4. INTRODUCTION:
The term Endodontics is not complicated. The reality is, the more we know
about the curvatures and innovations of the root canal systems, the more we
are attentive of nature’s anatomic complications.
From the beginning of the modern era of endodontics, there have been many
techniques, notions and strategies for preparing canal.
The clinical endodontics step forward was succeeding from utilizing the long
series of stainless steel hand files and various rotary gates glidden drills
combined with nickel titanium files for negotiating or shaping the canal .
The mechanical objectives of the root canal when properly performed,
endorse the biological objectives for shaping canals, filling and three
dimensional disinfection of root canal systems.
5. Over the decades, numerous display of files has emerged for negotiating and
shaping files.
Every new file has a more developed canal preparation techniques through
novelty in design ,movements and materials
Now a days our profession has visualized preparing root canal using “single
file technique”.
Recently the advances in endodontic root canal preparation focuses on the
idea that “less is more”.
6. HISTORY:
The combination of axial and rotational reciprocation was firstly introduced
in 1928 (Cur- sor Filing Contra-Angle; W & H, Bürmoos, Austria) followed
by axial reciprocation in 1958 (Racer; W & H) and rotational reciprocation
(Giromatic; Micro Méga, Besançon, France) in 1964 .
Since then, several handpieces were developed to drive the endo- dontic
instruments in a reciprocal movement . However, concerns were raised about
the shaping ability of endodontic files used in reciprocation with these
engine-driven devices in many studies.
In 1985, Roane et al introduced the balanced force technique using
instruments in rotational recip rocation for the preparation of curved root
canals.
8. They were the first to report the use of hand files with unequal clockwise and
counter-clockwise movements in reciprocation.
Consequently, handpieces using ‘rotational recipro- cation’ (referred to as
Reciprocation/Reciprocal in the text) systems were introduced such as the M4
(SybronEndo, Orange, CA, USA) , the Endo-Eze AET (Ultradent Products, South
Jordan, UT, USA) and the Endo-Express (Essential Dental Systems, South
Hackensack, NJ, USA).
The results on the shaping ability of curved canals with these recipro- cating
systems were not encouraging
In 2008, Yared introduced engine-driven single file reciprocation for the
preparation of curved canals. He reported good clinical results . He used an F2
ProTaper instrument (Dentsply Maillefer, Ballaigues, Switzerland) in
reciprocation with une- qual clockwise (CW) and counter-clockwise (CCW)
movements. The F2 ProTaper instrument was driven by an ATR motor (ATR,
Pistoia, Italy).
9. Dr. Ghassan Yared is an endodontist practicing in Guelph and Waterloo,
Ontario, Canada
In 2010, Dentsply introduced two single file (rotational) reciprocation systems,
Reciproc (VDW, Munich, Germany) and WaveOne (Dent- sply Maillefer) based
on the concept developed by Yared
10. The following is a mechanical classification of
each generation of rotary file systems:
1. First generation Ni-Ti files have passive cutting radial lands (encouraged
a file to stay centered in canal curvatures during work) and fixed tapers of 4%
and 6% over the length of their active blades
2. Second generation of Ni-Ti rotary files came to market in 2001 They have
active cutting edges and require fewer instruments to fully prepare a canal.
The clinical breakthrough occurred when ProTaper (DENTSPLY Tulsa
Dental Specialties) came to market, utilizing multiple increasing or
decreasing percentage tapers on a single file.
3. Improvements in Ni-Ti metallurgy became the hallmark of what may be
identified as the third generation of mechanical shaping files.
11. In 2007, manufacturers began to focus on utilizing heating and cooling
methods to reduce cyclic fatigue and improve safety when rotary Ni-Ti
instruments work in more curved canals
Examples of brand lines that offer heat treatment technology are Twisted File
(Axis Sybron Endo); HyFlex (Coltène); and GT, Vortex and WaveOne
(DENTSPLY Tulsa Dental Specialties).
4. Fourth generation utilizes reciprocation, which may be defined as any
repetitive up-and-down or back-and-forth motion .Blanc, a French dentist,
first introduced this technology in the late 1950s. Currently, the M4
(Axis/SybronEndo), Endo-Express (Essential Dental Systems), and Endo-Eze
(Ultradent Products) are examples of fourth generation files.
12. While reciprocation and rotation camps were busy fighting regarding the
merits of instrumentation motion, a novel concept of instrumentation and
file design was introduced.
This was the self-adjusting file (SAF). This file consists of a hollow,
collapsible cylinder made up of a very thin NiTi lattice that adapts to the
canal walls and sandpapers the dentin instead of cutting it.
13. 5. The fifth generation of shaping files has been designed such that the
center of mass and/or the center of rotation are offset which minimize the
engagement between the file and dentin.
Recent advances for endodontic canal preparation have focused on the
concept “Less is More” i.e. with use of only one or two files biomechanical
preparation of canal can be completed.
Thus, a single-file technique has developed for shaping the vast majority of
canals, regardless of their length, diameter, or curvature.
Today as there are large number of single file systems available, a
comparative evaluation of these systems need to be done.
