This document discusses the components and design of various endodontic instruments. It describes the parts of rotary instruments like the flute, radial land, relief, helix angle, rake angle, and pitch. It then reviews the designs of different instrument types like K-files, reamers, Hedstrom files, and Gates-Glidden drills. The document also discusses modifications to traditional designs as well as newer nickel-titanium rotary systems like ProFile, LightSpeed, ProTaper, Hero, and K3. Overall, the document provides an overview of the evolution of endodontic instrument design and the key features of different instrument types.

1. Nickel Titanium Instruments in
Endodontics: Part 2
Dr. Ashok Ayer
Department of Conservative Dentistry &
Endodontics
College of Dental Surgery
BPKIHS, Dharan

2. Contents:
1. Components of an endodontic rotary instrument
2. Instrument Designs
3. K-file
4. Reamers
5. Hedström Files
6. Gates-Glidden Drills
7. Instrument design Modifications
8. LightSpeed and LightSpeed LSX Instruments
9. ProFile
10. GT and GTX Files
11. HERO 642, Hero Shaper
12. ProTaper Universal
13. ProTaper Next
14. K3
15. FlexMaster
16. RaCe, Bio Race
17. EndoSequence
18. Twisted File
19. Path files
20. Self-adjusting file
21. ENDO-EZE reciprocating files
22. The WaveOne single-file reciprocating system
23. Endo Express and Safe Sider
24. Revo-S Sequence
25. Mtwo
26. Conclusions
27. References:

3. Components of an endodontic rotary
instrument

4. Components of Endodontic Instruments
Flute:
 Groove in the working surface used to collect
soft tissue and dentine chips removed from
the canal wall.
 The effectiveness of the flute depends on its
depth, width, configuration, and surface finish.
 Its effectiveness depends on its angle of
incidence and sharpness.

6.  Radial land/ marginal width:
 Is a flat cutting surface present between two grooves/
flutes.
 The land touches the canal walls at the periphery of the
file and reduces the tendency of the file to screw into
the canal,
 Reduces transportation of the canal.
 Reduces the propagation of microcracks on its
circumference,
 Supports the cutting edge, and
 Limits the depth of cut.

7.  Disadvantages:
 Clogging of the instruments,
 Friction and heat build-up,
 Inefficient cutting.
Rotary Profile niTi file, #5 (denTSPLY Tulsa dental,
Tulsa, OK). note the instrument’s wide marginal land (arrows)

8.  Relief:
 Surface area of land that is reduced to a
certain extent to reduce frictional resistance.
 Helix angle:
 The angle the cutting edge forms with the
long axis of the file.
 Augers debris collected in the flute from the
canal.
 This angle is important for determining
which file technique to use.

9. Components of the Quantec niTi rotary instrument
(Sybronendo, Orange, CA)

10.  Rake angle
 Is the angle formed by the leading edge and the
radius of the file.
 If the angle formed by the leading edge and the
surface to be cut (its tangent) is obtuse, the rake
angle is said to be positive or cutting.
 If the angle formed by the leading edge and the
surface to be cut is acute, the rake angle is said to be
negative or scraping

11. Positive and negative rake angles.
Positive angle results in cutting action
Negative angle results in scraping action.

12.  However, the rake angle may not be the same
as the cutting angle.
 The cutting angle, or the effective rake angle,
is a better indication of a file’s cutting ability
and is determined by measuring the angle
formed by the cutting (leading) edge and the
radius when the file is sectioned perpendicular
to the cutting edge.
 If the flutes of the file are symmetric, the rake
angle and the cutting angle are essentially the
same.

13.  The pitch of the file is the distance between a
point on the leading edge and the
corresponding point on the adjacent leading
edge.
 Most files have a variable pitch, one that
changes along the working surface.
 Because the diameter increases from the file
tip toward the handle, the flute becomes
proportionately deeper, resulting in a core
taper that is different from the external taper.

14. WaveOne variable pitch flute increases
safety

15. Instrument Designs
1. The difference between the file’s minimum and maximum
diameters can be reduced so that the torque required for
rotating the larger diameter does not exceed the plastic
limit of the smaller diameter.
2. The space between the tip and the maximum diameter
can be reduced so that the required torque does not
exceed the ultimate strength of any part of the file.
Cohen and Hargreaves. Pathways of
pulp,10th edition

16. 3. A zero taper or nearly parallel and fluted working
portion of the file can be provided for curved canals
so that the apical portion of the canal can be
enlarged without undue file stress and compression
of debris.
4.The continuity of the blade engagement can be
interrupted.
5.The number of flute spirals can be eliminated or
reduced to the smallest number necessary to prevent
excessive torque, which results from the
accumulation of debris.
6. Means can be provided to complete the file function
before the flutes fill with debris.

