endodontic insrument

7/29/2019 Endodontic insrument

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Dr. Muna Marashdeh

MSc. Endodontics


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Endodontics is the specialty of dentistry thatmanages the prevention, diagnosis, andtreatment of the dental pulp and the

periradicular tissues that surround the root ofthe tooth.

"Endo" is the Greek word ="inside "odont" isGreek ="tooth"

Endodontic treatment =treats the inside of thetooth


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The pulp Inside the toot

h,under enamel anddentin, is a soft tissuecalled the pulp

Extends from the

crown of the tooth tothe tip of the rootswhere it connects tothe tissuessurrounding the root

Contains

blood vessels,nerves

connectivetissue


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Creates thesurrounding hardtissues of the toothduring development

The pulp is important

during a toothsgrowth anddevelopment

Once a tooth is fullymature it can survivewithout the pulp,

because the toothcontinues to benourished by thetissues surrounding it


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Relief of pain = symptom free

To render the affected tooth biologicallyacceptable and functioning without a

diagnosable pathosis Removal of pulp from root(s) of tooth

Disinfections of root and surrounding bone

Root canal treatment is an attempt to retain atooth which may otherwise require extraction.


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1. Teeth with pulpal and /or priapical pathosis.

2. Teeth with no pulpal or periapical pathosismay need endodontic treatment due to:

The need for post and core construction torebuild the missing coronal

portion of the tooth

Traumatic pulp exposure due

to dental work or accidentalfracture.

Esthetic requirement


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1-Teeth with insufficientperiodontal support.2-Teeth with vertical root

fracture.4-Non restorable teeth which

can not properly function after endodontictreatment.

5-Non strategic teeth which can not serve inocclusion or as abutments after endodontictreatment


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Diagnostic phase

Preparatory phase

(cleaning & shaping)

Obturation phase


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During this phase the condition of the tooth isdetermined and the plan of treatment isdeveloped

Examination A kit for examination and diagnosis includes

(1) a front surface mouth mirror; (2) aperiodontal probe; (3) an explorer, such as thedouble-ended No. 5 explorer; (4) spoonexcavator ; (5)the Glick No. 1 instrument; and(6) cotton forceps.


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Endodontic Explorer

Explorers are double-endedinstruments with long tapered tinesat either a right or an obtuse angle.This design facilitates the locationof canal orifices. They are very stiffand should not be inserted into

canals or used for condensinggutta-percha.

Explorers should never be heated.


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Spoon Excavator

The spoon excavator is a long-shank instrument.

The excavator is used to removecaries, deep temporary cement,

or coronal pulp tissue.

The endodontic excavator has aright or left orientation similar tothat of operative hand excavators.

Excavators should not be heated.


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Glick No. 1 instrument

The Glick No. 1 instrument is usedfor placement of temporaryrestorations with the paddle endand removal (and thencondensation) of excess gutta-percha with the heated pluggerend.

The rod-shaped plugger isgraduated in 5-mm increments.


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During this phase the condition of the tooth isdetermined and the plan of treatment isdeveloped.

Instruments used for access and cleaning andshaping include (1)hand pieces (slow and highspeed),(2) burs, (3)rubber dam, (4) a 5- to 6-mlLuer-Lok syringe with a 27-gauge needle,(5)locking cotton pliers, (6) rotary instruments

(Gates-Glidden drills), (7) a plastic instrument(Glick No. 1) for temporary placement, (8)broaches and files, (9) a lentulo spiral drill, and(10) a millimeter rule.


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Rubber dam over the area to isolate the tooth, keep it clean and free ofsaliva during the dental procedure


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The nomenclature follows the recommendations of theInternational Organization for Standardization (ISO):

1. Hand-operated include K-type reamers and files,broaches, and Hedstrom-type files.

2. Engine-driven are hand types that have a latch that insertsinto a slow-speed handpiece. These include rotary (Gates-Glidden and Peeso) engine-driven reamers and files andreciprocating files or reamers.

