root canal preparation/ dental crown & bridge courses

Root canal preparation:
cleaning and shaping
INDIAN DENTAL ACADEMY
Leader in continuing Dental Education
www.indiandentalacademy.com

Contents:
 Introduction
 Definition
 Criteria for shaping
 Criteria for cleaning
 Objectives : biologic and mechanical
 Historical review
 Armamentarium: Irrigants, Devices( hand, rotary, lasers and
ultrasonics) & Medicaments
 Instrument manipulation

 Techniques:
 Apical- coronal techniques
- standardized technique
- step back technique
- balanced force technique
 Rotary instrumentation
 Ultrasonics
 Lasers
 Smear layer management: irrigants, medicaments, irrigation
techniques
 Procedural errors and management
 Cleaning and shaping in anatomical variation canals
 Conclusion
Coronal- apical techniques
- step down technique
- double flare technique
- crown down pressure less
technique
- canal master technique

Start with the end in mind

 The root canal system must be:
 Cleaned of its organic remnants
 Shaped to receive a three dimensional filling of the entire
root canal space
The canal is
 Cleansed primarily by irrigation
 Shaped primarily by instrumentation

Cleaning and Shaping
or
Shaping and Cleaning

Definitions
 Biomechanical preparation-
“Controlled removal of the root canal content and
the dentin by careful manipulation of the root canal
instruments and materials”
 Cleaning- removal of all contents of the root canal system
before and during shaping.
 Shaping- the development of a ‘logical’ cavity preparation
that is specific for the anatomy of each root.

Cleaning:
 Debridement is the removal of existing or potential irritants
from the root canal system.
 The goal is elimination.
 Objective:
 Reduce these irritants to a sub significant level.
 To obturate and sequester remnants within the canal.

 Principle of debridement:
 Instruments contact and plane walls to loosen debris
 Irrigants then flush the loosened and suspended debris,
chemical action further dissolves organic remnants and
destroys microorganisms.
Criteria for adequate cleaning (Walton)
 Clean dentinal shavings
 Clean irrigating solutions
 Glassy smooth walls

Shaping:
 Removal of a uniform layer of dentin in all dimensions and
all regions of the canal is also desirable.
 Is such uniform removal of dentin from all canal walls
achievable???
 The nature of canal dimensions, shape, and curves as well as
the physical properties of shaping instruments precludes the
possibility of a uniform, tapered , flowing preparation.

 Enlargement: enough to permit adequate debridement as well
as manipulation and control of obturating material and
instruments, but not so much that the chances of making
procedural errors and needlessly weakening the root are
increased.
 Taper: sufficient to permit deep penetration of spreaders or
pluggers.

Apical preparation
 Objective: Creation of apical matrix or constriction
 Master apical file (MAF): largest file that binds slightly at
correct working length after straight line access.
 Depending on apical foramen configuration and canal shape
and size, an apical stop or apical seat will be created by
apical preparation
 Apical stop: a barrier at the preparation end
 Apical seat: lack of complete barrier but the presence of a
constriction

Criteria for adequate shaping
 Instrument ( spreader) try-in (Walton)
 Three size larger than the first file binds (Grossman)
 For apical preparation (Walton)
- development of apical stop or apical seat

Biological Objectives ( Schilder )
 Removal of all tissue from the root canal space.
 Confinement of instrumentation to the roots themselves.
 No forcing of necrotic debris beyond the foramen.
 Creation of sufficient space for intra-canal medicaments.

Mechanical Objectives
 Continuously tapering funnel
from the apex to the access cavity.
 Cross-sectional diameter should
be narrower at every point
apically.
Continuous taper

 The root canal preparation should flow with the shape of the
original canal.
 The apical foramen should remain in its original position.
 The apical opening should be kept as small as practical

History:
 Fauchard – described instruments for trephination of teeth,
preparation of root canals and cauterization of pulps in his book
‘Le chirurgien dentiste’.
 Edward Maynard- developed first endodontic hand instruments.
 Arthur- used small files for root canal enlargement (1852)
 Gates Glidden drill in 1885 and K-file in 1915 were introduced.

 William H. Rollins(1889) developed the first endodontic
handpiece for automated root canal preparation.
 Austrian company W&H developed ‘Cursor filing contra-
angle’ handpiece (1928)

 Racer-handpiece (1958) and the Giromatic (1964)
 Richman first introduced the use of ultrasonic in endodontics
 Martin & Cunningham in the 1970s made ultrasonic devices
popular for root canal preparation.
 Standardization of instruments first proposed by
Trebitsch(1929) and Ingle(1958)
 ISO specifications for endodontic instruments published in
1974

 Ingle :1961: standardized technique
 Cleim and weine:1969-1974:step back tech
 Abous-Rass:1980:anticurvature filing
 Marshall:1980:crown down pressure less
 Goerig: 1982 step down
 Fava:1983/1992: double flare with modification
 Roane:1985:balanced force
 Torabinejad:1994:passive step back

ARMAMNETARIUM:

 Instrumentation of root canal
system requires both hand and
rotary files.
 No canal system can or should be
instrumented with rotary alone.

Broaches
 Barbed broaches
 Rasps
 Smooth broaches –
Pathfinder

K reamer vs. file

K file modifications
K-Flex
Flex-R

Flexofile
Flexicut
Golden Mediums

H-files:

H-file Modifications
 Burns Unifile
 Dynatrak S-file
 Safety Hedstroem
 NT Sensor file (MAC file)
 A-file

Unifile

Non-
cutting tip
A-File

H-File A-File

Safety Hedstroem
Safe sidedwww.indiandentalacademy.com

Apical Preparation Hand Instruments
 Apical Reamers (Otani)
 Canal Master (Wildey and Senia)
 Canal Master – U
 Flexogates
 Heliapical

Canal Master and Canal Master U
 Wildey and Senia
 1-2mm cutting head
 0.75 mm non-cutting head
 Blank shaft

Flexogates
 Hand modification of GG drills

Heliapical
 Apical 4-5mm length
 Blank shaft

Motion of instrumentation
 Filing / rasping: this terms refers to
push and pull action with instruments.
 Reaming: Indicates the clockwise /
right hand rotation of instrument. It is a
rotating pushing motion limited to ¼
to ½ turn.