17. 7.Any land width can be minimized to reduce
abrasion on the canal surface.
8.The file can be given an asymmetric cross-
section to help maintain the central axis of
the canal.
9.The number of flutes with similar helix angles
can be reduced. When helix angles are
dissimilar, screwing-in forces are reduced;
when flutes have no helix angles, screwing-
in forces are eliminated.

18. 10. Positive cutting angles can be
incorporated to enhance the efficiency of
canal enlargement.
11. Blades can be made appendages or
projections from the file shaft rather than
ground into the shaft.
12. Channels can be cut along the long
axis of the file to facilitate its removal if it
breaks.

19. K-file
 K-files were manufactured by twisting square or
triangular metal blanks along their long axis,
producing partly horizontal cutting blades.
 The tip is cutting and pyramidal
 Helical angle: 45˚
 Noncutting tips, also called Batt tips, are created
by grinding and smoothing the apical end of the
instrument

20.  NiTi K-files are extremely flexible and
are especially useful for apical
enlargement in severe apical curves.
 They can be precurved, but only with
strong overbending; this subjects the file
to excess strain and should be done
carefully.
 Because of their flexibility, the smaller
NiTi files (sizes up to #25) are of limited
use.

22.  Cross-sectional analysis of a K-file
reveals why this design allows careful
application of clockwise and counter
clockwise.
 Rotational and translational working
strokes.

23. Modification of K- files:
K flex file:
 Rhomboidal/ diamond cross- section
 Increased flexibility and cutting
efficiency

24. K- flex O file:
 Twisting a triangular cross section blank
 Non- cutting tip
 Increased flexibility but less cutting
efficiency

25. K- flex R file/ Roane file
 Machined from triangular cross section
blank
 Modified safe-end tip. (reduction in
cutting tip angle).
 Balanced force technique, cuts during
anticlockwise rotary motion

26. Triple flex file:
 Triangular stainless steel wire is twisted
 Has more flutes than reamer but less than
K- file.

27. C + files:
 Better buckling resistance than K – file
 Sizes: 008, 010, 015
 Length: 18, 21, 25 mm
 Used for initial penetration and cut
better, especially in calcified canals.

28. Reamers
 Triangular or square blank
 Triangular blanks are more flexible, have a larger
groove, more susceptible for fracture.
 Square blanks are stable and rigid and have
smaller groove.
 Helical angle 20˚
 Reaming: penetration, rotation (¼- ½) and
retraction.
 Retraction brings about the cutting action.

29. Less flutes compared to K-file:
 Files: tighter flutes: 1.93- 0.88 mm
 Reamers: looser flutes: 0.80- 0.28 mm
Example;
 No. 30 file: 22 flutes per 16 mm of blade
 No. 30 reamer: 15 flutes per 16 mm of
blade.

30. Hedström Files
 Hedström files are milled from round stainless steel
blanks.
 Cutting action: Retraction
 They are very efficient for translational strokes, but
rotational working movements are strongly discouraged
because of the possibility of fracture.
 Helical angle: 60˚
 Better cutting action than K-file (more positive rake
angle).

32.  Hedström files up to size #25 can be
efficiently used to relocate canal orifices and,
with adequate filing strokes, to remove
overhangs.
 Similarly, wide oval canals can be
instrumented with Hedström files as well as
with rotary instruments.

33. Modifications:
Unifile/ Dyanatrak:
 Designed with two spirals for cutting blades
 Cross section: ‘S’ shaped double helix
 High incidence of separation.
 Others: Hyflex file, S- file, Triple helix

34. A- file:
 Variant of H- file
 More flexible
 Flutes/ cutting edges are at acute angle to the
long axis of the file.
 When used in curved canals,
 Flutes on the inner edge collapse and hence no dentine
is removed,
 On the outer edge it opens, filling the dentine on the
outer curvature (simulates anticurvature filling)

35. U - file
 Heath 1988
 Cross- section: Six corners, two 90˚ cutting edges
at each of the three points of the blade.
 Radial land
 Adapt well to curved canals
 Non cutting tip
 E.g. Profile, GT files, Light speed, Ultra-flex files

36. Gates-Glidden Drills
 GG instruments are manufactured in a set and
numbered 1 to 6 (with corresponding diameters of
0.5 to 1.5 mm)
 GG drills are side-cutting instruments with safety
tips; they can be used to cut dentin as they are
withdrawn from the canal
 GG instruments should be used only in the
straight portions of the canal, and they should be
used serially and passively
 NiTi: FlexoGates

39. Instrument design
Modifications
The instrument tip has
two functions:
 To guide the file
through the canal and
 To enlarge the canal.

