Rotary endodontics in pediatric dentistry

2. ROTARY ENDODONTICS
IN PRIMARY TEETH
Dr Sarita Das
2nd year PGT

3. INTRODUCTION
In pediatric dentistry, premature loss of necrotic primary molars
has been a matter of great concern over the years.
In modern pedodontic practice, pulpectomy of such teeth is
treatment of choice over extraction.
Success of a pulpectomy procedure mainly depends upon the
biomechanical preparation of the root canal systems.

4. Manual instrumentation for root canal preparation is widely
used in primary teeth, with limitations regarding patient
cooperation and time consumption.
Therefore, practitioners are exploring the benefits of rotary
endodontics in modern-day practice

5. • Rotary instrumentation has made a quantum leap in the
field of endodontics.
• These changes lead to the introduction of rotary
endodontics in pediatric dentistry.
• However, the bizarre root canal morphology and thinner
root dentin limited the use of rotary endodontics in
primary teeth.
• To overcome such barriers, various modified protocols have
been introduced to prevent any undesirable complications

6. HISTORY
• 1800- First endodontic instrument Barbed Broach by
Edward Maynard
• 1852- Arthur recommended use of small files for cleaning
and shaping
• 1885- Gates Glidden drill were introduced

7. • 1889- William H Rollins developed first endodontic
handpiece for automated root canal preparation
• 1892- Oltramare- fine needles with rectangular cross
section mounted in dental handpiece
• 1915- k files

8. • 1928- Cursor filing contra-angle by Austrian company W&H
• 1958- Racer handpiece, popular in Europe
• 1962- Nickel Titanium discovered by William Beuhler &
Frederick Wang
• 1964- Giromatic (Micro-Mega, Besanc, France)

9. Material Science
Materials for manufacture of endodontic
instruments
Carbon steel Stainless steel
Nickel
Titanium alloy

10. Carbon steel
• Rigidity increases with increase in size
• Less resistant to breakage by bending or twisting
• Low cost
• Instruments easily corroded

11. Stainless steel
• Greater flexibility than carbon steel
• Greater resistant to fracture by twisting
• Less sharper than carbon steel
• Resistant to corrosion

12. Nickel Titanium Alloy
• Group of inter metallic alloys contain nickel and titanium
• Discovered by Buehler 1962 in the space program of naval
ordnance laboratory, maryland
• Introduced into dentistry by Anderson in 1972
• Nickel 56% titanium 46%
Advantage :
Shape memory & Super elastic

16. Advances in Nickel Titanium
Metallurgy

17. M wire NiTi: By Dentsply Tulsa Dental Specalities, USA
in 2007
• Contains all 3 crystalline phases: deformed & microtwinned
martensite, R phase and austenite
• Advantage: Greater flexibility and increased resistant to
cyclic fatigue as compared to traditional NiTi

18. R- Phase NiTi: By SybronEndo, USA
• R phase is an intermediate transition between austenite
and martensite
• Twisting of NiTi wire is only possible in R phase
• Advantage: Files have reduced stiffness & more fracture
resistant compared to standard NiTi files
Controlled Memory (CM) NiTi:
• Nickel 52%
• Files have superior cyclic fatigue resistant and increased
torque strength over traditional NiTi files

19. MAX wire
• Martensite-Austeniteelectropolish-fleX
• High flixibility and incredible fatigue resistant

20. Why Rotary??
Enhance ability to collect and remove
debris from canal system
Better control for maintaining the central
axis of the canal, reducing incidence of
ledging and perforation
Reduction in time requirement for canal
instrumentation

21. Components of a file

22. Design of Tip
The cutting instrument can have a
cutting or non-cutting tip.
Rotary files with cutting tips are more
aggressive than non-cutting tips.
A non-cutting tip will create a
concentric circle at the end of the
root that can be obturated easily.

23. Taper
The taper usually is expressed as the amount the
file diameter increases each millimeter along its
working surface from the tip towards the file
handle.
In past hand instruments were tapered at
constant 2% upto 16mm. New rotary files
incorporate a wide variation of constant or
variable tapers at different lengths of working
surface

24. Fixed: they increase at a standardized, consistent rate from the
tip of the file up to end of the flute. Fixed taper range from 0.02
to 0.12mm
Variable : within a single instrument taper varies, starting at
specific taper and altering tapers as it travels the shank so as to
improve cutting efficacy
Progressive taper instruments shape canal more quickly than
constant taper instruments.