14. ROTATIONAL RECIPROCATING MOTION:
Reciprocating motion regained popularity with the introduction of NiTi alloys
and endodontic torque control motors.
Here the file is a flute-designed instrument with cross sectional geometry that
aids in the cutting of the dentine in the CW direction) with unequal CW and
CCW rotational motion (144° CW and 72° CCW).
This development meant that the instruments required five rotations to
complete a full 360° rotation. At the same time, the elastic limit of the
instrument was not exceeded due to this motion
Based on these developments, manufacturers introduced single-file
reciprocating systems including WaveOne (Dentsply Tulsa Dental Specialities)
and Reciproc (VDW, Munich, Germany).
15. The major difference is that these instruments had a CCW cutting direction,
so the instruments could cut if the CCW movement was greater than the CW
movement.
However, except for these reciprocating instruments, all of the instruments
are designed for cutting in the CW direction.
Thus, if a clinician tries to use these reciprocating instruments with CW
rotating motors or tries to use CW cutting instruments with the reciprocating
motors (CCW motion is greater than CW motion), the instrument will neither
cut nor penetrate into the canal.
Reciprocating endodontic motors can be classified as open or closed motors,
with open motors allowing modification of angles and speed and closed
motors [(WaveOne), (Reciproc), (Elements motor; SybronEndo), (ATR
Technika; ATR)] which do not allow such modifications.
16. Today, the M4 (SybronEndo) , Endo-Eze AET (Ultradent) , and Endo-
Express (Essential Dental Systems) are examples of reciprocating sys- tems
that utilize small, equal 30 º angles of CW/CCW rotation.
17. ROTARY MOTION PLUS RECIPROCATING MOTION
( Adaptive motion)
In 2013, a new endodontic motor was introduced by Sybron Endo (Elements)
that aims to combine the advantages of both rotary and reciprocating motions.
When the instrument is not (or is minimally) stressed, the motion can be
described as a rotation of 600° in the CW direction, a stop and then a restart
in the CW direction.
When the instrument engages dentine or the root canal filling, the motion of
the instrument becomes reciprocal due to the increased stress.
The reciprocal angles are not constant, and the motor modifies the CW/CCW
angles from 600/0° to 370/ 50°, depending on the intracanal stress
18. RECIPROCATING ANGLE:
Knowing the actual reciprocating angles is important because it has been
shown that decreasing the reciprocation range of the instruments results in
increased cyclic resistance with less transportation but with longer
preparation times
According to the manufacturers, the ‘Wave- One ALL’ mode generates a
rotation of 170° CCW and 50° CW, and the ‘Reciproc ALL’ mode
generates a rotation of 150° CCW and 30° CW.
Recently, Fidler investigated the kinematics of reciprocating motors using a
high-speed video camera and found that the actual angles of the WaveOne
mode is 160° CCW and 41° CW, those of the Reciproc mode is 159° CCW
and 35° CW, and those of ATR Technika’s reciprocation mode is 1310° CW
and 578° CCW.
19. WAVE ONE
The WaveOne concept provides a single- file shaping technique, regardless
of the length, diameter, or curvature of any given canal.
In fact, it has been shown that a single-file reciprocating shaping technique
utilizing unequal CW/CCW angles is over 4 times safer and almost 3 times
faster than using multiple rotary files to achieve the same final shape
Strategically, only 1 file is generally utilized to fully shape virtu- ally any
given canal. However, there are 3 WaveOne files available to effectively
address a wide range of endodontic anatomy commonly encountered in
everyday practice .
The 3 WaveOne instruments are termed Small (yellow 21/06), Primary (red
25/08), and Large (black 40/08).
20. The Small 21/06 file has a fixed taper of 6% over its active portion.
The Primary 25/08 and the large 40/08 WaveOne files have fixed tapers of
8% from D1-D3, whereas from D4-D16, they have a unique progressively
decreasing percentage tapered design.
This design serves to improve flexibility and conserve remaining dentin in
the coronal two-thirds of the finished preparation.
21. Another unique design feature of the WaveOne files is they have a reverse
helix and 2 distinct cross-sections along the length of their active portions.
From D1-D8, the WaveOne files have a modified convex triangular cross-
section, whereas from D9-D16, these files have a convex triangular cross-
section.
The design of the 2 WaveOne cross-sections is further enhanced by a
changing pitch and helical angle along their active portions.
The WaveOne files have noncutting modified guiding tips, which enable
these files to safely progress through virtually any secured canal.
Together, these design features enhance safety and efficiency when shaping
canals that have a confirmed, smooth, and reproducible glide path.
22. This image depicts 2 different cross-sections on a single WaveOne file. The more
distal cross-section improves safety and inward movement.
23. ADVANCED NITI TECHNOLOGY:
Technological improvements in NiTi metallurgy have generated a new
supermetal, commercially termed M-wire.
Studies have shown that M-wire technology significantly improves the
resistance to cyclic fatigue by almost 400% compared to commercially
available 25/04 NiTi files.The good news is that reducing cyclic fatigue
serves to clinically decrease the potential for broken instruments.
