Advancements in biomechanical procedures in Endodontics

Advancements in Root Canal
Cleaning & Shaping:
Armamentarium & Techniques
Prepared by,
Dr.Sachin Sunny Otta
DR.SSO

INDEX
 INTRODUCTION
TIMELINE
HAND S. ENGINE DRIVEN
INSTRUMENTS
 ROTARY ENDODONTICS
INTRODUCTION - WHAY & WHY
CLASSIFICATION
HISTORY
METTALLURGY
 NiTi
COMPARISON WITH S.S
ADVANCES
CM-NiTi
 COMPONENTS OF FILE
 DYNAMICS OF ROTARY
SPEED
TORQUE
MOTOR & DEVICES
 GENERATIONS OF ROTARY
INSTRUMENTS
PT
FROFILE VORTEX
TF
MTWO
K3 XF
HYFLEX
SAF
 NiTi COMPLICATIONS
 GOLD FILES
WAVE ONE
PROTAPER
 ROTARY SHAPING GUIDELINES
 PROTAPER TECHNIQUE
 NiTi ROTARY PREPARATION
GLIDE PATH MANAGEMENT
TAC
AET
RECIPROCATING SYSTEM
 ARTICLE COMPARATIVE
STUDIES
 ULTRASONICS
 LASER ASSISTED CANAL
PREPARATION
 NIT
 SURFACE TREATEMNT OF
FILES
 STERILISATION OF FILES
 RESEARCH POSSIBILITIES
 CONCLUSION
 BIBLIOGRAPHY
DR.SSO

INTRODUCTION
 In recent years, advances in technology & demands from endodontists
for instrumentation that create faster & more standardised preparation
has influenced the direction taken by manufacturers when designing new
instruments.
 For nearly half a century endodontic instruments have been
manufactured according to guidelines set by the ADA. These guidelines
were rarely challenged until recently. With the discovery of new
technologies & materials, manufacturers & clinicians alike began to
question the solidity of these guidelines which was followed by advances
in leaps & bounds of both instruments and instrumentation techniques
that challenged what was conventional…
DR.SSO

DISADVANTAGES OF CONVENTIONAL FILES & TECHNIQUES
 Preparation is time consuming
 Occupational hazards (Carpal Tunnel Syndrome)
 Preparations not standardized
 Managing curved canals is difficult
 Chance of extrusion of debris into apical area during preparation
DR.SSO

ROTARY ENDODONTIC INSTRUMENTS
WHAT?
INSTRUMENTS WHICH ARE USED WITHIN THE ROOT CANALS AND
FOLLOW THE DYNAMICS OF ROTATIONAL MOTION
DR.SSO

ROTARY ENDODONTIC INSTRUMENTS
WHY?
 Rotary shaping instruments are replacing the Conventional hand file systems to
enhance shaping ability Of the canal, reduce clinical mishaps like
Blocks,ledges,transportation and perforation.
 When the clinician masters the method of use products of Rotary shaping
instruments, unpredictable file Breakage,metal fatigue,loss of cutting efficiency,
variation In length, diameter and curvature of the canal can be Avoided and
better shaping of the canals with disserved Taper will be achieved.
DR.SSO

CLASSIFICATION
GENERATIONS OF MOTORS
a) First generation motor without torque control.
b) Second generation motor with torque limiter.
c) Third generation motor with simple torque control.
d) Forth generation motor with apex locator and torque control
Rotary Handpiece
They are 3 types-
a) Micromotor handpiece
b) Reduction gear handpiece
c) Vertical Stroke handpiece
DR.SSO

CLASSIFICATION OF ROTARY
INSTRUMENTS
 Low-Speed Rotary Instruments
Gates-Glidden burs
Peeso instruments
 Rotary Instruments for Canal Preparation
Group 1: Passive
Group 2 : Active
Group 3 : Special
DR.SSO