26. Flute
• Fluting is a specific surface with a certain configuration,
which is created on the working part to impart the cutting
ability to the instrument
• In general the fluting is formed by grinding out a groove of
specific profile onto cylindrical or conical NiTi blank with
appropriate diameter.
• As a result of grinding process, adjoining flutes form cutting
blade.

27. • Flute is characterized by following parameters
1.Helical angle
2. Pitch
3. Flute depth
4. Configuration of fluting

29. Pitch

30. Helical angle
Variable helical angle
• Aid to move debris up and
out of the canal
Constant helical angle
• More prone to debris
accumulation
• Lead to need for increased
torque and instrument
separation
Angle between cutting edge
and long axis of the file

31. Rake Angle
• Rake angles affect the cutting efficiency of the instrument
• The rake angle is the angle formed by the cutting edge and
a cross section taken perpendicular to the long axis of the
instrument.
• 3 types: positive, neutral/zero/radial, negative depending
on whether radial line is ahead, over-lying or trailing the
face of the blade respectively

32. • The cutting efficiency of the positive rake angle is better
than neutral & negative rake angles
Positive (+) Cutting
Negative (-) Scraping
Neutral Planing

33. Radial Land
• A radial land is a surface that projects axially from the
central axis, between flutes, as far as the cutting edge, this
surface is called the land
• Located directly behind cutting edge

34. • Lack of this area allows instrument to be sharper &
consequently more efficient but it will result in decreased
thickness of metal
• Result of less metal is increase in flexibility
• But radial land improves irrigation flow apically and
movement of debris coronally, reduces canal
transportation, supports the cutting edge.

35. ROTARY SYSTEMS

38. Rotary systems in Pediatric
Dentistry
The use of NiTi rotary
files in primary teeth
root canals was first
described by Barr et al.
in 2000.
Since then various NiTi
rotary systems with a
modified technique have
found its use in
Paediatric Dentistry
Barr ES, Kleier DJ, Barr NV. Use of nickel-titanium rotary files for root canal
preparation in primary teeth. Pediatr Dent. 2000 Jan-Feb;22(1):77-8. PMID:
10730297.

39. Many authors have reported the clinical success of Profile,
ProTaper, Mtwo, FlexMaster, Light Speed LSX, Hero 642, K3, and
WaveOne rotary files in primary teeth.
Most recently, Kedo-S (the first rotary Pedodontic file) has
made a major breakthrough in the field of pediatric
endodontics

40. ProFile 0.04 (Dentsply Maillefer)
• It has a triple U-shaped cross-sectional design with flat
radial lands, a non-cutting tip, and constant taper with a 20°
helical angle and constant pitch.
• According to Barr et al. and Crespo et al. the pulpectomy
procedure began with a standard access and removal of
coronal tissue.
• A NiTi ProFile 0.04 was chosen that approximates the canal
size.

41. • It was inserted into the canal while rotating at a slow speed
of 150–300 rpm till the calculated working length, as
determined by pretreatment radiography.
• The canals were cleansed and shaped with sequentially
larger files until the last file.
• It was suggested that frequent inspection of each file for
flute unwinding or distortion was important, and the file
may be discarded after use on 5 primary teeth.

42. First rotary Ni-Ti
Developed in 1994
Blunt non cutting tip
Used at high torque of 150–300
rpm
Disadvantage of high fracture
incidence

43. ProTaper (Dentsply Maillefer,
Ballaigues, Switzerland)
• These instruments were designed by Dr. Cliff Ruddle, Dr.
John West, and Dr. Pierre Machtou
• It has a convex triangular-shaped cross-sectional design
with sharp cutting edges and no radial lands, non-cutting
tip, and variable taper with balanced helical angle and pitch
to prevent “screwing in” effect
• The ProTaper system is based on a unique concept and
comprises just six instruments, three shaping files and
three finishing files

45. • Kuo et al. 2006 used Sx file of ProTaper NiTi rotary system for
instrumentation to about 3 mm beyond the root canal orifice
with a slight buccolingual brushing motion to gain a straight
line access.
• The S2 file was then inserted into the canal while rotating till
the calculated working length.
• If a point of resistance was encountered, no attempt was
made to go beyond, so as to avoid the risk of instrument
separation.
• It was concluded that lateral perforation can be avoided by
using only SX and S2 files. As the gradual taper of SX files can
selectively remove the dentin in a safe way.
• S1 and F series were not used as the increased taper and tip
size resulted in excessive apical dentin removal

46. Azar et al. 2012 modified the sequence
of the three ProTaper instruments
slightly to prepare the canals.
Root canals were cleaned in a crown down method
with three instruments in the sequence from S1 in
the coronal third of the root canal, S2 in the middle
third, and F1 till the working length.

