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Endodontic instruments basic & hand instruments http://theoptimalsmile.wix.com/dentistry
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In considering the endodontic instruments those that are hand
operated are the most important.
However other specialised instruments such as explorers &
excavators have been designed to adapt to the root canal
treatment requirement.
Originally instrument for root canal treatment were few in
number and crude in design.
The earliest hand operative devices had long handles that were
best suited for anterior teeth.
As RCT diversified, small “finger” instruments were developed for
posterior teeth.
New designs in endodontics instruments have been introduced
and will continue to evolve.
MICRO
INSTRUMENTS
INTRACANAL INSTRUMENTS
GENERAL INSTRUMENTS
Classification
1) Front surface mouth mirror
2) Periodontal probe
3) Explorer
4) Cotton forceps
5) Endodontic explorers
DG 16
DG 16/23
6) Endodontic excavator
7) Endodontic ruler
8) Instrument organizer (endodontic kit)
used for arrangement of reamers and files according to the size and length.
provides holes for the files to be place vertically in a sponge which is saturated with disinfectant to maintain its sterility.
9) Endodontic syringe
tip of the instrument is flat to prevent penetration of the needle to the small canals;
also it has a groove in its tip to permit the irrigation which might be under pressure to flow coronally rather than forcing it to the apical foramen causing post operative pain.
10) Transfer sponge
A-Carbon steel-
contain less than 2.1% of carbon
Have high hardness than SS instruments.
Prone to corrosion, so cant be re-sterilised.
Prone to rust.
Example: barbed broch
B-Stainless steel instruments-
contain 18% chromium, 8-10% nickel, 0.12% carbon
Corrosion resistant
Stiff nature
Prone to fracture
Prone to distortion
C-Nickel titanium - contain 55% Ni and 45% Ti
Shape memory
Super elasticity
Low modulus of elasticity
Corrosion resisitant
Softer
Good resilience
Biocompatibility
Poor cutting efficiency
Don’t show signs of fatigue before they fracture
Poor resistance to fracture.
1-Broaches & Rasps:
Made from round stainless steel wire blank.
Working edges are created by cutting into the wire at an angle to its long axis.
The depth angle and number of cuts (barbs) will determine how the instrument is used
2- K Files & reamers:
Designed in 1904 by Kerr Manufacturing Co.
Are the most widely copied and extensively manufactured endodontic
instruments worldwide .
Previously made of Carbon Steel Presently made of Stainless Steel.
K File and Reamer are the oldest instruments used to machine dentin.
Produced by grinding graduated sizes of round Piano wire into either a
square or triangular configuration
These instruments are useful for penetrating and enlarging root
canals.
These instruments works primarily by compression and release
destruction of the dentin surrounding the canal.
Design & structure
Made from triangular
blanks.
More flexible.
The helix angle is small,
therefore effective only in
rotating motion
Has cutting tip
0.5-1 flute/mm.
Reamer: Sizes & Codes
comes in sizes 06 -
140,
all with a taper of 0.02.
design is identified by
the triangle symbol on
the handle.
Reamer: Recommended use
It is used by continuous
rotation when the resistance
is small or moderate
and by balanced force when
the resistance is greater.
In curved canals ledging
easily occurs with even small
reamer sizes if instruments
are not pre-curved.
Reamer: Safety tips
Reamers can be rotated only using
moderate pressure.
Use of force, particularly with
smaller sized instruments, may
result in distortion of the helical
structure and ultimately in fracture.
Each instrument should be checked
for symmetry by rotating it against
an even background before
introducing it into the canal.
K-file: Design & Structure
Made from rectangular blanks
Helix angle is greater than in a reamer, and therefore preparation by a K-file is effective both in rotary and filing motion.
The tip of the instrument is cutting
less flexible than reamers but are more effective in cutting.
1.5-2.25 flute/mm.
K-file: Sizes & Codes
K-files are produced in sizes 06 - 140,
all with a taper of 0.02.
K-file design is identified by the square symbol on the handle.
K-file: Recommended use
It prepares both in filing motion (up and
down) and when rotated.
In slightly curved canals -continuous
rotation when the resistance is small and
balanced force against greater resistance.
Compared to reamers, the use of
continuous rotation is limited because of
the screwing effect typical of K-file.
K-file: Safety tips
K-files can be rotated only using moderate
pressure.
Use of force, particularly with smaller sized
instruments may result in distortion of the helical
structure and ultimately in fracture.
Balanced force technique and filing instead of
continuous rotation should be used with sizes 06 -
15 to minimize fracture risk.
Each instrument should be checked for symmetry
by rotating it against an even background before
introducing it into the canal
Flexoreamer: Design & Structure
manufactured from a triangular steel wire that is twisted to give the typical shape of a reamer.