3. Ultrasonic and sonic are diverse in design.

4. Nickel-titanium is a cross-over design and has beenadapted both for hand instruments and rotary applications.


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To debride a region of the canal space completely,the instrument must contact and plane all walls.

Despite continual improvements in design andphysical properties, there are still no instruments

that totally clean and shape all root canal spaces. Stainless steel instruments are relatively inflexible,

which renders them not particularly adaptable tocanal curvatures.

Nickel-titanium instruments are more flexible andadapt more readily to fine, curved canals but haveno advantage over stainless steel files in irregularcanal spaces.


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A hand-operated reamer or file begins as around wire that is modified to form a taperedinstrument with cutting edges.

The instrument is used with a twisting(reaming) or pulling (filing) motion in anattempt to produce clean, smooth, symmetricalcanal walls.


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Several cross-sectional shapes of files arecommercially available .

Longitudinal and cross-sectional shapes of various hand-operated instruments. (Those markedwith an asterisk are brand names.)

Note that small sizes of K-reamers, K-files, and K-Flex* have a different shape than the largersizes


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Two techniques for manufacturing theseinstruments have been developed

Machined

Ground Twisted


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Machined One technique involves machining (grinding)

the instrument directly on a lathe; an exampleis the Hedstrom-type file, All nickel-titaniuminstruments are machined

Some manufacturers produce K-type filesusing the machined (lathe-grinding) process .

This change from the grinding and twistingmanufacturing process results in differentphysical and working properties from theoriginal K-type file

For instance, the machined file has lessrotational resistance to breakage than aground-twisted file of the same size.

Hedstrom file, machined byrotating a wire on a lathe.Note the spiral shape. Theseare efficient cutters (on thepull stroke) but are moresusceptible to separation

when locked and twisted.B and C, A machined K-typefile. Note that the transitionangle at the leading cuttingedge of the tip is rounded,rendering it noncutting


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Ground-Twisted Another technique consists of first grinding, then

twisting. Raw wire is ground into taperedgeometric blanks: square, triangular, and

rhomboid. The blanks are then twisted counterclockwise to

produce helical cutting edges. These are K-typefiles and reamers.

K-type files have more twists per millimeter of

length than the corresponding size of K-typereamer.

Both have a pyramidal tip (75 15 degrees) that isproduced by grinding after twisting.


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Ground-twisted instruments. A, A square file blank ground from wire.After twisting counterclockwise, the appearance of a file (more flutes) (B)and reamer (fewer flutes) (C).


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Lengths Files and reamers are available in three shaft lengths: 21, 25,

and 31 mm. Shorter instruments afford improved operatorcontrol and easier access to posterior teeth, to which limitedopening impairs access. The 25- and 31-mm instruments areused for longer roots. The 25-mm instruments are the mostcommonly used instruments during root canal preparation.


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Sizing Dimensions of K-type files and reamers are designated according to the diameters

of the instrument at specified positions along its length (as stated in ADAspecification No. 28)

File tip diameters increase in 0.05-mm increments up to the size 60 file (0.60 mm at

the tip), and then by 0.10-mm increments up to size 140. The diameter at the tip of the point is known as D0. The spiral cutting edge of the

instrument must be at least 16 mm long, and the diameter at this point is D16.


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The file diameter increases at a rate of 0.02 mmper running millimeter of length

The nickel-titanium rotary instruments have

other variable tapers of 0.04 and 0.06. For everymillimeter of length, these greater tapers makethese more aggressive in creating markedflaring preparation


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Tip Design Originally, the tip angle of K-type files and reamers

was approximately 75 degrees plus or minus 15 degrees

This design was intended to provide cutting

efficiency without an excessively sharp transition angle.

Newer designs have different tip angles and designs

in an attempt to minimize canal alterations.

Some machined K-files incorporate a so-called

nonaggressive tip or noncutting tip to provide lessdentin cutting by reducing the sharp tip

transition angle.