The e3 motor (Dentsply Tulsa Dental Specialties) is specially engineered
and programmed to drive the new WaveOne reciprocating files This motor
produces a feature-specific, unequal bidirectional file movement. Because
of the reverse helix design, the CCW engaging angle is 5 times the CW
disengaging angle.
24. The WaveOnE system utilizes an engaging angle that is 5 times the disengaging
angle.
Fortuitously, after three engaging/disengaging cutting
cycles, the WaveOne file will have rotated 360º, or turned one CCW circle.
This unique reciprocating movement enables the file to more readily advance
toward the desired working length.
25. SINGLE FILE / SINGLE USE CONCEPT
The WaveOne technique is both a single-file and single-use concept.
As stated, it is a single-file concept given that one single file is able to
transition a secured canal to a well-shaped canal, in most instances
The WaveOne concept must be considered a single-use concept due to the
obvious stress and wear on the active portion of the file.
26. FILE SELECTION:
The Small 21/06 WaveOne file is used when the Primary 25/08 WaveOne
file will not progress apically through a smooth reproducible glide path.
The 21/06 is designed to work in smaller diameter, longer length, or more
apically curved canals. In certain canals, when this file reaches the working
length, the clinician may deem the preparation completed or, alternatively,
may desire more deep shape.
In these instances, the Small 21/06 is considered a “bridge file” because it
promotes safety when transitioning back to the 25/08 WaveOne file. Even
in these instances, the WaveOne technique is still a safe and efficient 2-file
sequence compared to virtually all other mechanical shaping systems.
27. The Large 40/08 WaveOne file is used to complete the shape in larger
diameter canals that are typically straighter.
Examples include certain maxillary incisors, single-canal bicuspids, and
larger diameter canals within maxillary and mandibular molar teeth.
However, after carrying the Primary 25/08 file to the working length,
gauging procedures may confirm that the foramen is bigger than 0.25 mm.
In these instances, the clinician will require the 40/08 WaveOne file to fully
shape and finish these larger canal systems.
With experience, the clinician will learn to recognize these larger and more
straightforward canals and is encouraged to initiate canal preparation
procedures utilizing only the 40/08 WaveOne file.
28. a. If a 10 K-file is very resistant to movement, use WaveOne Small file.
b. If a 10 K-file moves to length easily, is loose or very loose, use WaveOne
Primary file.
c. If a 20 hand file or larger goes to length, use WaveOne Large file.
29. ADVANTAGES:
1. Only one NiTi instrument per root canal.
2. Better control of file breakage and thus increased patient safety. Less
instrument separation is due to unique reciprocating movement that will
prevent the instrument advancing from plastic deformation to its plastic
limit.
3. Eliminates procedural errors by using a single instrument rather than using
multiple files;
4. Simplicity: There is no need for disinfecting, cleaning, sterilizing and
organizing the Wave One NiTi files.
5. Optimal cutting efficiency
30. RECIPROC:
This new system uses single file reciprocation without prior use of hand files
and was launched by VDW GmbH, Munich, Germany in 2011.
Manufacturing: Made from an M-Wire nickel-titanium that offers greater
flexibility and resistance to cyclic fatigue than traditional nickel-titanium
Device Description: The flexible S-shaped cross-section having two
cutting edges gives fine cutting ability at decreased friction.
A regressive taper for a preparation with no unnecessary loss of tooth
substance at the coronal end. They have a continuous taper over the first 3
mm of their working part followed by a decreasing taper until the shaft.
RECIPROC cleans even severely curved canals (Bürklein., et al. 2012).
31. This system includes three Reciproc instruments R25, R40 and R50
Only one RECIPROC instrument is used for the canal preparation depending
on the initial size of the canal.
The three instruments have regressive taper, which are:
1. R25 has a diameter of 0.25mm at the tip and an 8% taper over the first
3mm from the tip. The diameter at D16 is 1.05mm.
2. R40 has a diameter of 0.40mm at the tip and a 6% taper over the first 3mm
from the tip. The diameter at D16 is 1.10mm.
3. R50 has a diameter of 0.50mm at the tip and a 5% taper over the first 3mm
from the tip. The diameter at D16 is 1.17mm.
33. RECIPROC® is battery operated motor used with RECIPROC system.
The battery is rechargeable and the motor can be used while the battery is
charging.
• There are preprogrammed settings for reciprocating system The instruments
are used at 10 cycles of reciprocation per second.
When the instrument rotates in the cutting direction it will advance in the
canal and engage dentine to cut it.
When it rotates in the opposite direction (smaller rotation) the instrument will
be immediately disengaged.
34. RECIPROC BLUE
The new RECIPROC® blue file generation combines the ease of the original
RECIPROC one file endo concept with enhanced safety in root canal
preparation and retreatment for patients.
An innovative heat treatment makes RECIPROC blue particularly flexible to
ensure a smoother and safer progression in the canal.
RECIPROC blue files are produced with Nickel- Titanium (NiTi) that goes
through an innovative heat treatment, modifying its molecular structure to
give it increased resistance to cyclic fatigue and additional flexibility as well
as its characteristic blue color.
The shape obtained by the RECIPROC blue instrument enables effective
irrigation and obturation with both cold and warm techniques.
35.
