Nickel–Titanium Rotary Instruments

Generations Of Niti Rotary Files

First Generation NiTi Rotary Files

Profile System:

Profile system made by Tulsa Dental was one of the first commercially available NiTi instruments. This system was introduced by Dr. Johnson in 1944. Profile NiTi line includes Series 29, orifice shapers, Profile 0.02, 0.04, and 0.06, GT files, and ProTaper instruments Series 29 instruments, instead of increasing each fie by 0.05 between sizes, it was increased by 29%.

Read And Learn More: Endodontics Notes

This system works well in small sizes but in bigger instruments. This much increase is not possible.

Profie 0.02, 0.04 and 0.06

• These have safe-ended noncutting tips with a negative rake angle (−20°) which makes them to cut dentin in scrapping motion. Profile instrument tends to pull debris out of the canal because of the presence of a 20° helical angle Recommended rotational speed for profiles
  is 150–300 rpm.
• The cross-section of the profile shows three U-shaped grooves with radial lands.
• The central parallel core present in the profile increases its flexibility.

Orifice Openers:

• They extend 19 mm below the head of the handpiece and have 10 mm of the cutting blade
• Series consists of six instruments which are safe-ended with increasing D0 diameters
• Used to prepare coronal two third of root canal system

Greater Taper Files (Steve Buchanan in 1994)

• GT files possess a U-shaped fie design with ISO tip sizes of 20, 30, and 40 and tapers of 0.04, 0.06, 0.08, 0.010 and 0.12
• Accessory GT files for use as orifice openers of 0.12 taper in ISO sizes of 35, 50, 70, and 90 are also available
• The maximum diameter of GT fie is 1 mm
• Recommended rotational speed for GT fie is 300 rpm
• The negative rake angle of the GT file makes it to scrape the dentin rather than cutting it.

Quantec File System:

• Quantec fie series were introduced in 1996 and are available in both safe cutting and noncutting tips with a standard size of 25 No. in 0.12, 0.10, 0.08, 0.06, 0.05, 0.04, 0.03, and 0.02 tapers. 0.02 tapered. Axes handles are 30% shorter than other files. Recommended speed is 340 rpm
• Files have reduced radial land which decreases the surface tension, contact area, and stress on the instrument
• Files have two flutes which increase the flute depth as compared to the three-flute design. This unique design minimizes its contact with the canal, thereby reducing the torque, providing greater space for debris removal, and reducing fie separation
• Quantec system utilizes the “graduated taper technique” to prepare a canal. It is thought that using a series of files of single taper results in decreases in efficiency as the larger instruments are used. This happens because more of the fie comes in contact with the dentinal wall which makes it more difficult to remove dentin.
• But in the graduated taper technique, restricted contact of the area increases the effiency of the instrument because now forces are concentrated on a smaller area.

HERO 642

• • HERO – High elasticity in rotation
  • 642 – 0.06, 0.04, and 0.02 tapers
• It was introduced by Daryl-Green
• HERO 642 (high elasticity in rotation, 0.06, 0.04, and 0.02 tapers) is used in at 300–600 rpm
• It has a tri helical Hedstrom design with a positive rake angle and sharp flutes. Cross section of HERO show geometrics similar to H fie without radial lands.
• Due to the progressively increasing distance between the flies, there is a reduced risk of binding the instrument in the root canal
• A larger central core provides extra strength and resistance to fracture.

Light Speed System :

• This system was introduced by Steve and Willian Wildely in 1990, now known as LS1
• Light speed system is an engine-driven endodontic instrument manufactured from nickel–titanium. This is so named because a “light” touch is needed as the “speed” of instrumentation is increased
• Light speed instrument is slender with a thin parallel shaft and has a noncutting tip with Gates-Glidden in configuration
• Recommended speed for use is 1,500–2,000 rpm
• These is available in sizes Nos. 20–140 including the half sizes, namely, 22.5, 27.5, 32.5. The half-sizes are also color-coded as full ones with the only difference in that half-size instruments have white or black rings on their handles
• The cutting head of the light speed system has three different geometric shapes:
  • Size 20–30 short noncutting tips at 75° cutting angle
  • Size 32.5 longer noncutting tip at 33° cutting angle
  • Size 35–140 longer noncutting tip with 21° cutting angle
• Cutting heads basically have three radial lands with spiral-shaped grooves in between.

Second Generation

Protaper Universal:

These were designed by Dr. Clif Ruddle, Dr. John West, and Dr. Pierre Machtou.

Features:

Progressive tapers:

This improves flexibility, and cutting efficiency, and reduces the number of recapitulations needed to achieve length. One of the benefits of a progressively tapered Shaping file is that each instrument engages a smaller zone of dentin which reduces torsional loads, fie fatigue, and the potential for breakage.

Convex triangular cross-section:

This feature reduces the contact area between the blade and dentin increases the cutting action and improves safety by decreasing the torsional load.

Helical angle and pitch:

Continuously changing the helical angle and pitch optimizes its cutting action, clears the debris out of the canal, and prevents screwing in of the instrument in the canal.

Variable tip diameters:

Variable D0 diameter allows fie to safely and efficiently follow the canal.

Modified guiding tip:

This allows each instrument to better follow the canal without damaging the root canal walls.

Short handles:

A short 12.5 mm handle improves access in posterior regions.

Shaping Files:

Finishing Files:

ProTaper Gold:

Developed with improved metallurgy, ProTaper Gold rotary files show the following features:

• Convex triangular cross-section and progressive taper
• Increased flexibility due to the advanced metallurgy process
• Greater resistance to cyclic fatigue so lesser chances of fire separation
• Shorter 11 mm handle
• The noncutting tip design allows each instrument to safely follow the canal while the small flat area on the tip enhances its ability to find its way through soft tissue and debris.