The helix angle is small, and therefore effective only in rotatory motion.
The tip of the instrument is non-cutting (bat-tip/inactive tip) making flexoreamer well suited for the preparation of evenly curved canals without risk of ledging.
Flexoreamer: Sizes & Codes
come in sizes 15 – 40.
all with a taper of 0.02.
Flexoreamers are best
distinguished from normal
reamers by the size code at the
top of the instrument: in
flexoreamers the colour of the
number is the same as the
colour of the handle.
Flexoreamer: Recommended use
The flexoreamer is well suited both
for straight canals and slightly
curved canals.
It prepares dentin in rotation but not
if used as a file.
The cutting efficiency and usability of
flexoreamers are excellent.
In slightly curved canals the
recommended technique sare
continuous rotation when the
resistance is small and balanced
force against greater resistance.
Flexoreamer: Safety tips
Flexoreamers can be rotated only using
moderate pressure.
Use of force, particularly with smaller
sized instruments, may result in
distortion of the helical structure and
ultimately in fracture.
Every instrument should be checked for
symmetry by rotating itagainst an even
background before introducing it into
the canal
FlexoFile: Design & Structure
FlexoFile: Sizes & Codes
FlexoFile: Recommended use
Flexofile is suited for both straight
canals and slightly curved canals.
Effective both in filing motion(up and
down) and when rotated.
In slightly curved canals the
recommended techniques are
continuous rotation when the
resistance is small and balanced force
against greater resistance.
Use of continuous rotation is limited as
compared to reamers because of the
screwing effect typical of K-files
FlexoFile: Safety tips
Flexofiles can be rotated (balanced
force) only using moderate pressure.
Use of force, particularly with smaller
sized instruments, may result in
distortion of the helical structure and
ultimately in fracture.
Every instrument should be checked
for symmetry by rotating it against an
even background before introducing it
into the canal
Hedstrom File: Design & Structure
Manufactured from round steel wire by
grinding.
The helix angle is close to right angle,
which is therefore preparation by H files
is effective only when using a filing
motion (up and down movement).
More positive rake angle.
blade with a cutting rather than a
scraping angle
Hedstrom File: Sizes & Codes
come in sizes 08 – 140.
all with a taper of 0.02.
H-file design is identified by the circle symbol on the handle.
Hedstrom File: Recommended use
can be used both in straight canals and curved canals.
Cut only in retraction.
In curved canals, files (sizes 20/25 and bigger) must be pre-curved to correspond to the shape of the curve.
H-files must always fit loosely in the canal to avoid risk for fracture.
Small sizes up to #25 can be used down into full preparation length while bigger sizes are often used 1 - 3 mm short.
Hedstroem File: Safety tips
Hedstrom files show a greater risk for fracture than reamers and K-files if used in a wrong way.
Hedstrom must always fit loosely in the canal and they must never be rotated.
In curved canals Hedstrom-files are pre-curved to correspond to the shape of the canal.
Before introducing them into the canal, all Hedstrom files must be inspected for possible earlier damage to the instrument and discarded immediately if an asymmetry in the cutting area is found
Rhomboidal or Diamond shaped
This new cross-section presents significant changes in instrument flexibility and cutting characteristics
The cutting edges of the high flutes are formed by the two acute angles of the rhombus and present increased sharpness and cutting efficiency
The alternating low flutes formed by the obtuse angles of the rhombus are meant to act as an auger, providing more area for increased debris removal
They are made up of SS
A hybrid instrument.
More flutes than reamer but fewer than
K-file.
Made from triangular stainless steel
blank by twisting, not ground.
More aggressive & flexible than regular
K-style instrument.
Made by removing the sharp
cutting edges from the tip of
instrument.
Have non cutting tip, so less
chances of ledge formation,
canal transportation when used
with balance force technique.
Triangular cross section which
provides it flexibility
Made up of NiTi and cut during
anticlockwise rotary motion.
Has noncutting safety side
along the length of the blade
which reduces the chances of
perforation.
The noncutting side is directed
to the side of canal where
cutting is not required.
Therefore prevents ledging of
the canals
It is called S because of its cross-
sectional shape.
Produced by grinding, which
makes it stiffer than H file.
The file is designed with 2 spirals
for cutting blades, forming double
helix design.
It has good cutting efficiency in
either filing or reaming action,
thus file can also be classified as
hybrid design.
Used for difficult and calcified canals.
Have better buckling resistance
than k files.
Available in size 8, 10, 15 of length
18, 21 and 25 mm.
Were described by Weine.
Comes under intermediate files provided with
half sizes between conventional instruments.
Available in sizes from 12-37 like 12, 17, 22,
27, 32, 37.
