Presentation includes bio prin of tooth prep.pdf

Biomechanical principles of tooth preparation

1. BIOMECHANICAL
PREPARATION
(BMP)
TOPIC:
MAHRUKH KHAN
BATCH D
4th YEAR BDS

2. WHAT IS BMP?
Endodontic treatment can be divided into three main phases:
1.Proper access preparation into the pulp space
2.Shaping and cleaning of the root canal
3.Obturation

Definitions:
Shaping and cleaning of the root canal consists of removing the
pulp tissue and debris from the canal and shaping the canal to
receive an obturating material.
CLEANING AND SHAPING OF
ROOT CANAL

3. OBJECTIVES AND GOALS OF SHAPING OF
RADICULAR PULP
ENDODONTIC INSTRUMENTS- STANDARDISATION
AND CLASSIFICATION
OBTURATION INSTRUMENTS
GUIDELINES FOR SHAPING OF ROOT CANAL
PHASES IN SHAPING OF ROOT CANAL: PHASE I, II,
III, IV AND V
PEDIATRIC CONSIDERATION
CONTENT:

4. SCHILDER’S OBJECTIVES OF SHAPING AND
CLEANING OF THE ROOT CANAL SYSTEM

5. ROOT CANALS SHOULD BE WIDENED FOR FOUR
REASONS:
1.TO ELIMINATE MICROORGANISMS ON THE CANAL
SURFACE MECHANICALLY
2.TO COMPLETELY REMOVE PULP TISSUE, BECAUSE
EVEN WHEN A VITAL PULP IS EXTIRPATED, TAGS OF
PULP TISSUE AND ODONTOBLASTS CLING TO THE
CANAL WALL AND ARE NOT REMOVED WITH THE
BODY OF THE PULP; THEY LATER UNDERGO
NECROSIS AND PROVIDE AN ENVIRONMENT FOR
BACTERIAL GROWTH
3.TO INCREASE THE CAPACITY OF THE ROOT CANAL
TO PERMIT IRRIGATING SOLUTIONS TO REACH THE
APICAL THIRD FOR EFFECTIVE DISINFECTION
4.TO SHAPE THE ROOT CANAL TO RECEIVE GUTTA-
PERCHA, BECAUSE THE WIDER THE CANAL, THE
EASIER IT IS TO FILL IT
GOALS OF SHAPING OF THE RADICULAR PULP

6. INGLE AND LEVINE’S STANDARDIZATION OF ENDODONTIC
HAND INSTRUMENTS
Instruments shall be numbered from 10 to 100; the numbers
to advance by 5 units to size 60 and then by 10 units to size
100. This has been revised to include numbers from 6 to 140.
Each number shall be representative of the diameter of the
instrument in hundredths of a millimeter at the tip; e.g., No. 10
is 10/100 or 0.1 mm at the tip, No. 25 is 25/100 or 0.25 mm at
the tip,etc
The working blade (flutes) shall begin at the tip, designated
site D0, and shall extend exactly 16 mm up the shaft,
terminating at designated site D16.
The diameter of D16 shall be 32/100 or 0.32 mm greater than
that of D0; e.g., a No. 20 reamer shall have a diameter of
0.20 mm at D0 and a diameter of 0.20 plus 0.32 or 0.52 mm
at D16. This sizing ensures a constant increase in taper of
0.02 mm/mm for every instrument regardless of size.
Following specifications were added later:
The tip angle of an instrument should be 75 ±
15°. Instrument sizes should increase by 0.05
mm at D0, between Nos. 10 and 60, e.g., Nos.
10, 15, and 20, and they should increase by 0.1
mm from Nos. 60 to 150, e.g., Nos. 60, 70, and
80.
Nos. 6 and 8 have been added for increased
instrument selection.
In addition, instrument handles have been
colorcoded for easier recognition

