A quick and concise recap of Endodontic Instruments. This presentation resolves the basic doubts within terminologies and provides visual conceptualization of the same.

1. Presented by : Ishaan Adhaulia

2. 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.

3. Classification of Instruments

4. Standardization of Instruments
Ingle & LeVine’s Original
Recommendations
•Files are numbered from 15 – 60
with an increment of 5
•From 60 onwards the increment is
10
• Cutting blades 16 mm in length (I1)
• The diameter of the instrument at tip
(D1) is determined by size in
hundredths of millimetres.
• Diameter at D2 is uniformly 0.32 mm
greater than D1 ensuring a constant
increase in taper of 0.02mm/mm

5. Modifications in Standardization
Four modifications were made in Ingle & LeVine’s
original proposed recommendation:
• Additional measurement at D3, 3 mm from tip (D1)
• Specification for angles of the tip: 75 degrees, ± 15
degrees
• Number 6 & 8 have been added for increased
instrumentation
• Colour coding added for quicker identification of
diameters of files.

6. Before diving into the classification, let us review the
components of an endodontic file.

7. Taper
It denotes the per millimetre increment in file diameter
from the tip towards the file handle. There are files with
variable taper such as,

8. Core
• It is the central cylindrical part of the file having its
circumference outlined and bordered by the depth of the
flutes.

9. Flutes
• 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.
FLUTE

10. 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.
Cutting Edge (Yellow)

11. Radial Land / Marginal Width
• Flat cutting surface present between two flutes/grooves
• The land touches the canal walls at the periphery of the file
and reduces the tendency of the file to screw into the canal
• Reduces transportation of the canal & propagation of micro-
cracks on its circumference
• Supports the cutting edge & Limits the depth of cut.
Radial Land indicated between
two black arrows.

12. Relief / Helix Angle
• Relief : Surface area of land that is reduced to a certain extent to
reduce frictional resistance.
• Helix angle : It’s the angle, the cutting edge forms with the long axis
of the file. All debris is collected in the flute from the canal. This
angle is important for determining which filing motion to use.

13. Rake Angle
• It is the angle formed between the leading edge and
the radius of the file
If the angle formed by the leading edge and
the surface to be cut (its tangent) is obtuse,
the rake angle is said to be positive or
cutting.
If the angle formed by the leading edge and
the surface to be cut is acute, the rake angle
is said to be negative or scraping

14. 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.

15. Filing Motions
1) Reaming
- A quarter turn clockwise and apically directed pressure
- Used with a reamer
2) Filing
- Push & Pull motion of an instrument
3) Combination of reaming and filing
- File is inserted with a quarter turn clockwise and
apically directed pressure (i.e. reaming) and then is
subsequently withdrawn (i.e. filing)
4) Watch Winding
- It is a back and forth oscillation of the endodontic
instrument right and left as it is advanced into the
canal
Reaming
Filing
Reaming & Filing
Watch Winding

16. Filing Motions
Circumferential Filing
- Used for canals that are larger and are not round.
- The file is placed in the canal and withdrawn in a directional manner
sequentially against the mesial, distal, buccal and lingual walls
Balanced Force Technique
- It’s the best technique as it involves clockwise rotation of instrument for 90
degree, then counter-clockwise rotation of instrument with apical
pressure (we will hear a clicking sound) for 120 degrees, then a final
clockwise rotation and the instrument is withdrawn.

17. Group 1 – Hand Operated Instruments
Barbed Broaches
• 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.
SMOOTH BROACH

18. Rasps
• Broaches and rasps show some significant differences in
taper and barb size.
• The broach has lesser taper of 0.007 to 0.010 mm and
the rasp has more taper of 0.015 to 0.020 mm.
• Barb height is much greater in the broach than in the
rasp.