36. SELF ADJUSTING FILE:
The SAF System is a shaping and cleaning system designed for minimally
invasive endodontic treatment.
The system consists of a self-adjusting file operated with a special RDT
handpiece-head and an irrigation pump (either the VATEA pump or the all-
in-one EndoStation unit, see below) that delivers a continuous flow of
irrigant through the hollow file.
Because the file is built as a lattice-walled cylinder,
no pressure is generated within the file;
any small pressure that is generated by the pump
to deliver the irrigant through the tube is eliminated
the moment the irrigant enters the file.
37. The SAF is the first file that does not have a solid metal shaft.The file is
designed as a hollow tube, the walls of which are made from a thin nickel
titanium lattice with a rough outer surface .
The file has an asymmetrically positioned tip ,located at the wall of the tube
as opposed to the symmetrically centered tips found in all conventional
nickel titanium rotary files.
The SAF system is extremely flexible and also extremely compressible, so
that a 1.5-mm diameter SAF may be compressed into a root canal in which
only a #20 K file could previously be inserted .
This compressibility also enables the file to adapt to the cross-sectional
shape of the canal.
38. When inserted into an oval canal with a 0.2-mm mesiodistal diameter, a
1.5-mm SAF will be compressed mesiodistally and thus spread
buccolingually as far as 2.4 mm .This will occur even if the operator is not
aware that the canal is oval; hence, the name "self-adjusting file".
Naturally, such a flattened file cannot rotate in the canal and is therefore
operated with in-and-out vibrations created by the RDT handpiece-head.
Irrigation tube connector on the SAF. A freely
rotating hub on the SAF is provided with a connector for
the irrigation tube
39. THE RDT HAND PIECE HEAD
The RDT handpiece-head has a dual mechanical function. It turns the rotation
of the micro-motor into a trans-line in-and-out vibration with an amplitude of
0.4 mm.
It also contains a clutch mechanism that allows the SAF to rotate slowly when
not engaged in the canal but completely stops the rotation once the file is
engaged with the canal walls.
The micromotor is operated at 5000 rpm, which results in 5000 vibrations/min,
and the operator uses pecking motions when using the SAF.
Free rotation of the file should occur at every out-bound part of every pecking
stroke, when the SAF file is disengaged from the canal walls.
This is required to ensure that when the SAF enters the canal during the in-
bound pecking motion, it will do so at a different, random circular position
every time, thus ensuring uniform treatment of the canal walls.
40. This random circular position also allows the asymmetrical tip of the file to
negotiate curvatures that may be found in the root canal. RDT heads are
available in several configurations and may be adapted to a large variety of
endodontic motors/handpieces
The VATEA irrigation pump
The VATEA (ReDent) is a self-contained peristaltic pump with a built-in
irrigant reservoir of 500 mL operated using a foot switch and powered by a
rechargeable battery.
The SAF file is provided with a freely rotating hub connected to a
polyethylene tube ,thus allowing for flow of the irrigant through the hollow
file and into the root canal.
The irrigant can be delivered into the tube at a rate ranging from 1-10 mL per
minute, with the typical recommended setting of 4 mL per minute
41. The EndoStation is equipped with a peristaltic pump that enables continuous
irrigation when used in “SAF mode”.
An external bottle is used as the irrigant container of the EndoStation, from
which the irrigant is drawn by the peristaltic pump into the tube and through
it to the attached file.
When used in “SAF mode”, both the micromotor and the irrigation pump are
simultaneously operated using a single foot pedal.
Once the irrigant enters the SAF, any pressure that may have existed in the
delivery tube disappears due to the lattice structure of the file. The irrigant is
continuously delivered into the root canal, and the vibrations of the file
combined with the pecking motion applied by the operator result in the
continuous mixing of the irrigant that is present in the root canal with fresh,
fully active irrigant.
42. Why did the pecking motion not cause
liquid extrusion while the syringe and
needle kept away from the apical foramen
cause a free flow?
Fluid mechanics analysis provides the answer to this question. Even with a
much larger apical foramen with a diameter of 0.35 mm, the liquid in the
canal is kept contained by surface tension. The bursting pressure needed to
break this surface tension is 832 Pa. The hydrostatic pressure of a 20-mm
column of water is 195 Pa, the stagnating pressure caused by 5000
vibrations per min within the liquid is 196 Pa, and the piston pressure
caused by the SAF pecking motion is only 3 Pa. Therefore, the total
pressure in the root canal (394 Pa) is not large enough to reach the bursting
pressure, and the liquid stays contained in the canal.
43. The metal mesh of the SAF wall is intimately adapted to the canal wall and
is continuously in motion, thus providing a scrubbing effect.
The combination of scrubbing with the continuous flow of fresh, fully
chemically active sodium hypochlorite results in highly effective cleaning
of the canal walls from any attached materials.
44. 3D SHAPING AND CLEANING:
Even though a random set of 2D periapical radiographs will not reveal this,
oval canals are quite common. Such canals may be found in 25% of all
roots, and in certain types of teeth, the incidence of oval canals may be as
high a 90%.