HISTORY
 The first description of the use of rotary devices seems to have been by
Oltramare In 1889
 William H. Rollins developed the first endodontic handpiece for automated
root canal preparation. He used specially designed needles, which were
mounted into a dental handpiece with a 360 degree rotation. To avoid
instrument fractures rotational speed was limited to 100 r.p.m.DR.SSO

 In 1928 the ‘Cursor filing contra-angle’ was developed
by the Austrian company W&H (Bu¨rmoos,Austria).
 This handpiece created a combined rotational and vertical
motion of the file.
 Finally,endodontic handpieces became popular in Europe
with the marketing of the Racer-handpiece (W&H) in
1958 and the Giromatic (MicroMega, Besanc¸on,France)
in 1964
 Ni-Ti rotary instruments introduced later use a 360 degree
rotation at low speed and thus utilize methods and
mechanical principles described more than 100 years ago
by Rollins.
 While hand instruments continue to be used, Ni-Ti rotary
instruments and advanced preparation techniques offer
new perspectives for root canal preparation that have the
potential to avoid some of the major drawbacks of
traditional instruments and devices.
DR.SSO

WHAT ARE ROTARY ENDODONTIC
INSTRUMENTS MADE OF??
 Historically, carbon steel and stainless steel instruments were used for root
canal instrumentation. In 1988, Walia and colleagues introduced nickel-
titanium (NiTi) files to endodontic.
 Since then, many NiTi file systems have been developed. Rotary NiTi
instruments have become popular as they can clean and shape root canals with
fewer procedural errors and more predictability than stainless steel hand files.
DR.SSO

NiTi..
THE NiTi SYSTEM
METTALURGY
 55% Ni & 45% Ti
 Shape memory & Super elasticity
 Elastic limit in bending & torsion is 2-3 times higher than steel instruments
 Modulus of elasticity lower than Steel – lower force exerted on radicular wall
dentin
 Austenitic Martensitic (Changes shape)stress
Reliving
stress
Original
shape
DR.SSO

Why Nickel-Titanium??
 Reversible rearrangement of the nickel and titanium atoms at the molecular
level. A new endodontic file is composed of nickel and titanium atoms arranged
in a body-centered cubic lattice structure NiTi alloys are unique in that applied
stress (i.e. bending) causes a called the austenite phase.
 When this file is placed in a curved canal, the atoms rearrange into a closely-
packed hexagonal array and the alloy is transformed into the more flexible
martensitic crystal structure. This molecular transition enables these files to
bend easily and around severe curves without permanent deformation.
DR.SSO

NiTi ROTARY INSTRUMENTS
ADVANTAGES
1. Gradual, evenly tapered radicular access
2. Fewer instruments required
3. Less time consuming
4. Better visibility (small headed hand piece)
DISADVANTAGES
1. Attempting to negotiate narrow curved canals,
without preparing a pilot channel with hand
instrument will cause instrument fracture.
2. Fracture may occur unexpectedly without any
sign of permanent deformation
3. More expensive than stainless steel
4. Become dull quicker than stainless steel
5. Shape memory makes it difficult to access root
canals in posteriors & to negotiate acute curves &
double curves.
DR.SSO

COMPARATIVE STUDY OF METALS
NICKEL TITANIUM STAINLESS STEEL
Excellent flexibility Less flexible
Conforms to canal Straightens and curvature transports canal
Plastic deformation Permanent deformation
DR.SSO

Advances in Nickel-Titanium Metallurgy
1) M-wire NiTi - Developed by Dentsply Tulsa Dental Specialties (Tulsa, OK, USA)
 Advantage: This material has greater flexibility and an increased resistance to
cyclic fatigue when compared to traditional NiTi alloys
2) R-phase NiTi – Developed by SybronEndo (Orange, CA, USA)
 Advantage: Files have reduced stiffness and more fracture resistance
compared to standard NiTi files.
3) Controlled-Memory (CM) NiTi
 Advantage: Files have superior cyclic fatigue resistance and increased torque
strength over traditional NiTi files.
DR.SSO