7. CLASSIFICATION OF ENDODONTIC INSTRUMENTS BASED ON METHOD OF USE
GROUP I: HAND-OPERATED ENDODONTIC INSTRUMENTS
A. BARBED BROACHES AND RASPS
B. K-TYPE REAMERS AND FILES
C. HEDSTROEM FILES
GROUP II: LOW-SPEED INSTRUMENTS WITH LATCH- TYPE ATTACHMENTS
A. GATES-GLIDDEN DRILLS
B. PEESO REAMERS
GROUP III: ENGINE-DRIVEN INSTRUMENTS
A. ROTARY NITI ENDODONTIC INSTRUMENTS
B. RECIPROCATING INSTRUMENTS
C. SELF-ADJUSTING FILE (SAF)
GROUP IV: ULTRASONIC AND SONIC INSTRUMENTS

8. GROUP I: HAND-OPERATED ENDODONTIC INSTRUMENTS
A. BARBED BROACHES AND RASPS
A barbed broach is a short
handle it in endodontic
instrument often used for
extirpation of the entire pulp
for the removal of debris‘s
and other foreign bodies
Barbed broaches are
recommended to be used in
the straight part of the root
canals and are not inserted
into the root canal until the
canal has been enlarged
throughout up to a size No.
20 or 25 reamer or file. This
precaution prevents
accidental breakage of
broaches inside the canal.

9. B. K-TYPE REAMERS AND FILES
The traditional reamer, manufactured from a triangular blank, and file, manufactured from a
square blank
The number of flutes twisted into each blade of a similar-sized instrument determines whether
that instrument is a reamer (less flutes) or a file (more flutes). For example, a No. 30 reamer
may have 15 flutes per 16-mm blade, and a No. 30 file may have 22 flutes per 16-mm blade
Reamers and K-type files do not break unless they have an undetected defect in the steel
shaft or until the instrument is strained or deformed, i.e., rotated on its axis when bound in a
root canal for several 360° twists
Modifications: K flex file and Flex R file

10. C. HEDSTROEM FILES
Hedstroem files, also known as H-files, are manufactured from a round
stainless steel wire machined to produce spiral flutes resembling cones or a
screw. This instrument has a higher cutting efficiency than K-instruments, but
it is fragile and fractures easily.
Modification: Safety hedstroem, Hyflex file, Unifiles,S-file

11. GROUP II: LOW-SPEED INSTRUMENTS WITH LATCHTYPE ATTACHMENTS

A. GATES-GLIDDEN DRILLS B. PEESO REAMERS
The Gates-Glidden drill has a long, thin
shaft ending in a flame-shapedhead, with
a safe tip to guard against perforations.
Enlarge root canal orifices
The Peeso reamer has long, sharp flutes
connected to a thick shaft.
It cuts laterally and is primarily used for the
preparation of post space when gutta-
percha has to be removed from the
obturated root canal.

12. GROUP III: ENGINE-DRIVEN INSTRUMENTS
A.ROTARY NITI ENDODONTIC INSTRUMENTS
One of the most significant changes in the practice of endodontics occurred with the evolution of nitinol, an
equiatomic alloy composed of nickel and titanium. This superelastic alloy does not exhibit proportional
strain under stress until a specific level is attained that ultimately causes fracture.
This unique property is due to the austenitic crystalline structure of the alloy which gets trans- formed into a
martensitic crystalline structure under stress. Thus, nitinol exhibits shape memory

13. B. RECIPROCATING INSTRUMENTS
The reciprocating instruments function at unequal bidirectional angles. The
counterclockwise engaging angle is five times the clockwise disengaging angle and is
designed to be less than the elastic limit of the file. Strategically, after three
counterclockwise and clockwise cutting cycles, the file will have rotated 360°, or one
complete circle

14. C. SELF-ADJUSTING FILE (SAF)
The file three dimensionally adapts both
longitudinally and along the cross-section
of the root canal system and this is its most
characteristic feature. This results in a
uniform cutting action of the dentin from
the canal walls and preserves the basic
shape of the root canal.

