A concise and brief presentation on cleaning and shaping of root canals. Colorful and well pictured. Ideal for UG students and PG students to get a good understanding of BMP techniques.

1. Cleaning and Shaping
of Root Canal
Systems
Presented by:
Dr Aaron Sarwal

2. Introduction
• Clinical evidence
demonstrates that root canal
systems can be cleaned and
shaped and obturated in
three dimensions with a high
degree of predictability,
approaching 100% success.
• The major objective of the
root canal treatment
procedure is to remove the
contents of the pulp space
and shape the walls of the
canal to receive the filling
material.
KNOWLEDGE
DESIRE
SKILL
Elements determining the predictability of
successful endodontics.

3. Brief History
• In 1852 Arthur used small files for root canal
enlargement.
• Ingle and Levine (1958) listed standardization for
instruments.
• Ingle described conventional technique/ standardized
taper technique of root canal preparation.
• Almost 50 years ago, Schilder introduced the concept
(and the expression phrase) "cleaning and shaping."
Cohen’s Pathways of the pulp 10th edition

4. Cleaning and Shaping
• Cleaning refers to removal of all contents of
root canal system before and during shaping
that is organic subtracts, microflora, bacterial by
products, food debris, caries, denticles
pulpstones previous root canal filling materials
and dentinal shavings.
• Shaping refers to specific cavity form with five
design objectives.
Cohen’s Pathways of the pulp 10th edition

5. Shaping of Root Canals
• Shaping process of the root canal can be
classified into five phases-
Phase I Negotiating the canal- “patency filling”
Phase II Coronal pre enlargement
Phase III Working length measurement
Phase IV Root canal shaping techniques
Phase V Root canal working width

6. Objectives of Cleaning and Shaping
• The primary objectives in
cleaning and shaping the root
canal system are to:
▫ Remove infected soft and hard
tissue
▫ Give disinfecting irrigants
access to the apical canal space
▫ Create space for the delivery of
medicaments and subsequent
obturation
▫ Retain the integrity of radicular
structures

7. Herbert Schilder's Five Mechanical
Objectives
Schilder H: Cleaning and shaping the root canal, Dent Clin North Am 18:269, 1974.
Develop a continuously tapering conical form in the root
canal preparation.
Make the canal narrower apically, with the narrowest cross-
sectional diameter at its terminus.
Make the preparation in multiple planes.
Never transport the foramen.
Keep the apical foramen as small as is practical.

8. Biological objectives:
• To completely debride the pulp
space from-
Pulp tissue
Bacteria / Microorganisms
Dentinal debris
Endotoxins

9. Weine’s Rules For Canal Preparation
1. Preparation must enlarge
the canal while
maintaining the general
form of the preoperative
shape, but it also must
develop the most desirable
shape to fill.

10. Weine’s Rules For Canal Preparation
2. Once working length is determined all
instruments should be kept within the confines
the canal.

11. Weine’s Rules For Canal Preparation
3. Instruments must be used extravagantly,
especially the smaller sizes.

12. Weine’s Rules For Canal Preparation
4. Canals must be prepared in wet environment

13. Motions of Cleaning and Shaping (Cohen, 6th ed)
• Used initially during cleaning and shaping, or
any time an obstruction blocks the foramen.Follow
• It is simply an in-and-out, passive motion
that makes no attempt to shape the canal.Follow-withdraw
• The precurved reamer should gently touch the
dentinal walls and "cart" away debris.Cart
• Carving is for shaping. Reamers are the best
instruments for carving and sculpting.Carve
• Smoothing is usually accomplished with files.
Also known as circumferential filing motionSmooth
• It means simply that the portal of exit has
been cleared of any debris in its path.Patency

14. Motions of Instrument Manipulation
• Several motions of manipulation are useful for generating or
controlling the cutting activity of an endodontic instrument.
• These may be referred to as envelopes of motion, historically
1. Filing
2. Reaming
3. Turn And Pull
4. Watch Winding
5. Balanced Force Instrumentation.
6. Anti-curvature Filing

15. 1. Filing
• The term filing indicates a push-
pull action with the instrument.
• The inward passage of a K-type file
under working loads is capable of
damaging the canal wall very
quickly, even when the slightest
curvature is encountered.

16. 1. Filing
Standard K-type file is pushed into a curved canal the junctional angles gouge the wall
rather than reorient to the curvature. This action can form a ledge very rapidly.

17. 1. Filing
The same motion with a modified tip produces little alteration of the canal wall since
most of the cutting ability has been removed.

