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1. BIOMECHANICAL PREPARATION-I
CONTENTS
INTRODUCTION
DEFINITION AND OBJECTIVES
PROCEDURAL TERMS
BASIC TERMS OF MOTIONS OF INSTRUMENTATION
GENERAL GUIDE LINES FOR CLEANING AND SHAPING
TECHNIQUES FOR PREPARING ROOT CANALS
MANAGEMENT OF SMEAR LAYER
CONCLUSION
REFERENCES

2. BIOMECHANICAL PREPARATION-I
INTRODUCTION
The second component of root canal treatment is canal preparation. Once the
proper working length is established the endodontic canal preparation is chemo
mechanical process. The term cleaning and shaping was associated with pervious
endodontic teaching. In 21st
century this has been changed to shaping and
cleaning. Instruments used to readily shape the canal to permit the ingress of
chemical agents into the root canal system.
Definition and objectives:
Schilder introduced the concept of cleaning and shaping almost 3-4 decades ago.
Biomechanical preparation refers to the controlled removal of dentin and root
canal contents by manipulation of root canal instruments and materials. It consists
of cleaning and shaping.
Cleaning: Refers to the removal of all root canal contents before and during
shaping which includes substrates, micro-flora, bacterial products, food, caries etc.
Shaping: Is the development of a logical cavity preparation that is specific for the
anatomy of each root (Raiden et al, JOE 1998).

3. Shaping refers to specific root canal form with particular design and objectives. It
involves carving and predetermined removal of root canal structure to achieve a
uniform, tapering, homogenous design.
The final design should be in such a way that it should permits effective irrigation
and captures a maximum amount gutta-percha and sealer into all foramina without
any extrusion of gutta-percha.
Generally speaking, the main two main objectives of cleaning and shaping are
Biological: Biologically the goal is to remove all pulp tissue remnants and
microorganisms and their substrates along with infected dentin.
Mechanical: To shape the canal in 3 dimensional design.
Biological objectives:
1) Confine all instrumentation within root canal space to maintain its spatial
integrity. Repeated instrumentation, extending beyond the constriction is
unwarranted. It causes peri radicular inflammation and often destroys the
normal biological constriction of root apex.
2) Avoid pushing contaminated debris past the confines of the apical
constriction. In many instances, post treatment pain and swelling can be
attributed to necrotic tissue and microorganisms and their toxins being
inoculated into peri radicular tissues as a result of indiscriminate cleaning
procedure. This induces rapid immunological response.
3) Remove all the potential irritants from entire root canal system. It helps in
uneventful healing.
4) Establish exact working length

4. 5) Create sufficient within the coronal half of the canal system to allow for
copious flushing and debridement.
Mechanical objectives:
1) Develop continuously tapering form of root canal preparation. The final
preparation should be an exact replica of the original canal configuration in
shape, taper, and flow but only larger.
2) Prepare a sound apical dentin matrix at the dentino cemental (DC) junction.
It provides the resistance form to the intraradicular cavity preparation. This
also prevent over instrumentation and apical movement of gutta-percha
sealer.
3) Prepare the canal to taper apically, with narrowest cross sectional diameter
at apical termination.
The apical third of canal preparation, especially apical 1/3 must provide a
tapering / parallel spatial configuration in order to ensure a firm seating of
the gutta-percha. It must also provide retentive cavity to enhance
condensation procedures.
4) Confine cleaning and shaping procedures to the canal system, there by
maintaining the spatial integrity of apical foramen. The delicate foramen
sometimes moves or transport due to improper sequencing of instruments,
insufficient irrigation.

5. The foramina may be transport internally or externally.
The external transportation of foramen may be caused due to failing to precurve
the files. This may occur in two forms
- Direct perforation (Blockage of apical foramen)
- Teardrop shape (over use of instrument)

6. Internal transportation occurs when portal of exit; is moved internal to
its external position by blocking the canal.
5) Keep the apical foramen size as small as possible. The operator must clean
the foramen by maintaining its patency, but do not enlarge or distort it.
When size of apical foramen increases it not only increases the risk of
tearing but it increases potential for microleakage.
PROCEDURAL TERMS:
1) Master apical file (MAF)
It is the largest file that binds lightly at correct working length after straight
line access. The file which binds first or smallest file is called initial apical
file.