40.  A clinician who is unfamiliar with the tip design of a
particular instrument is apt to do either of the
following:
 Transport the canal (if the tip is capable of
enlarging the canal and remains too long in one
position)
 Encounter excessive torsion and break the file (if a
noncutting tip is forced into a canal with a smaller
diameter than the tip).
 Transportation of the original axis of the canal can
occur by remaining too long in a curved canal with
a tip that has efficient cutting ability.

41.  As long as the file is engaged 360 degrees,
canal transportation is unlikely to occur.
 Only with overuse does the file begin to cut on
one side, resulting in transportation.
 Most instrumentation errors occur when the file
tip is loose in the canal, which gives it a
propensity to transport the canal.
 If the canal is smaller than the file, the prudent
use of a cutting tip is more efficient.
 If the canal is larger than the tip, using a less-
effective cutting tip can help prevent
transportation.
Cohen and Hargreaves. Pathways of
pulp,10th edition

42. Instrument System Cross-Section Tip Design Taper Other features
Profile Non cutting Fixed taper 20 degree helix angle
& constant pitch
Triple U shape with radial lands.
Neutral rake angle planes dentin walls.
LightSpeed Non cutting Specific instrument Thin, flexible noncutting
sequence produces shaft & short cutting
a tapered shape. Head.
ProTaper Non cutting Variable taper along Pitch & helix angle
balanced to prevent
taper lock.
Convex triangular shape,
sharp cutting edges, no radial lands.
HERO Non cuttingFixed taper; 2,4,6 % Variable pitch. Files have
a short cutting portion
(12- 16 mm).
Triangular shape with positive rake angle for cutting efficiency.
No radial lands.
Grossman’s Endodontic Practice. 12th Edition

43. K3 Non cutting Fixed taper Variable pitch & core
2, 4,6 % diameter.
Positive rake angle for cutting efficiency
Three radial lands, relief for reduced friction
FlexMaster Non cutting Fixed taper Individual helical angles
2, 4, 6% for each instrument to
Intro file has 11% reduce screw-in effect.
Convex triangular shape with
sharp cutting edges & no radial lands
RaCe Non cutting Fixed taper Alternating cutting edges
2,4,6,8,10% along the length due to
alternating twisting
& untwisting
Mtwo Non cutting Fixed taper Variable pitch, Steep
4, 5, 6, 7 % helical angle to reduce
screw-in effect.
S- shape design with two cutting edges, no radial lands.
Minimum core width to improve flexibility
Grossman’s Endodontic Practice. 12th Edition

44. Nickel-Titanium Rotary Instruments
 The specific design characteristics vary,
such as tip sizing, taper, cross section,
helix angle, and pitch.
 New designs continually are produced, but
the extent to which clinical outcomes (if
any) will depend on design characteristics
is difficult to forecast.

45. LightSpeed and LightSpeed LSX Instruments
 Developed by Steve Senia and William Wildey
in the early 1990s and now also known as LS1.
 Long, thin non-cutting shaft and short anterior
cutting part (0.25- 1.75mm)
 A full set consists of 25 LightSpeed LS1
instruments in sizes #20 to #100, including half
sizes (e.g., 22.5, 27.5); LSX does not have half
sizes, and a set includes sizes #20 to #80.

46.  The recommended working speed for LS1
instruments is 1500 to 2000 rpm and for
LSX, 2500 rpm.
 Both variants should be used with minimal
torque, owing to the thin shaft.
 Cross sections of LightSpeed LS1 cutting
parts show three round excavations, the U-
shape design common to many earlier NiTi
instruments,
 Whereas the LSX is shaped like a flat
chisel in cross section.

47. design features of a LightSpeed instrument. A, Lateral view
(scanning electron micrograph [SeM], ×50). B, Cross section (SeM,
×200). C, Lateral view. D, design specifications.

48.  Considerably more flexible than any
other instrument on the market.
 Cyclic fatigue is lower than with all other
instruments, allowing the use of higher
rpm speeds.
 All Light-Speed instruments feature a
noncutting tip.

49.  Because of their design, LightSpeed LS1
and LSX require specific instrumentation
sequences to produce canal shapes
amenable to root canal filling.
 The current recommendation calls for an
apical 4-mm zone to be prepared to a
cylindrical, nontapered shape.
 This section may then be filled with the
proprietary SimpliFill system

50.  A low incidence of canal transportation and
preparation errors.
 Loss of working length was also minimal in
most of these studies
Bergmans L et al.
Int Endod J 35:820, 2002

51.  Marending M, et al Compared the apical fit in
two dimensions of the first K-file versus the first
Lightspeed LSX instrument binding at working
length after an initial crown-down preparation.
 The apical large canal diameter was assessed
more accurately by the LSX instruments
 Instruments with a flat widened tip were found to
determine apical cross-sectional diameter
better than round, tapered instruments.
Marending M, et al. International
Endodontic Journal, 45, 169–176, 2012.