18. Circumferential Filing
• Instrument is first moved
toward the buccal side, then
reinserted & removed
slightly mesially. This
continues around the
preparation to the lingual
aspect & then to the distal
untill all dentin walls have
received rasping.
• Enhances preparation when
a flaring method is used by
widening the orifice of the
canal.
6th ed. Pg 166/7Weine
Reaming
action
Keyhole
Circumferential filing

19. 2. Reaming
• The term ream indicates
clockwise or right-hand
rotation of an instrument.
• Rotating any endodontic
hand instrument to the right
may be risky, though this risk
is subtle and goes unnoticed
until an instrument fractures
under the load.

20. 2. Reaming
This in turn increases the strain or working load against
the instrument. That strain continues to rise until the
instrument ceases to move.
As they slide into the canal more and more of the length of
the instrument engages the canal.
This configuration causes them to slide into the canal as
the edges rotate to the right.
The cutting edges of all endodontic files and reamers
spiral about the shaft of the instrument.

21. 2. Reaming
They have a nearly axial orientation of the cutting edges and feed themselves
into the canal with less force when rotated to the right than K-type or H-type
files.
Specialized instruments (i.e., reamers) manage the complexity of this motion.
If the instrument over inserts and bends, further rotation will
break it.

22. 3. Turn and Pull Motion
• A quarter turn to the right is followed by a
straight outward pull. The arrow indicates a light
inward force, which engages the file before
rotation.

23. 4. Watch Winding Motion
• Watch-winding is the back-and-forth oscillation of a file (30 to
60 degrees) right and (30 to 60 degrees) left as the instrument is
pushed forward into the canal.
The back-
and-forth
movement
of K-type
files and
reamers
causes them
to plane
dentinal
walls rather
efficiently.
Motion is
less
aggressive
than
quarter
turn-and
pull
motions, as
the tip is not
pushed as
far into the
apical
regions
30 to 60
degrees of
clockwise
rotation
pushes the
file tip and
working
edges into
the canal
30 to 60
degrees of
counter
clockwise
turn
partially
cuts away
the engaged
dentin.

24. 4. Watch Winding Motion
• The arched arrow indicates a gentle right and left rocking motion
that causes the instrument to cut while light inward pressure
(straight arrow) keeps the file engaged and progressing towards
the apex. The arc of rotation is indicated by the shaded region in
the circle.

26. 4. Balanced Force Technique
(James B. Roane 1985)
• When file engages, with apical
pressure, 1/4 turn (clockwise for all
instruments according to Buchanan its
easier for right handed dentists this
way!)
• Then again, with apical pressure, 3/4
turn counterclockwise
• If done properly, at this time you will
hear a "click" when the instrument is
cutting dentine . Repeat sequence 2 or
three time.
• The black arrow indicates that one
should alternate these two directions
until the working depth is reached.
• The inward pressure and the rotating
force should always be very light.

27. 4. Balanced Force Technique
(James B. Roane 1985)

28. Anti-curvature Filing
• Put forward by Abou-
rass, Frank, and Glick
• Involves filing away
from the inner curve
of a root to reduce the
risk of a strip
perforation.

29. Anti-curvature Filing

30. Recapitulation
• Re-instrumentation with a
smaller instrument following
each irrigation step.
• Use of a smaller instrument to
remove debris produced during
instrumentation.
• Prevents pushing debris
beyond the apex and apical
plug formation.

31. Techniques Of Pulp Space
Preparation
Apical to Coronal
• Standardized
preparation
• Step back preparation &
modifications by:
• Schilder
• Weine
• Passive step back
• Roane Balanced Force
Coronal to Apical
• Step down technique
• Double flare technique
• Crown down pressure
less technique
Hybrid technique
• Step back step down
combination procedure

32. Standardized Preparation John Ingle(1961)
• Same working length definition
for all instruments introduced into
root canal and relies on the
inherent shape of the instruments
to impart the final shape to canal.
• Negotiation of fine canals is
initiated with fine files that are
then advocated to WL and worked
until a next larger instrument may
be used.
• The final shape is predicted by the
last used instrument.
Hourglass preparation

33. FEATURES STEP- BACK STEP DOWN HYBRID
AUTHOR
CLEM AND WEINE
1969-74
GOERIG 1982
CONCEPT
Involves preparation of
the apical third initially
followed by middle and
coronal third of the
canal using larger
instruments.
Involves preparation of
the coronal two thirds of
the canal first followed by
middle and apical third of
the canal
Involves
combination of
crown down and
step back
techniques
SEQUENCE OF
INSTRUMENTATION
RECOMMENDED
INSTRUMENTS
Hand instruments
Hand and rotary
instruments
Hand and rotary