 Turn and pull- file inserted with ¼ CW rotation and
inwardly directed pressure (reaming) followed by subsequent
withdrawal (filing).

Advantages :
 Relatively safe
 Very effective when carefully implemented
Disadvantages :
 Hourglass canals
 Ledge formation

 Watch winding- It is the back and forth oscillation of file
(30-60°) to right and left as instrument pushed forward into
the canal.

 Very effective
 Less aggressive
 Less chances of ledging

 Watch winding and pull- The file (H-file) inserted with right
and left back and forth motion (rocking) until it meet
resistance. Then file must be freed by pull stroke.

 Circumferential filing (Lim & Stock)- instrument is first
moved toward buccal side of the canal, then reinserted and
moved mesially. This continues around the preparation to the
lingual aspect and then to distal until all walls have been
rasped.
Buccal
Mesial
Lingual
Distal

 Anticurvature filing- filing preferentially away from the
inner curve or furcal aspect (danger zone)

Techniques for preparing root canals
 Apical- coronal
techniques
- standardized technique
- step back technique
- balanced force technique
 Coronal- apical
techniques
- step down technique
- double flare technique
- crown down pressureless
technique
- canal master technique

APICAL- CORONAL TECHNIQUE

Apical coronal techniques
‘Working length is established first and full length of the
canal is then prepared, sequentially increasing it in size until
the final shape is established.’

Standardized Technique:
 First formal root canal preparation technique
 Introduced by Ingle( 1961)
 “single length technique”
 Canal is prepared by enlarging it sequentially to selected size
W.L determined
↓
Smallest instrument adjust to WL
↓
Sequentially enlarged the canal
↓
Obturate with silver points accepted

WL determined
Smallest reamer
introduced Successively larger reamer used

 Advantages
- easy to master
- preparation has the same shape, size
and taper as a standardized instrument
- less time consuming

 Disadvantages
- use of larger reamer may cause canal
deviation apically
- difficult to debride complex canals
- risk of extrusion of debris
- designed for single cone filling technique

Stepback Preparation( Telescopic/ Flare/
Serial Preparation)
 clem and weine (1969-1974)
 stepwise reduction of WL for larger files,typically in 1 or 0.5
mm.

WL determined Sequentially enlarged canal
till #25 to full WL in
circumferential manner
Stepping back by 1mm from
WL at size 30 followed by
recapitulation with # 25

Stepping back by 2mm
from WL at size 35
Stepping back successively
by 5mm from WL at size 50
Refining coronal flare
with GG 1,2,3

 How much is the Stepping back distance?
- 1mm – Stock
- 0.5mm - Walton
 How much to step back?
- up to straight midcanal portion (Ingle)
- up to at least # 60 or # 70 no. instrument (Walton)

Advantages
- gives consistently the best taper and apical stop design
- less likely to cause periapical trauma
- facilitates removal of more debris

- greater flare allows more packing of GP
- develops apical stop preventing overfilling
- allows greater condensation pressure
during obturation.

 Disadvantages
- apical blockage
- alteration of WL
- tendency for canal deviation

Modified step-back:
 Here after apical preparation the step back procedures begins
2-3mm up to the canal.
 Gives short, almost parallel retention form to receive primary
GP

Balanced force technique (Roane et al )
“Positioning and preloading an instrument
through a CW rotation and then shaping the
canal with a CCW rotation”

Flex- R- file
 Machined from the blank of triangular cross-section.
 Has increased stiffness and strength in smaller sizes and
increased flexibility in larger sizes
 Cut most efficiently in CCW rotary motion

 Canals are enlarged to 3 pre-determined sizes – 45, 60, 80
according to size of preparation.
 This dimensions refers to the size of the file used at third step
back.
 Apical Control Zone- apical preparation obtained in which
each step back from MAF is 0.5mm shorter than the previous
one

create and standardized its own apical constriction

PHASE I - Placement Phase
PHASE II - Cutting Phase
PHASE III - Removal Phase

PLACEMENT CUTTING REMOVAL

WL determined Enlarge the canal to
size 25 to full WL
Size 30 & 35, 0.5mm
short of WL

Size 40, 1mm short
of WL
Size 45, 1mm short
of WL
Gates Glidden size 2-6 to
complete the complete
flare

 Advantages:
 This technique balance and maintains the file central
even in curved canal.
 Better control of the file
 Allows selective cutting
 It avoids transportations

 Disadvantage:
 Wide preparation, may lead to perforation
 Instrument prone to fracture
 Improved tactile sense required to control the instrument

CORONAL APICAL TECHNIQUES

“ coronal portion of the canal is prepared first
before determining the working length.”

Step-down preparation (goerig )
 Also called as crown down technique
 Coronal aspect of the root canal prepared and cleaned before
the apical part.

16-18mm coronal
part of canal
prepared with H-file
Coronal flare prepared
With GG 123
WL determined. Enlarge
till no.25 to full WL
Step down and
apical shape by stepwise
decreasing of WL
of incrementally larger files
GG 3 extending 1-2mm

Advantages
 Straighter Access
 It eliminates coronal interferences
 It removes bulk of the tissue and micro organisms before
apical shaping
 WL retention
 Better and deeper penetration of irrigant
 Better control over apical instrumentation
 Reduces ‘piston in a cylinder effect’

 Shaping subjectively easier
 No measurable effect on canal transportation

Disadvantages
 Apical blockage
 Formation of Ledges
 Perforations

Passive step-back preparation
- Torabinejad in 1994.
- It is a combination of rotary and hand
instruments for the root canal preparation.
- Passive enlargement of root canal, apical to
coronal

WL determined
Patency with #15 k file verified
The canal is passively and progressively enlarged using #20 to 40
# 2GG,#3GG
After confirmation of WL
# 2GG,#3GG
# 15 to 40 canal is prepared with progressively larger inst at successively
shorter length