7. 2) Recapitulation: It is an important step especially in apical coronal
techniques. It means the use of the instruments in the correct size, and
sequence from smaller to larger and returning to smaller instruments from
time to time before advancing to a larger size.
Eg: After 15 no., 10 then 20, then use 10 and 15 and proceed to 25 and so
on.
This helps prevent packing of fillings and ensures patency of root canal
through the apical foramen.
3) Anti curvature filling: Described by Abou-Rose – It is a controlled as
directed preparation into safety zone of root canal away from the danger
zones.
Circumferential filing: Here 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 has been rasped

8. BASIC TERMS OF MOTIONS OF INSTRUMENTATION:
BMP is a dynamically delicate motion. The motion should be flowing, rhythmic
and energetic. There are 6 distinct, 6 motion of files and reamers.
A) Follow: is usually performed with files. They are used initially during
cleaning and shaping or any time an obstruction blocks the foramen.
B) Follow-withdraw: It is a simple in and out motion performed with file.
C) Cart: Extension of reamer to or near the radiographic terminus.
D) Smooth: It refers to finishing the preparation with files. It is usually
performed with circumferential filing motion.
Buccal
Mesial
Lingual
Distal

9. E) Patency: Refers to cleaning the portal of exit of root canal with small
size instruments.
F) Gauging: refers to knowing the cross sectional diameter of the foramen that
is confirmed by the size of the instruments that fits snugly at working length.
G) Tuning: It is ensuring that each sequentially larger instrument uniformly backs
out of canal by 0.5mm.
H) Scouting: It is estimating the gauge and anatomy of root canal with help of
instrument.
I) Filing / rasping: This term refers to push and pull action with instruments.
J)Reaming: Indicates clockwise / right hand rotation of an instrument. It is a
rotating, pushing, motion limited to quarter to half turn. The instrument must
be
restrained from
insertion to
obtain

10. cutting action. Reamers can be used in this motion. The instrument fracture is
increased when this motion is employed.
K) Turn and full: It is a combination of reaming and filling. Here file is
inserted with ¼ clock wise and inwardly directed hand pressure (reaming) into
canal by this action and file is withdrawn (filling).
Disadvantage:
1) Hourglass shape canal observed by Weine according to Schilder.
According to Schilder, while performing this motion the file is not
inserted toward apex rather it gradually moves the canal contents out
of canal. Instead of this he suggested recombining half revolution in
clockwise direction followed by withdrawal.
a. Watch-winding:

11. It is a back and forth oscillation of file (30-60°) to right and left as
instrument pushed into the canal. It is an effective motion very
useful during shaping procedures. 30-60° to right side rotation
pushes the file tip and working edges into canal and 30-60° left side
counter clockwise rotation cuts away the engaged dentine. Therefore
it is a predecessor of balanced force technique.
Advantages:
1. Canal centering, not necessitating precurving of
instrument.
2. It is less aggressive compared to the turn and pull motion.
Because here file is not pushed far into the apical region,
there is less chance of apical loading.

12. b. Watch winding and pull: This is primarily used with Hedstrom
files, when using H. files watch winding cannot cut dentin, it can
only wiggle and wedge the horizontal unidirectional edges tightly
into canal walls.
The file should inserted with right and left back and forth motion
(rocking) until you meet resistance then file must be freed by pull
stroke.
GENERAL GUIDE LINES FOR CLEANING AND SHAPING:
1) Direct straight line access
2) Rubber dam isolation

13. 3) Accurate working length is very important
4) Use instruments sequentially with recapitulation
5) Instrument stops and reproducible reference points should be used.
6) Do not force the instruments and regularly inspect and debride instruments.
7) Use copious irrigation and instrument in wet canals. Various chemicals can
be used like RC-Prep, EDTA, Glyde etc.
8) Confine instruments in root canal and do not force debris apically.
9) How much canal should be enlarged?
a. Anatomical structure
b. Accessibility of canal
c. Skill of operator
In adequate enlargement: limits cleaning, debridement, disinfection, obturation.
Excessive enlargement: perforations, spatial movement of apical foramen and
procedural problems.
Earlier two guide lines are used
- Enlarge canal at least 3 sizes larger than that of first instrument
which binds in the canal.
- Enlarge the canal until clean, white dentinal shavings appear in
flutes of instrument.
But these criteria is not valid today

