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Non ISO FileTechnique

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Use stainless steel instruments - filesfiles used manuallyfiles made by twisting wires of square,triangular or diamond cross section

These have ISO taper

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ISO stands forInternational Standards Organization

Taper is the amount by which thediameter of an instrumentincreases from tip to handle

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This is the taper set by the ISOIt is set at 0.02 per mmThis is commonly referred toas

02 taper

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02 taper does not match thetaper of root canalsRoot canals have tapers close to04, 06 or even 08

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By using a lot of instruments (files)in complex protocols e.g.

Crown Down, Step BackTechniques

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A series of files used from coronal toapical sequentially with recapitulation

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8

S/S instruments have to beused in reciprocating actioni.e. rotate clockwise, then anti-clockwiseor in push - pull action

If these are rotated continuallyin one direction, these fractureNot very flexible

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Push - pull action leads toledge formation in root canals

This action also pushes debrisinto the canal causingblockages

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By using these files manually inreciprocating actioni.e. Balanced Force Technique

But this is a very slow process

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tC

By using Greater Taper GT filesThe Greater Tapers matchhRRoot Canal tapersneeding fewer files

By making them of Nickel Titanium insteadof S / S so that these are flexible and can berotated continually in one direction withoutrisk of fracture

Thus NiTi GT Rotary instrumentswere born

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Made of Nickel Titanium alloyNiTi wires cannot be twistedTherefore, made by machining - makesthese files very expensiveThese have a Taper > ISO TaperTapers of 04, 06, 08, 10 & even 12These tapers are similar to taper of rootcanals

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ISO Greater Taper

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0208

04

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06

14

A ProFile Rotary File kitNote the large no. of files with different

tapers and tip diameters

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A ProFileinstrument

Cross-section is similar to thatof system GT with Triple U

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shape16

06 taper

08 taper

10 taper

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Invented by Dr. StephenBuchanan of USA in the1980’sHas revolutionisedEndodontic PracticeUsed in rotating actionwith special hand piecewith a low speed, hightorque motorNow several designs andbrands available

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NiTi exists in 2 forms with differentproperties

MartensiteLow temp form, low modulus, high strain

AusteniteHigh temp form, high modulus, low strain

Shape memoryNiTi exhibits super elasticity

Under stress, martensite austenite8/24/2009 Endo12 20

Bends and returns to original shape

Martensite Austenite Martensite

Can negotiate curved root canals better8/24/2009 Endo12 21

A curved canalprepared with

NiTi files

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System GT (Buchanan,Tulsa Dental)ProTaper (Dentsply)ProFile (Dentsply)RaCe (Schotlander)K3 (Sybron Kerr)QuantecFlexiMaster

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Note Triple Ucross-section ofthe rotary filecollect debris

Flat radial landskeep the filecentred on thenatural rootcanal whileenlarging it8/24/2009 Endo12 24

RaCe files have atriangular cross-section

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File tip is dome-shaped to preventledge formation &canallttransportation

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Progressively Tapered files

Differing percentage of taper alongthe length of the fileMakes the file even more flexible

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Note convextriangularcross-section

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Active cuttingbladesspeed upcutting ofroot canal wall

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Blunt tip prevents

ledge formation &perforations

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Six files3 Shapers

SX S1 S2

3 FinishersF1 F2 F3

Finishing File F3 recognisable by Blue band on handle8/24/2009 Endo12 31

Same basic file shapes and tapers butdesigned to be used manually

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Unique handle allows ease of use

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Fewer files needed due to better taperFaster completion of canal preparationFlexible, enabling easy use in curvedcanalsMore predictable outcome

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Mandibularsecond molar withabrupt curvatureof the distal canal.Note the apicalcontrol despitethe conservativecanal enlargement

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Before and after8/24/2009 Endo12 36

Before and after8/24/2009 Endo12 37