15. GROUP IV: ULTRASONIC AND SONIC INSTRUMENTS
A. ULTRASONIC UNIT B. SONIC HANDPIECE
The ultrasonic instrument consists of a piezoelectric or
a magnetostrictive unit that generates ultrasonic waves.
oscillating movement produces the cutting action of the
file and creates an ultrasonic wave.The ultrasonic
vibration produces heat that increases the chemical
effectiveness of the irrigating solution. It also pro- duces
two significant physical processes:cavitation and
acoustic streaming
Similar in shape and weight to dental handpieces
and are attached to existing air and water lines.
These instruments are used in a manner similar to
the ultrasonic system in. The only difference is that
the sonic system uses water as an irrigant and
requires special instruments known as:
Rispi Sonic
Shaper sonic
Trio sonic (or Helio sonic)

16. OBTURATION INSTRUMENTS
Spreader
Long tapered and pointed end instrument
Used to compress gutta percha in lateral condensation
It can be classified as hand spreader and finger spreader
Finger spreader is like files and is smaller and shorter to be used in the posterior teeth

17. Plugger
Long and blunt flat tip blade instrument used for vertical condensation of obturating
material
It is of two types long handled and finger type

18. Lentulo-spiral
Function is placement of sealer in canal.
Also used in obturation of primary teeth with paste system.
It can be used as hand held or in a slow speed handpiece.
They have reverse spiral shape which enables easy insertion of material in canal.

Advantage is ease of work and minimal time consumption.

Disadvantage is breakage or frocking of spiral.

19. THE TOOTH TO UNDERGO ROOT CANAL
THERAPY IS IDENTIFIED BY PENETRATING THE
ENAMEL AT THE SITE OF THE ACCESS CAVITY.
THE RUBBER DAM IS APPLIED AND THE FIELD
OF OPERATION IS DISINFECTED; I.E., THE
TOOTH,CLAMP, AND RUBBER DAM ARE
SCRUBBED WITH A STERILE COTTON-TIP
APPLICATOR SATURATED WITH A 5.2%
SOLUTION OF SODIUM HYPOCHLORITE .
THE ACCESS CAVITY IS COMPLETED.
IN POSTERIOR TEETH, AFTER COMPLETE
REMOVAL OF THE ROOF OF THE PULP
CHAMBER, THE CORONAL PULP IS REMOVED
WITH SHARP ENDODONTIC SPOON
EXCAVATORS.
THE CHAMBER IS IRRIGATED WITH A 5.2%
SOLUTION OF SODIUM HYPOCHLORITE AND IS
DRIED WITH SUCTION.
GUIDELINES FOR SHAPING OF ROOT CANAL

20. THE CANAL ORIFICES ARE LOCATED BY
PROBING WITH ENDODONTIC EXPLORERS
ALONG THE ANATOMICAL GROOVES
LOCATED IN THE CHAMBER FLOOR AND
LEADING TO THE ROOT CANALS OR AT
THE POINT ANGLE FORMED BY THE WALLS
AND FLOOR OF THE PULP CHAMBER.
THESE ANATOMICAL GROOVES,
SOMETIMES CALLED THE. DENTINAL MAP,
UNITE THE CANAL ORIFICES THAT ARE
PRESENT AT THE END OF THE GROOVES.
THE GROOVES ARE DARKER THAN THE
FLOOR OF THE PULP CHAMBER.
THE OPERATOR MUST BE FAMILIAR WITH
THE ANATOMICAL VARIATION
ENCOUNTERED IN DIFFERENT TEETH AND
MUST SEARCH FOR THEM IN EVERY
TOOTH USING RADIOGRAPHS AND VISUAL
AND TACTILE EXPLORATION.
A DENTAL OPERATING MICROSCOPE
(DOM) IS A VALUABLE TOOL IN ENSURING
THE TRACING AND NEGOTIATION OF
COMPLEX ROOT CANAL ANATOMY.