When scans generated with Cone-Beam Computed Tomography (CBCT)
are presented in an axial view, the presence of oval canals is rather obvious
Paqué et al. studied the efficacy of shaping oval root canals in the distal
roots of mandibular molars and found that when ProTaper files were used
with circumferential motion and brushing, 69% of the canal wall was
unaffected by the procedure. This is far from what a dentist expects and
intends when performing root canal treatment in such roots..
45. When SAF was used in similar canals, with the results studied and evaluated
by the same team using the same methods, 23% of the canal wall was
unaffected by the procedure.
This is not a perfect result, but is much closer to what the operator has in
mind when performing root canal treatment in such canals.
Similar results were reported by Metzger et al., further showing the efficacy
of the SAF System in removing a uniform layer of dentin from the walls of
an oval root canal without machining the canal to generate a round cross-
section with the hope of including the entire perimeter of the canal within the
preparation
46. PACKING CANAL RECCESS WITH DEBRIS
The SAF works in a totally different manner than rotary instruments.It does
not rotate in the canal and does not cut the dentin.
The gentle abrasive action of the SAF file removes a layer of dentin by
converting it into a thin powder that is continuously suspended and carried
coronally by the flow of the irrigant.
The SAF system produces no cut dentin chips and therefore does not have
the tendency to pack such chips into the isthmus. It is not surprising, then,
that a recent study has shown that packing of the isthmus with dentin
particles by the SAF is almost negligible: 1.7% of the isthmus volume is
packed with dentin by the SAF vs. 10.1% by rotary files
47. OTHER FACTORS:
The SAF uses a minimally invasive approach, removing only a thin
uniform layer of dentin from the entire perimeter of the canal. This,
combined with the lower tendency to straighten curved root canals, makes
using the SAF safer in terms of maintaining dentin integrity
In retreatment, the addition of SAF removed more gutta percha than the
ProTaper alone.
Thus, it seems that the combination of a rotary file used to remove the bulk
of the root filling followed by cleaning of the canal using the scrubbing
effect of the SAF is an effective cleaning method for retreatment.
48. In comparison with the other two types of Ni-Ti instruments assessed in
the study, the Self Adjust- ing File system produced minimal postoperative
pain after single-visit root canal treatment
49. ONE SHAPE
This system was developed by Micro Mega, Besancon, France.
One Shape , the one and only NiTi instrument in continuous rotation for quality
root canal preparations
Manufacturing: The One Shape system consists of only one instrument
made of a conventional austenite 55-NiTi alloy.
Device Description: One Shape is a new concept of single- file
instrumentation where a single instrument is used in a full clockwise
rotation.
The One Shape system consists of only one instrument, which has a tip size of
25 and a constant taper of 0.06. and is characterised by different cross sectional
designs over the entire length of the working part.
50. At the apical part there are three symmetrical cutting edges.
In the middle the number decreases to two cutting edges; this part is
asymmetrical. In the coronal part there are two S shaped cutting edges
The file has a non-cutting safety tip. As recommended by the
manufacturer, the rotational speed for One Shape is 400 rpm.
One Shape protocol is easy to learn, safe and quick.
Therefore, it might be a good alternative to existing reciprocating single
file systems without the need to use a special endodontic motor generating
the reciprocating motion.
51. The advantages of One Shape are
Root canal shaping with one single instrument
Root canal treatment is done approximately 4 times faster than a
conventional treatment.
Minimal fatigue along the length of the file virtually eliminates the risk of
separation
The variable pitch of One Shape reduces instrument screwing effects
ABC (Anti Breakage Control): The instrument will unwind to avoid
separation
Its non-working (safety) tip ensures an effective apical progression avoiding
obstructions which are often preceded by instrument separation.
52. The first zone presents a variable 3-cutting-edge design. The second, prior
to the transition, has a cross-section that progressively changes from 3 to 2
cutting edges. The last (coronal) is provided with 2 cutting edges
53. F360
F360 is a single instrument used in continous rotation.
The F360 (Komet, USA) endodontic file system permits preparation of most
root canals with a simplified, time-saving sequence requiring only two files.
The files have a unique S-curve design and a thin instrument core to deliver a
high level of cutting efficiency while respecting natural root canal morphology.
F360 files are available in two sizes 025 (Red F360) and 035(Green F360) are
required for most root-canal preparations. Their 0.04 taper promotes optimal
debridement of the canal, maintains file flexibility and thus reduces preparation
errors and permits ideal shaping of the root canal for subsequent obturation
with any method, according to the company
54. In addition to sizes 025 and 035, the F360 files are offered in sizes 045 (White
F360) and 055(Red F360) to meet additional clinical situations such as wide
roots, and all F360 files are available in three lengths L21, L25 and L31.
The pre-sterilized, single-use files are designed to prevent cross contamination,
eliminate the need to clean, disinfect, and sterilize the instruments and reduce the
risk of fracture due to cyclic fatigue.
The advantages of F360 are
Highly flexible
Minimize canal transportation
55. T ONE FILE
This file was introduced in the year 2014, by miraculous dental solution in
India.
The file is available in tip size of 21, 25, 30 and 40 with a taper of 8%
having length of 21, 25 and 31 mm.
This file has a convex triangular design which provides better rotation and
proficient cutting.