52. ProFile
 [DENTSPLY Tulsa Dental] was introduced by Ben
Johnson in 1994.
 Have increased tapers compared with
conventional hand instruments
 The ProFile system was first introduced as the
“Series 29” hand instruments in .02 taper, but it
soon became available in .04 and .06 taper.
 The tips of the ProFile Series 29 rotary
instruments had a constant proportion of
diameter increments (29%).

53. Design features of a ProFile
instrument. A, Lateral view
(scanning electron micrograph
[SeM], ×50). B, Cross section
(SeM, ×200). C, Lateral view.
D, design specifications.

54.  Cross sections of a ProFile instrument show a
U-shape design with radial lands and a parallel
central core.
 Lateral views show a 20-degree helix angle, a
constant pitch, and bulletshaped noncutting
tips.
 Together with a neutral or slightly negative rake
angle, this configuration facilitates a reaming
action on dentin rather than cutting.
 Also, debris is transported coronally and is
effectively removed from the root canals.

55.  ProFile instruments shaped canals without
major preparation errors in a number of in
vitro investigations.
 A slight improvement in canal shape was
noted when size .04 and .06 tapered
instruments were used in an alternating
fashion.
Bryant ST et al. Int Endod J 31:275, 1998.
Int Endod J 32:155, 1999.

56.  Comparative assessments in vitro
suggested that ProFile prepared mesial
canals in mandibular molars with less
transportation than K3 and RaCe.
 Loss of working length did not exceed 0.5
mm and was not affected by the use of
.06 tapered instruments.
Bryant ST et al. Int Endod J 32:155,
1999.
Al-Sudani D et al. J Endod 32:1198,
2006.

57.  Newer ProFile family of instruments is the
Vortex (DENTSPLY Tulsa Dental).
 The major change lies in the non-landed cross
section, whereas tip sizes and tapers are similar
to existing ProFiles.
 Manufactured using M-Wire, Profile Vortex also
have varying helical angle to counteract the
tendency of non-landed files to thread into the
root canal.

58. GT and GTX Files
 Steve Buchanan in 1994.
 This instrument also incorporates the U-file design and
was marketed as ProFile GT.
 The system was first produced as a set of four hand-
operated files and later as engine-driven files.
 Four tapers (.06, .08, .10, and .12).
 The maximum diameter of the working part was 1 mm.
 This decreased the length of the cutting flutes and
increased the taper.

59.  The instruments had a variable pitch and an
increasing number of flutes in progression to the tip;
the apical instrument diameter is 0.2 mm.
 Instrument tips were noncutting and rounded, these
design principles are mostly still present in the
current incarnation, the GTX instrument.
 The main differences are the NiTi alloy type used
(M-Wire, manufactured by SportsWire, Langley,
OK) and a different approach to instrument usage,
emphasizing the use of the #20 .06 rotary.

60. Design features of a GT-file. A, Lateral view (scanning electron micrograph
[SeM], ×50). B, Cross section (SeM, ×200). C, Lateral view. D, design
specifications

61.  The GTX set currently includes tip sizes 20, 30,
and 40 in tapers ranging from .04 to .08.
 The recommended rotational speed for GT and
GTX files is 300 rpm, and the instrument should
be used with minimal apical force to avoid
fracture of the tip.

62.  Studies on GT files found that the prepared
shape stayed centered and was achieved
with few procedural errors.
 A shaping assessment using μCT showed
that GT files machined statistically similar
canal wall areas compared with ProFile and
LightSpeed preparations.
 These walls were homogeneously machined
and smooth.
Hata G et al. J Endod 28:316, 2002
Peters OA et al. Int Endod J 34:221, 2001.
Park H: Oral Surg Oral Med Oral Pathol
Oral Radiol Endod 91:715, 2001.

63. HERO 642, Hero Shaper
 First-generation had neutral or slightly negative
rake angles.
 Second-generation systems were designed with
positive rake angles, which gave them greater
cutting efficiency.
 HERO instruments (MicroMega, Besançon,
France); the original system known as HERO 642
has now been replaced by HERO Shaper, with very
little difference in the instrument design.