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Torsional Limits Torsional limit is the amount of rotational torque that can be

applied to a locked instrument to the point of breakage(separation).

Smaller steel hand-preparation instruments (less than size 20) can

withstand more rotations without breaking thanlarger (greater than size 40) instruments. Machined K-type files have different physical and

working properties than ground-twisted files. Machinedfiles are weaker, demonstrating less plastic deformationbefore failure occurs.Therefore this tendency toward lessvisible deformation before separation requires morecaution with the use of machined files to avoid

instrument failure.


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Color Coding Color coding of file handles designates size. Color coding of the

newer nontraditional instruments varies according to the

manufacturer.


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Barbed broaches are stainless steel instruments with plastichandles. The tapered-wire broach is barbed by scoring and pryinga tag of metal away from the long axis of the wire.

Barbs entangle and remove canal contents.

This instrument should be neither bound in thecanal nor aggressively forced around a canal

curvature. Either action may cause the barbs

to engage the canal wall, preventing the broach

from being removed intact or fracturing.

Barbed broaches should not be reused.

Single-barbed broaches are available in

presterilized bubble packaging.


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Lentulo spiral drills are twisted wire instruments used in theslow-speed handpiece .

They have been used to spin pastes, sealer, cements, or calciumhydroxide into the canal. They must be used with care to avoid

throwing quantities of unset material out of the apex. The drill must be rotated so that it will not screw itself into the

canal; it may lock and separate.


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Rotary Instruments Some preparation techniques require slow-speed rotary

instruments to facilitate preparation, primarily in establishingstraight-line access, the most common are Gates-Glidden drills

and Peeso reamers


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. Table shows the comparative ISOsizes of both Gates-Glidden

drills and Peeso reamers.

Size Gates-GliddenDrills

PeesoReamers

No. 1 0.4 mm 0.7 mm

No. 2 0.6 mm 0.9 mm

No. 3 0.8 mm 1.1 mm

No. 4 1.0 mm 1.3 mm

No. 5 1.2 mm 1.5 mm

No. 6 1.4 mm 1.7 mm


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Gates-Glidden Drills Gates-Glidden drills are elliptically (flame) shaped burs with a latch

attachment. Gates-Glidden drills are used to open the orifice. They also achieve

straight-line access by removing the dentin shelf and rapidly flaring thecoronal and middle third of the canal.

Gates-Glidden drills are designed to break high in the shank region. Thisdesign allows easier removal of the brokeninstrument from a tooth; fracture near the cuttinghead may block a canal Importantly, these drills must be continuously

rotated. If they stop, the head may lock in the canal, with

torsional failure and fracture. Gates-Glidden drills are available in 15- and 19-mm lengths. The shorter instruments are helpful in posterior teeth,

where access to the canal orifice is limited.


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Peeso Reamers Peeso reamers are also used as adjunctive devices

in canal preparation. They are basically similar toGates-Glidden drills but have parallel cutting sides

rather than an elliptical shape. These instrumentsare available with or without safe tips. Peeso reamers have been suggested as a

means of improving straight-line access,although they are less flexible and less wellcontrolled than Gates-Glidden drills. Both types are aggressive and can rapidlyover enlarge the canal.


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Engine-Driven Nickel-Titanium Files

Engine-driven nickel-titanium files allowgreater control in small, curved canals. These

instruments do not have a cutting end andhave less tendency to transport the apicalpreparation. The files are available in a varietyof shapes and designs


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Broaches

Removal of pulp requires a broach that will notbind and yet is large enough to ensnare the tissue.Binding should be minimized because of possible

breakage. Reamers and Files

Two types of motion are common in root canalpreparation: reaming and filing

Reaming consists of rotating the instrumentclockwise and scribing an arc from one cuttingedge to the next.


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Filing requires a series of repetitive motions. First, the instrument is advanced to its full length into the

canal space using a passive twiddling (teasing withoutplaning) motion.