CONTROLLED MEMORY NiTi
TECHNOLOGY
 To optimise the instrumentation of curved canals in a safe predictable manner,
a revolutionary metal was introduced.
 CM NiTi files are manufactured with new NiTi metal alloys, which has been
subjected to a patented thermo-mechanical process.
 They demonstrate martensitic properties at room temperature (which is not
observed in conventional NiTi metal)
 The introduced file has tremendous flexibility & virtually no memory.
 This memory-free property allows the instrument to adapt to root canal
curvatures, following root canal anatomy without creating undesirable lateral
force on outer canal walls.
 They can also be pre-curved in cases with limited access & can be pre bent to
allow clinician to bypass ledges.
DR.SSO

 Traditional NiTi is austenitic at room temperature, exhibiting shape memory. So
they always try to straighten in curved canals resulting in over instrumentation,
canal straightening & unfavourable stress which can lead to cyclic fatigue
failure.
 800% increase in instruments resistance to cyclic fatigue stresses.
 The fluted portion tend to straighten out or unwind itself before the file
completely breaks.
DR.SSO

COMPONENTS OF A FILE
 1) Taper
 2) Flute
 3) Land
 4) Helix angle
 5) Rake angle
 6) Pitch
 7) Cutting edge
DR.SSO

DYNAMICS OF ROTATIONAL MOTION
DEFINITION: WHEN A PARTICLE OR PARTICLES OF A RIGID BODY MOVE IN CONCENTRIC
CIRCLE ROUND A COMMON CENTRE,THE MOTION IS CALLED ROTATIONAL MOTION.DR.SSO

 RADIAN: It is defined as the angle subtended at the centre of a circle by an arc
equal in length to radius of the circle. i.e. theta in the diagram
WHAT IS ANGULAR VELOCITY?
 The angular velocity of a rotating particle is defined as the time rate change of
angular displacement.
 Angular velocity=theta/time.
WHAT IS ANGULAR ACCELARATION?
 Angular acceleration of a rotating body is defined as the time rate change of
angular velocity.
 Angular acceleration=angular velocity/time.
DR.SSO

WHAT IS r.p.m.?
 The rotational speed is expressed in revolution per minute
 Abbreviated as r.p.m.
 If N be the r.p.m. then in 1minute there is N complete revolution.
 So ,for one complete rotation it takes=60/N second.
RELATION BETWEEN TORQUE AND ANGULAR ACCELARATION
ROTATION OF A RIGID BODY?
 A rigid body means a body in which the distance between each pair of
particles remain invariant.
WHAT IS TORQUE?
 It is the sum of moments of the force acting on the particles.
 Torque act in a rotational manner.
DR.SSO

IMPORTANCE OF SPEED
 Speed refers not only to revolutions per minute but also to the surface feet per
unit that the tool has with the work to be cut.
 In endodontics, speed varies from 150-40,000 rpm
 Greater the speed, more the cutting efficiency.
 But at higher speed, there are more disadvantages such as :
1) loss of tactile sensation
2) breakage of instruments preceded by flute distortion
3) change in anatomical curvature of canal
4) loss of control
DR.SSO

IMPORTANCE OF TORQUE
 According to Marzouk, torque is the ability of the handpiece to withstand
lateral pressure on the revolving tool without decreasing its speed or
reducing its cutting efficiency.
 Torque is dependent upon the type of bearing used and the amount of energy
supplied to the handpiece.
 Torque is another parameter that might influence the incidence of instrument
locking, deformation, and separation.
 Theoretically, an instrument used with a high torque is very active and the
incidence of instrument locking and consequently deformation and separation
would tend to increase, whereas a low torque would reduce the cutting
efficiency of the instrument, and instrument progression in the canal would be
difficult.
 Conventional endodontic motors to recent motors use a wide range of speed of
150 rpm - 40,00Orpm, which are either controlled by electrical or air-driven
instructions handpieces.
DR.SSO