64.  Cross sections of HERO instruments show
geometries similar to those of an H-file without radial
lands.
 Tapers of .02, .04, and .06 are available in sizes
ranging from #20 to #45.
 The instruments are relatively flexible (the acronym
HERO stands for high elasticity in rotation) but
maintain an even distribution of force into the cutting
areas.
 HERO instruments have a progressive flute pitch
and a noncutting passive tip.

65. Design features of a HeRO instrument. A, Lateral view (scanning electron
micrograph [SeM], ×50). B, Cross section (SeM, ×200). C, Lateral view. D,
design specifications

66.  Research with HERO files indicates a shaping
potential similar to that of the FlexMaster and
the ProFile.
 HERO Shapers were found to have a better
centering ability compared to RaCe
instruments in resin blocks.
Hülsmann M et al. Int Endod J
36:358, 2003. Garala M et al. Int Endod J 36:636, 2003.
Aydin C et al. Oral Surg Oral Med Oral
Pathol Oral Radiol Endod 105:e92, 2008.

67. ProTaper Universal
 The instruments were designed by Cliff
Ruddle, John West, and Pierre Machtou.
 Originally comprised just six instruments:
three shaping files and three finishing files.
 This set is now complemented by two larger
finishing files and a set designed for
retreatment procedures.

68.  In cross section, ProTaper shows a modified K-type
file with sharp cutting edges and no radial lands.
 This creates a stable core and sufficient flexibility for
the smaller files.
 The cross section of finishing files F3, F4, and F5 is
slightly relieved for increased flexibility.
 A unique design element is varying tapers along the
instruments’ long axes.
 The three shaping files have tapers that increase
coronally, and the reverse pattern is seen in the five
finishing files.

69. The differences between Shaping and
Finishing file shapes

70. Design features of a ProTaper instrument. A, Lateral view (scanning electron
micrograph [SeM], ×50). B, Cross section (SeM, ×200). C, Lateral view. D,
design specifications.

71. Tip diameter (mm)
Sx 0.19 At D9 = 1.1 mm
S1 0.185 At D14 =1.2 mm
S2 0.20 At D14 = 1.1 mm
Tip Diameter (mm) Taper (mm)
(D₀- D₃)
F1 0.2 0 7%
F2 0.25 8%
F3 0.30 9%
F4 0.40 5%
F5 0.50 4%

72. Cross section of Finishing files
Triangular cross section of Shaping files

73.  The finishing files have rounded noncutting
tips.
 The convex triangular cross section of
ProTaper instruments reduces the contact
areas between the file and the dentin.
 The first is the preparation of a glide path,
either manually or with special rotary
instruments.

74. Optimal helical angle with variable pitch on
the cutting flutes, designed to maximise
efficiency and again prevent the file
screwing into the canal.
The tip design is a modified non-cutting tip
which acts as a guide in the root canal but
does not cut.

75.  A more lateral “brushing” working stroke. Such
a stroke allows the clinician to direct larger files
coronally away from danger zones and
counteract any “threading-in” effect.
 In a study using plastic blocks, the ProTaper
created acceptable shapes more quickly than
GT rotary, ProFile, and Quantec instruments
but also created somewhat more aberrations.
Yun HH et al. Oral Surg Oral Med Oral
Pathol Oral Radiol Endod 95:228, 2003.

76.  A study using μCT showed that the ProTaper
created consistent shapes in constricted
canals, without obvious preparation errors,
although wide canals may be insufficiently
prepared with this system.
 It has been recommended that ProTaper be
combined with less tapered, more flexible
rotaries to reduce apical transportation.
Peters OA et al. Int Endod J 36:86, 2003. Javaheri HH et al. J Endod 33:284, 2007

77. Protaper Next
 The convergence of a variable tapered design on
a given file (ProTaper Universal), innovative M-
Wire technology, and a unique offset mass of
rotation.
 Off-centred, rectangular cross section giving the
files a unique, snake-like swaggering movement.
 This improved action creates an enlarged space
for debris removal, optimises the canal tracking
and reduces binding.

78. X1, X2, X3, X4, and X5
Corresponding to sizes:
17/04, 25/06, 30/07, 40/06, and 50/06, respectively.
Recommended speed is 300RPM with
a torque from 4-5.2Ncm.

79.  M-Wire technology: Improves the
resistance to cyclic fatigue by almost
400% when comparing files of the same
tip diameter, taper and cross-section.
 Offset mass of rotation: Asymmetrical
rotary motion and, at any given cross-
section, the file only contacts the wall at 2
points.

80.  Clinically, this provides 3 significant
advantages:
 Reduced engagement due to the swaggering effect
which limits undesirable taper lock.
 Affords more cross-sectional space for enhanced
cutting, loading, and augering debris.
 Allows any PTN file to cut a bigger envelope of
motion compared to a similarly-sized file with a
symmetrical mass and axis of rotation.
 This means a smaller-sized and more flexible PTN
file can cut the same-size preparation as a larger
and stiffer file with a centered mass and axis of
rotation.

