Reciprocation in Endodontics

1. P R E S E N T E D B Y
D r . H a t e e m S h a r i e f
RECIPROCATION IN
ENDODONTICS

2. CONTENTS
• Introduction
• Definition
• History
• Types of RM for endodontic instrumentation
• Types of Reciprocating Hand Pieces
• Types of Reciprocating File Systems
• Mechanical properties of Reciprocating Files
• Conclusion
• References

3. INTRODUCTION
• The armamentarium of endodontics has grown in
complexity over the past 40 years.
• The rotary files have been subjected to constant
evolution in the form of metallurgy, design features, and
the manner in which these instruments are driven
(rotary/reciprocation)

4. Enhanced ability to collect and
remove debris from the canal
system
CCW rotation will convey
debris in coronal direction from
the canal ramifications and AF.
Reduction in the time required
for instrumenting the canal.
Produces greater taper in canal
preparation.
Conventional NiTi instruments
in rotary movement are
subjected to structural fatigue
that if continued will lead to
fracture.
Increased canal preparation
and increased microcrack.
Rotary instrumentation has the
following advantages & disavantages
over hand instrumentation:
Gourav K S et al, Rotary Endodontics or Reciprocating Endodontics:
Which is New and Which is True? 1O.5005/jp-journals-10042-1035

5. Advantages of reciprocation
• Binding of the instruments into the root canal dentin
walls is less frequent, reducing torsional stress.
• The reduction in the number of cycles within the root
canal during preparation results in less flexural stress on
the instrument.
• There is decreased risk of instrument fracture.
Gourav K S et al, Rotary Endodontics or Reciprocating Endodontics:
Which is New and Which is True? 1O.5005/jp-journals-10042-1035

6. • According to CJ Ruddle a mechanical reciprocating
movement has merit because it somewhat mimics
manual movement and reduces the various risks
associated with continuously rotating a file through canal
curvatures.
Ruddle CJ. Endodontic canal preparation rotation vs
reciprocation. Endod Pract 2012 Jan;5(1):56.

7. DEFINITION
It is defined as any repetitive back and forth motion
that has been clinically utilized
- Ruddle CJ

8. HISTORY
Early Era of Mechanical Instrumentation
• Mechanical instrumentation of the root canal space has
been an early objective of endodontic science, beginning
in the 19th century when pioneers were trying to develop
endodontic mechanical instruments.
• In 1912, Kerr Company had in its catalogue ‘‘K’’-style
rotary ‘‘broaches’’ made of carbon steel to be activated
by treadle-type, foot-powered handpieces.

9. • The first endodontic motor in the market, introduced
around 1925, can be considered the Endocursor (W&H,
Burmoos, Austria), which allowed the use of
conventional K or Reamer SS files with a complete 360
rotating motion combined with vertical strokes
• Reciprocation was first introduced in the late 1950s by
the French dentist, Blanc.

10. There are many variations of RM, including:
 Complete reciprocation (oscillation)
 Partial reciprocation (rotational effect)
 Hybrid reciprocation (combined movements)
Hybrid reciprocation can be fixed or flexible — i.e., it can shift from
one type of reciprocation to the other in the canal based on
mechanical resistance and torque.
Nicola MG et al. The
reciprocating movement
in endodontics.
FEBRUARY 2016
ENDODONTIC
PRACTICE

11. • Different types of RM for endodontic instrumentation:
Complete reciprocation with vertical
oscillations
• Racer
• Self-Adjusting File
Complete reciprocation with horizontal
rotational oscillations
• Giromatic
• Intra-Endo 3 LD
• Dynatrak system
• M4 Safety Handpiece
• Endo-Gripper
• NSK TEP-E10 R,
• Endo-Eze AET system,
• Tilos system, and
• Endo-Express SafeSider

12. Complete reciprocation with combined
oscillations
• Canal Finder System
• Excalibur
• Canal-Leader 2000
• Endolift
• Endoplaner
• EndoPulse system
Partial reciprocation with rotational effect
• ATR Teknica
• WaveOne
• WaveOne Gold
• Reciproc

13. Hybrid reciprocation
• TF Adaptive/Elements motor
Nicola Maria Grande, et al. Current Assessment of Reciprocation in
Endodontic Preparation: A Comprehensive Review—Part I: Historic
Perspectives and Current Applications. J Endod 2015;41:1778–83.

