Cardiac Output, Venous Return, and Their Regulation
Preparation of the root canal system
1. Preparation of the RootPreparation of the Root
Canal SystemCanal System
Prepared By:Prepared By:
Bawar Yahya AhmedBawar Yahya Ahmed
University of SulaimaniUniversity of Sulaimani
Class 5 - Group EClass 5 - Group E
3. Root canal preparationRoot canal preparation
Cleaning is the removal of all contents of the root
canal system before and during shaping: infected
materials, antigenic materials, organic substances,
microflora, bacterial by products, food, caries, tissue
remnants, denticles, pulp stones, collagen,
inflammatory chemicals, contaminated canal filling
materials, and dentinal debris created during canal
shaping procedures. Cleaning entails accomplished by
both mechanical instrumentation and chemically by
irrigation.
4. Root canal preparationRoot canal preparation
Shaping is a mechanical process accomplished
(with files, reamers, Gates-Glidden drills, slow speed
burs, high speed diamonds-tipped drills, and sonic and
ultrasonic, and nickel-titanium instruments of variable
taper) to establishment of a specific cavity from that
permits pluggers, spreaders, and other Obturation
instruments to fit freely within the root canal system
and to generate the pressures needed to transform and
capture a maximal Obturation cushion, forcing gutta-
percha and a microfilm of sealer into all foramina.
Equally important, shaping facilitates three-dimensional
cleaning by providing easy direct access for file,
reamer, rotary instruments and irrigant during the
treatment process.
5. OBJECTIVESOBJECTIVES
biologicalbiological
Complete removal ofComplete removal of
pulpal tissuepulpal tissue
bacteriabacteria
mechanicalmechanical
Continuously taperingContinuously tapering
preparationpreparation
Maintaining original anatomyMaintaining original anatomy
Maintaining position of apicalMaintaining position of apical
foramenforamen
Narrow apexNarrow apex
6. Objectives of root canal preparationObjectives of root canal preparation
1. Biological
2. Mechanical
7. Objectives of root canal preparationObjectives of root canal preparation
From aFrom a biologicalbiological perspective, the goals ofperspective, the goals of
chemomechanical preparation are tochemomechanical preparation are to
eliminate microorganisms from the rooteliminate microorganisms from the root
canal system, to remove pulp tissue thatcanal system, to remove pulp tissue that
may support microbial growth, and tomay support microbial growth, and to
avoid forcing debris beyond the apicalavoid forcing debris beyond the apical
foramen which may sustain inflammation.foramen which may sustain inflammation.
8. BIOLOGIC OBJECTIVES
1. Confine all instrumentation within the root canal space to
maintain its spatial integrity.
2. Avoid pushing contaminated debris past the confines of
the apical constriction
3. Remove all the potential irritants from the entire canal
system.
4. Establish the exact W.L and completely clean and shape
the canal system during the first treatment visit.
5. Create sufficient width in the coronal half of the canal
system to allow for copious flushing and debridement.
9. MECHANICAL OBJECTIVES
1. Develop a continuously tapering conical form in the root
canal preparation. The final preparation of this system should
be an exact replica of the original canal configuration in
shape, taper.
2. Prepare a sound apical dentine matrix at the DC junction.
This provides the resistance form to the intraradicular
cavity preparation. This also prevents the over- extension of
instruments and controls the apical movement of gutta-percha
sealer during obturation.
3. Prepare the canal to taper apically, with the narrowest
cross- sectional diameter at the apical termination (apical
dentin matrix).
4. Confine cleaning and shaping procedures to the canal
system, thereby maintaining the spatial integrity of the apical
foramen.
10. PrinciplesPrinciples
Note: the current concept
of root canal preparation is
not cleaning and shaping,
but shaping and cleaning.
11. Principles of RCTPrinciples of RCT
Principles of Endodontic cavity preparation Endodontic cavity
preparation may be separated into two anatomic divisions:
(a) Coronal preparation
(b) Radicular preparation.
12. Principles of RCTPrinciples of RCT
Black's principles of cavity preparation can be modified to include
the Root canal 'cavity' preparation
1. Coronal:
I. Outline Form
II. Convenience Form
III. Removal of the remaining carious dentin (and defective
restorations)
IV. Toilet of the cavity
13. Principles of RCTPrinciples of RCT
Black's principles of cavity preparation can be modified to include
the Root canal 'cavity' preparation
2. Radicular:
I and II. Outline Form and Convenience Form
IV. Toilet of the cavity
V. Retention Form
VI. Resistance Form
14. Outline FormOutline Form
To achieve optimal preparation, three factors of anatomy must be considered:
(1)the size of the pulp chamber,
(2)the shape of the pulp chamber,
(3)the number of individual root canals,
their curvature, and their position
internal
The finished outline form should
accurately reflect the shape of the
pulp chamber.