81. K3
 Dr. McSpadden; the Quantec 2000 files were followed
by the Quantec SC, the Quantec LX, and the current K3
system (all by SybronEndo).
 The overall design of the K3 is similar to that of the
ProFile and the HERO in that it includes instruments
with .02, .04, and .06 tapers.
 The most obvious difference between the Quantec and
K3 models is the K3’s unique crosssectional design: a
slightly positive rake angle for greater cutting efficiency,
wide radial lands, and a peripheral blade relief for
reduced friction.

82. Design features of a K3 instrument. A, Lateral view (scanning electron
micrograph [SeM], ×50). B, Cross section (SeM, ×200). C, Lateral view. D,
design specifications.

83.  Unlike the Quantec, a two flute file, the K3
features a third radial land to help prevent
threading-in.
 In the lateral aspect, the K3 has a variable pitch
and variable core diameter, which provide apical
strength.
 This complicated design is relatively difficult to
manufacture, resulting in some metal flash
 A round safety tip, but the file is about 4 mm
shorter than other files

84.  Tested in vitro, K3’s shaping ability seems to be similar to
that of the ProTaper and superior to that achieved with hand
instruments.
Bergmans L et al. Int Endod J 36:288, 2003.
Schäfer E et al. Int Endod J 36:199, 2003.

85. FlexMaster
 .02, .04, and .06 tapers.
 The cross sections have a triangular
shape, with sharp cutting edges and no
radial lands.
 This makes for a relatively solid instrument
core and excellent cutting ability.
 The overall manufacturing quality is high,
with minimal metal flash and rollover.

86. Design features of a FlexMaster instrument. A, Lateral view (scanning
electron micrograph [SeM], ×50). B, Cross section (SeM, ×200). C,
Lateral view. D, design specifications.

87.  Have rounded, passive tips; the tip
diameters are 0.15 to 0.7 mm for size
.02 instruments and 0.15 to 0.4 mm for
size .04 and .06 files.
 In addition to the standard set, the Intro
file, which has a 0.11 taper and a 9-mm
cutting part, is available

88.  Several studies indicate that the
FlexMaster allows centered preparations in
both constricted and wider canals and that
it performed on par with other systems.
Hübscher W et al. Int Endod J 36:740, 2003.
Hülsmann M et al. Int Endod J 36:358, 2003.
Weiger R et al. Int Endod J 36:483, 2003

89. RaCe, Bio Race
 The name, which stands for reamer with
alternating cutting edges, describes just one
design feature of this instrument
 Light microscopic imaging of the file shows flutes
and reverse flutes alternating with straight areas;
this design is aimed at reducing the tendency to
thread the file into the root canal.
 Cross sections are triangular or square for #.02
instruments with size #15 and #20 tips.
 The lengths of cutting parts vary from 9 to 16 mm

90. Design features of an RaCe instrument. A, Lateral view (scanning electron
micrograph [SeM], ×50). B, Cross section (SeM, ×200).C, Lateral view. D,
design specifications.

91.  The surface quality of RaCe instruments
has been modified by electropolishing.
 Two largest files (size #35, #.08 taper
and size #40, #.10 taper) are also
available in stainless steel.
 The tips are round and noncutting

92. EndoSequence
 The Sequence rotary instrument is
produced by FKG in Switzerland and
marketed in the United States by Brasseler.
 This is another instrument that adheres to
the conventional length of the cutting flutes,
16 mm, and to larger tapers, .04 and .06, to
be used in a crown-down approach

93. Design features of a Sequence instrument. A, Lateral view (scanning electron
micrograph [SeM], ×50). B, Cross section (SeM, ×200). C, Lateral view. D,
design specifications.

94.  A unique longitudinal design called alternating
wall contact points (ACP) reduce torque
requirements and keep the file centered in the
canal
 An electrochemical treatment after
manufacturing, similar to RaCe files, that results
in a smooth, polished surface.
 This is believed to promote better fatigue
resistance, hence a rotational speed of 600 rpm
is recommended for EndoSequence.
Koch KA et al. Dent Clin North Am 48:159,2004.

95. Twisted File
 In 2008, SybronEndo presented the first fluted
NiTi file.
 Manufactured by plastic deformation, a process
similar to the twisting process that is used to
produce stainless steel K-files.
 According to the manufacturer, a thermal
process allows twisting during a phase
transformation into the so called R-phase of
nickel-titanium.
 The instrument is currently available with size
#25 tip sizes only, in taper .04 up to .12.