14. The root canal enlarged atleast till 25-30 number in the apical potion and no. 40 or
larger in middle or coronal portion of root canal, will permit effective irrigation.
TECHNIQUES FOR PREPARING ROOT CANALS
Apico-coronal
- Standardized preparation
- Stepback and its modifications
- Roane balanced force technique.
Coronal apical
- Step down
- Double flare
- Crown down presureless
- Canal master and technique
Hybrid technique: Step back and step down combination.
STANDARDIZED TECHNIQUE:
By John Ingle (1961) done in narrow canals with circular cross sections.
Standardized files are used

15. W.L determined
↓
Smallest instrument adjust to WL
↓
Sequentially enlarged the canal
↓
Obturate with silver points accepted
STANDARDIZED TECHNIQUE:

16. Disadvantages
- Risk of extrusion of debris
- Alteration of WL
- Difficult to debride complex canals
- Possibility of canal deviation
- Vertical root fracture if over instrumentation carried out
STEP BACK PREPARATION: (Telescopic or serial root canal preparation)
Introduced by Klem
WL determined Dentine
removed by
size 15 reamer
Dentine
removed by
size 20 reamer
Dentine
removed by
size 25 reamer

17. Developed by Weine, Martin, Walton, and Mullaney.
Indicated: Canal with narrow apical constriction and
Steps:
Determine working length
↓
Take the instrument which fits into C.W.L. and file circumferentially and till next
instrument reaches WL irrigate.
↓
Repeat until no 25 or two sizes larger than the fill which binds at apex.
↓
Once no. 25 file reaches to WL then each larger size file should used to prepare
canal by reducing 1mm (Explain using diagram)
↓
After each file it is very important to recapitulate with smaller number file (No.25)
with copious irrigation to maintain patency.
↓
Refine coronal preparation with G.G Ds (No.1, 2, 3)

18. STEP BACK PREPARATION:

19. Advantages:
- Less periapical trauma
- More debris removal
- Greater flare, more G.P. peak
WL determined Sequentially enlarged canal
till #25 to full wl in
circumferential manner
Stepping back by 1mm from
WL at size 30
Stepping back by 2mm from
WL at size 35
Stepping back by 5mm from
WL at size 50
Refining coronal flare with
GG 1,2,3

20. - No over extrusion of G.P due to develop of apical matrix
- Increase condensation pressure can exerted → fills more accessory
and lateral canals.
Disadvantages:
- Apical blockage
- Alteration of W.L.
- Tendency for canal deviation.
PASSIVE STEP BACK PREPARATION:
Passive step back preparation was proposed by Torabinajad in 1994. Here the
combination of rotary and hand instruments are used for root canal preparation.
Here enlargement of root in apical to coronal without application of force i.e.,
rotating at 1/8 to ¼ turn.
Advantage: Reduces the risk of apical transportation.
MODIFIED STEP BACK: Here after apical preparation, the step back
procedures begin 2-3mm up the canal. This provides short almost parallel
retention form to receive primary gutta-percha.
BALANCED FORCE TECHNIQUE:
Introduced by Roane and Sabala in 1985.
- Flex R files are commonly used for this technique.

21. - Canals are enlarged to 3 predesignated sizes 45, 60, 80 according to
size of apical preparation.
- This dimension refers to the size of the file used at third step back.
- Each step back from master apical file at PDL is 0.5mm shorter than
previous one. This apical preparation zone is called apical control
zone.
Here we preparing canal not till apical constriction or foramen but to radiographic
length corresponding to the PDL. Thus it will prepare its own apical constriction.
Here instrument is used in an oscillatory motion i.e., right and left with different
arc in different direction.
To insert an instrument it is rotated quarter turn in a clockwise direction (right)
with gentle inward pressure. It pulls the instrument into the canal and engages the
cutting edges equally in all directions into the surrounding walls.
Next the instrument rotated counter clockwise (left) at least 1/3 of revolution. This
motion unthreads the instrument and drives it out from canal. In order to prevent
this and obtain cutting action clinician must press inward pressure while giving
this rotation.

22. Once the file has reached the desired WL length the files is made free by one or
more counter clockwise rotation. Then file is removed from canal with slow
clockwise rotation, which effectively loads debris into flutes and removes away
from the canal.
Caution: The inward pressure and rotating force should always very light.
Steps:
 Irrigate coronal part of canal.
 Determine the largest file which will reach
radiographic apex without force. This will helps in the selection of
predesigned preparation i.e., 45, 60, 80.
 Now Flex-R files are used to the apex create
apical control zone.
 Smoothing and accentuating flare of coronal two
third is done using Gates glidden drill (i.e., 2, 3, 4, 5, 6). The Gates Glidden
drill should remain 3-6 short of working length.
Advantages:
This balance maintains the file in central even in curved canal.
It avoids transportations (Montgomery 1988)
Disadvantage: Strip perforations.