Advantages
 Provides significantly cleaner canals
 Less chances of transportation
 Ease of clinical application
 Applicable in every canal type

Crown Down Pressureless Technique
 Introduced by Marshall & Pappin
 Described by Morgan & Montgomery
 Facilitate preparation in curved canals without causing the
deviation.
 Rotary action is used to cut dentin

Determine
radicular access
Widen 16mm of
coronal portion of
canal till 35 no.
Prepare the canal
with 30 no. file
without apical force
Prepare the canal with
10 no. file without
apical force

Repeat the
sequence starting
with size 40
Prepare the canal
15 no. file at full
WL
Repeat the
sequence with 45
Prepare the canal
20 no. file at full
WL

Repeat the sequence
starting with size 50
Prepare the canal
25 no. file at full WL

 Advantages
 Less extrusion of debris
 Effective in maintaining canal shape
 Less chance of alteration of working length

Double Flare technique (Fava)
 Indication:
 For straight canals
 Straight portion of curved canals.
 Contraindication
 Calcified canals
 Young permanent teeth with open apices

WL determined Introduce larger file (35) about
14mm coronal portion of the
canal
File with no. 30, 1mm deeper
than size 35
Continue deeper till WL reached
with smaller filewww.indiandentalacademy.com

File with size 10 to 1mm deeper
than size 15 (# 10 now at WL)
Prepare the canal till size
25 at full WL
.
Prepare apical portion
of canal by step back
preparation

Modified Double Flare technique:
 Advocated by Saunders & Saunders
 Uses non cutting tipped instruments with step back technique
 Preparation starts in the coronal part of the canal

# 40 Flex R file with balance force introduced in the straight
part of the canal
Sequentially larger sizes used to inst. straight part
Coronal 4-5mm inst. with GG (2 and 3)
# 20 file extended to WL. Canal prepared sequentially with BF
tech

 Preparation continued until clean dentin shaving obtained
 MAF varies between # 35-40 file
 Step back with Balanced force done to prepare remaining
curved portion

Canal Master Technique
 Introduced by Wildey and Senia
 Uses Canal Master instrument (SW Instrument)
- cutting portion reduced to 1-2mm with
0.75mm non cutting pilot tip
- the cutting portion resembles reamer with
blunted edges
- rest of the instrument is parallel sided
shank of round cross section
- maximum efficiency with CW rotary motion

 Canal Master (SW)
instrument

WL determined
Prepare the beginning of
the curve using canal
master-U (size 50)
Size 80 in instrument to
beginning of curve
size 20 to full WL (up
to # 50 )

size 50 to full WL
Size 55 1mm shorter
than WL
Size 60 2mm shorter
than WL
Size 80 4mm shorter
than WL

Advantages
 Prevents transportation of the canal
 Small cutting head provides minimum cutting surface with
maximum control
 Increased flexibility
 Instrument stays centre in the canal
 It gives finer tactile perception

 Evaluation of four methods of preparing curved canals :Rev Fr
Endod. 1990 Mar;9(1):23-30
 They compared four preparation types, two hand preparation and two
engine driven ones. The step back technique is not suitable for the curved
canal preparation.
 A comparison of maintenance of canal curvature using balanced-
force instrumentation with three different file types. J Endod. 1995
Jun;21(6):300-4
 NT files used with the BF technique were significantly less likely to
change canal curvature than either FR or KF files when instrumenting
curved root canals.

 A comparison of Flex-R files and K-type files for enlargement of severely
curved molar root canals. J Endod. 1989 Jun;15(6):240-5
 The balanced force technique and a step-back method for cleaning and
shaping root canalswere evaluated
 less apical transportation with the use of the balanced force technique
when compared with a step-back technique in canals exhibiting both
more curvature.
 Canal blockage and debris extrusion with eight preparation techniques. J
Endod. 1995 Mar;21(3):154-8
 The techniques included were standardized, stepback with reaming, stepback with
circumferential filing, stepback with anticurvature filing, double-flare, stepdown,
crown-down pressureless, and balanced force.
 most extrusion occurring with the stepback techniques with circumferential and
anticurvature filing and the least extrusion with the balanced force and crown-
down pressureless techniques.

 Effectiveness of two different methods for preparing curved root
canals. Endod Dent Traumatol. 1994 Oct;10(5):215-9
 The instrumentation systems tested were the Canal Master and a standard
circumferential filing technique in which conventional K-files were used.
 Canal Master instrumentation technique provided well-centered and
tapered preparations. Conversely, the use of conventional K-files with a
standard circumferential filing technique resulted in frequent alterations
of the initial pattern of the root canals, showing transportation of the
apical foramen and ledge formation.

THANK YOU

Engine driven instrumentation

Classification of Automated devices
(by Stock)
Automated devices
Sonic
Ultra Sonic
Rotary Reciprocal
Vertical Random
Rotary are Gates Glidden, Peeso Reamer.
Reciprocal ¼ turn hand pieces are Giromatic , Kerr endo lift, Racer,
Endocursor.
Vertical hand pieces are Canal finder, Canal Leader.
Random hand pieces are Excaliber.

 Reciprocal quarter turn:
 Instrument activated by 90° reciprocate arc
 Example, Giromatic
Giro-pointer (16mm long orifce opener)
Giro-broach
Giro-file (H-file configuration)
Giro-reamer
 This handpiece rotates at speed of 1000cycles/min.
Giromatic handpiece Reciprocal quarter turn

 Disadvantages
 Pack the debris in the canal
 Preparation took longer time
 Tendency to create ledges and flaring in apex
 Less effective compare to hand instrument
 Difficult to use in narrow canals.

