Prepared by: Dr. Hashim M. Hussein

M.Sc. of Conservative Dentistry29/7/2015

• NiTi was developed by Buchler in 1963. First use of NiTi in endodontic was

reported by Walia et al., in 1988.

• Hand instruments have been in clinical use for almost 100 years and they are

still an integral part of cleaning and shaping procedures. Files, Reamers and

Hedstroms are considered to be the principles endodontic hand instruments for

root canal preparation procedures and all other instruments take their origins

from these three basic forms.

• NiTi was not designed for initial negotiation of the root canal, because of

extreme flexibility of it. On the other hand, the greater stiffness of stainless steel

instruments allowed them to be used for path finding and to establish canal

patency.

• When using the stainless steel files, occurrence of procedural

errors cannot be avoided especially in case of curved canals, such

as ledge formation.

• Various brands of NiTi rotary systems introduced and become

popular such as LightSpeed, ProFile, GT, ProTaper, HERO, K3,

FlexMaster, RaCe, EndoSequence, Twisted, ProTaper Next.

• These instruments are generally used in low speed torque control

handpiece with 360° file rotation and rotation rate of 150-350

rpm; however, they differ from one to another in the cross

sectional geometry, rake angle, tip design and taper.

• Various brands of NiTi rotary systems introduced:

• The rotary instruments improve:

1. Working safety

2. Shorten working time

3. Well-shaped root canals

4. Few canal transportations

• These instruments are generally used in low speed torque control hand piece with 360

degree file rotation and rotation rate of 150-350 RPM; however, they differ from one to

another in the cross sectional geometry, rack angle, tip design and taper.

6. Flex Master

7. Race

8. Quantec

9. Mtwo

10. ProTaper

1. Profile

2. GT file

3. Light speed

4. Hero 642

5. K3

• ProTaper rotary file developed in 2001 by group of

endodontists: Dr. Cliff Ruddle, Dr. Pierre Machtou, Dr.

John West, in cooperation with Dentsply Maillefer.

• As a logical consequence of the success of the ProTaper rotary file,

ProTaper hand file is available in market. It used in teeth with

difficult canal anatomy and/or problematic handpiece access.

• This system has three shaping and five finishing files.

Auxiliary shaping ProTaper file (SX):

• No identification ring on its colored

handle.

• Shorter overall length of 19mm.

• SX is available with 14mm of cutting

blades.

• The complex file design allows for efficient shaping of the coronal

aspects of the root canal and relocation of canal orifices in the

direction of overhanging dentine area resulting in a straight line

access. SX file is designed to replace GG drills.

• Diameter at tip of instrument (D0), and at D14.

• Taper was increased from D1-D9 (3.5% to 19%).

Shaping ProTaper files (S1, S2):

• They have purple and white identification rings on their handles

respectively.

• S1 is designed to prepare the coronal one-third of the canal and has an

increasing taper from Dl-D14 (2%-11%).

• S2 is designed to enlarge and prepare the middle third of the canal and

has an increasing taper from D1-D14 (4%-11.5%).

• Also, they do progressively enlarge

its apical 1/3 because these

instruments are already at WL after

initial preflaring.

• Diameter at tip of instrument

(D0), and at D14.

Finishing ProTaper files (F1, F2, F3):

• The finishing ProTaper files (Fl, F2 and F3) have yellow, red and

blue identification rings on their handles with D0 diameter of

0.20mm, 0.25mm and 0.30mm respectively.

• Finishing files have a fixed

taper in the first 3mm

from D1 to D3 (i.e. 7%,

8% and 9% for F1, F2 and

F3 respectively).

• Each file has a decreasing taper from D4 to D16:

Ensure a continuous flexibility within the file.

Avoids too large diameter at the shaft area of the instrument.

Reduces the potential for dangerous taper lock by engaging less dentine

and thereby decreasing the chances of breakage.

It enhances the strength of the files while making them rather stiff.

Finishing ProTaper files (F4, F5):

• Some modification are introduced such as the addition of two larger

files; F4 and F5 to help in apical preparation of larger canals.

• F4 had two black rings with ISO 40 tip size and 6% apical third taper

while F5 had two yellow rings and ISO 50 tip size with 5% apical third

taper.

• The body of both files progressively decreasing in taper and that

produce excellent flexibility.

• Finishing files have a fixed

taper in the first 3mm

from D0 to D3 (i.e. 6%,

5% and for F4 and F5

respectively).

A. Multiple tapers:

• A unique feature of the shaping files is their progressively tapered

design which clinically serves to significantly improve flexibility,

cutting efficiency and typically reduces the No. of recapitulations

needed to achieve length, especially in tight or more curved

canals.

• This design feature allows each shaping file to perform its own “crown

down” work. One of the benefits of a progressively tapered shaping file

is that each instrument engages a smaller zone of dentin, which reduces

torsional loads, file fatigue and the potential for breakage.

B. Non-cutting modified guiding tip:

• The tip of these instruments is modified non cutting making it less

aggressive. This allows each instrument to accurately follow a smooth

reproducible glide path, and importantly, enhances its ability to load soft

tissue and loose debris into the intrablade flutes, where it can be efficiently

augured out of the canal.

C. Convex triangular cross-section with convex cutting edges:

• This design results in three shape blade edges that improve cutting ability

and tactile sense. It also reduces contact area between dentine and the

cutting blade of the instrument.

D. Helical angle and pitch:

• ProTaper files have a continuously changing HA and pitch over their

14mm of cutting blades. Changing the pitch and helical angles over the

active length of blades optimizes its cutting action. Importantly,

changing the pitch and helical angles of a file, in conjunction with a

progressively tapered design, prevents each instrument from

inadvertently screwing into the canal.

• Ensuring straight line access and check the patency of the canal.

• Once WL is confirmed, use each instrument progressively down to the WL.

• Always irrigate the canal before engaging the file; use instrument in well

irrigated and lubricated canal with EDTA.

• Clean the instrument directly after use and inspect for the sign of distortion.

• Avoid cyclic fatigue from overuse of file.

• ProTaper rotary files should be used at a constant and stable speed between

150-350 rpm.

• Withdraw the file once the WL is reached.

• For a better result, RPT shaping files should be used with a brushing action.

RPT files used with very light apical pressure. Shaping and finishing PT files do

not use more than 3-5 seconds inside canal.

• Each instrument should do minimal shaping. Only two, three, or four passes

may be required for the file to engage restrictive dentin and care the shape to

the proper depth.

• The ProTaper instruments should be used passively within the

canal and their use may be continued as long as they move easily

in an apical direction.

• To optimize PT safety, the pencil lead analogy is used to qualify

the specific recommended pressure. The desired pressure on an

instrument should be equivalent to the pressure used when

writing with a pencil without breaking the lead.

Rotary ProTaper technique

Technique sequence for short length canals:

• Use SX to resistance or no more than three quarter estimated working length.

• Use 15 K-file to full WL.

• Use SX to full WL.

• Use F1 to WL.

• Use F2, F3, F4 and F5 as in medium and long canals.

Technique sequence for medium and long length canals:

• Use S1 to resistance or no more than three quarter estimated canal length.

• Use SX to resistance.

• Use S1 to full W.L.

• Use 15 K-file to full WL.

• Use S1 to full WL in one or more passes.

• Use S2 to working length.

• Use F1 to working length.

• Use F2 if foramen is larger than size 20.

• Use F3 if foramen is larger than size 25.

• Use F4 if foramen is larger than size 30.

• Use F5 if foramen is larger than size 40.