23. BALANCED FORCE TECHNIQUE:
STEP DOWN PREPARATION:
- Suggested by Schilder in 1974
WL determined Enlarge the canal to
size 25 to full WL
Size 30, 0.5mm short
of WL
Size 40, 1mm short
of WL
Size 45, 1mm short
of WL
Gates Glidden size 2-
6 to compare the
complete flare

24. - Goerig named and explained technique in detail.
Principle: Coronal aspect of root canal prepared and cleaned before the apical
part.
Steps:
1) Prepare coronal part of canal to depth 16-18mm or beginning of curve
using H.file i.e, starting from 15, 20 and 25.
2) Refine coronal portion of preparation with no 1, 2, 3 G.Gs.
- Find out working length
- Now using step back technique to complete the preparation.
Advantages:
– Reduces the canal curvature enabling straighter access to the apical
region.
– Allows early debridement of the coronal part of the canal which may
contain bulk of organic debris.
– Enables better and deeper penetration of irrigant early in the
preparation.
– Allows better control over apical instrumentation.
– Less extrusion of debris
Disadvantages:
1) Formations of ledges, apical blockage and perforations.

25. STEP DOWN PREPARATION
DOUBLE FLARE TECHNIQUE OR HYBRID TECHNIQUE:
Steps:
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
Prepare apical
portion by step
back

26. Determine working length
↓
Introduce larger instrument coronal to curve in canal. This instrument should fit
loosely in the canal.
↓
Irrigate introduce next size instrument 1mm deeper than the previous one
↓
Again go 1mm deeper with next size instrument
↓
Continue till working length is established (Confirm with radiograph)
↓
Now prepare the canal by step back technique
Indications: - For straight canals.
- Straight portion of curved canals.
Contraindications:
- In calcified canals
- Young permanent teeth with open apices.

27. DOUBLE FLARE TECHNIQUE OR HYBRID TECHNIQUE
CROWN DOWN PRESSURELESS TECHNIQUE:
Indication: Curved canals.
WL determined
Introduce larger file about
14mm coronal portion of the
canal
File with no. 30, 1mm deeper
than size 35
File with size 10 to 1mm deeper
than size 15 (now at WL)
Prepare the canal with size 25 at
full WL
Prepare apical portion of canal by
step back preparation.

28. Aim: Facilitate preparation curved canals without causing the deviation
Here the rotary action is used to prepare the canal.
Steps:
- Determine the radicular access by placing no.35 file till the 16mm of
coronal portion of canal. If this file is not going inside the canal
instrument canal with smaller instrument.
- Determine provisional W.L. 3mm short of apex using radiograph.
- Place no.35 file as far it goes without apical force. At this point turn
two full revolutions without apical force.
- Now use next smaller size (no. 30) in a same way.
- Repeat the sequence till you reached provisional W.L.
- Determine definitive working length.
- Now prepare the canal starting from no.40 till the W.L. reached.
- Again start with no. 45
- Then with No. 50
Advantage: - Less extrusion of debris
- Effective in maintaining canal shape.
- Less chance of alteration of W.L.
CROWN DOWN PRESSURELESS TECHNIQUE

29. CANAL MASTER-U TECHNIQUE:
Here root canal preparation is done using a special instrument which cuts only at
apical 1-2mm of root canal.
They come in both hand held and mechanized. The apical 0.75mm of the hand
instrument is safe ended and helps in maintain of curvature.
Steps:
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

30. - Determine working length
- Prepare to the beginning of the curve using rotary instrument i.e.,
starting from no. 50 to 80.
- Now prepare the curve in step back fashion.
Advantage: Avoids the need of recapulation.
Disadvantage: The instruments have tendency to fortune.