34. PRINCIPLE
MOTION OF
INSTRUMENTATI
ON
• Coronal
instrumentation
with reaming
motion and apical
instrumentation
with
circumferential
filing
• Reaming motion
• Coronal
instrumentation with
reaming motion and
apical
instrumentation with
circumferential filing
ADVANTAGES
• Popular technique
employed with 2%
SS files
• Ability to prepare
proper apical stop
• Shaping is easier
• Elimination of the
bulk of micro
organisms, tissue
and debris from
middle coronal
third before
shaping apical third
• Minimizes debris
extrusion
• Better penetration
of irrigants
• Optimizes the
advantages of crown
down and step back
techniques
LIMITATIONS
• Extrusion of debris
into periapex
• Tendency to
straighten the
canal
• Gauging of the
apical third is done
as the last phase of
the procedure
• Middle third should
be carefully prepared
in order to prepare a
continuous tapered
preparation

35. STEP BACK PREPARATION
(Telescopic, Serial root canal prep)
• Phase I
• Apical preparation up to the
file #25(MAF) to full WL
with recapitulation using
prior size files.

36. STEP BACK PREPARATION
(Telescopic, Serial root canal prep)
• Phase II
• Stepping back procedure in 1
mm increments
• Recapitulation with no. 25
file till full working length

37. STEP BACK PREPARATION
(Telescopic, Serial root canal prep)
• Phase II-A
• Refining phase
• Gates Glidden no 2, 3, 4 are
used to create coronal and
middle preparations.

38. STEP BACK PREPARATION
(Telescopic, Serial root canal prep)
• Phase II-B
• Return to # 25 last file (MAF)
• Short of working length to
smooth the step back with
vertical push- pull strokes
(circumferential filing) H files
used.
• Guttmann “final prep should
be exact replica of original
canal configuration”

39. STEP BACK PREPARATION
(Telescopic, Serial root canal prep)
• Final Preparation
• Final form with smooth taper.
Advantages
Better tactile
awareness
Keeps apical
preparation small
in its original
position- gradual
taper
Ability to prepare
proper apical stop
Avoids zipping
Disadvantages
Chances of
pushing debris
into peri-
radicular tissues
WL likely to
change as canal
curvatures are
eliminated

40. Modifications Of Step Back
• Schilder
▫ Advocated canal bed enlargement, shaping
consisted of placing instrument larger than MAF to
a point of 1st binding and then using reaming
action to enlarge coronal portion, no force applied
apically, Gates glidden used coronally
▫ Allows body of canal to be prepared without
procedural errors, permits natural morphology
• Weine
▫ precurving of files to minimize canal alteration

41. Modifications Of Step Back
• Passive Step- Back
▫ Developed by Torabinejad uses a combination of hand
and rotary instrument to develop flared preparation.
▫ Gradual enlargement of root in apical to coronal
without application of force, rotating at 1/8 to one
quarter turn
• Advantages:
▫ Reduces risk of apical transportation, removal of
debris and canal obstruction, gradual passive
enlargement
▫ Also advocated for use with ultrasonic instruments

42. Modifications Of Step Back
• Modified Step- Back
▫ The preparation is completed in the apical area,
and then the step-back procedure begins 2 to 3
mm up the canal.
▫ This gives a short, almost parallel retention form to
receive the primary gutta-percha point when lateral
condensation is being used to fill the canal.
Ingle 5th ed. pg530

43. Apical to Coronal Preparation:
Advantages and Disadvantages
ADVANTAGES
Conservation
of tooth
structure
especially in
cervical third
DISADVANTAGES
Apical plug
Decreased
volume of
irrigating
solution
Procedural
mishaps

44. Coronal To Apical Preparation:
Advantages and Disadvantages
ADVANTAGES
Better tactile awareness in
negotiating the delicate
apical third
microanatomy.
It reduces pressure
Holds greater volume of
irrigant - enhances
cleaning.
Removal of dentin mud
decreases post treatment
problems
Improves identifying the
foramen
EPT more reliable
DISADVANTAGES
Increased removal of
tooth structure

45. Step Down Preparation
• First suggested by Schilder in 1974
• Goerig 1982 named and described the technique in
detail
• Principle- coronal aspect of the root canal is
prepared and cleaned before the apical part

46. Step Down Preparation
1
• In this method, the access cavity is filled with sodium hypochlorite, and
the first instrument is introduced into the canal.
2
• Start with exploration of the canal with a fine, stainless steel, .02 taper
(No. 8, 10, 15, or 20 file, determined by the canal width), It is important
that the canal be patent to the apical constriction before cleaning and
shaping begin.
3
• Sometimes the chosen file will not reach the apical constriction, and
one assumes that the file is binding at the apex. But, more often than
not, the file is binding in the coronal canal.
4
• In this case, one should start with a wider (0.04 or 0.06 taper)
instrument or a Gates-Glidden drill to free up the canal so that a fine
instrument may reach the mid- and apical canal.