ROLE OF HANDPIECE
 A handpiece is a device for holding rotating instrument, transmitting power to
them and for positioning them intra orally.
 Both speed and torque in a handpiece can be modified by the incorporation of
gear systems.
 A common method of gearing a handpiece is the use of an epicyclic ball-race
gear system.
 This is usually located in the shank of the handpiece.
 The basic design is a modification of a ball-race bearing.
DR.SSO

ROLE OF MOTOR
 Torque control motors allow the setting of torque generated by the motor.
 In low torque control motors, torque values set on the motor are supposed to
be less than the value of torque at deformation and at separation of the rotary
instruments.
 Where as in high torque control motors, the torque values are relatively high
compared to the torque at deformation and at separation of the rotary
instruments.
DR.SSO

REVERSE - ROTATION
 During root canal preparation all the instruments are subjected to different
levels of torque.
 If the level of the torque is equal or greater than the torque at deformation or at
separation, the instrument will either deform or separate.
 With low torque control motors, the motor will stop rotating and can even
reverse the direction of rotation when the instrument is subjected to torque
levels equal to the torque values set on the motor.
 The latest development with regard to torque control is the incorporation of gear
systems within the handpiece that regulates torque depending on the size of
the rotary instrument. (Endoflash- Kavo, Anthogy Ni-Ti control- Dentsply). This
obviates the need for torque control motors.
DR.SSO

First-generation motor without torque control Fully electronically controlled second-generation motor with
sensitive torque limiter.
Third-generation simple torque-controlled motor Forth-generation motor with built-in apex locator and torque
control
DR.SSO

NEW ADVANCEMENT OF DEVICES
 The Midwest eStylus electric handpiece system includes a motor,tubing, and
remote controller.
 Available attachments include a Red 1:5 attachment for high-speed work, a
Blue 1:1 attachment for low-speed work, a Green 10:1 attachment for rotary
endodontics, and a straight 1:1 attachment for trimming, adjusting, prophy, and
other uses.
DR.SSO

The Red 1:5 eStylus attachment accepts friction
grip burs and supports high-speed operations
up to 200,000 rpm.it provides brilliant optics
and a 4-port water spray.
The Green 10:1 eStylus attachment
accepts latch burs and files,and
supports lows-peed operations,
including rotary endodontics, from
4000 rpm to 150 rpm. It provides
brilliant optics, but omits water
spray since endo procedures do not
use water.
The Blue 1:1 eStylus attachment accepts latch burs
and supports low-speed operations from 40,000
RPM to 1500 rpm.It provides brilliant optics and a
4-port water spray.
DR.SSO

A rotary endodontic system incorporates three key elements into its operation
1) Torque-sensing, which monitors how much twisting force the file is encountering
2) Auto-reversing, which will reverse the rotation of the file if the file exceeds the torque
limit
3) Constant file rotational speed, which many file manufacturers recommend.
 All these features help to reduce the chance of files breaking in the canal. Torque limits
and speed control allow the dentist to adjust the unit’s feel and develop the appropriate
degree of finesse during rotary endodontic procedures.
 One electric system available today, the Midwest eStylus from Dentsply Professional,
incorporates all of these features into its wireless controller.
DR.SSO

ENGINE DRIVEN INSTRUMENTS FOR CANAL
PREPARATION
Group 1: Passive preparation; Presence of radial lands
 First commercially successful rotary instruments
 U-shaped cross section: Radial land
 Safe but inefficient cutting(reaming action)
 Quantity & quality of smear layer produced is more
DR.SSO

1. Light speed
 NiTi
 LS1
 Long, thin, non cutting shaft & short anterior cutting head
 #20 to #100
 LSX (SybronEndo)
 Low incidence of canal transportation
2. ProFile
 Series 29 (29% constant diameter increment)
 Increased taper
 Reaming action on dentin
DR.SSO

3.GT & GTX files
 Hand operated files evolved to engine driven system
 0.6,0.8,0.10,0.12
 Max diameter of working part 1mm
 Decreases the length of flutes with increasing taper
 Variable pitch & growing number of flutes
 Non cutting & rounded tips
 GTX : M-wire alloy with no other changes in physical or shaping properties
 Machined similar to canals walls
 Available for small (#20), medium (#30) & large (#40) canal diameter
DR.SSO