 Vertical:
 Vertical movement (0.3 to 1mm) with free
rotational movement.
 Example, canal finder system: Canal master-U
and H-file with safe ended tip may be attached.
 Canal leader:
 It is 4:1 speed reduction handpiece.
 Vertical movement of 0.4-0.8mm and
contralateral rotation (30°)
 K-file with safe ended tip, H-file with safe
ended tip.
Canal leader
Vertical
movement with
free rotation

 Random:
 Random lateral vibration movement.
 Rotates at 20,000 to 25,000 rpm.
 It is bulky and difficult to use especially in posterior part of the
mouth.
Random movement
(Excalibur)www.indiandentalacademy.com

Nickel Titanium Revolution
54% Nickel is present
44% Titanium is present
2% or less Cobalt is present
Recently Boron was added to increase surface hardness [Lee et al J.O.E.
22:54, 1996]
Alloy exist in 2 different crystallographic forms -
1. At high temperature a body centered cubic lattice referred to as
AUSTENTIC phase which is a stable and stronger phase.
2. On cooling this AUSTENTIC phase transforms to a closely packed
hexagonal lattice referred to as MARTENSITIC phase which is the
weaker phase.

Advantages
2 –3 times more elastic flexibility (Walia et al 1988)
Can retain shape of curved canals and do not straighten out like
S.Steel instruments.
Superior resistance to fracture in clockwise and anticlockwise rotation
owing to ductility (Walia et al 1988)
Undergoes large amount of elastic deformation.

Cutting efficiency of Ni-Ti-Nol is only 60% then that of
matching S.Steel file
Does not give any indication of wear before it fractures
Disadvantages

Technique

Crown-down technique is the serial use of the instrument,
starting with the larger sizes and progressing toward the
smaller. NiTi rotary- shaping files are best used in a crown
down pressureless technique

Scouting the coronal 2/3rds
No: 10 and 15 hand files(0.02 taper) are used to scout the coronal 2/3rds.
Scouting instruments provide the following important information (Ruddle C.J):
•Cross sectional diameter of the canal
•Whether the canal is open, partially restricted or calcified
•Straight line access presence or absence-critical as it simplifies all
subsequent instrumentation procedures
•Pulp space anatomy

Instrument is inserted into the canal and passively pushed
apically with its handle gently rocking back and forth (15º CW & 15º
CCW)
This results in apical file movement :
In straight canals the file may slide to working length
In canals that are more curved, narrow or exhibit interradicular
divisions, rate of taper of the instrument often exceeds the rate of
taper of the canal. Consequently apical file movement is limited
.

 If the scouting file encounters restriction, when the file is snug, the file
should be pulled 1-2mm. The pull stroke will ensure that the instrument cuts
away form the terminus towards the region of the canal having an increasingly
larger cross sectional diameter. This cutting cycle is repeated around 5-6
times.
 Pre enlargement procedures are directed towards creating space for
more efficient rotary instruments

Prepare coronal third of canal

 Gates Glidden drills – safe tip
 Orifice opening
 Deeper penetration into straight canals
 Removal of lingual shoulder

Availability – Nos. 1 to 6

 Start crown-down instrumentation only after the canal at the root apex has
been enlarged with hand files to the size of a size 15 stainless steel K-file.
 Enlarge the coronal third of the canal with a suitable rotary instrument such as
an orifice shaper.
 One only has to penetrate 3 to 5 mm into the canal.
 Keep the file rotating at the manufacturer’s recommended speed.
 Move into the canal and out. Don’t dawdle and leave the instrument rotating
in the canal.
 Irrigate the canal with sodium hypochlorite or EDTA after using each
instrument.
 Check that the canal is still patent by passing a size 15 stainless steel K-file to
the apex and back.

Establish straight-line access to each canal orifice
 With the access cavity it is essential to have straightline access to
canal orifices. If there is a deviation of more than 20 degrees the case
is not suitable for rotary Ni-Ti instrumentation.

Establish working length and glide path using hand files.
 Hand files are used to establish working length and to
prepare the glide path for the rotary files

Prepare middle AND apical third of canal:

NON-AGGRESSIVE ROTARY FILE SYSTEM
Ni- Ti
Rotary Instruments
Pro Taper
Greater
Taper
Quantec
2000
Hero 642
Light Speed
Profile
K 3
RACE

Criteria:
•Flute design
•Radial land
•Cutting angle
•Non-Cutting tip
•Working surface
•Frictional resistance

Flute design – Should have progressively larger flute space distal to the blade
to avoid compaction of debris to form an effective channel for debris removal.
Radial land - is ground in the zone of contact between
the instrument and the canal wall. While working in
continuous rotation this section brings the following
advantages
•Cutting effectiveness giving more mass to cutting edge.
•Preservation of natural canal path with no risk of zip, thus
instrument remains concentric with the natural canal
•Safety due to the continuous rotating movement, removes
all danger of the instrument screwing itself into the canal
Cutting angle – Should be slightly positive for effective cutting action. If its too
much positive it binds without forming chips. If it has negative angle it will
scrape dentin rather than cutting it.

Frictional resistance- Should have a small marginal land.
Working surface or Taper :Decrease surface of instrument coming in contact
with the canal by giving greater taper. As a result all the forces get concentrated
in smaller area giving better cutting action.
Non -cutting tip (Pilot tip)- Functions as a guide allowing easy
penetration with only a minimum of apical pressure.
Core: The core is the cylindrical center part of the file having its
circumference outlined and bordered by the depth of the flutes.

 PRECAUTIONS TO BE TAKEN
 Instrument should be used with light pressure,as forcing these instruments
might break.
 In curved canals at the point of curvature if the nickel titanium
instruments are used continuously at the same point it will cause fatigue
of the alloy at that point of use.
 But on the other hand if a slight in and out movement is used, the fatigue
effect is disturbed along the entire length.Hence it is suggested that the
instrument be used in and out movement.
 Each instrument should be used in the root canal for only about 5 to 10
seconds.