19. Kerr Files (K-Files)
• In 1904 Kerr Manufacturing Company designed the, K-
style files and reamers.
• K-files were manufactured by twisting square or
triangular metal blanks along their long axis, producing
partly horizontal cutting blades.
• The tip is cutting and pyramidal
• Helical angle: 40˚

20. Kerr Reamers (K-Reamers)
• 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-Reamers have larger and less number of flutes
compared to K-Files.

21. K-File /Vs/ K-Reamer
K-File (Triangular Cross section) K-Reamer (Square Cross Section)

22. Modified K-Files
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
• Rhomboid shape gives the file 2 cutting edges and 2 non-
cutting edges which increase the chip space.

23. Flex-R by Roane (1985)
• The Flex-R file by Roane (1985) is the first to utilize a
non-cutting tip that helps avoid ledge formation in curved
canals.
• The principle of the Flex-R is based upon removal of the
sharp corners at the instrument tip (dual conical form).

24. 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

25. Hedström File (H-File)
• Hedström files are milled from round stainless steel
blanks.
• Cutting action: Retraction
• They are very efficient for translational strokes, but
rotational working movements are strongly discouraged
because of the possibility of fracture.
• Helical angle: 60˚
• Better cutting action than K-file (more positive rake
angle).

26. Modifications of H-File
• 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 & a triple helix design in HeliFile
• S – File can be used with any hand motion (filing or reaming)
thus this file can also be classified as hybrid design
S - file HeliFile

27. Group 2 – Low Speed Instruments with latch type
attachment
1) Gates Glidden Drills
- This has a long, thin shaft ending in a flame-shaped head with a
non-cutting safe tip to guard against perforation.’
- They are used to remove the lingual shoulder during access
preparation of the anterior teeth & to enlarge orifices.
- 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

28. Peeso Reamers
• It has long sharp flutes with a safe tip connected to a
thick shaft.
• It should be used at slow speed, as they cut aggressively
and are inflexible
• It cuts laterally and is primarily used for the preparation
of post space when gutta-percha has to be removed
from the obturated root canal.

29. Group 3 – Engine Driven Instruments
Nickel Titanium Rotary Endodontic Instruments
- These instruments are made up of Nitinol, an equi-atomic alloy
composed of nickel and titanium
- They exhibit “shape memory” due to austenitic crystalline structure
transforming into martensitic crystalline structure under stress.
- 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
NiTi flex - 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.

30. Reciprocating Instruments
- They function at unequal bidirectional angles
- The novel reciprocating movement allows a file to
progress more readily, cut efficiently, and effectively
auger debris out of the canal
- Eg : WaveOne system and Reciproc
Reciproc Files

31. Self Adjusting File
- Introduced by Zvi Metzger
- The file three dimensionally adapts both longitudinally and
along the cross-section of the root canal system (characteristic
feature)
- This results in a uniform cutting action of the dentin from the
canal walls (60-75 µm thick) and preserves the basic shape of
root canal.
- File maintains the canal cantering ratio and stays within the
canal & maintains the canal anatomy.

32. Group 4 – Ultrasonic Hand Instruments
• The first ultrasonic instrument goes back to Richman (1957)
• The ultrasonic instrument consists of a piezoelectric or a magnetostrictive
unit that generates ultrasonic waves
• The piezo-electrical units are better in that they are more powerful and
generate lesser heat than the magnetostrictive systems.
• The hand-piece holds a K-file or a specially designed diamond file that,
produces movements of the shaft of the file between 0.001 and 0.004
inch at a frequency of 25–30 kHz

33. Sonic Instruments
•Sonic hand-pieces operate at 2–3 kHz when used
inside root canals.
•They are similar in shape and weight to dental hand-
pieces and are attached to existing air and water
lines.
•These instruments are used in a manner similar to
the ultrasonic system in instrumentation of the root
canals. The only difference is that the sonic system
uses water as an irrigant and requires special
instruments known as:
- Rispi Sonic
- Shaper sonic
- Trio sonic (or Helio sonic)

34. Thank you for your patience