Achieve Efficiency By Understanding RCT Tools Part 2

by | Sep 14, 2020 | Dental Materials | 0 comments

Endo Files

Do You Fully Know & Understand Endo Instruments, so, You can Make Your Endo Treatment Efficient?

Please check out our Part 1: CLICK THIS This discusses the materials used to manufacture the different Endodontic tools and instruments, its standardization, their advantages and disadvantages.

On this Part 2, we will enumerate and review the different Endo tools and instruments we can choose from to achieve a successful Endodontic treatment and create satisfied patients.


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


Smooth Broaches are short handled instruments used as a pathfinder. These broaches are made of carbon steel, they are less likely to collapse when forced down in a fine canal due to their increased flexibility and resistance to cyclic fatigue.

Smooth Broaches


In 1904 Kerr Manufacturing Company designed the, K-style files and reamers. Files are instruments that enlarge canals with reciprocal insertion and withdrawal motions.


Reamers are K- type instruments (manufactured by Kerr company), they are use to cut and enlarge canals with rotational motions. They have triangular blank and lesser number of flutes than files. They cut by inserting into the canal, twisting clockwise one quarter to half turn and then withdrawing, penetration, rotation and retraction.

Reamers have a rake angle which makes them most efficient in rotary motion, hence reaming is preferred. Reamer has fewer numbers of flutes than file, cutting efficiency is same as that of files because more space between flutes causes better removal of debris.
Reamer tends to remain self centered in the canal resulting in less chances of canal transportation.

K Reamers


K Files are used for cutting dentin in the filing motion. It is the instrument most commonly used for cleaning and shaping. The K-file works on the "pull" stroke - that is, by scraping the canal walls as it is withdrawn from the canal. It is advanced to the full working length rotated 1/4 to 1/2 turn clockwise, and withdrawn while being pressed against one of the walls.

They are triangular, square or rhomboidal in cross-section, manufactured from stainless steel wire, which is grounded into desired shape. It is design in a tighter twist of file spirals to increases the number of flutes in files (more than reamer). Its triangular cross-sectioned files show superior cutting and increased flexibility than the file or reamers with square blank.

K Files


It was realized that square blank of file results in total decrease in the instrument flexibility. To maintain shape and flexibility of these files, K-flex files were introduced.

K-flex files are rhombus in cross section having two acute angles and two obtuse angles. Two acute angles increase sharpness and cutting efficiency of the instrument. Two obtuse angles provide more space for debris removal. Also the decrease in contact of instrument with canal walls provide more space for irrigation. They are used in filing and rasping motion.

K Flex Files


A variant of K flex files that 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.

Flex-R Files


These files are made of specially treated stainless steel for stiffness and strength. The result is easier access to challenging, calcified canals.



H-Files or Hedstroem files are used for probing, permeabilization or extraction of debris. Made of stainless steel or NiTi, these files can only be used in traction because of their profile. This files are essentially used for enlargement of the canal after passage of the K-File and for evacuating debris and organic tissue.

Hedstroem files should be used to machine straight canals because they are strong and aggressive cutters. Since they lack the flexibility and are fragile in nature, the H-files tend to fracture when used in torquing action.

H-Type Files


The “S” File, is a variation of the H-files also appears in a 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 Files


Microdebriders are type of H-Files characterized with a short staff bent at an angle of 200 deg. Available in sizes 20 and 30 and tapered in 0.02. The flutes when used, clear away paste, pulpal residues, gutta-percha, and calcification. These instruments also allow additional shaping of the canal.



Rotary instrumentation is known to have an improved cutting efficiency when compared with hand filing techniques. Electric endodontic motor offers torque and speed that can be easily controlled on the system chosen. Despite the advantages of rotary systems, using rotary instruments are prone to breakage and perforation. It is always recommended to create a glide path with hand files in each canal prior to rotary instrumentation. There are numerous rotary files available on the market, including a variety of systems from different manufacturers.


Is 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. Usually it has a modified safe tip like non-cutting tip.

The safety design of Gates-Gliddens is that its weakest part lies at the junction of shank and shaft of the instrument. If its cutting tip jams against the canal wall, fracture occurs at the junction of shank and the shaft but not at the tip of the instrument. This makes the easy removal of fractured drill from the canal.

It is best used for
1. For coronal flaring during root canal preparation
2. During retreatment cases or post space preparation for removal of gutta-percha.
3. Widen the canal when an instrument has fractured within it.

If used incorrectly, for example using at high rpm, incorrect angle of insertion, forceful drilling, the use of Gates-Glidden can result in procedural accidents like perforations, instrument separation.

Gates Glidden Drills


It has long sharp flutes with a safe tip connected to a thick shaft. Most often used in preparing the coronal part of the root canal for a post and core.

Their tip diameter varies from 0.7 to 1.7 mm. and should be used in brushing motion.

Disadvantages of using Peeso reamers are:
1. They do not follow the canal curvature and may cause perforation by cutting laterally.
2. They are stiff instruments.
3. They have to be used very carefully to avoid iatrogenic errors.

Peeso Reamer

Instruments used for root canal Filling

These instruments are used to compact the gutta-percha into root canal during obturation.


Is a type of obturating instrument made from stainless steel and are designed to facilitate the placement of accessory gutta-percha points around the master cone during lateral compaction technique These spreaders do not have standardized size and shape. They are not used routinely because excessive pressure on the root may cause fracture of root.

Hand Spreaders


Is a type of obuturating instrument that has short length that allows a degree of tactile sense and allow them to rotate freely around their axis. It is standardized and color coded to match the size of gutta-percha points. manufactured from stainless steel or nickel titanium

Stainless steel spreaders may pose difficulty in penetration in curved canals, may cause wedging and root fracture if forced during compaction. They also produce great stresses while compaction. While NiTi spreaders are recently introduced spreaders which can penetrate the curved canals and produce less stresses during compaction. They may bend under pressure during compaction.

Finger Spreaders


They consist of diameter larger than spreader and have blunt end .They are used to compact the warm gutta-percha vertically and laterally into the root canal and may also be used to carry small segments of guttapercha into the canal during sectional filling technique. Calcium hydroxide or MTA like materials may also be packed into the canals using pluggers.

Hand Pluggers


They are used for vertical compaction of gutta-percha. Use to apply controlled pressure while compaction, and have more tactile sensitivity than hand plugger. Care should be taken with spreaders and pluggers while compacting the gutta-percha in canals. They should be cleaned prior to their insertion into the canal; otherwise the set sealer from previous insertion may roughen their surface and may pull the cone outside the canal rather than packing it. Also one should discard the instrument when it has become bent or screwed to avoid instrument separation while compaction.

Finger Pluggers


They are used for applying sealer to the root canal walls before obturation.It can be used both hand or rotary instruments



In conclusion, as the technology advances, Endodontic instruments have led to the improvement of our ability to shape root canals easier and with potentially fewer procedural complications. Moreover, the tools now also allow us to save time, safer method and be minimally invasive that reduces the excessive widening of root canal which will weaken the tooth being treated. In general, we are lucky because we are now in the era wherein innovative tools are already readily available for us to choose from and make our Endodontic treatments not anymore as much as a nightmare as before.


Dr. Bryan Anduiza - Writer

Dr. Jean Villanueva - Editor


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