biomechanical preparation of root canal systems

2. Cleaning & Shaping of
root canal systems
PART 1
Guided by :
Dr. P. Karteek
varma
Presented by
:
V.Sindhu
II MDS

3. 1. INTRODUCTION
2. OBJECTIVES
-MECHANICAL
-BIOLOGICAL
-CLINICAL
3.INSTRUMENT MOVEMENTS FOR
SHAPING
1. WATCH WINDING
2. REAMING
3. FILING
4. ROTARY

4. 8. PRECURVATUREOF FILES
9. RECAPITULATION
10.PREPARATION TECHNIQUES
-STANDARDIZED
-STEPBACK
-ANTICURVATURE
-STEPDOWN
-BALANCED FORCE
-CROWN DOWN PRESSURELESS
-DOUBLE FLARE
11.MANAGEMENT OFCURVEDCANALS
12.CONCLUSION
13.REFERNCES

5. INTRODUCTIO
N
• 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.

6. 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

7. 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

8. 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

9. 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

10. HERBERT SCHILDER'S FIVE
MECHANICAL OBJECTIVES
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.
Schilder H: Cleaning and shaping the root canal, Dent Clin NorthAm 18:269, 1974.

11. BIOLOGICAL
OBJECTIVES:
• To completely debride the pulp
space from-
Pulp tissue
Bacteria / Microorganisms
Dentinal debris
Endotoxins

12. 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.

13. WEINE’S RULES FOR CANAL PREPARATION
2. Once working length is determined all
instruments should be kept within the confines
the canal.

14. WEINE’S RULES FOR CANAL PREPARATION
3. Instruments must be used extravagantly,
especially the smaller sizes.

15. WEINE’S RULES FOR CANAL PREPARATION
4. Canals must be prepared in wet environment

16. 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 motion
Smooth
• It means simply that the portal of exit has
been cleared of any debris in its path.
Patency

17. INSTRUMENT
MOVEMENTS
WHILE SHAPING

18. 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
 Filing
 Reaming
 Turn And Pull
 Watch Winding
 Balanced Force Instrumentation.
 Anti-curvature Filing

19. 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.

20. 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.

21. 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.

22. 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.
Weine 6th ed. Pg 166/7
Reaming
action
Keyhole
Circumferential filing

23. 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.

24. 2.
REAMING
The cutting edges of all endodontic files and reamers
spiral about the shaft of the instrument.
This configuration causes them to slide into the canal as
the edges rotate to the right.
As they slide into the canal more and more of the length of
the instrument engages the canal.
This in turn increases the strain or working load against
the instrument. That strain continues to rise until the
instrument ceases to move.

25. 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.

26. 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.

27. 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.

28. 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.

29. 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

30. 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.

31. ANTI-CURVATURE
FILING

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

33. TECHNIQUES
Apical to Coronal
• Standardized
preparation
• Step back preparation &
modifications by:
• Schilder
• Weine
• Passive step back
• Roane Balanced Force
Coronal toApical
• Step down technique
• Double flare technique
• Crown down pressure
less technique
Hybrid technique
• Step back step down
combination procedure

34. 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.

35. 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

36. 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

37. 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.

38. 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

39. 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.

40. 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”

41. 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

42. 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

43. 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

44. 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

45. APICAL TO CORONAL PREPARATION :
ADVANTAGES Conservation
of tooth
structure
especially in
cervical third
DISADVANTAGES
Apical plug
Decreased
volume of
irrigating
solution
Procedural
mishaps

46. CORONAL TO APICAL
PREPARATION:
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

47. 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

48. 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.