Profile series
 Developed by Tulsa Dental co in 1994.
 Design
 Radial landed U-shaped flutes
 Cutting edges with 20° negative rake
angle
 Bullet shaped nose tip design with
rounded transition angle.
 Variable taper shaft Variable taper shaft
Bullet shaped nose tip

Range of instruments
 There are 3 instruments
 Profile orifice shapers: 5-8% taper,
available in no. 1-6 and length 19mm
Used to prepare coronary section of the
canal. The handle has 3 colour rings.
 0.06 profile taper: Taper 6%
Available no. 15 to 40;
length 21-25mm
used to prepare middle section of canal.
The handle has 2 coloured rings.
 0.04 Profile: Taper 4%
No. 15-90
Available in length 21, 25, 31mm.

Motor and speeds
 150-350rpm
 Independent electrical motor
Golden keys
 Light pressure
 In and out movement
 Irrigation
 Before canal preparation instrument the
canal with stainless steel hand file (#10)

Technique
 Crown down
Profile orifice shaper #3 (0.06/#40) (for
large canals #4 orifice shaper)
Profile orifice shaper #2 (0.06/#30)
Profile 0.06 taper #25

 Determination of working length
 Apical preparation
Profile 0.04 #20 to full working length
Profile 0.04 #25
Large canals #30, 35 also can be used
 Final flaring by 0.06 taper #20

Advantage of Profile Series
 Canal centering and maintain canal curvature
 Less instrumentation time
 Gives good coronal flare to the preparation
 Less transportation and ledging
 Less debris extrusion (Hinrich et al)
 Gives 3D effect for preparation.

Disadvantages
 Loss of tactile sensation.
 Intra canal separation
 Low cutting efficiency
 Corrosion

Profile Greater Taper Rotary Instrument
(GT Rotary)
 Designed by Steve Buchanan
 Variable pitched flutes
 Larger spacing of the flutes at the shank

 GT Rotary files
 4 files in this group (length 21 &
25mm)
 The handle has 2 colored rings
 Available in different
taper(12%, 10%, 8%, 6%)
 Used in preparation of coronal
third of the canal.

 GT rotary files
 4% taper, #20-35 (21,25 & 35mm length)
 Only one ring on their handle
 GT Accessory files
 12% taper #35,50, and 70 (21 & 25mm length)
 3 grooves on their handle
 For refining of coronal preparation

Operational sequence
 Crown down
 By using GT rotary files
 Profile GT 0.12 taper, #20
 Determination of W.L
 Apical preparation
 Profile 0.04 taper, #20

HERO-642 Rotary System
Features and Benefits:
 Three cutting edges for a positive cutting in
curette effect.
 Bigger inner core.
 Progressive fluting (less screwing effect).
 Three variable tapers.
 Tip which stays centre in the canal.
 Versatile.
 Economical.

Speed
 Contra angle hand piece at 300-600rpm.
Range of instruments:
 Available in 3 tapers.
 2% taper # 20-45 (21,25, 29mm length)
 4% taper #20-30 (21,25, 29mm length)
 6% taper # 20-30 (21, 25mm length)

Technique:
 For easy canals.
 Locate the canal orifice and determine working length.
 Use 0.06 taper #30 to 2/3 of W.L. (in and out and
circumferential movement).
 0.04 taper #30 2mm short of working length.
 0.02 taper # 30 to full working length.
 Recaptulate with hand file and irrigate.

 For canal with average difficulty.
 Same procedure but sequence begin with #25.
 For difficult canal:
 Same procedure but sequence begin with #20.

Quantec Rotary System
 Design features and benefits:
 Safe ended tip.
 Short handle.

 Set of 8 instruments available in different taper.
 0.12 taper
 0.10 taper
 0.08 taper
 0.06 taper
 0.05 taper
 0.04 taper
 0.03 taper
 0.02 taper #15-40 17, 21, 25mm length
 High torque control gear reduction slow speed handpiece
(300-350 rpm)
Identical tip
size # 25
17, 21,
25mm length

 Technique:
 Straight line access and check for patency.
 Determination of W.L.
 Establishment of glide path.
 Use instrument with 0.12 taper advance till you encounter
resistance.
 Follow the sequence till 0.03 taper.
 Apical preparation with 0.02 taper file from #15-40 to full
W.L.

Pro-taper rotary system
 Developed by Clifford Ruddle, Jhon West
,Pierr Machtou.
 Progressive taper: 3.5% to 19%
 Modified guiding tip and varying tip diameter
 Convex triangular cross section
 Varying helical angle and balanced pitches
 New shorter handle: 12.54mm

 Range of instrument
 Shaping files (3 files) SX, S1, S2
 Finishing files (3 files) F1, F2, F3
 SX or auxillary shaping files
 Highest increase in taper from D0 to D9 (3.9% to
19%)
 Shaping file 1 or S1 (purple ring)
 Shaping file 2 or S2 (white ring)
 Finishing files
 F1 (#20 Yellow ring, 7% taper from D1 to D3)
 F2 (#25 Red ring, 8% taper from D1 to D3)
 F3 (#30 Blue ring, 9% taper from D1 to D3)

Guidelines
 Straight line access
 Irrigation
 Smooth glide path
 Clean the flutes regularly
 Torque control electric motor at 200 to 300rpm
 Never force the file apically (light brushing motion)
 Use the instrument sequentially

Straight line axis
& gliding path
S1-file
(brushing motion)
SX-file Determination of W.L.
And S1 to full W.L.
S2 file – full W.L. F1 file – full W.L. Gauging of apical
Foramin (K-file #20)
F2 file – full W.L.
Operational Sequence

 Advantages
 High cutting efficiency
 Fewer instruments to complete the preparation
 Less debris in apical region
 File stress is minimized
 Less transportation and gouging
 Increased tactile sense
 Disadvantages
 Canal transportation
 Difficult to use in curved canals
 Cutting efficiency decreases with use

Light speed rotary system
Design features
 Short cutting head with long non cutting taperless
shaft.
 Flat radial land and U shaped blade.
 Slightly longer non cutting pilot tip
Range of instrument
 Set of ISO sized rotary files no.20-140, in length
21, 25, 31mm.
 Half size instruments 22.5, 27.5, 32.5 (white or
black ring on handle)

Guidelines
 Instrument should rotate at constant speed i.e., 1500-
2000rpm.
 Straight line access
 Patency of the canal should be maintained
 Use the instrument in proper sequence
 Irrigation i.e., NaOCl and EDTA
 Immediately withdraw a instrument once it reaches
working length while rotating.