The file has no screw in effect and is capable in debris removal efficiently.
56.
57. XP ENDO SHAPER
The XP-endo Shaper is the latest addition to the XP-endo ®
range.
It is a truly innovative shaping instrument which can be used to
radically simplify endodontic sequences.
It results from the combination of two cutting-edge technologies:
Made with MaxWire ® alloy, like the XP-endo Finisher, it offers
remarkable flexibility and fatigue resistance, and the ability to
progress within the canals with ease and agility, expanding or
contracting according to the canal morphology.
With an initial taper of .01, the XP-endo Shaper expands once
inside the canal, achieving a taper of at least .04
58. Booster Tip (BT), the XP-endo Shaper benefits from a unique geometry,
featuring six sharp edges at the tip.
The BT tip respects the trajectory of the canal, whilst removing more
material with each pass.
It enables to start shaping an ISO diameter smaller than the one of the
instrument.
In the case of the XP-endo Shaper, the BT enables it to start shaping after a
glide path of at least ISO 15, and to gradually increase its working field to
achieve an ISO 30.
59. Its unique geometry featuring six sharp edges, the BT-Tip (Booster Tip)
respects the trajectory of the canal, whilst removing more material with each
pass.
It enables to start shaping an ISO diameter smaller than the one of the
instrument. For example, an ISO 35 instrument with BT-Tip already works at
a diameter of 0.15 mm
This snake- shaped instrument is made of a proprietary alloy (MaxWire
[FKG Dentaire SA] [Martensite-Auste nite electropolish-fleX]) that reacts at
different temperature levels . The file has an initial taper of .01 in its M phase
when it is cooled, but, upon exposure to body temperature (35 C), the taper
changes to .04 according to the mo- lecular memory of the A phase
60.
61. Within the limitations of this study, it can be concluded that the XP-
endo Shaper, iRaCe, and EdgeFile systems showed a similar shapin ability.
Despite the XP-endo Shaper system significantly altering the
overall geometry of the root canal to a more conical shape, neither
technique was capable of completely preparing the long oval-shaped canal
of mandibular incisors.
62. XPS instruments were found to be more resistant to cyclic fatigue
compared with PTG F3 and K3XF 30 instruments.
This improved cyclic fatigue resistance might be attributable to the
MaxWire alloy and the smaller taper size of the instruments.
63. SINGLE FILE RECIPROCATION AND CYCLIC
FATIGUE:
When used in curved canals, an instrument is sub- jected to cycles of
compressive and tensile stresses caused by the repeated bending of the
instrument in the canal curvature.
In addition, the instrument is subjected to torsional fatigue resulting from
the repeated stresses in torsion during the frequent en- gagement of the
root canal walls and continuous dentine cutting.
With extended use, the stresses ac- cumulate, leading to torsional and
flexural fatigue and weakening of the instrument, and ultimately fracture
64. Several studies , except for one , have shown that reciprocation extends the
flexural cyclic fatigue life of the tested instruments in comparison with
continuous rotation.
However, these results are not clinically relevant with regards to single file
recip- rocation for at least two reasons.
First, in continuous rotation, multiple instruments are used to prepare a
canal.
The use of these instruments in a sequential manner would reduce the
stresses to which these instruments are subjected.
In single file reciproca- tion, only one instrument is used; stresses on the
instrument would be expected to be higher than the stresses on each of the
instruments used in con-tinuous rotation.
65. It is noteworthy that the WaveOne and Reciproc single file reciprocating
instruments are intended for single use.
Second, these studies did not include an evaluation of torsional fatigue.
Flexural and torsional fatigue might be inter-dependent.
For example, the changes in the physical properties of an instrument
subjected to flexural fatigue might also affect the torsional fatigue resistance
of the in- strument.
Comparing the flexural fatigue resistance of WaveOne and Re- ciproc
instruments found that the latter performed better.
The difference between both instruments was attributed to the cross section,
and the reciproca- ting movement (angles and speed of reciprocation)
66. SINGE FILE RECIPROCATION WITHOUT OR
WITH A MINIMAL GLIDE PATH AND SHAPING
ABILITY
A glide path is a minimal canal enlargement required before the use of
rotary instruments in continuous rotation to minimise the incidence of
binding and torsional fracture.
For example, a glide path with a size 20 file is required for the safe usage
of ProTaper instruments .
The WaveOne instrument was claimed to be able to safely and completely
prepare a canal with only one instrument following the creation of a small
path with a size 10 file
67. One of the claims of the Reciproc single file reciprocation system is that
the creation of a glide path is not required to reach the working length in
the majority of the canals, regard- less of the severity of the curvature .
This would help to reduce canal aberrations and procedural er- rors usually
encountered with the use of hand files to create a glide path
Also, some authors consider that single file reciprocation is a modification
of the balanced force technique , which allows the preparation of severely
curved canals with large and rigid stain- less steel hand instruments.
Yet, concerns were raised regarding the shaping ability of Reciproc and
WaveOne instruments, considering that these in- struments are relatively
large and are used in curved and narrow canals without any prior
instrumenta- tion or following a minimal canal preparation with a size 10
hand file.