4.K3
 Quantec 2000 – Quantec SC – Quantec LX – K3
 Similar to Profile but includes 0.2,0.4 & 0.6 taper
 Slight positive rake angle for cutting efficiency, wide radial land
& peripheral blade relief for reduced friction
 Presents with third radial land to help prevent threading
(unlike 2-fluted quantec)
 Round safety tip
 4mm shorter than other files
 Less canal transportation than RaCe but more than ProFile
DR.SSO

Group 2: Active cutting; Triangular cross section
 More active cutting flute design
 Radial lands absent
 Efficient cutting but high potential for preparation errors
1. Protaper Universal
2. Hero 642
3. Flex master
4. raCe
5. Endosequence
6. Twisted files
7. Profile vortex
8. Mtwo
Group 3: Special
1. Wave one
2. SAF
3. Endo Eze
4. Sonic & ultrasonicDR.SSO

• 50% increase in
cyclic fatigue
resistance
• Enhanced safety
• Increased
flexibility
DR.SSO

PART ROTARY SHAPING GUIDELINES
 PROTAPER TECHNIQUE
 NiTi ROTARY PREPARATION
TAC
AET
 ARTICLE COMPARATIVE STUDIES
 ULTRASONICS
 LASER ASSISTED CANAL PREPARATION
 NIT
 SURFACE TREATEMNT OF FILES
 STERILISATION OF FILES
 RESEARCH POSSIBILITIES
 CONCLUSION
 BIBLIOGRAPHY
DR.SSO

 ENDODONTIC GLIDE PATH is a smooth radicular tunnel from canal
orifice to physiologic terminus(foraminal constriction)
 Mininal size: Super loose no.10 endodontic file
 GP must be discovered if already present in the endodontic anatomy or
prepared if it is not present.
 GPM is essential for prevention of rotary file separation & most effective
rotary use.
 Risk of taper lock can be reduced by performing coronal enlargement &
creating a glide path before using NiTi rotary
DR.SSO

Lack of glide path results in:
 Ledge formation
 Blockage of root canals
 Transportation
 Zip formation
 Perforation
 Creating an .02 tapered glidepath is critical for the safe and effective use
of nickel-titanium rotary shaping instruments.
 Glidepath can be further described as a manual glide path created with
handfiles, or a mechanical glide path created with rotary files.
DR.SSO

G-File Instrumentation Sequence
 Determine the working length with small diameter number 8 or number 10 k-
files.
 Rotating G1 instrument is introduced into the canal, progressing with a slow
movement without any apical pressure until the working length has been
reached.
 After irrigation, the G2 instrument is used in the same way.
 The last file is used again to check canal patency and confirm the working
length.
DR.SSO

V-Glide Path™2 File Instrumentation Sequence
 Establish patency with no.10 K File.
 First no. 13 file is introduced into the canal, till the working
length.
 The canal is first irrigated and then no.17 file is used up to the
full working length
Pre Shapers Instrumentation Sequence
 Pre Shapers are single use instruments.
 Achieve patency and determine the working length with a size
10 hand files.
 Use Pre Shapers size 14/0.2 to full working length.
 Use Pre Shapers size 18/0.2 to full working length.
 Glide path in done
DR.SSO

 PathFile NiTi rotary files
(Dentsply Maillefer) were
introduced to for glide path
enlargement. The system
consists of three rotary
instruments that can be
used for glide path
enlargement.
DR.SSO