14. There are 3 critical distinctions with unequal bidirectional movement.
CCW engaging
angle has been
designed to be
smaller than the
elastic metallurgical
limit of the file.
This system utilizes an engaging
angle that is 5 times the
disengaging angle. After three
engaging/ disengaging cutting
cycles, the 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
compared to an
equal bidirectional
movement, an
unequal
bidirectional
movement
strategically
enhances auguring
debris out of the
canal
1. Yared, G: Canal preparation using only one NiTi rotary instrument: preliminary
observations, Int Endod J 41:4, pp. 339-344, 2008.
2. De-Deus G, et al.: Assessment of apically extruded debris produced by the
single-file ProTaper F2 technique under reciprocating movement, Oral Surg Oral
Med Oral Pathol Radiol Endod 110:3, pp. 390-394, 2010.

15. • Types of Reciprocating Hand Pieces
1. Giromatic
2. Endocursor
3. M4 safety handpiece
4. Endogripper

16. Giromatic
(MicroMega)
1964.
Performs reciprocation 90CW/ 90CCW,
Speed at 3,000 rpm.
Accepts - latch type instruments.
It was able to negotiate narrow canals and retain
original shape during the enlargement process up
to a size 25.

17. M4 Safety Hand
piece
It is marketed by sybron-Kerr.
It has a 4:1 gear ratio
It has a chuck that locks regular hand files in
place by their handles.
safety Hedstrom files are recommended.
It has a 30 degree reciprocating motion.

18. Endo-Gripper
10:1 gear ratio
45° turning motion.
Uses regular hand files.
Flex-R and Onyx R
files.

19. 4:1gear ratio.
Has a “Press Button type chuck”
Spring chuck holds standard hand instruments
Produces Oscillating file movements.
Uses reciprocating movement of 60°.
ENDOCURSOR
LT version -
Large optic outlet - provides illumination,
Small head - ensures optimum visibility in
molar area.

20. TYPES RECIPROCATING
FILE SYSTEMS

21. Peregrination of endodontic tools-past to present. 2016

22. ENDO-EZE RECIPROCATING
FILES
• Recently introduced
addition for Giromatic
handpieces

24. Endo Express and Safe Sider
• 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.
• Flat-side of the SafeSider: Act as chisels in the clockwise
and counter clock-wise motion allow to remove debris
easily.

25. WAVEONE RECIPROCATING FILE
SYSTEM (DENTSPLY)
• Triangular cross section
• small, medium, and large
diameter canals,
• (lengths 21,25 and 31mm)
• M-Wire -provide - flexibility
and greater resistance to
cyclic fatigue.

27. WAVEONE GOLD
Product Features
• Single-file and single-use concept
• Reverse helix; semi-active and
modified guiding tip
• Offset parallelogram-shaped cross-
section, limiting the engagement zone
• New supermetal technology termed
Gold-wire
• Unique, unequal bidirectional
reciprocation movement

28. RECIPROC (VDW)
One complete rotation of 360° is completed in several
reciprocating movements.
The angle in the cutting direction is greater than the angle
in the reverse direction, so that the instrument continuously
progresses towards the apex.
INSTRUMENT DESIGN:
set of 3 instruments:
•R25 - diameter of 0.25 mm - .08.
•R40 diameter of 0.40 mm - .06.
•R50 diameter of 0.50 mm - .05.

29. Self Adjusting File(SAF)
• Hollow file designed as a
compressible, thin-walled
pointed cylinder either 1.5
or 2.0 mm in diameter
composed of 120um thick
nickel-titanium lattice.
• The surface of the lattice
threads is lightly abrasive
which allows it to remove
dentin with a back-and-
forth grinding motion.