Next, the file is rotated (a quarter turn or more) and then

withdrawn from the canal space while the tip is pushedfirmly against a canal wall, much as a paintbrush is appliedto a wall when painting.

The twiddling, reaming, and withdrawal motions arerepeated with the file tip pushed against a different portionof the canal wall on each outstroke until all walls have been

planed (circumferential filing). Hedstrom-type files and files with a similar design ( S& U)

are used only with a filing motion because they have lesstorsional resistance to breakage.


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Separation of hand files in the canal is prevented byregularly inspecting the instrument for defects such as

(1) unwinding of the flutes (twisting clockwise and openingof the flutes),

(2) roll-up of the flutes (excessive continued clockwise

twisting after unwinding), (3) tip distortion (the tip hasbeen bent excessively) (4) corrosion. If an instrument exhibits any

signs of wear, it should bediscarded immediately. Prevention is the key toavoiding untimely instrumentseparation.


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Rotary Instruments All of the engine-driven nickel-titanium files rely on

rotational motion only and therefore have a reamingaction.

Avoidance of Instrument Separation The number of canals that can be prepared with a

nickeltitanium instrument varies from 4 to 16,depending on the size and curvature of the canals andpressure used with the files. When the canal is smallerand more curved, there is more wear and tear on the

instrument. All manufacturers suggest discarding the files if any

deformation occurs. Studies have suggested that lowerspeeds reduce the likelihood of instrument fracture


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During this phase the root canals are filled with aninert material to achieve a hermetic seal as close aspossible to the anatomic apex.

Instruments and materials used for obturation

include (1)Gutta percha (2)Paper points (3)Rootcanal sealer (4)spreaders or pluggers, (5) Glick No.1 for heat transfer and temporary placement, (6)locking cotton pliers, and (7) 5/7 plugger or

pluggers used for vertical condensation. Several filling techniques are available. The two

most practiced techniques are , lateral and verticalcondensation.


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Lateral Condensation The instruments used for lateral condensation are

spreaders and small pluggers . They are used for condensing and adapting gutta-

percha and creating space for accessory cones. They areeither handled, with a shank attached to a metalhandle, or finger-type, with only a plastic handle .

The handled instruments are stiff because they aregenerally made of annealed stainless steel. Fingerspreaders and pluggers are not annealed and therefore

are dead soft, giving them more flexibility. Handledinstruments do not negotiate curved canals. Fingerspreaders and pluggers are best suited for obturatingcurved canals.


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Finger spreaders and pluggers have different tips.

Pluggers are flat, whereas spreaders are pointed.

Finger spreaders and pluggers behave similarly and areused interchangeably in lateral condensation.

Both stainless steel and nickel-titanium spreaders areavailable.

The obvious advantage of nickel-titanium spreaders over

stainless steel spreaders is greater spreader penetration in

highly curved canals.


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Vertical Condensation In this obturation technique the filling material is alternately

softened (with heat) and then vertically compacted with pluggers.

The softened gutta-percha filling material is pushed into the

interstices of the canal, but this technique offers less apical controlof the material than lateral condensation.

Vertical condensation instruments can be

divided into two categories: those that are

heated to transfer heat to the guttapercha

and those that condense the gutta-percha


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STERILIZATION AND DISINFECTION Endodontic instruments are contaminated with blood,

soft and hard tissue remnants, and bacteria andbacterial byproducts.

Thus they must be cleaned often and disinfectedduring the procedure and then sterilized. Also, becausethe instruments may be contaminated when new, theymust be sterilized before initial use.

Different sterilization techniques are available. Small kits, such as those used for examination, may

conveniently be bagged, sterilized, and stored in thepackage until needed.

Larger kits for treatment may be more rapidly andeasily handled in cassettes for sterilization and storage


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Central , lateral, canine.( upper, lower)

Premolars, molars ( upper, lower)

endodontic insrument

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