TACTILE CANAL ACTIVATION (TCA)
 For a given root canal and a given file, the operator’s tactile feedback during the
instrumentation procedure differs according to the kinematics of the file used.
 Passively inserted files (non-activated) give a tactile sensation that is determined by the
frictional resistance generated when the file engages the dentinal walls.
 The tactile sensation with an activated file (rotating or reciprocating), however, as the
result of cutting, can more accurately be determined by the ability of the file to resist
advancement around curvatures while in action (McSpadden, 2007).
 The TCA technique can be defined as the activation of a motionless engine-driven
file only after it becomes fully engaged inside a patent canal.
 TCA utilizes file activation only after maximum engagement of the flutes is reached and
a tactile feedback of the anatomy is felt. Inserting files passively (non-activated) inside
the root canals and using controlled-memory instruments that can be pre-curved
before file insertion is suggested to be advantageous, especially when complicated
canal systems are encountered and limited mouth opening hinders canal negotiation
and visualization.
 The TCA technique can be divided into in-stroke and out-stroke components.
DR.SSO

 A) After accessing the pulp chamber and
locating the canal orifices, technical patency
to length is confirmed
 B) The first file to be used is mounted on the
handpiece of an endodontic motor and
inserted passively inside the canal until
maximum frictional resistance (point P).
 C & D) The file is activated and pushed
apically (in-stroke) until the activated file
resists further advancement (point A) and
withdrawn from the canal.
 E) After file withdrawal, the file is inactivated;
the flutes are cleaned and checked for any
possible deformations. Irrigation and
patency confirmation follows. The second
time that the same file will be inserted
passively inside the same canal, it will reach
deeper inside the anatomy (point P).
 F) Activating the file again the same way will
guide the file even more apically closer to
length (point A).
 G) The work to be done by this file is
completed when the file can reach working
length without having to activate it and is
then withdrawn
DR.SSO

ADVANTAGES
 Minimize the time of engagement with an activated file by using file activation
only when needed for advancement.
 Most of the anatomical root canal variations can be enlarged safely to the
desired instrumentation size, irrespective of the degree and complexity of canal
curvatures, by maintaining a tactile sensation of the anatomy throughout the
whole procedure.
 Although the TCA technique can be used with all instrumentation systems
available (rotary or reciprocation), controlled-memory systems are the only
ones where the files can be pre-bent for easier negotiation of challenging cases
(abrupt curvatures, ledges, and limited mouth-opening patients).
DR.SSO

ANATOMIC ENDODONTIC TECHNOLOGY
(AET)
 The AET preparation technique comprises three phases:
1. Coronal access (using the Access Bur Kit, Ultradent Inc.)
2. Coronal-middle preparation (using Shaping filesTM; Ultradent Inc.)
3. Apical preparation (using Apical files, Ultradent Inc.)
DR.SSO

CORONAL PHASE
 Aims: To open and clean the pulp chamber and identify canal orifices.
 Instruments and method: ‘Access bur kit’ comprising:
1. Round and tapered diamond burs to prepare the access cavity.
2. Non end-cutting burs to remove the chamber roof in multi-rooted teeth without
damaging the chamber floor and to remove dentine overhangs and residual
enamel interferences.
3. Safe-point diamond bur to prepare axial line access by removing dentin
interferences
DR.SSO

CORONAL-MIDDLE PHASE
 Circumferential shaping following the anatomic contour and eliminating
interferences in the middle section of the canal in order to obtain the
straightest possible access towards the apical region.
 Instruments. Shaping filesTM (Ultradent Inc.): four stainless steel (S1, SC, S2,
S3) instruments with a square cross-section.
 Shaping filesTM are available in lengths of 16 mm (X-short), 20 mm (short), 24
mm (medium) and 27 mm (long). The Endo-Eze (Ultradent Inc) handpiece is a
dedicated handpiece for the Shaping filesTM with a 30 right-30 left
reciprocating action.
 This permits four different working lengths for each instrument length, as
follows: 13, 14, 15 and 16 mm for the 16 mm length; 17, 18, 19 and 20 mm for
the 20 mm length; 21, 22, 23 and 24 mm for the 24 mm length; 24, 25, 26 and
27 mm for the 27 mm length
DR.SSO