22. PHASES IN SHAPING OF THE ROOT CANAL
PHASE I: NEGOTIATING THE CANAL- ‘PATENCY FILLING’
PHASE II: CORONAL PRE-ENLARGEMENT
PHASE III: WORKING LENGTH MEASUREMENT
A. ANATOMIC CONSIDERATION
B. RADIOGRAPHS
C. METHODS OF DETERMINING WORKING LENGTH
D. INSTRUMENTATION GUIDELINES
PHASE IV: ROOT CANAL SHAPING TECHNIQUES
A. STEP BACK TECHNIQUE: 1. CONVENTIONAL 2. PASSIVE
B. STEP DOWN: 1. CROWN DOWN PRESSURELESS.
2. DOUBLE FLARE 3. BALANCED FLARE
C. HYBRID TECHNIQUE
PHASE V: ROOT CANAL WORKING WIDTH

23. PHASE I: NEGOTIATING THE CANAL- ‘PATENCY FILLING’
THE CONCEPT OF CREATING
A PATH UP TO THE WORKING
LENGTH WITHOUT BLOCKING
OR ALTERING THE ORIGINAL
ROOT CANAL ANATOMY IS
KNOWN AS PATENCY FILING.
SIZE 10 OR SMALLER K FILE
PASSIVELY THROUGH APICAL
FORAMEN
RECOMMENDED TO USE
PRECURVED STAINLESS K
FILE IN REAMING MOTION
OBSTRUCTION OR
CALCIFICATION- SIZE 8 OR 6
K FILE OR PROFINDER FILE

24. PHASE II: CORONAL PRE-ENLARGEMENT
IT IS A CONCEPT OF ENLARGING THE CORONAL THIRD OF THE
ROOT CANAL PRIOR TO THE ESTIMATION OF THE WORKING
LENGTH.
ORIFICE ENLARGERS.EG NITI SYSTEM OR GATES GLIDDEN DRILL
POTENTIAL ADVANTAGES
1.PREVENTS PREMATURE BINDING OF THE SHAPING
INSTRUMENT TO THE CANAL WALLS
2.REMOVES THE CORONAL THIRD DEBRIS BEFORE THE
SHAPING INSTRUMENTS NEGOTIATE THE APICAL THIRD. THIS
REDUCES THE POTENTIAL FOR EXTRUSION OF DEBRIS BEYOND
THE WORKING LENGTH
3.CORONAL PRE-ENLARGEMENT ALLOWS THE OPERA- TOR TO
GAUGE THE APICAL THIRD OF THE CANAL MORE ACCURATELY
CLINICAL NOTE
ORIFICE ENLARGERS ARE INSTRUMENTS THAT ARE MEANT FOR
ENLARGING THE CANAL ONLY AT THE LEVEL OF THE ORIFICE
AND HENCE THE INSTRUMENT AND ENLARGEMENT SHOULD
BE RESTRICTED TO A DEPTH OF 3–4 MM INTO THE CANAL
ORIFICE.

25. PHASE III: WORKING LENGTH MEASUREMENT
DEFINITION: WORKING LENGTH IS DEFINED AS THE DISTANCE FROM A CORONAL REFERENCE POINT TO THE POINT AT WHICH
CANAL PREPARATION AND OBTURATION SHOULD TERMINATE. THIS IS USUALLY THE APICAL TERMINUS OF THE ROOT CANAL, ALSO
TERMED AS THE MINOR CONSTRIC- TION OR THE MINOR DIAMETER OF THE APICAL FORAMEN.
A. ANATOMIC CONSIDERATIONS
B. RADIOGRAPHS C. METHODS OF DETERMINING WORKING
LENGTH
I. RADIOGRAPHIC METHODS:
INGLE’S TECHNIQUE (RECOMMENDED)
OTHERS:
1. BEST’S METHOD
2.BREGMAN’S METHOD
3.BRAMANTE’S TECHNIQUE
4.GROSSMAN’S METHOD
5.WEINE’S METHOD
6.KUTTLER’S METHOD
7.X-RAY GRID METHOD
8.XERORADIOGRAPHY
9.DIRECT DIGITAL RADIOGRAPHY
II. ELECTRONIC APEX LOCATORS
III. NONRADIOGRAPHIC METHODS (NOT
RECOMMENDED)
1.TACTILE SENSE
2.APICAL PERIODONTAL SENSITIVITY
3.PAPER POINT METHOD
ANATOMIC APEX
RADIOGRAPHIC APEX
APICAL FORAMEN ( MAJOR DIAMETER)
APICAL CONSTRICTION ( MINOR DIAMETER)
CEMENTODENTINAL JUNCTION