47. Pinheiro et al. 2012 prepared the root canal
with ProTaper using a handpiece with an
electric motor X-Smart.
At a speed of 300 rpm and torque of 3 N/cm,
S1 and S2 ProTaper files were used for
shaping the primary molar root canals.
For F1 and F2, 2 N/cm torque with a speed
of 300 rpm was used with an anticurvature
filing method for finishing the canals.

48. Advantages
• Reduces friction, increases the cutting efficiency, lowers
the risk of instrument separation, replaces Gates-Glidden
drills, selective removal of dentin.
Disadvantages
• Cannot be used twice in same root and unexpected lateral
perforation.

49. M two (VDW, Munich, Germany)
• It is a new generation of NiTi rotary instruments with an
“italic S” cross-section with two cutting blades, noncutting
tip, fixed taper, and variable pitch.
• Azar et al. 2011 used four 21-mm Mtwo instruments
(10/0.04, 15/0.05, 20/0.06, and 25/0.06) in a crown down
technique with a maximum speed of 280 rpm till the
working length in primary teeth.

51. Advantages
• Increased instrument stability, efficient dentine removal,
excellent lateral cutting ability, automatic upwards
transport of debris, no screw-in effect, short working time,
efficient preparation and no unnecessary loss of tooth
substance.
Disadvantages
• High deformation rate, instrument fractures, and high cost

52. Flex-Master (VDW, Munich,
Germany)
These NiTi rotary files have a convex triangular-shaped cross-
sectional design with sharp cutting edges and no radial lands,
non-cutting tip, fixed taper, and individual helical angles to
prevent “screwing in” effect

53. FlexMaster Instruments
• Working length 21, 25, 31 mm and working part 16
mm
• Taper .02, .04, .06
– .04 and .06 used for crown-down phase
– .02 for safe apical enlargement
FlexMaster Intro File
For conical enlargement of the root canal orifice.
• 11 % taper
• 19 mm working length, 9 mm active working part
• ISO size 22 at the tip

55. Bahrololoomi et al. 2007 used 25 mm-long Flexmaster
rotary files with a modified crown down technique with
35/0.06, 35/0.04, 30/0.06 and 40/0.02 tapers for
instrumentation.
Shaping was completed with a gentle
advance and withdrawal motion.
Instruments were removed when
resistance was felt and changed for the
next instrument.

56. • Moghaddam et al. 2009 enlarged the root canal orifices
with the orifice shaper “Introfile” of Flex-Master file system
until the root canal middle third was reached.
• Crown down preparation was performed with a 64:1 speed
gear reduction handpiece.
• At first, 25/0.04 rotary file was used until resistance was
felt followed by 25/0.02 rotary file till working length

57. Makarem et al. 2014 conducted a randomized controlled
clinical trial (hand instrument & flex master) in the pulpectomy
of primary second molar teeth and achieved superior
radiographic findings and less chair time with Flex-Master
system.

58. Advantages
• Superior radiographic findings, less chair time, occasional
instrument fracture, safe, less canal transportation and
fewer canal aberrations, prepare curved canals rapidly, and
with minimal transportation

60. Dr. Sarita Das
2nd Year PGT
ROTARY ENDODONTICS
IN PRIMARY TEETH

63. Many authors have reported the clinical success of Profile,
ProTaper, Mtwo, FlexMaster, Light Speed LSX, Hero 642, K3, and
WaveOne rotary files in primary teeth.
Most recently, Kedo-S (the first rotary Pedodontic file) has
made a major breakthrough in the field of pediatric
endodontics

64. Light Speed (SybronEndo)
• It has a triple U-shaped cross-sectional geometry with
radial lands, a short cutting head and a long, noncutting,
taperless shaft

65. The existing range covers sizes from 20-
160. This enables optimal preparation of
the root canal at the apex.
The constant optimal speed is within the
range between 750-2500 rpm and is thus
considerably higher than for all other
rotating NiTi instruments.