 Complete the manual glide path and canal negotiation using the first
ShapingTM file (yellow) before starting mechanical preparation.
 Insert Shaping files into the Endo-Eze hand-piece at the Coronal-middle length
established, and direct the instruments with their reciprocating action
circumferentially, brushing the canal walls in order to remove interferences and
obtain straight-line coronal-radicular access .
 Active brushing should be performed only when the Shaping instruments are
being pulled out of the canal.
 The four shaping instruments are used sequentially for approximately 1 min
each in the sequence shaping 1 (yellow-S1), shaping ‘C’ (red-SC), shaping 2
(light blue-S2) and shaping 3 (green-S3). They should be pushed laterally
mainly using the upper half of the instruments.
DR.SSO

APICAL PHASE
 Aims: To shape and clean the apical third of the canals whilst respecting the
electronically determined apical limit and maintaining the original apical
foramen diameter as narrow as possible. To create an ‘apical stop’ for
obturation.
 Instruments: Apical files (Ultradent Inc.) in lengths of 19, 23, 27 and 30 mm:
• Manual Stainless steel files with tip diameters ranging from 0.08 mm up to
0.20 mm with a square cross-section; • Manual NiTi files with tip diameters
ranging from 0.25 to 0.50 mm and above with a square cross-section and
round noncutting tip.
 Apical files have a 0.02 taper in sizes 0.8–20 and a 0.025 taper in sizes 25–50
and above; they have an active part 10 mm in length.
 Stainless steel Apical files with diameters ranging from size 08 up to size 20
and with 1/4 turn and withdrawal movements until reaching the WL with the
size 25 Apical NiTi.
 Continue with the Apical NiTi (size 30, 35, 40, etc.) until reaching the final
Diameter of Apical Preparation (DAP); alternating EDTA and NaOCl should be
used as irrigants.
DR.SSO

 Defined as repetitive back-and-forth motion
 Initially, all reciprocating motors & hand pieces worked in 90 degree CW/CCW
rotation
 Later, M4,Endo-Eze,Endo Express utilized 30 degree CW/CCW rotation.
 But they performed with decreased cutting efficiency, more inward pressure
& limited capacity to drag debris out.
 In 2011, Wave One & Reciproc were introduced as Single File Shaping
Technique
DR.SSO

ULTRASONICS
 In 1976 Howard Martin developed a device for preparation and cleaning of root
canals and named this technique as ‘endosonics’.
 Ultrasonic devices are driven by Magnetostriction or Piezoelectricity,
resulting in oscillation (25–40 kHz) of the inserted file which initiates Acoustic
micro streaming in the irrigation fluid.
 Initially, it was felt that ultrasonics allowed root canal preparation to be carried
out concurrently with activated irrigation, because of cavitation effects.
 However, several studies have demonstrated that acoustic streaming should be
regarded the main mode of action.
DR.SSO

Shaping
 Only few studies have been published reporting good shaping ability of ultrasonic
systems. Several reports have presented pictures of longitudinal grooves in the root
dentine following the use of ultrasonically activated files
Cleaning ability
 The cleaning and disinfecting capacity of ultrasonics still is subject of controversy.
 If ultrasonics is used for irrigation purposes care should be taken to introduce the
ultrasonic instrument and activate the unit to oscillate the file in the irrigant without
touching the root canal walls.
Working safety
 Apical blockages, ledging, loss of working length, a higher risk of perforations and
increased amount of apically extruded debris as well as instrument fractures have been
described for ultrasonic preparation.
Working time
 Time required for ultrasonic preparation has been shown to be shorter, longer or equal
when compared with hand instrumentation.
 The use of an ultrasonic device may be recommended for passive ultrasonic irrigation
but not for root canal preparation.DR.SSO

LASER ASSISTED CANAL
PRERARATION
 Nd: YAG-, KTP-, Er : YAG-, (Ho) : YAG-, XeCl-Excimer-, argon-
and free-electron lasers.
 Laser irradiation has been demonstrated to be able to change or
modify the structure of dentine, thereby reducing its permeability
and melting or carbonizing its surface.
 Side effects of lasers such as thermal damage to dental hard
tissues resulting in cracks or injury to the surrounding soft tissues
such as ankylosis, cemental lysis and bone remodelling
 Lasers are recommended by some authors for disinfection but at
present are not suited for the preparation of root canal systems
DR.SSO