26. D. INSTRUMENTATION GUIDELINES
INSTRUMENTS SHOULD BE FITTED
WITH INSTRUMENT STOPS.
INSTRUMENTS SHOULD BE USED
IN A SEQUENCE OF SIZES
STARTING FROM SMALLER SIZED
INSTRUMENTS TO LARGER SIZES.
ALL INSTRUMENTATION SHOULD
BE DONE USING STERILE
INSTRUMENTS IN A WET CANAL.
INSTRUMENTS SHOULD BE
CHECKED FOR DEFORMATION AND
DISCARDED IF STRAIN IS PRESENT.
INSTRUMENT GUIDELINES

27. A. ANATOMICAL CONSIDERATIONS
THE MOST CRITICAL AREA FOR CANAL DISINFECTION IS
THE APICAL 3–4 MM, WHICH SHOULD BE ENLARGED TO
FACILITATE THE FLOW OF IRRIGANTS TO THE BIOLOGICALLY
CRUCIAL APICAL THIRD.
B. PRECURVING
IN SHAPING A ROOT CANAL, ONE SHOULD ALWAYS
PRECURVE THE STAINLESS STEEL FILE BLADE BEFORE
INSTRUMENTATION. THIS PROCEDURE FACILITATES THE
INSERTION OF THE INSTRUMENT TO ITS WORKING LENGTH
AND PREVENTS LEDGING OF THE CANAL WALLS. THE
CURVATURE OF THE BLADE CAN BE ESTIMATED BY
REVIEWING THE DIAGNOSTIC RADIOGRAPH AND
OBSERVING THE ANATOMICAL FEATURES OF THE ROOT
CANAL.
THE CURVE IS PREPARED BY GRASPING THE BLADE
WITH A GAUZE SPONGE AND CAREFULLY BENDING THE
BLADE UNTIL THE DESIRED CURVATURE IS ATTAINED. THE
DIRECTIONAL SILICONE STOP SHOULD BE SET TO INDICATE
THE DIRECTION IN WHICH THE FILE HAS BEEN CURVED.
C. IRRIGATION
IRRESPECTIVE OF THE INSTRUMENTATION MOTION,
FREQUENT IRRIGATION OF THE ROOT CANAL FACILITATES
INSTRUMENTATION, DEBRIDES THE CANAL, AND HELPS TO
DISINFECT THE CANAL. IDEALLY, 2 ML OF THE IRRIGANT PER
CANAL PER INSTRUMENT CHANGE IS CLINICALLY
RECOMMENDED.
SHAPING AND
CLEANING
GUIDELINES