96. Design features of a Twisted File (TF) instrument. A, Lateral
view (scanning electron micrograph [SeM], ×50). B, Cross
section (SeM, ×200). C, Lateral view. D, design
specifications.

97.  Twisted Files size #25 .06 taper were more
flexible than ProFiles of the same size.
 The manufacturer recommends a conventional
crown-down technique after securing a glide
path with a size #15 K-file.
 Specifically, for a “large” canal, tapers .10 to
.06 should be used, and in a “small” canal,
tapers .08 to .04 are recommended.
Gambarini G et al. Oral Surg Oral Med Oral
Pathol Oral Radiol Endod 105:798, 2008

98. Path Files
 Mechanical glide path and Preflaring.
 Available in 3 ISO sizes (013, 016 and 019) and
3 lengths (21, 25 and 31mm).
 Flexible and resistant to cyclic fatigue, they offer
many advantages compared to manual solutions

99. NiTi – Square Section – 2% Taper
 High strength against cyclic fatigue
 Flexibility
Tip design (transition angle reduction)
 Reduced risk of ledges and canal transportation
PathFile™ K-File

100.  Helio P. Lopes et al.
(Buckling Resistance of Pathfinding
Endodontic Instruments):
 The results indicated that the buckling
resistance decreased in the following order:
C+ file > C-Pilot file > PathFile
 Considering that buckling resistance may
influence the performance of instruments
during the negotiation of constricted canals,
the C+ files showed significantly better
results than the other instruments tested.
Helio P. Lopes et al . J Endod 2012;38:402–404

101. Self-adjusting file
The instrument is made as a
hollow, thin NiTi lattice
cylinder that is compressed
when inserted into the root
canal and adapts to the
canal’s cross-section.
It is attached to a vibrating
handpiece.
Continuous irrigation is
applied through a special hub
on the side of its shank.

102. The SAF instrument adapted
into a root canal that was
initially prepared with #20 K-file.
Right: A #20 K-file in the canal.
Left: The SAF file in its relaxed
form.
Center: The SAF file inserted
into the same narrow canal.
It will apply delicate pressure on
the canal wall, attempting to
resume its original shape.

103. The abrasive surface
and details of the lattice
of the SAF instrument.
The extreme elasticity is
the total of the elasticity
of each of the delicate
NiTi segments.

104. The VATEA continuous irrigation unit used with the SAF instrument.
The unit has two containers and provides a continuous flow (low
pressure, 5 ml/min) of either irrigant (i.e., sodium hypo-chlorite and
edTA) through double silicon tubes that are connected to the hubs on
the front of the device.
It is controlled by finger-operated switches located on the handpiece.

105. A micro–computed tomography (microCT) analysis of the operation
of the SAF instrument in a flat canal with extremely oval cross-
section.
Right: Buccolingual and mesiodistal views of the root canal
reconstructed from microCT.
Left: Cross-sections at 4 and 6 mm from the apex.
Red: before, blue: after treatment.

106. ENDO-EZE reciprocating files
 The endo-eze file system (Ultradent, South Jordan,
UT) is a recently introduced addition for Giromatic
handpieces.
 The set has four instruments that are designed to
clean the middle third of the canal.
 The sizes and tapers are 0.10 #0.025 taper, 0.13
#0.35 taper, 0.13 #0.45 taper and 0.13 #0.06 taper.
 The use of stainless steel hand instruments is
suggested for the apical third of the canal

109. The WaveOne single-file reciprocating system
 Single-use, Single-file system to shape the
root canal completely from start to finish.
 M-Wire technology.
 Improving strength and resistance to cyclic fatigue
by up to nearly four times in comparison with
other rotary NiTi files.
 At present, there are three files in the
WaveOne single-file reciprocating system
available in lengths of 21, 25 and 31 mm

111.  The WaveOne Small file is used in fine
canals. The tip size is ISO 21 with a
continuous taper of 6 %.
 The WaveOne Primary file is used in the
majority of anals. The tip size is ISO 25 with
an apical taper of 8 % that reduces towards
the coronal end.
 The WaveOne Large file is used in large
canals. The tip size is ISO 40 with an apical
taper of 8 % that reduces towards the coronal
end

112.  The instruments are designed to work with a reverse cutting
action.
 All instruments have a modified convex triangular cross-
section at the tip end, and a convex triangular cross-section at
the coronal end . This design improves instrument flexibility
overall
WaveOne apical cross-section,
modified convex triangular
WaveOne coronal cross-section, convex
triangular.