Technique
 light speed technique
 Initial apical rotary (IAR)
 Master apical rotary (MAR)
 Final rotary (FR)
 Steps
 Proper access and coronal flare
 Determination of W.L
 Establishment of patency with hand K-file no.15
 Gauge the apical canal diameter and determine (IAR).
 Begin apical instrumentation with IAR size and end with the master
apical rotary (MAR) size.
 Instrument 4mm short of WL with next larger size.
 Instrument middle third with 3 to 4 larger size.
 Recapitulate to WL with the MAR

Hybrid / light speed & taper technique
 Coronal third of the canal prepared by using tapered
instrument.
 Apical portion of the canal cleaned by using light speed
instrument.
Advantages
 Larger apical preparation
 No or little transportation (Glossen et al, JOE 1995)
 More flexible
Disadvantage
 Time consuming

 Designed by Dr. John McSpadden (2002)

k3
Radial land relief
Reduces friction on canal walls
+ve rake angle provide
Active cutting action
3 rd radial land stabilizes
And keeps the inst centered
Wide radial land provides
blade support To resist tortional stresses
Safe ended tip minimizes
Apical transportation
variable core diameter
enhances flexibility
350 rpm speed

Range of instrument
 Body shapers
 0.08, 0.10 and 0.12 taper with tip size 25 (17, 21 & 25 length).
 Apical preparation files
 0.02 taper file, #15-40 (21, 25, 30mm length)
 0.04 taper file Tip size #15-60 (21, 25, 30mm
 0.06 taper file length)
Guidelines
 Never force a instrument apically
 Irrigation
 Patency should be maintained during preparation.
 Check the flutes of the file frequently.
 Use electric torque control motor with auto reverse to rotate the file (300-
350rpm)
 The instrument should not use more than 5-7 seconds

Technique
 Straight line access and locate the canal orifices
 Patency of the canal checked hand K-file
 Use 0.12 taper body shaper to resistance (3-4mm down
the canal)
 Take next 0.10 taper body shaper to resistance.
 Us e 0.08 body shapers to resistance
 Recapitulate and irrigation
 Determination of WL
 Use K3-rotary files in a crown down fashion
 With sequence (from larger tip size to smaller with fixed taper)
 With varying taper (mixing the taper as the tip size diminishes)

 With sequence
 Start apical instrumentation 0.06 #35 or larger to #15
until full WL (in narrow canal use 0.04 taper)
 Variable taper sequence
 0.06 K3 # 40 to resistance
 0.04 K3 # 25 to WL
 0.06 K3 # 25 to WL

Combination of K3 & light speed technique
 Advantages
 Excellent cutting ability
 Robust sense of tactile control
 Excellent fracture resistance
 More flexible
 Less screwing effect in the canal (variable flute pitch)
 They can be use easily in posterior teeth

Range of instrument
 Available in different tapers with ISO color
coding
 0.02 taper (#15-40)
 0.04 taper (#25-35)
 0.06 taper (#25-40)
 0.08 taper (#35-40)
 0.10 taper (#35-40)
 These instrument available in two kits
 12mm handle
 15mm handle
 Speed: Cordless single micromotor at a speed of
125-625 rpm.

S-Apex
 Apical preparation after using Race
 Inverted taper
 Non-threading
 Predetermined breaking point
 15-30 sizes
Weakest part at 16mmwww.indiandentalacademy.com

 Advantages
 Less work torque
 No screw-in effect
 More debris removal
 Reduce risk of metal fatigue
 Improved resistance to instrument fracture
 Optimum control

M Two
 Taper – 04-07
 10-40 sizes
 4 instruments
25, .07 taper, 30,.05 taper, 35, .04 taper and 40, .04 taper.

 Almost straight flutes
 2 flutes

Endo-Eze AET Instrument Motion
30°
30°
Internal water spraywww.indiandentalacademy.com

Endo-Eze AET Shaping Files
.025 .035 .045 .060
.10 .13 .13
Taper of File
Diameter at Tip
Shaping
File 1
Shaping
File 2
Shaping
File 3
.025
Shaping
File C
K-File Cross Section

Apical Hand Files
Working area =
12mm
Lengths:
19, 23, 27, 30mm
Tapers:
10-20 = ISO (.02)
25-50 = .0225
Triangular
Cross Section
Triangular
Cross Section

Ultradent
Endo-Eze AET
Hybrid
Hand
Reciprocating
~4-7 Steps

Ultrasonic Oscillation instruments
 Martin and Cunningham
 TYPES OF UNITS
 1.ULTRASONIC FREQUENCY 20-30 KHz.
 2. SONIC UNITS FREQUENCY 1-6 KHz.
 Piezoelectric unit generating ultrasonic waves which activates
a magnetostrictive handpiece
 K files or special diamond files are used
 Movement of file shaft between 0.001-0.004 inch at 20000-
25000/sec frequency

Method of action
 Initially described to be by cavitation or implosion.
Cavitation occurs when the ultrasonic file vibrates in a liquid
to produce alternating compression and rarefaction of
pressure. Leads to development of negative pressure within
the exposed cells which causes implosion.
 Acoustical streaming is a process by which a vibrating file
generates a stream of liquid to produce eddies and flows of
oscillation (Ahmed et al)
 Disadvantage:
 Shaping using larger files (no 30) zipping was always seen
(Chenail et al 1985)

MAGNETOSTRICTIVE
PIEZOELECTRIC
N = NODES
A = ANTINODES

 10 or 15 no files are recommended
 File inserted to full WL
 File movement- circumferential motion with smooth push &
pull stroke
 Time duration- at least 1minute
 Copious NaOCl irrigation must

Cavitation
Acoustic Microstreaming

 Advantages
 Better cleaning
 Enhanced chemical
and anti-bacterial
action of irrigant
 Disadvantage
- apical third of the canal
needs to be hand
instrumented

