ENDODONTIC INSTRUMENTSPart 2

Manual preparation instruments1. REAMER 2. K-FILE 3. FLEXOREAMER 4. FLEXOFILE 5. HEDSTROEM FILE 6. NiTi

A.REAMER :Design & Structureor

motion .

rotating

Reamer: Sizes & CodesReamers come in sizes 06 - 140, all with a taper of 0.02. Reamer design is identified by the triangle symbol on the handle.

R08-10

R15-R40 R45-R80

R90-140

Reamer: Recommended useA reamer is the most effective hand instrument in 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. Reamers are excellent instruments in straight canals but poorly adaptable to curved canals .

In technique the file is placed to working length and rotated clockwise 90 degrees with light pressure to engage dentin. The file is then while apical pressure is maintained to cut and enlarge the canal. Debris is removed with a final clockwise rotation that loads the flutes with loosened debris.

Reamer: Safety tipsReamers only using moderate pressure. Use of force, particularly with smaller sized instruments, may result in of the helical structure and ultimately in

Each instrument should be checked for symmetry by rotating it against an even background before introducing it into the canal .

B. K-FILEK-file: Design & StructureManufactured from steel wire that is twisted to give the typical shape of a K-file. between the long-axis and the cutting blade is greater than in a reamer, and therefore preparation by a K-file is effective both in rotary and filing motion.

of the instrument is cutting which

makes the K-file best suited for the preparationof straight canals.

Small K-files( ISO 06 - 15) can be also used inwithout the risk of ledging.

Small K-files are particularly good for the initialpreparation of very narrow canals.

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.

K06-10

K15-40 K45-80

K90-140

Colour coded by size. The 6 colours used most often are:size 15 (white); 20 (yellow); 6 (pink), 25 (red); (grey) and 30 (blue); 10 (purple) 35 (green); (black).

K-file: Recommended useThe K-file is suited for the preparation of It prepares dentin effectively both in filing motion (up and down) and when rotated.

In slightly curved canals the techniques are resistance is small and

recommended when the against

greater resistance.Compared to reamers, the use of continuous rotation is limited because of the screwing effect typical of Kfiles.

K-file: Safety tipsCan 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.

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.

E. HEDSTR0EM FILEHedstroem File: Design & Structure Hedstroem files are manufactured from round steel wire by grinding. The angle between the long-axis and the cutting blade is close to right angle, which is why preparation by Hedstroem files is effective only when using a filing motion (up and down movement).

Hedstroem File: Sizes & CodesHedstroems come in sizes 08 - 140, all with a taper of 0.02. H-file design is identified by the circle symbol on the handle.

H10-H40

H45-H80

H90-H140

Hedstroem File: Recommended useHedstroem can be used both in straight canals and curved canals. The hedstroem prepares dentin effectively only when using a filing, up and down motion. 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. This is easily obtained by selecting a smaller H-file after each rotating instrument. 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 tipsHedstroem files show a greater risk for fracture than reamers and K-files if used in a wrong way. Hedstroem must always fit loosely in the canal and they must never be rotated . In curved canals Hedstroem-files are pre-curved to correspond to the shape of the canal . Before introducing them into the canal, all Hedstroem files must be inspected for possible earlier damage to the instrument and discarded immediately if an asymmetry in the cutting area is found.

The use of irrigating solutions is an important part of effective chemomechanical preparation. Antibacterial agent. Tissue Flush

solvent.

debris.

Lubricant. Eliminate

the smear layer.