30. Continuous irrigation
The irrigant is carried with the file to the apical region
and is exchanged several times during the treatment
while being agitated by the SAF’s sonic vibration.
This effectively provides zero-pressure irrigation and
eliminates the risk of irrigant extrusion beyond the apex.

31. TF ADAPTIVE (SYBRON ENDO)
"Rotary when you want it, Reciprocation
when you need it“

32. 23 mm

33. R – PILOT (VDW)
• The first motor driven glide path instrument in
reciprocating motion

34. • WaveOne® Gold Glider

35. MECHANICAL PROPERTIES
OF RECIPROCATING FILES

36. CYCLIC FATIGUE RESISTANCE
• Reciprocating motion provided greater
resistance to cyclic fatigue than continuous
rotation.
• Cyclic fatigue of rotary instruments are
influenced by several factors, such as
rotational speed, angle of curvature of the
root canal, torque, instrument design, alloy,
and type of kinematics used.

41. • From these studies, it could be concluded that
kinematics had an influence on cyclic fatigue and that
reciprocating motion had better resistance to cyclic
fatigue than its counterpart.

42. TORSIONAL RESISTANCE
• In terms of maximum torsional load, both Reciproc and
WaveOne showed significantly higher torsional
resistance than ProTaper.
• WaveOne had a higher torsional resistance than
Reciproc and OneShape.
•
1. Kim HC, Kwak SW, Cheung GS, et al. Cyclic fatigue and torsional
resistance of two new nickel-titanium instruments used in reciprocation
motion: Reciproc versus WaveOne. J Endod 2012;38:541–4.
2. Elnaghy AM, Elsaka SE. Torsion and bending properties of
OneShape and WaveOne instruments. J Endod 2014;41:544–7.

43. CLEANING EFFECTIVENESS
• Studies have shown that thorough cleanliness is often
not attained, especially in the apical third.
• The shaped canal may still contain bacteria and debris
after mechanical shaping.

44. • In microCT analysis –
• WaveOne usage led to more debris accumulation than
ProTaper, especially in the isthmuses
• When comparing volume of debris generated after
different apical enlargement with RFs or rotary files, it
showed that all canals contained packed debris with no
significant difference between the systems.
Robinson JP, et al. Reciprocating root canal technique induces greater
debris accumulation than a continuous rotary technique as assessed by 3-
dimensional micro-computed tomography. J Endod 2013;39:1067–70.
De-Deus G, Marins J, Silva EJ, et al. Accumulated hard tissue debris
produced during reciprocating and rotary nickel-titanium canal
preparation. J Endod 2015;41:676–81.

45. B€URKLEIN S, ET AL. SHAPING ABILITY AND CLEANING
EFFECTIVENESS OF TWO SINGLE-FILE SYSTEMS IN SEVERELY
CURVED ROOT CANALS OF EXTRACTED TEETH: RECIPROC
AND WAVEONE VERSUS MTWO AND PROTAPER. INT ENDOD
J 2012;45: 449–61
• Amount of debris and SL remaining after RCP with
rsfs (reciproc or waveone) or RF (mtwo or protaper).
• Mtwo and Reciproc led to better debris removal in the
apical third than WaveOne and Protaper.
• These results suggested that the file design was more
decisive than the number of instruments used and their
kinematics.
• Remaining SL revealed that there was no significant
difference between different systems.
• Amaral P et al. also showed similar findings in another
study.

46. SHAPING ABILITY
• in vitro study using simulated resin canals showed more
canal transportation with continuous rotation than with
reciprocating motion.
• However, in ex vivo studies using extracted natural teeth,
the results were not consistent.
• The reason for the difference between in vitro studies
and ex vivo studies may lie in the fact that resin blocks
could not represent the anatomic variability of the root
canal system.

