

58. MOTORS FOR ROTARY INSTRUMENTS Work on the principle of continuous rotation within the root canal at a fixed slow speed

59. GATES – GLIDDEN DRILL This has a long, thin shaft ending in a flame-shaped head with a non-cutting safe tip to guard against perforation. It is made of hardened carbon steel. The flame shaped head cuts laterally and is used with a gentle, apically directed pressure. It has a modified safe tip i.e. non-cutting tip. These instruments come in sizes 1 to 6 LOW-SPEED ROTARY INSTRUMENTS

60. PEESO- REAMER It has long sharp flutes with a safe tip connected to a thick shaft. It is most often used in preparing the coronal part of the root canal for a post and core. LOW-SPEED ROTARY INSTRUMENTS

61. GG DRILL SIZES V/S PEESO REAMER SIZES

62. NICKEL-TITANIUM ROTARY ENDODONTIC INSTRUMENTS The greatest innovation in endodontic instrumentation in recent times is probably the introduction of nickel titanium rotary instruments . Nickel-titanium alloy ( Nitinol ) was discovered by Buehler and Wang at the US Naval Ordnance Laboratory in the early 1960s. The name Nitinol was derived from the elements that make up the alloy, nickel and titanium, and “ nol ” for the Naval Ordnance Laboratory.

63. SUPER-ELASTICITY OF NICKEL-TITANIUM ALLOY Super-elasticity and shape memory of NiTi alloy is because of phase transformation in their crystal structure. The alloy exists in two crystallographic forms i.e. parent Austenitic phase which is stronger and stable than the daughter Martensitic phase. On release of stress, the structure reverts back to Austenite. Austenite  Martensite  Austenite

64. DESIGN OF NICKEL-TITANIUM ALLOY NiTi flex-files are manufactured from nickel-titanium wire that is ground to give the typical profile of a K-file. The tip of the instrument is non-cutting (' batt -tip') which makes the NiTiflex -file well suited for the preparation of curved canals without the risk of ledge formation. NiTiflex -files come in sizes 15 - 60, all with a taper of 0.02.

65. NICKEL-TITANIUM ROTARY ENDODONTIC INSTRUMENTS

66. NICKEL-TITANIUM ROTARY ENDODONTIC INSTRUMENTS

67. NICKEL-TITANIUM ROTARY ENDODONTIC INSTRUMENTS

68. NICKEL-TITANIUM ROTARY ENDODONTIC INSTRUMENTS

69. CLINICAL CONSIDERATIONS DO’S DON’TS Assess canal anatomy thoroughly Instrument blindly Achieve straight line access prior to instrumentation Staying in canals for long Follow crown-down sequence Use of same files repeatedly Use glide path for patency of canal Forceful instrumentation Use files for 5 to 10 seconds only Rotation for too long Adequate irrigation and lubrication Dry instrumentation Wipe flutes after each use Use of unclean files Examine files before, during and after use Use files without inspection

70. CONCLUSION From a biological perspective, root canal treatment is directed toward the elimination of micro-organisms from the root canal system and the prevention of reinfection . Technological advances in the form of rotary NiTi instruments have led to dramatic improvements in the ability to shape root canals with potentially fewer procedural complications.

71. REFERENCES Ingle’s Endodontics: 5th & 6th Edition Torabinejad & Walton’s Endodontics Principle & Practice: 4 th Edition Grossman’s Endodontic Practice: 11 th and 13th Edition Cohen’s Pathways Of Pulp:9th Edition Franklin Weine’s Endodontic Therapy:6th Edition