68. De-Deus et al showed that 80% of canals with a moderate to a severe
curvature could be prepared with a Reciproc instrument without a glide path.
The Reciproc instrument was able to reach the requisite length in 67% of
the canals, in which a size 10 K-file had been previously unable to
penetrate.
In a similar situation, an attempt to create a glide path with hand files will
likely lead to procedural errors, especially with inexperienced operators .
They attributed the efficacy of the no glide path concept to the angles used
in reciprocation, and the flexibility and the cut- ting ability of the Reciproc
instruments.
Several studies have evaluated the de- gree of canal transportation,
preparation time, the occurrence of canal aberrations and the incidence of
instrument fracture associated with the Reciproc and WaveOne systems.
69. Different methodologies were used to compare the single file reciprocating
systems to instruments used in continuous rotation.
The re- sults showed that single file systems, Reciproc and WaveOne,
performed at least equally to the rotary multiple file systems
However, the manufacturers’ recommendations with regards to the use of
Recip- roc and WaveOne instruments were not followed;
all the studies were done on canals after the crea- tion of a glide path with a
size 15 file, or on canals in extracted teeth or resin blocks that had a diameter
compatible with ISO size.
Interestingly, only one study compared experi- enced and inexperienced
operators .
70. They showed that the canal preparation by inexperienced opera- tors with
Reciproc required less time compared to experienced operators using
multiple Twisted File instruments
Future studies should evaluate the shaping ability and the efficacy (ability to
reach the working length) of single reciprocation without or with a minimal
glide path in accordance with the manufacturers’ instructions.
The canal preparation of the MB2 canal in a max- illary molar is challenging
considering the com- plexity of the canal anatomy and the presence of
calcifications mainly in the coronal third of the canal.
Yared suggested the use of the R25 Reciproc instrument without a glide path
for the preparation of MB2 canals in maxillary molars. He discussed the
benefits of this approach compared to traditional techniques for the
management of the MB2 canal.
71. SINGLE FILE RECIPROCATION AND DENTINAL
DEFECTS:
The current standards require the use of instruments in a sequential
manner to shape the canal.
The use of a single file without or with a minimal glide path to completely
prepare a canal to a desired shape raised concerns about the stresses
generated and the possible formation of dentinal defects during the
preparation procedure.
Only two studies have compared the pres- ence of dentinal defects and
microcracks following canal preparation with single file reciprocation (Re-
ciproc and WaveOne), and single and multiple file continuous rotation.
72. Bürklein et al found that Reciproc and WaveOne instruments resulted in
significantly more microcracks in the apical level than multiple file rotary
systems.
However, flaws in the methodol- ogy could have affected the results. It was
not clear whether the preparation technique recommended by the
manufacturer of Reciproc was followed : “A slow in-and-out pecking
motion. The amplitude of the in-and-out movements should not exceed 3
mm.
Only very light pressure should be applied”. In the study of Bürklein et al ,
the Reciproc was used with a slow in and out pecking motion;
They did not make any reference to the amount of pressure applied or to the
amplitude of the pecking motion.
73. For example, a greater pecking amplitude in the inward direction might
increase instrument binding in the canal, which would result in the
generation of an excessive stress.
Also, the authors did not follow the recommendations of the manufacturer
regard- ing the use of the Reciproc instrument : prior to using the R40
Reciproc instrument, a hand file size 20 should go passively and directly to
the work- ing length with a gentle watch winding movement but without a
filing action.
The protocol used by the authors could have resulted in the inclusion of
canals not large enough for the safe usage of the R40 instrument.
74. Similarly, it did not appear that a size 20 hand file could reach the working
length passively prior to using the WaveOne size 40 ac- cording to the
manufacturer’s instructions .
Also, in their study, the largest rotary instruments used at working length
had a smaller taper compared to Reciproc and WaveOne.
Liu et al showed that Reciproc and the Self Ad- justing File (ReDent Nova,
Ra’anana, Israel) caused less dentinal defects compared to single and mul-
tiple file rotary instruments.
They attributed these results to the reciprocating movement considering that
more dentinal defects occurred after a rotary instrument with a smaller taper
was used to the working length. ent.
75. However, the Reciproc technique was not applied according to the
manufacturer’s instructions: the coronal third of the canals was en- larged
with a Gates Glidden drill and a glide path with a size 15 file was created
prior to using the Reciproc instruments
The larger instruments (for example, the Large WaveOne and the R50
Reciproc) should be included in these investigations.
Also, the use of finite element analysis models al- lowing the inclusion and
the control of different variables should be used to evaluate the stresses
generated with single file reciprocation under dif- ferent conditions.
76. SINGLE FILE RECIPROCATION AND APICA
EXTRUSION OF DEBRIS:
Bürklein and Schäfer demonstrated, in vitro , that multiple file rotary
systems were associated with less apical extrusion of debris compared to
single file reciprocating systems.
The manufacturers of Reciproc and WaveOne recommended that a size 20
file goes pas- sively to the working length, without any hand filing (for
Reciproc), prior to using the size 40 reciprocating instruments
In another study , apically extruded debris and irrigant was produced
equally with the R40 Reciproc instrument (size 40 and 0.06 mm/mm taper
over 3 mm from the tip) and the Mtwo full-sequence re- treatment rotary
instruments provided an adequate test apparatus was used.