47. • Root canals of extracted human teeth have more
irregularities compared with irregularities of the resin
blocks.
• Because continuous rotating instruments use files in a
gradual sequence whereas reciprocating motion
instruments use only 1 file to prepare a canal,
continuous rotating instruments may show better
centering ability than reciprocating motion instruments in
ex vivo studies

50. • According to the study of Wu et al, apical transportation
greater than 300 mm could negatively affect the sealing
of the obturation. Comparing the results, all 19 studies
reviewed reported that the transportation value was less
than this limit.
• Both reciprocating and continuous rotating motion would
be used in the clinic without any significant difference in
shaping ability and transportation tendency.

51. CUTTING EFFICIENCY
• Capability of a file to efficiently remove dentin depends
on
• number of flutes
• cross-sectional area design
• Sterilization
• chip removal capacity
• helical and rake angle
• tip design
• metallurgical properties, and
• surface treatment of the files
Plotino G, Giansiracusa Rubini A, Grande NM, et al. Cutting efficiency of
Reciproc and waveOne reciprocating instruments. J Endod 2014;40:1228–
30.

52. • No significant difference in cutting ability of Reciproc and
Twisted File, thus showing that this movement does not
reduce the cutting ability of these files.
• Reciproc and TF Adaptive showed a significantly higher
cutting efficiency than WaveOne.
Giansiracusa Rubini A, Plotino G, Al-Sudani D, et al. A new device to
test cutting efficiency of mechanical endodontic instruments. Med Sci
Monit 2014;20:374–8.
Plotino G, Giansiracusa Rubini A, Grande NM, et al. Cutting
efficiency of Reciproc and waveOne reciprocating instruments. J
Endod 2014;40:1228–30.

53. APICAL DEBRIS EXTRUSION
• Apically extruded debris generated by canal preparation
contains dentin, necrotic pulp tissue, and bacteria.
• The debris is the main cause of periodontal ligament
inflammation.
• According to the articles reviewed, it is controversial if
the reciprocating movement produces more apical debris
extrusion than the continuous rotation.

56. • In particular, in vivo studies would be valuable because
the absence of periapical tissues in in vitro studies may
have limited clinical implications.
• Periapical tissues may serve as a natural barrier
providing a physical back pressure, thereby limiting the
apical extrusion of debris and irrigants.

57. DENTINAL DEFECTS OR CRACKS
• The contact between the instruments and canal wall
creates momentary stress concentrations in dentin.
• Such stress concentrations may leave dentinal defects,
which can result in vertical root fracture.

58. • The reciprocating motion was reported to reduce the
torsional stress by periodically reversing the direction of
rotation of the instrument.
• This may help to reduce the magnitude of the forces
generated on the root dentin and prevent root cracks and
fractures.

61. • It is still controversial which motion is better concerning
dentinal defects or cracks.
• The risk of dentinal defects was reported to be related to
the cross section, size, taper, method of manufacturing,
and materials or alloys used in instruments along with
the preparation technique.
• A few studies discussed that the nature of the
manufacturing material of instruments has more
influence than the motion of the instrument in dentinal
defect or crack formation.

62. • Clinically, the reported failure rate of endodontic
treatment because of vertical root fracture is low.
• Furthermore, vertical root fractures may be a result of
following factors:
• physical traumatic injury
• occlusal loading
• parafunctional habit
• resorption-induced pathological root fractures
• root canal obturation procedures
• post space preparation

63. SHAPING TIME
• Reducing the shaping time (ST) allows clinicians to
spend more time refreshing NaOCl using activation
techniques to enhance its cleaning and disinfection.
• Several studies have reported that using RSFs reduced
the ST compared with CRF.