66. The instrument tip consists of
a Batt tip
As instrument size increases,
the working length becomes
longer and the pitch of the
Batt tip smaller

67. For Protaper, the root canals were instrumented with SX orifice opener
rotary file for widening the orifice and then with S1–F2 till the full working
length.
The rotary Light Speed LSX instruments were used in the canal preparation
to a size 50 for anteriors and to a size 40 for molars.
Vieyra et al. 2014 instrumented the root canals with rotary Light Speed LSX
instruments and ProTaper.

68. • Appeared like Gates
Glidden drill
• Used in beginning of 1990
• Low torque handpiece at
1500 rpm
• Disadvantage is too many
instruments in sequence

69. Hero (Micro-Mega, Besancon,
France)
The Hero instruments are an example of a
second-generation rotary system.
The first rotary NiTi instrument designed
without radial lands
Three essential rules must be followed when using the
HERO
•The difficulty of the case, including consideration of
the canal curvature, and degree of dentine
mineralization
•The correct levels of penetration for each taper must
be respected
•Circumferential shaping of the canal is achieved using
a brushing motion.

70. Taper Available Sizes Available Lengths (mm)
2% 20, 25, 30 21, 25
4% 20, 25, 30, 35, 40, 45 21, 25, 29
6% 20, 25, 30 21, 25

71. The technique of using HERO Shaper in Primary
Teeth
Preparation is performed with 21 mm nickel-titanium instruments with 2 and
4% tapers using the crown down technique.
The working length can be re-evaluated once the coronal two-thirds has been
prepared.
The first penetration with a #10 K-file coupled to an electronic apex locator
will confirm the first evaluation.
A pre-operative radiograph is used to estimate the working length.
The canal orifice must be opened and preferably enlarged.
The canal orifice must be located and an access cavity prepared by removing
all coronal interferences.

72. It may not be necessary to use the 0.04 instruments in that scenario
However, if the canal is large or its curve is moderate, it can allow a 0.06
instrument to penetrate to the apex.
The waves should not exceed the penetration levels of the files, i.e., 0.06 at
2/3 WL and 0.04 at WL.
The rotation speed must be kept constant and not exceed 600 r.p.m.

73. Advantages
• Limited numbers of files are required, simpler, short
operating time, remove interferences, facilitate treatment
more efficiently, uniform dentine removal and symmetrical
canal shapes.
Disadvantages
• Risk of breakage must be taken into consideration; no
pressure should be applied on the head of the handpiece,
use at constant rotational speed and high cost

74. K3 (SybronEndo, Orange, California)
Introduced initially in North America in January 2002
The K3 system was designed by Dr. John McSpadden
(Lookout Mountain, Georgia)
It has an asymmetrical design with a slightly positive
rake angle for optimum cutting, three radial lands
with peripheral blade relief, fixed taper, a noncutting
tip, and variable pitch.

76. Technique of using K3 Rotary System in Primary
Teeth
After use of each file, the root canals are irrigated with 1 mL of 1% NaOCl.
This system is used with at 350 rpm and slow torque
The canals are cleansed and shaped with 3 progressively larger tapered
files, using the “crown down” technique; each instrument is changed
according to the manufacturer’s recommendation.
The working length is established by placing the first adjusting file to
radiographic working length; the instrumentation is started with the 0.06
taper file.
The pulpectomy procedure is begun with standard access and removal of
coronal tissue.
Ochoa-Romero T, Mendez-Gonzalez V, Flores-Reyes H, Pozos- Guillen AJ. Comparison between rotary and
manual techniques on duration of instrumentation and obturation times in primary teeth. J ClinPediatr
Dent 2011;35(4):359-63.

77. Advantages
Excellent cutting characteristics, increased flexibility, canal
tracking, prevents screwing in effect, minimum wear of
root canal walls, less time, less canal transportation, resist
torsional and cyclic fatigue, reduces patient’s fatigue and
tactile control
Disadvantages
High cost, use at a particular speed (300 – 350rpm),
handling should be gentle and should never be forced.