77. However, they only used the R40 against the recommendations of the manu-
facturer which require using the smaller R25 Re- ciproc instrument (size 20
and 0.06 mm/mm taper over 3 mm from the tip) to the full working length
followed by the R40 and which could result in less debris extruded beyond
the apex.
Neuropeptides, inflammatory process mediators, can be released from C-type
nerve fibres present in the periapical tissues when stimulated by extruded
debris and irrigants .
A recent in vivo study has shown that the neuropeptide levels following
canal preparation with Reciproc were similar to the levels observed in a
negative control group (no canal prep- aration) and lower than the levels
expressed follow- ing the use of WaveOne
78. . The authors attributed the differences between Reciproc and WaveOne to
the instrument design. The instrument kinematics did not appear to influence
the amount of debris extruded apically
Future studies should evaluate the release of neuropeptides and other
inflammatory mediators, the incidence of flare-ups, and the incidence and
the quality of postoperative pain associated with the use of single file
reciprocation strictly as recommended by the manufacturers for initial
treatments and re- treatments.
79. SINGLE FILE RECIPROCATION AND CLEANING
ABILITY:
The results obtained from different studies were con- troversial. One study
showed that a full-sequence rotary system resulted in cleaner canals than
with WaveOne .
However, the methodology was ques- tionable because the irrigation
parameters such as volume and time of irrigation were not controlled .
The other studies showed that the main canal clean- liness was comparable
for both systems . Dietrich et al demonstrated that the SAF and K3
(SybronEndo, Orange, CA, USA) files performed significantly better than
the WaveOne with respect to isthmus cleanliness.
80. However, this difference might be related to variations in isthmus width and
length, among the teeth included in the experimen- tal groups, which cannot
be standardised
Future studies should be conducted with an ir- rigation protocol standardised
among the experi- mental groups.
Irrigation techniques such as passive ultrasonic irrigation, which is more
efficient than conventional needle irrigation, should be used for the
comparison of canal cleanliness between single file reciprocation and rotary
instrumentation.
Single file reciprocation significantly reduces the working time compared to
multiple-file rotary sys- Tems
81. A longer final irrigation/exposure to the irrigant would be possible with
single file recipro- cation compared to a full-sequence rotary instru-
mentation for a similar appointment duration and would warrant
investigating its influence on canal cleanliness.
82. SINGLE FILE RECIPROCATION AND BACTERIAL
ELIMINATION:
The simplification of the canal preparation process and the shorter
working time associated with single file reciprocation have raised
concerns about its abil- ity to disinfect the root canal space.
The antibacterial activity of the single file recip- rocation technique was
comparable with the con- ventional rotary techniques and the Self Adjust-
ing File in regular and oval shaped canals .
However, those studies were performed in vitro . Considering the
complexity and the nature of the endodontic flora, the bacterial elimination
ability of single file reciprocation should be evaluated in clinical studies.
83. SINGLE FILE RECIPROCATION AND ROOT
CANAL RE - TREATMENT
The manufacturer claimed that Reciproc instruments could be used
efficiently for root canal retreatment Procedures.
It was also stated that a solvent might not be required during the
retreatment procedures with Reciproc .
The use of a solvent led to more gutta- percha and sealer remnants on root
canal walls and inside dentinal tubules making the removal of the
obturating material more difficult and time-con- suming Zuolo et al found
that the Reciproc was more effective in removing obturation material than
the Mtwo (VDW, Munich, Germany) retreatment rotary instruments
84. A solvent was used with both systems. Reciproc was also faster than the
Mtwo retreatment Instruments despite the non-use of a solvent in the
study by Lu et al. The longer working time with the rotary retreatment
system was attributed to the time spent changing instruments
85. CONCLUSION:
The Single File System is an exciting all new concept in the preparation of the
root canal.
Normally while preparing root canal the multiple NiTi files of different
diameter and taper are used to gradually enlarge the root canal.
But with the introduction these single file system only one file is required to
prepare the canal to an adequate size and taper, even in narrow and curved
canals.
These files not only shape the canal, but decrease the working time too by
preparing the canal extremely quickly in many instances.
Further research and clinical results are required for better application of these
file systems.
86. REFERRENCES:
Ghassan Yared, Ghada Alasmar Ramli ,Single file reciprocation: A
literature review ENDO (Lond Engl) 2013;7(3):171–178
Single file endodontics: boon or myth? Parimoo D, Gupta R, Tomer A,
Rohilla S* Asian Pac. J. Health Sci., 2016; 3 (2):102-105
Single file niti-rotary systems Kumar SR1, Gade V2 IJMDS ●
www.ijmds.org ● January 2015; 4(1)
Entering A New Era in Endodontics with Revolutionary Single File
Systems: A Comprehensive Review Paritosh Sharma*, Munish Goel,
Shweta Verma, Gurmeet S Sachdeva, Neeraj Sharma and Vijay Kumar
EC Dental Science 5.3 (2016): 1100-1122.