49. 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.
WL
determined
Sequentially enlarged canal till #25 to full
wl in circumferential manner

50. 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.
• No. 3 GG Drill
• No. 2 GG Drill
• No. 1 GG Drill
Coronal refinement with G.G. drills

51. 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

52. ROTARY INSTRUMENTS THAT ARE
USED IN CROWN DOWN TECHNIQUE
• Profile
• Profile GT
• Quantec
• Light speed
• protaper
• Race
• Hero 642
• Hyflex
• K3

53. MODIFICATIONS OF CROWN DOWN
TECHNIQUE
• Crown Down Pressureless
• Balanced Force Technique
• Double Flare Technique

54. 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.

55. BALANCED FORCE TECHNIQUE

57. 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

58. 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

59. 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

60. 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

61. 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

62. 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

63. 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

64. 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

65. 5. ZIPPING
• Refers to transportation of the
apical portion of the canal
• It is characterized by a normally
curved canal which has been
the
straightened, especially in
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

66. 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

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

68. 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

69. 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.

70. 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”

72. CURVES OFTHEAPICAL THIRD
• Straightening these curves would mean displacing the
apical foramen from its original position
• Always start with small, precurved instruments, such as a # 08 or
10 K-type file
• Precurvature should reflect the degree of apical curvature
• Start only after confirming the file is at the radiographic apex.
• Bath in sodium hypochlorite
• Make small excursions of fractions of a millimeter.
• Always recurve reintroduce a smaller file- maintain
apical patency and curvature
• No Reamers – as it will cause HOURGLASS shape

73. • If one creates a ledge,
 -start over again with the first small file with very short
accentuated apicall precurvature ( #08 #10)
 -Insert in the canal with precurvature aligning the apical
curvature.
 -use step back,watch winding or balance force to eliminate
the ledge.

74. • An easier and faster way to get the same result -hand GT Files.
• Overbend to 180 degree by an endobender
• The GT File is rotated counter-clockwise (the direction of the flute twists)
until it snugs tightly
• With apical pressure turn it 360 degree clockwise
• Initially file progressively tightens till about 180 degree-
• Then it releases and easily turns
• Now rotate counterclockwise again into the canal
• Again reverse it clockwise to 360 degree with pressure
• Do 3 cycles before removing the file.

75. CURVES OFTHE MIDDLE THIRD
• Partially straighten this
• upper and lower second premolars-common –first
curve mesialy and second distally
• Double curve the files
• Curves Facing the same direction as the canal
• Withdraw –irrigate-recurve-reintroduce-reorient the file
periodically.

76. • The nickel titanium instruments, remain centered within the root canal
removing dentin on 360°
• they don’t straighten the curvatures but they maintain them

77. CURVES OFTHE CORONAL
THIRD
• mesial roots of lower molars
• Mesiobuccal roots of upper molars
• Before working,
 -straighten these curves
 - perform an early enlargement of the coronal middle
thirds This helps in,
- Better direct access
- Eliminates the restrictive dentine-so more tactile sense
- Reduces bifurcation stripping and other mishaps
- Better irrigant penetration

78. Negotiating
calcified canals

79. • Copious irrigation with 2.5 to 5.25% NaOCl.
• Dissolve organic debris
• Lubricates the canal
• Suspends the chips and pieces in solution
• Always advance the instrument slowly.
• Always clean the instruments on withdrawal and inspect
before reinserting.
• When a fine instrument reach the approximate canal length take a
radiograph. Do not remove the instrument.
• Use chelating agents
• Flare the orifice and coronal enlargement improves tactility
• Do access opening without anesthesia.
• Ask patient to indicate if he feels sharp sensation .

80. • Insert small number file
• if file is inserted only a mm or two into pulp, the
reaction is sharp
• If it is in PDL, reaction will be less sharp.
• Do not remove large amount of dentin to find the canal.
• Tooth strength and pulp floor landmarks will be
compromised.

81. MANAGMENTOF
CSHAPED CANALS

82. • Common In mandibular second molar + maxillary first molar
(usualy when roots are fused)
• Maxillary molar- MB +palatal canals
• Mandibular second molar- MB + distal canal
• Do continuous circumferential filing along the periphery of C
with hypo irrigation.
• Do not over prepare
• Because Only little dentin in inter radicular surface.