NON INSTRUMENTATION TECHNIQUE
(NIT)
 By Lussi et al.
 Uses a vacuum pump and an electrically driven piston, generating
alternating pressure and bubbles in the irrigation solution, inside the root
canal.
 This is expected to enhance the ability of sodium hypochlorite to dissolve
organic pulp tissue. Following the cleansing procedure the root canal
may be obturated by the vacuum pump with a sealer
 In a recent in vivo study 22 teeth (18 patients) were cleansed using the
NIT and, following extraction, investigated under the microscope for intra-
canal residual tissue.
 The mean percentage of teeth with tissue remnants and remaining debris
in the coronal third of the root canal was shown to be 34.4%, 55.8% in
the middle third, and even 76.6% in the apical part.
 Additionally, intra-operative problems as severe pain, underextension and
apical extrusion of sealer or breakdown of vacuum have been reported
(A, B) Root canals surface following cleansing
with the NIT of Lussi
demonstrating insufficient cleaning ability
with lots of
remaining debris and tissue
DR.SSO

Research Possibilities For Future Developments Of
Rotary Endodontic Instruments
 Use of ion implantation and thermal nitridation to
provide harder and wear resistant cutting edges in the
file.
 Investigation of failure models in Ni-Ti files ’to develop
mathematical models to accurately predict the life
expectancy of these files during use.
 Optimization of flexibility, bending and torsional
strength of files without sacrificing cutting ability, by
using modern mechanics and analysis methods: for
example, finite element analysis.
DR.SSO

BIBLIOGRAPHY
 Shaping of the root canal system: A multistep technique livio gallottini
 Histological evaluation of the effectiveness of five instrumentation techniques for cleaning the apical third of root canals jos6 F.
Siqueira jr, DDS, msc, marcos C.P. Ara~jo, DDS, paulo F. Garcia, DDS, msc,ricardo C. Fraga, DDS, msc, and carlos J. Sabbia
dantas, DDS
 SHAPING FOR SUCCESS EVERYTHING OLD IS NEW AGAIN by clifford J. Ruddle, DDS
 Cohen 11th edition
 Ingle 5th edition
 New developments in rotary nickel-titanium instruments, lieutenant commander evan whitbeck, DC, USN and colonel kathleen
mcnally, DC, USA 6)current challenges and concepts of the thermomechanical treatment of nickel-titanium instruments, ya
shen, DDS, phd,* hui-min zhou, DDS, phd,† yu-feng zheng, phd,‡ bin peng, DDS, phd, and markus haapasalo, DDS, phd
 NEW DIRECTIONS IN ENDODONTICS, exclusive interview with clifford J. Ruddle, DDS
 Revolutions in endodontic instruments- A review ‘revathi M “rao CVN and “*‘lakshminarayanan L
 Current developments in rotary root canal instrument technology and clinical use: A review ove A. Peters, DMD, MS,
phd1/frank paqué, dr med dent2
 Mechanical preparation of root canals: shaping goals, techniques and means MICHAEL HU¨ LSMANN, OVE A. Peters & paul
m.H. Dummer
 The principles of techniques for cleaning root canalsb GR young,* P parashos,† HH messer‡
 Mechanical preparation of root canals: shaping goals, techniques and means MICHAEL HU¨ LSMANN, OVE A. Peters & paul
m.H. Dummer
 ENDODONTIC CANAL PREPARATION: NEW INNOVATIONS IN GLIDE PATH MANAGEMENT AND SHAPING CANALS by
drs. Clifford J. Ruddle, pierre machtou and john D. West
 Newer trends in endodontic treatment: A review article · january 2018
 Comparative evaluation of various techniques of biomechanical preparation: A SEM study ramesh chandra, ambrish kaushal,
ram autar, amit anand and anshul chandra^
DR.SSO

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DR.SSO

Advancements in biomechanical procedures in Endodontics

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