64. • Paque et al : Shaping outcomes with the single-file F2
ProTaper and conventional ProTaper were similar.
However, the single-file F2 ProTaper was markedly
faster in reaching the WL.
• Burklein et al : All instruments respected the original
canal curvature. The use of Reciproc and OneShape
required less time compared with Mtwo and F360.
Paque F, Zehnder M, De-Deus G. Microtomography-based comparison of
reciprocating single-file F2 ProTaper technique versus rotary full sequence.
J Endod 2011; 37:1394–7.
B€urklein S, Benten S, Sch€afer E. Shaping ability of different single-file
systems in severely curved root canals of extracted teeth. Int Endod J
2013;46:590–7.

65. • Goldberg et al (63) 2012 WaveOne had excellent
centering ability with a low risk of fracture/blockage and
a short shaping time regardless of the operator’s
experience.
• One study did not detect significant differences between
Reciproc and Mtwo used in RM and CR in ST,
suggesting that kinematics did not influence the latter.
Goldberg M, Dahan S, Machtou P. Centering ability and influence of
experience when using WaveOne single-file technique in simulated
canals. Int J Dent 2012; 2012:206321.
Hwang YH, Bae KS, Baek SH, et al. Shaping ability of the conventional
nickeltitanium and reciprocating nickel-titanium file systems: a comparative
study using micro-computed tomography. J Endod 2014;40:1186–9.

66. It is difficult to distinguish the respective influence of
different parameters, including kinematics, file design, and
the number of instruments on the ST.

67. Foraminal enlargement
• when the root canal is instrumented beyond the major
foramen, the enlargement achieved might improve
bacterial removal and enhance irrigation.
• Some studies have related root canal instrumentation
beyond the major foramen to microcrack creation, sealer
extrusion, and foraminal deformation

68. • According to a study by Silva et al. root canal
instrumentation at the apex or 1 mm beyond the apex
promoted deformation of the major foramen regardless
of the kinematics.
Silva Santos AM et al. Foraminal Deformation after Foraminal
Enlargement with Rotary and Reciprocating Kinematics: A Scanning
Electronic Microscopy Study.

69. Bacterial Reduction
• Disinfection of the RCS is of utmost importance in
endodontic therapy.
• Investigators compared the bacterial reduction in oval-
shaped RCs using Reciproc R40 and BioRaCe under the
same irrigation protocol, and they found that both
systems were comparable, yielding significant bacterial
reduction.
Alves FR, Rocas IN, Almeida BM, et al. Quantitative molecular and
culture analyses of bacterial elimination in oval-shaped root canals by a
single-file instrumentation technique. Int Endod J 2012;45:871–7.

70. • Machado ME et al. reported significant count reductions
of Enterococcus faecalis when WaveOne and Reciproc
were used.
• Similar observations have also been reported by
Nabeshima CK et al.
1. Machado ME, Nabeshima CK, Leonardo MF, et al. Influence of
reciprocating single file and rotary instrumentation on bacterial reduction
on infected root canals. Int Endod J 2013;46:1083–7.
2. Nabeshima CK, Caballero-Flores H, Cai S, et al. Bacterial removal
promoted by 2 single-file systems: Wave One and One Shape. J Endod
2014;40:1995–8.

71. • Another study evaluated the ability of Reciproc R25,
SAF, and TF systems to reduce bacterial counts
confirmed the ability of all systems to promote significant
bacterial reduction.
• A clinical study showed that both RFs and CRFSs
showed similar effectiveness in reducing endotoxins and
cultivable bacteria.
Siqueira JF Jr, et al. Correlative bacteriologic and microcomputed
tomographic analysis of mandibular molar mesial canals prepared by self-
adjusting file, reciproc, and twisted file systems. J Endod 2013;39:1044–50.
Martinho FC, Gomes AP, Fernandes AM, et al. Clinical comparison of the
effectiveness of single-file reciprocating systems and rotary systems for
removal of endotoxins and cultivable bacteria from primarily infected root
canals. J Endod 2014;40:625–9.

72. • Based on these results, it can be stated that the
mechanical action of endodontic files on dentin together
with adequate exposure to NaOCl irrigation is more
effective for disinfection than the kinematics of files.