28. D. RESTRICTING INSTRUMENTS AND IRRIGANTS WITHIN THE
ROOT CANAL SPACE INSTRUMENTS AND IRRIGANTS SHOULD BE
CONFINED TO THE ROOT CANAL TO PREVENT TRAUMA TO
PERIRADICULAR TISSUES, AND DEBRIS SHOULD NOT BE FORCED
THROUGH THE APICAL FORAMEN. ONE MUST NOT FORCE AN
INSTRUMENT IF IT BINDS.
E. RECAPITULATION
RETURNING TO A SMALLER INSTRUMENT FROM TIME TO TIME
BEFORE ADVANCING TO A LARGER SIZE HELPS TO PREVENT THE
PACKING OF DENTIN FILINGS AND ENSURES PATENCY OF THE
ROOT CANAL THROUGH THE APICAL FORAMEN
F. REMOVAL OF DENTINAL DEBRIS FROM USED INSTRUMENTS
THE DENTINAL DEBRIS CREATED DURING THE SHAPING
PROCEDURE PARTIALLY CLOGS THE FLUTES OF THE
INSTRUMENT. THIS DEBRIS SHOULD BE REMOVED BY
SQUEEZING THE BLADE BETWEEN LAYERS OF WET GAUZE AND
TURNING THE INSTRUMENT COUNTERCLOCKWISE. BEFORE
REINSERTING, THE INSTRUMENT SHOULD BE INSPECTED FOR
DEFORMATION. NO INSTRUMENT SHOULD BE REINSERTED INTO
THE SAME CANAL/OTHER CANAL WITHOUT PERFORMING THIS
STEP.

29. PHASE IV: ROOT CANAL SHAPING TECHNIQUES
FUNCTIONAL MOTIONS OF INSTRUMENTATION
REAMING FILLING

30. WATCH
WINDING
CIRCUMFERENTIAL
FILLING
ANTI CURVATURE
FILLING

31. STEP BACK
TECHNIQUE
1.Conventional
step back
2.Passive step
back
STEP DOWN
TECHNIQUE
1.Crown down
2.Crown down
pressureless
3.Double flare
4.Balanced flare
HYBRID
TECHNIQUE
TECHNIQUES OF
SHAPING AND CLEANING

32. CONVENTIONAL STEP BACK (TELESCOPIC) TECHNIQUE
BY CLEAM, WEINE
CONCEPT: PREPARATION
OF APICAL THIRD>
MIDDLE THIRD>
CORONAL THIRD USING
LARGER SIZE INSTRUMENTS
MOTION OF
INSTRUMENTATION:
CORONAL-REAMING,
APICAL-CIRCUMFERENTIAL

33. Completion of gross debriment and determination
of working length
Use of size 10 file followed by 15, directly inserted
into canal orifice to desired length using reaming
motion
Canal is irrigated , solution along with debris is
aspirated
Inspect the file and clean the flutes. Continue the
procedure.
Apical foramen is cleaned
Apical third is serially enlarged to develop apical
stop of atleast 25 file
Increasing size of file and decreasing working length
> coronal taper

34. Files are inserted sequentially till unforced
contact with walls of canal
Recapitulation
Body of canal preparation is completed
No 2 & 3 gated glidden drill (coronal)
Circumferential filling using master apical
file. Smooth put and refine steps
Body is instrumented with atleast 3-4
larger files with recapitulation between
each size
Instrumentation is completed. Walls are
smooth and clean. Continuous taper in
apical direction

35. Advantages:
Popular technique employed with 2%
standardized SS files
Ability to prepare a proper apical stop
prior to preparation of the middle third
and coronal third of the root canal
Limitations:
Extrusion of debris into the periapex
Tendency to straighten in the canal
Loss of working length

37. PASSIVE STEP BACK TECHNIQUE
BY TORABINEJAD
INSERTION OF PROGRESSIVELY LARGER HAND INSTRUMENTS
AS DEEP AS THEY CAN BE PASSIVELY PLACED
GATES GLIDDEN DRILLS CAN BE USED FOR ADDITIONAL
CORONAL ENLARGEMENT.
APICAL INSTRUMENTATION USING STEP BACK TECHNIQUE

38. CROWN DOWN TECHNIQUE
BY GEORIG
CONCEPT: INVOLVES
PREPARATION OF
CORONAL, 2/3RD>
MIDDLE >APICAL
THIRD OF THE CANAL
MOTION OF
INSTRUMENTATION:
REAMING