Ultrasonic file holder

Sonic oscillations:
SONIC AIR OSCILLATIONS

 Operate at 1500-6500 cycles /min.
 Prepare the canal by push & pull and circumferential strokes.
 Uses water as an irrigant
 Usually not requires diamond files
 Cleaning enhanced by acoustic micro-streaming with two areas of
turbulence - One at mid shank
- one at tip of the instrument.
 Rispi file (coronal 2/3rd
of canal)
 Heli-sonic file, Shapers – For apical 1/3rd

Sonic instruments
 RispiSonic
 ShaperSonic
 TrioSonic

Endosonic handpiece with file
Push & pull Circumferential

 Weichman and Johnson (1971)
 Laser systems for R.C. preparation can be by
 Thin optical fiber – Nd: YAG, Er,Cr: YSGG, Argon & Diode
 Hollow tube – CO2 & Er:YAG
 Used following Biomechanical preparation for additional
cleansing.
 Laser irradiation- ability to remove debris & smear layer after
BMP.
Lasers

 Steps:
 Working length determined
 Enlarge apical region with #15 file
 Begin with preparation with laser energy at 1500 milli
joules.
 Fiber optic inserted to working length and moved
circumferentially first apically and then coronally to
enlarge upto #60 file.
 Four exposures of 15 seconds are made.

 Limitations :
 Emission of laser energy-directed along the root canal & not
laterally to root canals
 Thermal damage to periapical tissues
 Hazardous for teeth in close proximity to mental foramen &
mandibular nerve

 “SIDE FIRING SPIRAL TIP”
 Designed to fit the shape & volume of canals prepared by
Ni-Ti rotary instruments.
 Emits Er: YAG laser- laterally to the walls of root canal walls
through the spiral slit located along the tip.
 Tip is sealed at its far end, preventing transmission of
irradiation to & through the apical foramen.

Non-instrumentation technology for root
canal preparation
 Lussi et al (1993)
 Consist of vacuum pump that is inserted with irrigant
(NaOCl)
 Cleaning by bubbling cavitation which loosened the debris in
the canal Which is removed out by negative suction.
 Disadvantage
 Cleans the root canal but it will not do any shaping.

Irrigants
Functions of irrigants :
Antimicrobial activity
Flushing action - debridement of the canal system
Dissolution of necrotic and vital tissues
Lubrication
Removal of smear layer
Bleaching action

commonly used irrigants:
 Sodium hypochlorite
 Iodine solutions
 Chlorhexidine gluconate
 EDTA
 Citric acid
 MTAD
 EAW: electrochemically activated water
 PAD:photo activated disinfection
 Ozone
 Endox

Commonly used medicaments:
 Calcium hydroxide
 Iodine and iodine and calcium hydroxide mixtures
 Antibiotics.

Cleaning regime:

Irrigation technique
 Disposable plastic syringes of 2.5 or 5 ml capacity with
25 or 27 gauge blunted needles.
 Plastic syringes in the 10 to 20 ml range may offer the best
combination of sufficient solution volume and ease of
handling.
 The barrel tip should be a Leur Lok design , rather than
friction fit to prevent accidental needle dislodgement during
irrigation.

 The needle should be bent to an obtuse angle, to reach the
canals of posterior as well as anterior teeth.
 The needle is inserted into the root canal so that it does
not binds.
 Sufficient room between needle and canal wall allows for the
return flow of the solution and avoids forcing of solution into
the periapical tissue.

 Return of solution is collected on
- gauge piece
-aspirated
 In narrow root canals, the tip of the needle is placed in the
root canal and the irrigant is discharged until it fills the pulp
chamber.

 Drying should be done with absorbent points.
 Most of the residual irrigating solution may be removed from
the root canal by holding the needle of the syringe in the canal
and withdrawing the plunger slowly.
 Compressed air must not be used for drying the root canal
because tissue emphysema may result if an air bubble
penetrates the periapical tissue.

Special considerations in curvatures
 Precurving of instruments:
 Easy insertion
 Prevent ledging.
 It is best to enter canals only with the files
precurved. the file will have a better chance to
traverse any canal curvatures, if obstruction is
encountered, mild rotation of the handle will
allow the tip to slide off and continue towards the
apex

 Pre-curving can be done by grasping with a gauge
sponge and carefully bending with the blades of files
until desired curvature is attained.
 Two types of precurving :
 Placing extremely sharp curve at the tip of
instrument.
 Gradual for entire length of the flutes.

 Stop may be altered with a nick or flat end to indicate
the curve.
 Rubber stop with teardrop shape

COMMERCIAL DEVICES

 Anticurvature filling:
 It maintains the integrity of canal walls at their thin
portion and reduces the possibility of root perforation /
stripping.
 Maintains digital control over the instrument and the
preparation of the curved canal.

Narrow curved canals
 The apical segment of root canals is cleaned with no10
file to WL.
 If the file binds firmly 1mm or 2mm short of WL, it
shouldn't be forced apically beyond this point.
 The SS tip of file is cut 1mm.
 A diamond file is used to to reestablish and to smooth
the tip.
 The file is precurved.
 It may be necessary to modify subsequent inst in this
manner to effect the apical prep that is at least #25 or
30.

S shaped/Double / Bayonet shaped
canal:
 First clean the apical foramen with no.10 file.
 Introduce small H-file to junction of middle and apical
third of canal and file the inner portion of curve.
 After filing the inner portion of the curve of the middle
third once with H file.
 One should recapitulate with no 10 file to WL and
irrigated.
 Repeat until curve is eliminated.
 Instrumentation of apical third of the root canal
follows.