113. WaveOne variable pitch flute increases
safety

114.  The specially designed NiTi files work in a similar but
reverse “balanced force” action using a pre-
programmed motor to move the files in a back and
forth “reciprocal motion”
 The counter-clockwise (CCW) movement is greater
than the clock-wise (CW) movement. CCW movement
advances the instrument, engaging and cutting the
dentine.
 CW movement disengages the instrument from the
dentine before it can (taper) lock into the canal.
 Three reciprocating cycles complete one complete
reverse rotation and the instrument gradually
advances into the canal with little apical pressure
required.

115. Clinical
procedure

116. Endo Express and Safe Sider
 Reciprocating Motion.
 SafeSiders have 16 flutes compared to 24
flutes for files.
 Less flutes leads less engagement with the
walls of the canal which means less
resistance, binding and virtually no instrument
separation.

117.  Flat-side of the SafeSider:
 Act as chisels in the clockwise and counter
clock-wise motion allow to remove debris
easily.
 SafeSiders are safely used at least 3
times more than NiTi instruments before
they are discarded.

118. Revo-S Sequence
 The asymmetrical cutting profile of the
Revo-S facilitates penetration by a snake-
like movement, and offers, a root canal
shaping which is adapted to the biological
and ergonomic imperatives.
 It is composed of only two instruments for
apical penetration (SC1 and SC2), and a
recapitulating and cleaning instrument (SU)

119. Revo-S instruments for apical progression (SC1 & SC2), &
cleaning (SU).
The working lengths are adapted for a crown-down
preparation.
The asymmetry alternates with the symmetry, in order to
optimize the canal penetration (SC1), the strength (SC2), &
the cleaning (SU)

120. Apical finishing instruments with an asymmetrical cross
section allowing the final shaping of the apical third.
The selection of preparation diameter adapted to most
clinical cases, and
Cleaning without pushing debris beyond the apical
foramen

121. Mtwo
 VDW, Munich, Germany
 The standard set for this system includes
four instruments with variable tip sizes
ranging from #10 to #25, and tapers ranging
from .04 to .06 (size 10/.04 taper, size
15/.05 taper, size 20/.06 taper, size 25/.06
taper

122.  After this basic sequence, that gives the canal a
#25/.06 shape, the system is conceived to permit
three different approaches to root canal
preparation.
 The first sequence allows clinicians to achieve
enlarged apical diameters using the size 30 (.05)
taper, 35 (.04) taper or 40 (.04) taper;
 The second leads to a .07 taper that can facilitate
vertical condensation of gutta-percha, maintaining
a size #25 apical preparation;
 The third implies the use of the Mtwo apical files

124. SEM image of Mtwo instrument cross-section, showing the two blade
cutting surfaces resulting in an “Italic S” design.
.

125.  The Helical angle (HA) of Mtwo instruments
is variable and specific for the different files
 HA is more open (greater) for the bigger
sizes (less flutes for instrument length), and
it decreases for the smaller sizes (more
flutes).
 This determines a greater cutting efficiency
for the bigger sizes and a greater
mechanical resistance together with a
tendency to advance in the canal for the
smaller ones.

126.  The HA is variable in the same instruments,
it increases from the tip to the handle as
does the spiral pitch,
 While it is constant for the smaller files,
especially for the #10 .04, the first rotary
instrument that is introduced in the root
canal.
 The variable HA reduces the tendency of
the instrument to be sucked down into the
canal

127.  The MtwoR instruments are specifically
designed for the retreatment of obturation
materials.
 The retreatment files are Mtwo R 15/.05 and
Mtwo R 25/.05, presenting an active tip that
allows clinicians to easily penetrate obturation
material.

128. Conclusion:
 An explosion in knowledge and technology has created
an exciting time in the specialty of endodontics.
 New instruments and materials seem to appear faster
than clinicians can learn about the preceding versions.
 This has created an educational challenge for
practitioners, universities, and manufacturers, requiring
a greater degree of cooperation among these groups
than ever before.
 Clinicians should only use those instruments and
materials that have been shown safe and effective by
independent studies.
Cohen and Hargreaves. Pathways of pulp,10th edition

129.  Most systems include files with tapers greater than the #.02
stipulated by the ISO norm.
 The Light-Speed LS1 and LSX are different from all other
systems;
 The ProTaper, RaCe, and Twisted File have some unique
features; and most other systems have increased tapers.
 Minor differences exist in tip designs, cross sections, and
manufacturing processes, but the clinical effects of these
modifications currently are unknown.
 Even in vitro, tests have only begun to identify the effect of
specific designs on shaping capabilities, and differences in
clinical outcomes in regard to these design variations
appear to be minimal.
Cohen and Hargreaves. Pathways of pulp,10th edition

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