K 3 Rotary File System

Dr. John McSpadden in 2002 in North America introduced the K3 system.

• K 3 files are available in the taper of 0.02, 0.04, or 0.06 with ISO tip sizes. An Axxess handle design shortens the file by 5 mm without affecting its working length
• These files are flexible because of the presence of variable core diameter
• The cutting head shows three radial lands with relief behind two radial lands. Asymmetrically placed flutes make the K 3 system with superior canal tracking ability, add peripheral strength to K3 system, and prevent screwing into the canal
• Positive rake angle makes effctive cutting surface
• K 3 files are color-coded to differentiate various tip sizes and tapers
• Body shapers available in taper 0.08, 0.10, and 0.12, all with tip size 25 are used to prepare the coronal third of the canal.

Race Files (Reamers with Alternating Cutting Edges)

• Race has a safety tip and triangular cross-section. This file has two cutting edges, fist alternates with a second which has been placed at different angles. Alternating cutting edges help in reducing working time and decreasing operation torque. Noncutting safety tip helps in perfect control of the instrument
• It has variable pitch and helical angle which prevents the file from screwing into the canal
• Electrochemical treatment of these files provides better resistance to corrosion and metal fatigue.

Third Generation Files

TF Twisted Files:

These are the first flted NiTi files manufactured by plastic deformation. these are available in tip sizes from #25 to #50 and tapers from 0.04-.12.

The unique features of these files are:

1. R-phase heat treatment technology is used to optimize the molecular phase which increases fie flexibility and resistance to cyclic fatigue.
2. Twisted design, not ground; twisting helps preserve grain structure and reduces the formation of microfractures, making the file even more durable. Grinding weakens the metal’s structure at the molecular level and creates microfractures on the metal’s surface.
3. A proprietary surface conditioning treatment of the fie.

Fourth-Generation Reciprocating Instruments

Reciprocation is defined as repetitive back-and-forth motion and it has been clinically utilized to use stainless steel fies since 1958. In rotation, NiTi files require less inward pressure and take the debris out of the canal, whereas reciprocation mimics manual filing. These instruments result in less debris removal because of pecking motion and can result in debris extrusion.

Advantages of reciprocating motion:

• Less binding of the instrument leads to canals so less torsional stress.
• Decreased risk of instrument separation
• Less flexural stress due to a reduction in a number of cycles within the root canal.

Disadvantages of reciprocating motion:

• An increased amount of debris extrusion during the instrumentation procedure.
• Causes cracks in dentin due to reciprocating instrumentation technique.

WaveOne NiTi File System:

It is a single-use, single-fie system to shape the root canal completely from start to finish. It works in a similar but reverse “balanced force” action moving in a back-and-forth “reciprocal motion.” There is three files in the WaveOne single-file reciprocating system, available in lengths of 21, 25, and 31 mm.

There are used at a speed of 300 rpm with a torque of 5 N cm. These work with a reverse cutting action. They have a modified convex triangular cross-section at the tip end. These work with a reverse cutting action.

They have a modified convex triangular cross-section (Fig. 13.53) at the tip end.

• WaveOne small fie has a tip size of ISO 21 with a taper of 6%. It is used in fie canals
• WaveOne primary fie has tip size of ISO 25 with the taper of 8% that reduces toward the coronal end
• WaveOne large fie tip size of ISO 40 with the taper of 8%. It is used in large canals

WaveOne Gold:

WaveOne Gold incorporates the metallurgical advancements of Gold wire, improving flexibility by 80% over of WaveOne. It has a parallelogram-shaped cross-section, which helps in improving cutting effiency and debris removal within the canal. It’s variable taper helps it to perform better in smaller and narrower canal anatomy. Tip sizes match ISO Numbers 020, 025, 035 and 045

Self-Adjusting File:

The Self-Adjusting File is a hollow Nickel–Titanium latticelike cylinder that scrubs the canal walls by vertical vibrations. Its hollow shape allows for the continuous flow of irrigant through its lumen to achieve superior disinfection. It is available in lengths 21, 25, and 31 mm and two diameters 1.5 and 2.0 mm.

It is used at 5,000 vertical vibrations per minute. Its abrasive surface acts similarly as sandpaper by scrubbing uniformly and gradually enlarging the root canal circumferentially. The slow, low-torque rotation occurs when the SAF is not engaged with the canal walls, allowing circular repositioning throughout the process.

TF Adaptive file system:

TF adaptive fie works as rotary under normal conditions but changes to reciprocation when stress is increased on fie. these features allow better resistance to cyclic fatigue with higher durability.

Available in different sizes; for small canals as 20/0.04, 25/0.06, and 35/0.04, and for medium to large-sized canals as 25/0.08, 36/0.06, and 50/0.04.

Fifth Generation Instruments

Revo-S:

Revo-S has snake-like movement inside the canal. It has an asymmetrical cross-section which provides more flexibility and less stress on the instrument. It works in a cyclic way (3C concept); cutting, clearance, and cleaning at rotation speeds ranging between 250 and 400 rpm. It consists of three instruments: SC1, SC2, and SU.

Protaper Next:

Features:

Shortens the shaping time; high cutting effiency reduces
the shaping time.

Swaggering Effect: Protaper Next’s innovative off centered rectangular cross section gives the fie a snake-like “swaggering” movement as it moves through the root canal. This helps in better removal of debris and canal tracking

M-WIRE NiTi improves fie flexibility, greater resistance to cyclic fatigue, and cutting effiency.