39. Patency of canal is first established with size 8 or 10 K file
Preparation of coronal 2/3rd using Hedstroem file size 15,20,25 to
working length of 16-18mm or point where file starts binding
Flaring of Coronal segment of canal with Gates glidden drill no
2,3or 4. Each drill is sequentially shorter
Apical instrumentation with size 10 or 15 k file till working length
determination
Larger file (iso k file size 60) placed in canal to level of binding and
instrumented using watch winding motion until resistance
Repeat sequentially, smaller files until working length is reached
Recapitulation. Irrigation.
Apical portion is enlarged to appropriated master apical file size
Final canal tapering using master apical file with circumferential
filling motion

43. Advantage:
Shaping is easier
Elimination of the bulk of the tissue, debris,
and microorganisms from coronal and
middle third before apical shaping
Minimizes debris extrusion
Better access and control over apical
enlarging instruments
Better penetration of irrigants
Limitations:
Gauging of the apical third is done as the last
phase of the procedure

44. FOR USE WITH
STAINLESS STEEL
INSTRUMENTS
CONCEPT: COMBINATION
OF CROWN DOWN AND
STEP BACK TECHNIQUE
MOTION OF
INSTRUMENTATION:
CORONAL-REAMING,
APICAL-CIRCUMFERENTIAL
FILLING
HYBRID TECHNIQUE

48. Advantage:
Ability to shape the canal predictably
with hand instrumentation using
stainless steel instruments
Optimizes the advantages of crown-
down and step-back techniques
Limitation:
Middle third preparation has to be
done care- fully in order to prepare a
continuous tapered canal preparation

49. PHASE V: ROOT CANAL WORKING WIDTH
THE SURFACE OF
ROOT CANAL IS
IRREGULAR AND IS
INTERSPERSED WITH
RECESSES, CREVICES
AND FISSURES, THE
RESULT OF THE
POSITION OF
SECONDARY AND
REPARATIVE DENTIN

50. ROOT CANALS ARE OFTEN INADEQUATELY ENLARGED. IN THE PAST, TWO
GUIDELINES WERE CONSIDERED SUFFICIENT FOR INSTRUMENTATION:
1.ENLARGE A ROOT CANAL AT LEAST THREE SIZES BEYOND THE SIZE OF
THE FIRST INSTRUMENT THAT BINDS.
2.ENLARGE THE CANAL UNTIL CLEAN, WHITE DENTINAL SHAVINGS
APPEAR IN THE FLUTES OF THE INSTRUMENT BLADE.
BOTH THESE GUIDELINES CANNOT BE CLINICALLY RECOMMENDED
ANYMORE. THE COLOR OF DENTINAL SHAVINGS IS NO INDICATION OF
THE PRESENCE OF INFECTED DENTIN OR ORGANIC DEBRIS.
ROOT CANALS SHOULD BE ENLARGED, REGARDLESS OF INITIAL WIDTH,
TO REMOVE IRREGULARITIES OF DENTIN AND TO MAKE THE WALLS OF
THE CANAL SMOOTH AND TAPERED.
THE PREPARED ROOT CANAL SHOULD BE SMOOTH AND LARGE ENOUGH
TO ALLOW ADEQUATE DEBRIDEMENT AND OBTURATION.
TRADITIONAL CONCEPT

51. CURRENT CONCEPT
THE FACTORS THAT SHOULD BE TAKEN INTO CONSIDERATION
BEFORE DECIDING THE OPTIMUM SIZE OF ENLARGEMENT AT
WORKING LENGTH ARE AS FOLLOWS:
INITIAL CANAL WIDTH WHICH HAS TO BE ASSESSED BOTH
CLINICALLY AND RADIOGRAPHICALLY. THE CANAL OF A NARROW
TOOTH, SUCH AS A MANDIBULAR INCISOR, CANNOT BE
ENLARGED AS MUCH AS THE CANAL OF A MANDIBULAR CANINE.
WHETHER THE ROOT CANAL IS VITAL, CALCIFIED, OR INFECTED.
PRESENCE OR ABSENCE OF PERIRADICULAR PATHOLOGY/
RESORPTION.
RADIUS OF CANAL CURVATURE WHICH COULD MAKE THE
SHAPING PROCEDURE MORE DIFFICULT.
CANAL CONFIGURATION, WITH MORE ATTENTION TO BE GIVEN
TO COMPLEX ANATOMIES LIKE A C-SHAPED CANAL AND THE
ISTHMUS REGION.