15.
16. Convenience FormConvenience Form
Removing excess of coronal dentin, so as to allow
passage of larger instruments, for better
instrumentation, irrigation and obturation.
Four important benefits are gained through convenience
form modifications: (1) unobstructed access to the canal
orifice, (2) direct access to the apical foramen, (3) cavity
expansion to accommodate filling techniques, and (4)
complete authority over the enlarging instrument.
17.
18. Removal of the remaining carious dentin
(and defective restorations)
Removal of the Remaining Carious Dentin and
Defective Restorations : Caries and defective
restorations remaining in an endodontic cavity
preparation must be removed for three reasons:
1. To eliminate mechanically as many bacteria as
possible from the interior of the tooth,
2. To eliminate the discolored tooth structure, that
may ultimately lead to staining of the crown,
3. To eliminate the possibility of any bacteria-laden
saliva leaking into the prepared cavity.
19. Toilet of the Cavity
•All of the caries, debris, and necrotic
material must be removed from the
chamber before the radicular preparation
is begun.
•If the calcified or metallic debris is left in
the chamber and carried into the canal, it
may act as an obstruction during canal
enlargement.
• Soft debris carried from the chamber
might increase the bacterial population in
the canal
20. Retention form
Near parallel walls in the apical 2-3
mm ensure a snugly fitting G.P
[ Apical TUG BACK ] .
Most crucial for preventing apical
leakage.
21. Resistance form
Resistance to overfilling is provided
by maintaining the integrity of the
natural constriction of the apical
preparation
Prevents over instrumentation
Prevents forcing debris or
obturating material
Provides a stop, against which G.P
can be compacted. .
22. TYPES OF ROOT CANALTYPES OF ROOT CANAL
PREPARATIONSPREPARATIONS
Crown downCrown down
Step backStep back
hybridhybrid
42. IrrigationIrrigation
An ideal irrigant:An ideal irrigant:
Is nontoxicIs nontoxic
Dissolves vital and necrotic tissueDissolves vital and necrotic tissue
Is bactericidalIs bactericidal
Lubricates the canalLubricates the canal
Removes the smear layerRemoves the smear layer
43. Sodium hypochloriteSodium hypochlorite
Dissolves vital and necroticDissolves vital and necrotic
tissuetissue
Is bactericidalIs bactericidal
Lubricates the canalLubricates the canal
53. TaperTaper
Taper of instruments in U of M file kitTaper of instruments in U of M file kit
Stainless steel files – 0.02 taperStainless steel files – 0.02 taper
OS – variable tapers ranging from 0.05 toOS – variable tapers ranging from 0.05 to
0.080.08
Series 29 rotary Profiles – 0.06 taperSeries 29 rotary Profiles – 0.06 taper
NiTi hand files – 0.04 taperNiTi hand files – 0.04 taper
54. Tip DesignTip Design
Non-cutting tipNon-cutting tip
Bullet nose (60 degree) tipBullet nose (60 degree) tip
Smooth transition angle whereSmooth transition angle where
tip meets flat radial landstip meets flat radial lands
55. Tip DesignTip Design
Designed to follow a pilot holeDesigned to follow a pilot hole
Guides instrument through canalGuides instrument through canal
during preparationduring preparation
58. Cross sectional geometryCross sectional geometry
Radial lands separated by three u-Radial lands separated by three u-
shaped flutesshaped flutes
Provide space for accumulation ofProvide space for accumulation of
debrisdebris
Moves debris out of canalMoves debris out of canal
59. Length of cutting bladeLength of cutting blade
Traditionally 16 mmTraditionally 16 mm
Orifice shapers – 10 mmOrifice shapers – 10 mm
60. Sizing of instrumentsSizing of instruments
ISO sizesISO sizes
Number refers to tip diameter inNumber refers to tip diameter in
tenths of mmtenths of mm
The tip diameter increases byThe tip diameter increases by
0.05 mm from sizes 10 to 60,0.05 mm from sizes 10 to 60,
then by 0.10 mmthen by 0.10 mm
61. Sizing of instrumentsSizing of instruments
% increase in diameter from #10% increase in diameter from #10
to #15 file is 50%to #15 file is 50%
Difference between #55 and #60Difference between #55 and #60
is only 9%is only 9%
62. Sizing of instrumentsSizing of instruments
Series 29Series 29
Progressive 29% increase in tipProgressive 29% increase in tip
diameterdiameter
Instruments are better spacedInstruments are better spaced
More instruments in smaller sizesMore instruments in smaller sizes
and fewer large instrumentsand fewer large instruments