47. Step Down Preparation
Prepare the coronal portion of the canal to the depth of 16-18 mm
or to the beginning of the curve using Hedstroem files 15,20,and
25 in a circumferential filling motion.

48. Step Down Preparation
• Gates Glidden drills 1,2
&3 are then used to
refine the coronal
preparation, the no 3
drill extending 1-2 mm
into the canal orifice.
• A – No. 3 GG Drill
• B – No. 2 GG Drill
• C – No. 1 GG Drill

49. The next sequence of instruments are used in
crown down fashion
The instruments are used in a watch-winding
motion until the apical constriction (or working
length) is reached.
When resistance is met to further penetration,
the next smallest size is used.
Irrigation should follow the use of each
instrument and recapitulation after every other
instrument
Then the apical preparation done upto 25 size
with enough lubrication, irrigation, and
recapitulation

50. Rotary Instruments that are used in crown
down technique are-
• Profile
• Profile GT
• Quantec
• Light speed
• protaper
• Race
• Hero 642
• Hyflex
• K3

51. Modifications Of Crown Down Technique
• Crown Down Pressureless
• Balanced Force Technique
• Double Flare Technique

52. CROWN DOWN PRESSURELESS
• Suggested by Marshall and Pappin.
• Basic sequence similar to step down technique
• Used in rotary system and hand system with
greater taper
• Early coronal flaring GG drills is followed by an
incremental removal of dentin from coronal to
apical direction- hence called as ‘crown-down’
technique.
• Straight K files are then used in large to small
sequence with a reaming motion with no apical
pressure- hence called as ‘pressureless’ technique.

53. Balanced Force Technique

54. Double-Flare Technique
• Fava presented this technique
• Consisted of exploratory action with small size
file, a crown- down portion with K files of
descending sizes, and an apical enlargement to
size #40 or similar.
• He recommended stepping back in 1mm
increment with ascending file sizes and frequent
recaptulations with MAF

55. Hybrid Technique
• Achieving patency with pre curved no. 10 or smaller K file
• Passive pressureless placement of sequential sizes of # 15, 20 and 25
K files to the point of canal binding
• Coronal pre enlargement with GG drills in the sequence no. 3, 2 and 1
( Not beyond 3 -4 mm of canal orifice)
• Establishing the working length
• Placement of 40 or smaller k file to the point of canal binding

56. Hybrid Technique
• Enlarging working length from size 15 k file to
recommended master apical file sizes
• Canal preparation done with sequential use of
progressively larger instruments placed successively
short of working length
• This step back is performed till middle third to obtain
continuous taper preparation

57. Non-instrumentation Root Canal Cleansing
• Lussi and his associates
at the University of Bern,
Switzerland, introduced
devices to cleanse the
root canal “without the
need of endodontic
instrumentation.”
• The first device, reported
in 1993, consisted of a
“pump” that inserted an
irrigant into the canal,
creating “bubbles” and
cavitation that loosened
the debris.

58. Mishaps During Cleaning and Shaping
1. Loss Of Working Length
2. Blockage Of The Canal System
3. Ledging
4. Breakage Of Instruments In The Canal
5. Zipping
6. Stripping Or Lateral Wall Perforation
7. Overinstrumentation
8. Overpreparation/Underpreparation

59. 1. Loss Of Working Length
• CAUSES:
▫ Due to rapid increases in file size and
accumulation of dentinal debris in the
apical one third of the canal
▫ Malpositioned instrument stops
• PREVENTIVE MEASURES:
▫ Frequent irrigation with naocl
▫ Recapitulation
▫ Periodic radiographic verification of
working length
▫ Proper use of instruments stops
▫ Use of directional stops in
▫ Curved canals

60. 2. Blockage Of The Canal System
• CAUSES:
• Packing of dentin
chips, tissue debris,
restorative materials,
cotton pellets, paper
points or a fractured
instrument in the canal