31. CANAL MASTER-U TECHNIQUE:
SPECIAL CONSIDERATION IN CURVATURES:
As an instrument is curved an internal elastic forces are developed. These force the
attempt to return the instrument to its original shape. This mainly acts at the
junction of instrument tip and cutting edges. This force is mainly responsible for
alteration or straightening of the final canal shape and location.
Guidelines precautions:
WL determined Prepare the beginning
of the curve using canal
master-U (size 50)
Size 80 in instrument to
beginning of curve
Prepare the canal with
size 20 to full WL
Prepare the canal with
size 50 to full WL
Size 55 1mm shorter
than WL
Size 60 2mm shorter
than WL
Size 80 4mm shorter
than WL

32. 1) Pre-curving of instruments therefore facilitate easy insertion and prevent
ledging. Curvature can be estimated by reviewing the diagnostic radiograph
or use of small number files. Precurving can be done by grasping the blade
with a gauze sponge and carefully bending with the blades of files until
desired curvature is attained.
2) Anti-curvature filing – Described by Abou-Rass et al, Frank and Glick. It
is controlled or directed preparation into safety zones of root canal away
from danger zones method of applying instrument pressure so that shaping
occur away from the inside of root curvature especially in coronal and
middle 1/3rd
of canal.
The file should be moved away from the inside of curve, so that the cutting
flutes are only against the safer part of root canal.
3) Radicular access: Described by Schilder. It creates more space in coronal
portion of canal which enhances placing and manipulating subsequent files
and increases the depth of irrigation. It is done by using rotary instrument /
circumferential filing.
4) Double or Bayonet shaped canal: First clean the apical foramen with
no.10 file. No introduce small
H.file to junction of middle and
apical third of canal and file the
inner portion of curve.

33. 5) Dilacerated canal:
 Enlarge cervical and middle third of canal first.
 Now introduce small H-file to beginning of curve
and do circumferential filing. Irrigate and
recapitulate with small no. 10 file.

34. This should performed till middle and cervical third of canals opens so that apical
third can be instrumented without forcing the instruments. Now the prepare the
canal using no.15 file by dulling its outer portion in apical third and inner portion
in middle third of instrument. It will prevent the transportation of apical foramen
and over instrumentation.
Reverse flaring / preflaring:
Here coronal portion of root canal flared before the completion of apical portion.
Advantage:
 Effective penetration of irrigate which produce
more cleaning.
 It removes the dentine interferences in coronal
part of canal, which enhances better
instrumentation in apical area.
 Plugger and filling materials penetrate to apex
more easily through large orifice.
Instrument used are:
- 0.4 taper Ni-Ti instrument.
- Me-XIM

35. i. Made up Ni-Ti
ii. Available in different taper
iii. Run in greater reduction hand piece at 340rpm.
6) Extremely narrow canals: Smaller instruments and mid sized Golden medium
files along with chemical chelators.
ROOT CANAL PREPARATION USING AUTOMATED DEVICE:
Preparation of root canal using hand instruments is hard work and time
consuming. So most of the operator used engine driven instruments for cleaning of
root canal. Many of automated devices are available all of which has advantages
and disadvantages. None of these are most predictable as compare to hand
instruments.
Classification: Based on type of movement of cutting instruments
1) Rotary: Eg: Gates Glidden, Peesoreamer, Canal master. They are used in
the straight part of canal with very slow speed.
For this group now new 16:1 gear handpiece is added. It runs at 300rpm. It runs
Ni-Ti files. They mainly used for preparation of curved canals.
Reciprocal quarter turn: In this type the instrument activated by 90 ° reciprocate
arc.

36. Example:
- Giromatic – first introduced
i. Giro-pointer 16mm long orifice opener
ii. Giro-broach
iii. Giro-file H. configuration
iv. Giro-reamer
- Endo-cursor
- Racer
The giromatic hand piece rotates the instrument in the high speed of
1000cycles /min.
Disadvantage:
Giromatic handpiece
Reciprocal quarter turn

37. - The instrument packs the debris in the canal.
- Preparation takes longer time and had a tendency to create ledges
and flaring in apex
- Less effective compared to hand instruments (Grossman)
- Difficult in use narrow canals.
Vertical: In this the hand piece produces vertical movement (0.3-1mm) with free
rotational movement.
Vertical movement with free rotation
Example:

38. a) Canal finder system: For this canal master U
and H file with safe ended tip may be attached.
b) Canal leader: It 4:1 speed reduction hand
piece. It has a vertical movement of 0.4-0.8mm and contra lateral rotation
which is restricted to 30°.
3 cutting instruments:
- K-file with safe ended tip
- H-file
- H-file with safe ended tip.
Random: These hand pieces will produce random lateral vibrational movement.
This rotates at 20,000-25,000 rpm modified K-file can be attached to this hand
piece.
Disadvantage: Handpiece some what bulky and difficult or especially when using
in posterior part of the mouth.