53. PEDIATRIC CONSIDERATION
Rotary instruments were introduced to pediatric endodontics by Barr in 2002
In the bygone decade, several rotary NiTi endodontic file systems have been
launched to improve the shaping procedure. However, all these systems
recommended the use of a series of files to accomplish the final shape.
Recently, the concept of single-file systems has been introduced and is
currently being debated for its applicability in contemporary endodontics.
Newer file systems in Pediatric endodontics
Kedo file system:
Kedo files system are the world's first files designed for root canal
preparation in primary teeth. Kedo files are available in Hand type
(Kedo - SH) and rotary type (Kedo - S)

54. Kedo-S pediatric rotary file system :
The Kedo-S file system consists of three Ni-
Ti rotary files. The total length of the files is
16 mm. The working length of the files is 12
mm.
D1: diameter of 0.25mm, primary molars
with narrow canal
E1: diameter of 0.30mm, wider molar canals
U1: diameter of 0.40mm, primary incisors
They have a gradual taper aiding in easy
coronal enlargement and straight line
access. This gradual taper also help in
efficient canal preparation and avoids over
instrumentation of the inner wall of root
surface.

55. Kedo SG Blue (controlled
memory files):
Kedo SG Blue file system consists
of three Ni-Ti rotary files. The
total length of the files is 16 mm.
The working length of the files is
12 mm. The files are named as D1,
E1, U1
It has super flexibility and 75%
greater resistance to cyclic
fatigue.
Controlled memory

56. PRO AF baby gold file advanced
pediatric rotary endodontic file system
Pro AF Baby Gold file (Dentobizz) consist
of 5 files made up of NiTi CM wire-
Flexible with Constant taper of 4%, 6%.
Specially designed and registered short 17
mm file.
High Flexibility with minimal chances of
separation.
A versatile rotary file system suitable for
conservative preparation of all canals.
Less number of files per canal, most
canals required only
2 files for preparation.

57. TO MINIMIZE THE RISK OF FRACTURE IN CLINICAL PRACTICE, THE
FOLLOWING GUIDELINES ARE RECOMMENDED:
• ALWAYS CREATE A GLIDE PATH AND PATENCY WITH SMALL HAND
FILES.
• ENSURE STRAIGHT LINE ACCESS AND GOOD FINGER RESTS.
• USE A CROWN-DOWN SHAPING TECHNIQUE DEPENDING ON THE
INSTRUMENT SYSTEM.
· SHAPE BEFORE USING THE NARROWER, MORE FRAGILE
INSTRUMENTS IN THE APICAL REGIONS.
• USE A LIGHT TOUCH ONLY, ENSURING TO NEVER PUSH HARD ON THE
INSTRUMENT.

58. THE PARTICULAR CANAL ANATOMY AND INSTRUMENT DESIGN
CHARACTERISTICS.
• DO NOT HURRY INSTRUMENTATION AND AVOID RAPID JERKING
MOVEMENTS.
• REPLACE FILES SOONER AFTER USE IN VERY NARROW AND VERY
CURVED CANALS.
• EXAMINE FILES REGULARLY DURING USE, PREFERABLY WITH
MAGNIFICATION.
• KEEP THE INSTRUMENT MOVING IN A CHAMBER FLOODED WITH
SODIUM HYPOCHLORITE.
• PRACTICE IS ESSENTIAL WHEN LEARNING NEW TECHNIQUES AND
NEW INSTRUMENTS.

60. Reference:
Grossman’s endodontic
Textbook of pediatric dentistry by
Nikhil Marwah
Report by Department of Pediatric
and Preventive Dentistry Sardar
Patel Post Graduate Institute of
Dental and Medical Sciences,
Lucknow