61. 3. Ledging
• A ledge is an artificially created
irregularity on the surface of the
root canal wall that prevents the
placement of instruments to the
apex of an otherwise patent canal
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

62. 4. Breakage Of Instruments In The Canal
• Causes of breakage
 Torsional fatigue
 Flexural fatigue
• Management
 Bypass
 Retrieval
• Prevention
 Knowledge of the physical
characteristics of the instrument
 Flaws, such as shiny areas or
unwinding are detected on the flutes
 Instrument bending or crimping
occurs due to excessive use
 The file kinks instead of curving
 Corrosion is noted on the instrument

63. Classification of Damaged Instruments
Type I Bent instruments
Type II Stretching or straightening of twist
contour without bending
Type III Peeling or tearing off of metal at
the edges without bending or
straightening
Type IV Partial reverse twisting of
instruments
Type V Cracking along the file axis
Type VI Fracture of the instrument
T. Sotokowa classified the types of damage to instruments:
Unused Blunt Distorted

64. Retrieval of Separated Instruments
• Ultrasonic Tips
• Stieglitz forceps
• Perry gold foil pliers
• Peet splinter forceps
• Hartment 3½ CVD mosquito forceps
• Forceps

65. Masserann Kit - Introduced By Masserann
EXTRACTORSTREPHAN BUR
MASSERANN KIT

66. Masserann Kit – Technique of Application

67. 5. Zipping
• Refers to transportation of the
apical portion of the canal
• It is characterized by a normally
curved canal which has been
straightened, especially in the
apical third
CAUSES
▫ Failure to pre-curve files.
▫ Rotation of instruments in
▫ Curved canals.
▫ The use of large , stiff
▫ Instruments to bore out
▫ A curved canal.
APICAL FORAMEN TENDS TO BECOME
TEARDROP SHAPED OR ELLIPTICAL

68. 6. Stripping Or Lateral Wall Perforation
Refers to thinning of the lateral
root wall with eventual perforation
CAUSES
• Overzealous instrumentation In
the mid-root areas of certain teeth,
usually molars
PREVENTION
• Use of anti-curvature filing.
• Clean & shape the canals using
small files extravagantly & in a
sequential manner.
• Avoid using large-diameter
instruments as well as rotary
instruments

69. Diagnosis Of Perforations
• The key factors for repair are immediate sealing
of the perforation.
• Diagnosis Of Perforation:
▫ Apex locators
▫ Surgical microscopes
▫ Radiographs
▫ Paper points
▫ Bleeding
▫ Pain
▫ Loss of tactile sensation

70. Perforation Repair Materials
 MTA - latest, attaches to cementum,
long setting time
 Glass ionomer- good flow
 Composite- curing is a problem at mid
root level
 Zinc oxide eugenol - irritates the
tissues
 IRM- less eugenol - less irritation
 Super EBA- less eugenol than IRM
 Gutta percha - for apical perforation
 Amalgam- not used any more

71. 7. Over-instrumentation
• Violates the periodontal ligament and
alveolar bone.
• Loss of apical constriction creates:
▫ An open apex
▫ Lack of an adequate apical seal
▫ Pain & discomfort to the patient

72. Prevention of Over-instrumentation
Using good radiographic technique
Accurately determining the apical constriction of the
root canal
Using stable instrument stops placed perpendicular to
the shaft of the instrument
Retaining all instruments within the confines of the
canal system.
Occlusal refinement or reduction prior to working
length determination and instrumentation
Attention to detail during all cleaning and shaping
procedures and
Assessing the integrity of the apical stop with stiff
paper points or files.

73. 8. Under-preparation
• It is the failure to remove pulp tissue,
dentinal debris, and micro-organisms
from the root canal system.
• Underprepared canals are best
managed by adhering to sound
principles of :
▫ Proper length determination
▫ Canal cleaning & shaping
▫ Recapitulation
• Treatment for
overpreparation/underpreparation is
“retreatment”

74. Conclusion
• Endodontist has a wide array of
instruments and techniques at its
disposal.
• Ni-Ti Rotary instruments need
the practitioners expertise and
one should use them in-vitro prior
to clinical use
• Even the best of instruments have
its limitations in the hand of an
inexperienced practitioner.
• Experienced endodontist should
choose tried and tested
instruments and techniques.

75. References:
• Grossman’s Endodontic Practice 13th Edition
• Cohen’s Pathways of the Pulp, 6th Edition
• Ingles' Endodontics, 6th Edition
• Weine’s Endodntic Therapy, 5th Edition
• Essentials of Endodontics, Vimal Sikri