73. Removal of root canal fillings
• The proper removal of RCFMs from inadequately
prepared and filled RCs requires a substantial effort and
can be challenging and time-consuming.
• According to some studies application of RFs is as
effective as CRFs yet no one system is able to effectively
remove RCFM completely from the RCS.
1. Helvacioglu-Yigit D, et al. Efficacy of reciprocating and rotary systems for
removing root filling material: a micro-computed tomography study.
Scanning 2014;36:576–81.
2. R€odig T1, et al. Efficacy of reciprocating and rotary NiTi instruments for
retreatment of curved root canals assessed by micro-CT. Int Endod J
2014;47:942–8.

74. • One study showed that ProTaper used with adaptive
motion enhanced the removal of RCFMs from the RCS
compared with CR.
• This might be attributed to the synergistic effect of both CR and
RM
C¸apar ID, Arslan H, Ertas H, et al. Effectiveness of ProTaper Universal
retreatment instruments used with rotary or reciprocating adaptive motion in
the removal of root canal filling material. Int Endod J 2015;48:79–83.

75. CONCLUSION
The conclusions from the literature can be summarized as
follows
• Reciprocation extends the lifespan of all types of files tested.
• The amplitude of reciprocation has a significant influence on
the cyclic fatigue life of the files tested.
• Reciprocation does not reduce the cutting efficiency of the
files tested.
• Reciprocating and rotary motion have similar cutting
efficiency.
• Reciprocating files shape canals well and preserve the
original canal anatomy.

76. • The cleaning effectiveness of reciprocating files is
comparable to full rotary file sequence systems.
• Reciprocating single file usage reduces the shaping time
compared to a full sequence rotary system.
• Dentin microcracks occur independently of the type of
file and its kinematics.
• The results of published studies show that the use of
reciprocating files would lead to fewer or an equivalent
amount of dentin microcracks compared with full
sequence rotary systems.

77. • RFs can promote significant bacterial reduction, but like
rotary full sequence systems, they are not able to
completely disinfect the RCS.
• The ability of RFs to extrude less debris than rotary files
remains a matter of debate.
• Reciprocating files are effective in removing root canal
filling material in less time as compared to rotary files,
yet no system is able to remove the filling material
completely from the RCS.

78. REFRENCES
• Kinematic Effects of Nickel-Titanium Instruments with Reciprocating or
Continuous Rotation Motion: A Systematic Review of In Vitro Studies
So-Yeon Ahn, DDS, Hyeon-Cheol Kim, DDS, MSD, PhD, and Euiseong
Kim, DDS MSD, PhD J Endod 2016;july :1-9
• Gourav K S et al, Rotary Endodontics or Reciprocating Endodontics: Which
is New and Which is True? 1O.5005/jp-journals-10042-1035
• Ruddle CJ. Endodontic canal preparation rotation vs reciprocation. Endod
Pract 2012 Jan;5(1):56.
• Nicola MG et al. The reciprocating movement in endodontics. FEBRUARY
2016 ENDODONTIC PRACTICE
• Nicola Maria Grande, et al. Current Assessment of Reciprocation in
Endodontic Preparation: A Comprehensive Review—Part I: Historic
Perspectives and Current Applications. J Endod 2015;41:1778–83.

79. • Yared, G: Canal preparation using only one NiTi rotary instrument:
preliminary observations, Int Endod J 41:4, pp. 339-344, 2008.
• De-Deus G, et al.: Assessment of apically extruded debris produced by the
single-file ProTaper F2 technique under reciprocating movement, Oral Surg
Oral Med Oral Pathol Radiol Endod 110:3, pp. 390-394, 2010.
• Kim HC, Kwak SW, Cheung GS, et al. Cyclic fatigue and torsional
resistance of two new nickel-titanium instruments used in reciprocation
motion: Reciproc versus WaveOne. J Endod 2012;38:541–4.
• Elnaghy AM, Elsaka SE. Torsion and bending properties of OneShape and
WaveOne instruments. J Endod 2014;41:544–7.