78. The Wave One Reciprocating System
New Wave One NiTi file system from
DENTSPLY is a SINGLE file system, to
shape the root canal completely from the
beginning till the end.
the technique requires only one hand
file, followed by one single Wave One file
to shape the canal thoroughly.

79. • The Wave One single-file reciprocating system consists of
three files.
• Lengths available are 21, 25 and 31mm:

80. The Wave One Small file:
• They are used for the instrumentation of fine canals.
• The tip size is ISO 21, with a continuous 6% taper.
The Wave One Primary file:
• Used for the instrumentation of the majority of the canals.
• The tip size is ISO 25 with8% apical taper that reduces
towards the coronal end.
The Wave One Large file:
• Used for the instrumentation of large canals.
• The tip size is ISO 40 with 8% apical taper that reduces
towards the coronal end.

81. Technique of using Wave One in Primary
Teeth
Straight-line
access,
Wave One
files
selection;
Single-file
shaping;
Copious irrigation
with 5% NaOCl and
EDTA before,
during, and after
instrumentation.

82. Wave One file selection and Clinical
Procedure
• A good pre-operative IOPA radiograph will give an estimation of a
number of canals, canal size, canal length, and degree of its
curvature. Only the first-hand file into the canal will aid in the
selection of the Wave One file as follows:
• Use Wave One Small file in the canals where 10 K-file is very
resistant to movement
• Use Wave One Primary file in the canals where 10 K-file moves to
whole canal length easily or passively.
• Use Wave One Large file in the canals where a 20 K-file or larger
goes to the whole length.

83. Single-file Shaping
• Insert hand file into 2/3rd of the canal length and provide watch-
winding motion.
• In motion insertion of Wave One file to 2/3rdof the canal length.
• Copious irrigation.
• Insert hand file to a full length of the canal, confirm with an apex
locator and reconfirm with a radiograph.
• Insert Wave One file to a full length of the canal.
• Confirm the diameter of apical foramen with hand file of the same size
as Wave One file (snug fit implies complete preparation)
• If Wave One file is loose at the apical end, consider the next size of
Wave One file

84. Guidelines for use
Use Wave One files with a progressive up and down
movement 3-4 times with minimal force application.
Removal of a file is recommended on a regular basis
followed by cleaning the file and irrigating the canal.
Confirm the patency of the canal if the file does not
progress and consider using a smaller Wave One file.
Glide path management is minimal with Wave One
shaping files

85. • Complete hand preparation of an apical portion of the non-
reproducible glide path in severely curved canals should be
considered.
• If used short of a length, the brushing action of Wave One
files can help to relocate the canal orifice and to expand
coronal shape.
• Copious and constant irrigation with NaOCl and later EDTA,
to avoid instrumentation in a dry canal.
• Activation of irrigating solutions to enhance their
effectiveness in short preparation time, ideally use
EndoActivator (DENTSPLY Maillefer)

86. Advantages
• One instrument per tooth, low cost, less instrument
separation, decreased global shaping time,
eliminates of procedural errors using a single
instrument and possibility of prior contamination

87. Twisted Files
• Third generation of NiTi rotary instruments: the twisted file (TF) with
R-phase technology with three innovative methods of manufacturing
R-phase heat treatment, metal twisting, and special surface
conditioning (deoxidation).
• These processes have shown to increase the instrument resistance,
provide greater flexibility, and maintain the sharpness of the flutes.
• Prabhakar et al.reported better cutting efficiency of twisted files over
ProTaper rotary system. Hence these files can be efficiently
incorporated into the contemporary pedodontic armamentarium

88. Kedo –S Rotary System
Kedo-S (Reeganz Dental Care); Kids
Endodontic Shaper is the world’s first
rotary file exclusively for shaping
primary teeth.
It is invented by Dr.Ganesh
Jeevanandan and came into existence
in Nov 2016.

