Endodontic instruments

ENDODONTIC
INSTRUMENTS
Aaron Sarwal
MDS 2nd Prof
Batch 2017

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

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.

CLASSIFICATION OF
ENDODONTIC INSTRUMENTS
According to Grossman
EXPLORING
INSTRUMENTS:
to locate the canal
orifice and
determine patency of
the root canal. E.g.
endodontic
explorers, smooth
broaches
(pathfinders).
DEBRIDING
INSTRUMENTS:
to extirpate the pulp
and remove any
foreign debris. E.g.
barbed broach.
CLEANING AND
SHAPING
INSTRUMENTS:
to clean and shape
the root canal
laterally and apically
e.g. reamers and files.
OBTURATING
INSTRUMENTS:
to cement and pack
gutta-percha
into the root. E.g.
spreaders, pluggers
and lentulospirals.

CLASSIFICATION OF CLEANING
AND SHAPING INSTRUMENTS
According to ISO – FDI (Based on use)
Group I: Hand Use only eg. K-Files, H-Files
Group II: Engine driven latch type eg. Gates Glidden Drills,
Peso reamers
Group III: Engine driven Ni-Ti Rotary Instruments eg. Profile,
Protaper
Group IV: Engine driven 3-D Adjusting Instuments eg Self
Adjusting File System
Group V: Engine driven reciprocating Instruments eg.
WaveOne
Group VI: Sonic and UltraSonic Instruments

CLINICAL CLASSIFICATION
1. INSTRUMENTS USED FOR DIAGNOSIS
1. Endodontic Explorers
2. Tooth Slooth
3. Dental Transilluminator
4. Pulp Vitality Tester

2. INSTRUMENTS USED FOR ACCESS OPENING
1. Diamond Rose Head Burs
2. Tapered Fissure
3. Carbide Burs
4. Safe End Long Burs
5. Endo Z Bur

3. INSTRUMENTS USED FOR CANAL PREPARATION:
a) INSTRUMENTS USED TO REMOVE PULP TISSUE:
i. Barbed Broaches
i. Endodontic Excavators
a) INSTRUMENTS USED FOR ROOT CANAL PREPARATION
i. Reamers
ii. Files

4) INSTRUMENTS USED FOR ROOT CANAL OBTURATION:
i. Lentulo spirals
ii. Spreaders
iii. Pluggers
iv. Condensors
v. Heat carriers
vi. Thermomechanical
compactors

STANDARDIZATION OF
 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.

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

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

STANDARDIZATION OF
#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

STANDARDIZATION OF
GEOMETRIC SHAPE CODING

MAKE OF ENDODONTIC INSTRUMENTS
METALLURGY

Alloys Used for Manufacturing
Endodontic Instruments
• These alloys contain less-than 2.1 percent
of carbon.CARBON STEEL
• These are corrosion resistant instruments.
• They contain 18 percent chromium, 8-10
percent nickel and 0.12 percent carbon.
STAINLESS STEEL
• These instruments contain 55 percent
nickel and 45 percent titanium.NICKLE - TITANIUM

METALLURGY OF ENDODONTIC
INSTRUMENTS
CARBON STEEL
ADVANTAGES
• Higher hardness than stainless steel
instruments.
DISADVANTAGES
• Prone to corrosion, so cannot be
autoclaved.
• Prone to rust.
e.g. Barbed Broach

INSTRUMENTS
STAINLESS STEEL
Example: K-file,
ADVANTAGES
• Corrosion resistance
DISADVANTAGES
• Stiff in nature
• Prone to fracture
• Prone to distortion

INSTRUMENTS
NICKLE-TITANIUM
ADVANTAGES
• Shape memory
• Super elasticity
• Low modulus of elasticity
• Corrosion resistant
• Softer than steel
• Good resiliency
• Biocompatibility
DISADVANTAGES
• Poor cutting efficiency.
• NiTi files do not show signs of fatigue before they
fracture.
• Poor resistance to fracture as compared to stainless steel. HyFlex CM NiTi Files

MAKE OF ENDODONTIC INSTRUMENTS
MANUFACTURING AND DESIGN

MANUFACTURING OF
•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:
MACHINING
• The instrument is directly
machined on the lathe for
example H-file and NiTi
instruments are machined.
GRINDING AND TWISTING
• Raw wire is ground into tapered
geometric blanks, i.e. square,
triangular or rhomboid.
• Blanks are twisted
counterclockwise to produce
cutting edges.

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

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.

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

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

INSTRUMENTS
FLUTE
 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.

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.

INSTRUMENTS
LAND/MARGINAL WIDTH
 The surface that projects axially from the central axis as far as the cutting
edge between the flutes
FUNCTIONS
• Prevents ‘‘screwing in’’ of
the file
• Supports the cutting edge
• Limits the depth of cut
• Reduces the propagation
of micro-cracks on its
circumference.
• Maintains the file in the
centre of root canal.

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.

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.

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.

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.

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
INSTRUMENTS

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.
INSTRUMENTS

TERMS USED WITH ENDODONTIC
INSTRUMENTS

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

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

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

ELASTIC DEFORMATION
 Reversible deformation that does not exceed the elastic limit.
TERMS USED WITH

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

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

 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

 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

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

 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

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

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

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

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.

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

 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

 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

 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

 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

 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

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

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

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

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

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

GG DRILL SIZES V/S PEESO REAMER SIZES

NICKEL-TITANIUM ROTARY
 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.

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

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.

NICKEL-TITANIUM ROTARY

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

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.

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

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