Used for narrow canals.
They are formed by cutting 1 mm from tip of
instrument.
In 1959, a new line of standardized instruments and filling material was introduced by ingle and levine
A formula for the diameter and taper in each size of instrument and filling material was agreed on.
A formula for a graduated increment in size from one instrument to the next was developed.
A new instrument numbering system based on instrument metric diameter was established.
After the introduction of standardized instruments, about the
only changes made were
the universal use of stainless rather than carbon steel
the addition of smaller (Nos. 6 and 8) and larger (Nos. 110-
150) sizes as well as color coding.
It was not until 1976 that the first approved specification for
root canal instruments was published (ADA Specification No.
28)
The numbering system, last revised in
2002, using numbers from 6 to 140, is
based on the diameter of the
instruments in hundredths of a
millimeter at the beginning of the tip of
the blades, a point called D0 (diameter
1 mm) , and extending up the blades
to the most coronal part of the cutting
edge at D16 (diameter 2-16 mm in
length).
Additional revisions are under way to
cover instruments constructed with
new materials, designs, and tapers
greater than 0.02 mm/m
Instruments with a taper greater than
the ISO (International Standards
Organization) standard of 0.02 mm/mm
have become popular: 0.04, 0.06, 0.08,
0.10, and 0.12.
This means that for every millimeter
gain in the length of the cutting blade,
the width (taper) of the instrument
increases in size by 0.04, 0.06, 0.08,
0.10, or 0.12 of a millimeter rather than
the ISO standard of 0.02 mm/mm.
These new instruments allow for
greater coronal flaring than the 0.02
instrument
comes in three lengths:
standard, 25 mm;
long, 31 mm; and
short, 21 mm.
Taper
usually is expressed as the amount the file diameter increases each millimeter along its working surface from the tip toward the file handle.
Flute
It is the groove in the working surface used to collect soft tissue and debris
Leading (cutting) edge
The surface with the greatest
diameter that follows the groove
(where the flute and land
intersect) as it rotates.
.
land (marginal width)
If a surface projects
axially from the central
axis as far as the cutting
edge between flutes
Relief
o To reduce frictional resistance,
some of the surface area of the
land that rotates against the canal
wall may be reduced to form the
relief.
Helix angle
The angle the cutting
edge forms with the
long axis of the file
Rake angle
angle formed by the
leading edge and the
radius of the file.
cutting angle/effective rake angle
is a better indication of a file’s cutting ability
determined by measuring the angle formed by the
cutting (leading) edge and the radius when the file is
sectioned perpendicular to the cutting edge
If the flutes of the file are symmetric, the rake angle
and the cutting angle are essentially the same.
Pitch
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
long, tapered and pointed end instrument, -compress gutta percha into the apex and periphery of the prepared canal and also towards the irregularity of canals
leaving a space for insertion of auxiliary root canal filling material cones.
Pluggers have blunt or flat ended tips.
M series plugger-spreaders
double-ended long-handled instruments
Handles colour coded Corresponds to standard sizing and taper of K-type files
Finger held spreaders and condensers
similar to K-type files with plastic or metal handles.
Instruments have been designed to take full advantage
of the increased visibility obtained with dental operating
microscopes, endoscopes, and orascopes.
Better visualization of the surgical site would have
limited value without microsurgical instruments such as
ultrasonic tips for root-end preparation and micro-
mirrors for inspecting the root end.
1- micro-mirrors
Small round
Medium oval
2-Retractor
Care must be taken to rest the retractors only on bone, not on the reflected soft-tissue flap or on the neurovascular bundle
3-Elevator
4-Curette
Jacquette
spoon
Rubinstein Mini-Molt
5-Scaler
6-Surgical forceps
1-Castroviejo needle holder
2-Castroviejo scissor
3- microcondenser & plugger
4-Messing gun type syringe
5-Plugger with teflon sleeve
6- Another delivery system designed specifically for MTA placement. Kit includes a variety of tips for use in different areas of the mouth and a single-use Teflon plunger.
7- Hard plastic block with notches of varying shapes and sizes MTA is
mixed on a glass slab to the consistency of wet sand and then packed
into a notch. The applicator instrument is used to transfer the
preformed plug of MTA from the block to the root end.
Current NiTi hand preparation procedures that use files with a
greater or variable taper are a substantial improvement over
instrumentation with 0.02 tapered stainless steel files
particularly when used in curved root canals.
These newer instruments should produce canals with a better
shape, using fewer instruments in a shorter time.
Microsurgical instruments such as ultrasonic tips for root-end
preparation and micro-mirrors for inspecting the root end
enhances better visualization and contributed to rapid
development of peri-radicular surgery.
Recommended