39. ROOT CANAL PREPARATION BY SONIC OSCILLATION:
Example:
- Sonic air 1500
- Mega sonic 1400
They operate at 1500-6500 cycles/minute. The vibrational wave form is generated
in hand piece and it is transferred to shank of the file. Due to this file move both in
lateral and vertical direction. The cleaning also enhanced by acoustic micro
streaming at middle and tip of the shank.
Endosonic hand piece with file

40. It will accept 3 types of files
- Rispisonic (coronal 2/3rd
of canal)
- Heli-sonic file
- Triosonic For apical 1/ 3rd
- Shapers
ULTRA SONIC OSCILLATION: Here ultrasonic oscillations are produced in
file shank. It consists piezoelectric unit which generate ultrasonic wave which
activate magnetostrictive stack hand piece when activated produce movement of
shaft.
Piezoelectric ultrasonic unit Ultrasonic file holder
The greater amount of movement seen at file tip in a frequency 20,000 to
25,000 / second.
Two types of files are available:
- Modified K file at tip

41. - Diamond impregnated file.
File should activate only after insertion into the canal.
File should moved circumferential motion with smooth push and pull stroke along
the walls canal for a period of one minute with copious irrigation with NaOCl.
This should repeat with 20, 25 no. files.
Advantages:
1) More cleaning due to acoustic micro streaming.
Acoustic micro streaming
2) Chemical and bactericidal action of irrigant enhanced due heat which
generated during movement of file.
LASERS: Weichman and Johnson are suggested use of laser in endodontics in
1971. Initially Nd: YAG, CO2 laser were used.
Recently Argon laser, Excimer, Holmium, YAG laser, with various wave length
are tried.
Er: YAG laser at 8Hz &2W is widely used.

42. Laser Unit
Fiber optic tip inside the root canal
These can be delivered using optical fiber with 200-400mm diameter (equal to no
20-40 file) along with air water spray as a coolant.
Action: By melting the dentin surface and vaporization of debris and pulpal
tissue remnants.
Straight / slightly curved, wide root canals are good indications.
Fiber optic tip

43. Steps:
- W.L determined
- Enlarge apical region with # 15 with copious irrigation (irrigants
like)
- Begin the preparation with laser energy level at 150milli joules.
- Fiber optic inserted to W.L. and enlargement done circumferentially
first apically then coronally to enlarge upto #60 instrument.
- Four exposures of 15 seconds are made
The average time to complete the preparation is 1 minute.
Levy compared the laser technique with a step back procedure and found the
former is better.
The recently: ArF Excimer at 193nm; XeCl at 308nm are also tried for root canal
preparation.
NON-INSTRUMENTATION TECHNOLOGY FOR ROOT CANAL
PREPARATION:
Lussi et al (1993) introduced a device that cleanses the root canal without
instrumentation.
It consists of pump that is inserted with an irrigant (like NaOCl), it is attached to
root canal through tubes. The cleaning is by bubbling and cavitation which
loosened the debris in the canal. This debris removed out side by negative pressure
(suction).
Disadvantage: It cleans the root canal but it will not do any shaping.

44. SMEAR LAYER MANAGEMENT:
When the blades of any file engage and cut dentine a smear layer of organic and
inorganic debris formed in root canal.
If the smear layer is removed then tighter interface between the obturation material
and dentine walls is possible. If smear layer is left then root canal system is
incompletely sealed and potential for microleakage and subsequent failure
increases significantly.
Various chemicals are available to removal of smear layer.
- 17% EDTA
- Ultra-Sonics
- EDTA and micro-brushes can be used with rotary or ultrasonic hand
pieces.

45. CONCLUSION
“Cleaning and Shaping is a game and, as such, can be played at various skill
levels. Visualizing and executing great play can move the clinician towards
mastery and winning the inner game of endodontics.”
- Ruddle

46. REFERENCES:
 GROSSMAN 11TH EDITION
 COHEN 8TH AND 6TH EDITION
 INGLE 5TH EDITION
 STOCK 2ND EDITION
 WALTON
 WEINE 5TH EDITION
 DCNA, 1984
 JOE, 1992
 JOE, 1991
 JOE,1993
 TRIPLE O, 1994
 BDJ, 2004