89. Available in Hand type (Kedo- SH) and rotary type (Kedo-S,
Kedo-SG, Kedo -SG Blue, Kedo- S Square And Kedo S plus ).

90. 1st generation kedo
rotary files 2016
•Kedo-S rotary file consisting of D1,
E1, and U1 files, wherein U1 files
are for upper and lower anterior
primary teeth, D1 for mesiobuccal
and mesiolingual canals, and E1 for
distal and palatal canals of the
primary molar teeth.
•They have a working length of 12
mm with a total length of 16 mm.
The uniqueness of these files is the
presence of variable taper (4%–8%)
with varying tip diameter

91. The tapering of the instrument is according to the
diameter of the primary root canal to enable
effective canal preparation and to avoid over-
instrumentation.
With the use of Kedo-S instrument in curved canals,
the original anatomy of primary root canal can be
maintained, which is mainly because of the file
design and flexibility.
This enables it to closely adapt to the irregular and
tortuous canals of primary teeth

92. • The Kedo-S rotary files have instrumentation time of 2–3
minutes approximately.
• This greatly reduces the operator and patient’s fatigue,
thereby increasing the quality of the treatment.
• Better quality of obturation while comparing with
reciprocating and manual instrumentation.
• Disadvantages include the high cost of the constant
torque handpiece and the files itself.
• For using Kedo-S files, it requires appropriate training for
better results

95. 2nd generation kedo rotary
files 2017
•Kedo-SG rotary files are heat-
treated NiTi rotary files utilizing
the M-Wire technology.
•These files result in better
obturation quality due to its
efficient preparation of primary
root canals

96. 3rd generation kedo
rotary files 2018
•The next generation is the
Kedo-SG Blue consisting of
three files D1, E1, and U1,
which have greater cyclic
fatigue resistance with its
titanium oxide coating.
•These files are super flexible
and have 75% of greater
resistance to cyclic fatigue than
its earlier generation

98. 4th generation kedo rotary files
2019
P1 A1

99. • Kedo-S Square rotary file has revolutionized the arena of
pediatric endodontics as being the first exclusive single
pediatric rotary file system.
• It consists of two files, one file to be used for anterior
primary teeth (A1) and one file to be used for posterior
primary teeth (P1).
• It has a dual core made of NiTi heat-treated alloy and
coated with titanium—oxide.
• Kedo-S Square rotary files have a unique feature that
includes a variably variable taper design that provides the
flexibility and efficiency to facilitate consistently successful
cleaning and shaping

100. They also have variably variable cross section; that is, the apical
5 mm has triangular cross section with three-point contact to
root canal, whereas the coronal 7 mm has teardrop cross
section with two-point contact. This enables reduced apical
dentin removal and less aggressive preparation
Advantages of Kedo-S Square
• Superior flexibility,
• Less dentin removal, and
• Increased resistance to cyclic fatigue due to its
TiO2 coating

102. 5th generation kedo files
2021
Apical third Blue
Coronal third Gold

103. Neoendo Flex Rotary Files (Orikam,
India)
• NiTi Rotary Files
• Utilize a proprietary heat treatment
– Tough file with unique flexibility
– Flutes do not open up when stress levels are reached
• Cross-section – Triangular with sharp cutting edges
• Non-cutting safety tip
• Most cases require just 2 to 3 files
• Simple usage protocol
• Speed: 350 RPM
• Torque: 1.5 Ncm

109. Other systems
• Prime PedoTM (India)
• DXL-Pro PedoTM (India)
• Pro AF Baby GoldTM (India)
• NeolixTM (France)
• Denco® Kids files (China)
• Sani® Kid rotary files (China).

110. Prime PedoTM and DXL-ProTM are the new
paediatric rotary files developed for use in
primary teeth.
Prime PedoTM file system consists of four
files (Starter, P1, P2, Endosonic file).
DXL-ProTM file system has three files (#30,
#20 and #25).

111. The differences between two file systems are: Endosonic file
with 2% taper in Prime PedoTM kit allow for conservative
apical preparation of primary molars.
The DXL-ProTM file used for apical preparation has a 6% taper.
Both files possess controlled memory.
This controlled memory allows them to be centred in the
curved canals of primary molars

116. Summary and Conclusion
• The research in the field of rotary endodontic
instruments is an ongoing process.
• With every passing day, newer systems with better
efficiencies are being introduced.
• NiTi rotary system in Paediatric Dentistry is like a double-
edged sword with great advantages and disadvantages.
• There is a reduction in tactile sensitivity during apical
preparation if compared with manual preparation, so to
control working length, previous training of the operator
in rotary instrumentation is important.
• The high cost of and need for training to learn the
technique are other limitations Ni-Ti rotary systems.