Dilacerated canal:
 Enlarge the cervical and middle third of canal first.
The apical segment can be cleaned.
 Introduce small H-file to beginning of the curve and
with out forcing the file apically do circumferential
filing.
 Irrigated and refiled to WL with no 10 file

 Repeated until middle and cervical thirds are
open wide enough that apical third can be
instrumented without forcing the instruments.
 One should prepare no 15 file by dulling the
flutes on the outer portion of the apical third and
inner portions of the middle third of the curved
instrument.
 Prevents transportation and over instrumentation

Procedural Accidents
Procedural accidents in endodontics are those unfortunate
occurrences that happen during treatment, some due to inattention to
detail, and others totally unpredictable.
Complex pulp space systems acknowledged to exist
biologically , but technically inaccessible can now be uncovered with
the use of surgical microscopes and Ni-Ti instruments.

 Loss of working length
 Ledging, zipping, elbow
 Separated instruments
 perforation
 Over instrumentation
 Canal blockage

 It is a very common and frustrating error usually noted on a
master cone radiograph.
 It is actually secondary to the other procedural errors.
loss of working length

 Sound, reproducible reference points should be used.
 Direction and reference stops.
 Pre curving
 Consistent radiographic angles
 Copious irrigation
 Sequential file sizes

Ledging
Any deviation from the original canal curvature results in the formation of a
ledge.
CAUSES
Inadequate access cavity preparation
False estimation of pulp space direction
Failure to pre-curve SS instruments
Failure to use instruments in a sequential manner
Attempt to retrieve separated instruments
Attempt to prepare calcified canals

 Early recognition of ledge formation is advantageous
 Ledges created by larger files are more difficult to bypass
 Smaller files, precurving
 The file is inserted into the canal and circumferentially rotated to
detect the catch. once the catch is felt, the file is carefully rotated in
with slight in out motion until tip of the file bypasses the obstruction
and negotiates the canal to length.
 File is verified radiographically
 The file is not removed ,the file is used circumferentially and with
small amplitude strokes to dislodge the packed debris apically.

Transportation, elbows and zips
Transportation or transposition of the apical
portion of the canal

 Zips cant be altered once formed.
 Elbows and zips are caused by the file attempting to straighten in
the canal as it is worked up and down.
 Filing produces a narrowest cross sectional area at the elbow and
with the canal widening into the zipped region further apically. The
resultant space is difficult to clean and obturate.

Strip Perforation
Danger
zone
Safe
zone
Strip perforation occurs in the middle part
of the inner curve of a root canal if
excessive dentine is removed during
preparation.
This may be result of relatively large and
stiff files attempting to straighten within the
root canal or overuse of GG or orifice
shapers

Debris/ Dentin mud
Prevented by irrigation and recapitulation
If blockage has already occurred, NaOCl or EDTA used to
soften the accumulated followed by use of scouting files.
Canal Blockage

CONCLUSION:
 The revolution of automated endodontic combined with
advances in hand instrumentation have changed the
long we shape and clean canals.
 Thus combining the art of proper shaping and the
science of immaculate cleaning will culminate in ideal
preparation that will lay the foundation for ideal
obturation and healing and ultimately successful
therapy.

Cutting tips:
 Makes rotary more aggressive
 It has the ability to enter narrow ,calcified canals.
 Going long with cutting tip : elliptical tear upon retraction
 Non cutting tip : concentric circle
 Cutting tip on a non-landed file:distinct possibility of
transportation.
 Profile ,GT, K3, employ a non-cutting tip.
 ProTaper and the RaCe have cutting tips

Taper
 Same taper but with varying apical tip diameters Eg Profile that
has a constant taper (.04) but has varying apical tip diameters
 Same apical tip size but taper varies from .04 to .12. Eg
Quantec files use a graduated increase in taper
 variable or graduating tapers :each successive file is only
engaging a minimal aspect of the canal wall.
 frictional resistance is reduced and requires less torque to
properly run the file.

Radial lands
 Combination of a non-cutting tip and radial land that keeps a
file centered in the canal. Eg Profile
 Peripheral strength can also be added to a file by extending
the width of the radial land.

 full radial lands (Profile, GT) or their lands recessed (Quantec).
 full land design effectively keeps the file centered,
 recessed land feel allows for less frictional resistance.
 The K3,like the Profile, is a three fluted file with three lands. However,
two of the lands are broad and recessed, while the third one is a narrow
full land.
 Relieved portion of the recessed lands minimizes resistance while the
extended width maximizes strength
 ProTaper and RaCe do not have the benefit of radial lands.

Rake angles
 Positive rake angles will cut more efficiently than neutral rake angles,
which scrap the inside of the canal.
 Most conventional endodontic files utilize a negative or “substantially
neutral” rake angle.
 A negative rake angle is least aggressive but the cutting efficiency of a
file can also be effected by the blank design.
 For example, the ProTaper has a negative rake angle but due to its
modified K blade and progressive taper, the instrument cuts very
effectively.

Helical angle
 Helical angle is the angle that the cutting edge makes with the long axis
of the file.
 Files with a constant helical flute angle allow debris to accumulate,
particularly in the coronal part of the file.
 Additionally, files that maintain the same helical angle along the entire
working length, will be more susceptible to the effect of “screwing in”
forces.

 The RaCe file, is unique and utilizes an “alternating helical
design” that reduces rotational torque by using spiraled and
non spiraled portions along the working length
 This design feature also reduces the tendency of the file to get
“sucked into” the canal.

Pitch
 Pitch is the number of spirals or threads per unit
length.
 The result of a constant pitch and constant helical
angles, is a “pulling down” or “sucking down into”
the canal.
 significant in rotary instrumentation when using files
with a constant taper.
 K3, file has purposely been designed with constant
tapers but with variable pitch and helical angles.
 The result is a dramatic reduction in the sense of
being “sucked down into” the canal. This is very
significant, especially when performing a fully tapered
.06 preparation.

File Cutting tip Radial
land
Variable
helical
angle
Variable
pitch
Rake angle K blade U blade
protaper Yes: No Yes Yes Negative yes
Race Yes: No Yes Yes Negative Yes
K3 No Yes Yes Yes Positive
Light speed No Yes Yes
Quantec No Yes Yes Positive
Profile .
04/.06
No Yes Neutral Yes
GT No Yes Neutral Yes
29 No Yes Neutral Yes

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