83. TEN RULES TO FOLLOW
1) Do not begin endodontic therapyunless a recent and up-to- date
preoperative radiograph is available.
2) The instruments must always be precurved and equipped with a directional
rubber stop.
3) Do not begin to work to the foramen, without first having
radiographically ascertained the position of the instrument in the canal.
4) The endodontic instrument does not work for itself, but prepares the
canal for the following instrument.
5) All endodontic instruments work on withdrawal, arriving where the
canal will accept them: “Take what the canal will give you!”

84. 6) In multirooted teeth, one always performs the cleaning and shaping
of one canal at a time, always starting from the easiest.
7) Each root canal deserves a series of new instruments.
8) The instruments’ working length must always be checked
electronically first and then radiographically: never take an X-ray without
consulting a reliable electronic apex locator.
9) It is advisable not to trust one’s tactile sense.
10) Never progress to the next step unless the preceding step has been
completed.

85. 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

86. CONCLUSIO
N
• 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.

89. UNIVERSAL PROTAPER HAND
FILE
(MODIFIED BALANCED FORCE)
• PROTAPER ROTARY :- Prof.Pierre
Machtou, DR.Clifford Ruddle,
Prof.John West with the
Dentsply/Maillefer.
• HAND PROTAPER was then introduced.
• 2006 – UNIVERSAL PROTAPER

90. ENGINE DRIVEN INSTRUMENTS FOR
CANAL PREPARATION
• SAF SELFADJUSTING FILE TECHNIQUE
• Hollow file
• Adapts itself to the original canal anatomy and shape.
• Compressible & Thin walled pointed cylinder design.
• It has continuous irrigation by a special irrigation
apparatus. (VATEA Irrigation device)
• Single use design.

91. • Insert into the canal while vibrating
• Pushed till the measured WL
• Operate in two cycles of 2minutes
each.
• In and out manual motion
• Continuous fresh irrigation
• File removed and infected after each
cycle.

92. PROTAPER NEXT
ROTARY
TECHNIQUE
• M wire technology
• Progressive taper on a single file
• Cross section- rectangular.
• Offset design (i.e. the center of
mass/centre of rotation, or both are
offset)
• This produce a mechanical wave of motion
• That travels along the active file length.
• 300rpm 2*5.2Ncm torque.

93. • SX file-
preflare the orifice
Eliminate dentine triangles
Use in Brushing motion
 creates lateral space
 improves contact between the file and
dentine.
• Glide path (#15 file or path files)
• Insert X1 file
Irrigate
Recapitulate

94. • Progress till the WL
• Use X2
• Brush against dentinal wall till WL
• Re-irrigate
• If #30 file snug at length, the shape is finished.
• Use X4 & X5 to prepare and finish larger canals

95. Hand protapers
Light clockwise rotation
Engage dentin until snug
Counter clockwise (1/4 turn )
Disengages the file + cuts dentin
Rotate clockwise (3/4)
Simultaneously withdraw file
Repeat until desired lenth

96. BLENDIN
G
• the clinician’s final attempt to blend or marry the
various aspects of the enlargement procedure to
create the ideal shape of an endodontic cavity
preparation.
• usually files used in a rasping and push-pull motion
• instruments are precurved
• applied to the outer wall of each arch to insure a
smooth transition from one plane of the endodontic
cavity space to the next.
• The finished preparation should then provide
Unimpeded exit and entry of instruments and
materials,
with effortless access of the apex.

97. SIGNATURE
• This defines the artistic result that the clinician renders on
completion of the endodontic cavity preparation.
• It bears the attributes of a fine sculpture or carving and is
unique,
• i.e., each clinician will incorporate small nuances to the
preparation that are solely attributable to his artistic ability
and workmanship.
• Talented clinicians can often identify their work, or so called
signature, merely by glancing at a radiograph shown to them
at random