2. INTRODUCTION
The main goal of the endodontist is to remove the infected tissue and
bacteria from the root canal which allows the healing of periapical lesion or
to prevent the infection from periradicular tissue.
So the irrigation of the root canal with antibacterial solution is an important
step.
The efficacy of irrigation depends on working mechanism of the irrigant and
ability to bring the irrigant in contact with the element, material and
structure.
3. SIGNIFICANCE OF ENDODONTIC
IRRIGATION
Irrigants are the chemical agents delivered into the root canal and they worn
to dissolve the tissue remnants, to kill the microorganism, and to clean the
root canal effectively and safely without any consequences.
Combination of products in the correct irrigation sequence contributes to a
successful treatment outcome7 The ideal irrigant solution should have the
following properties: It should have the broad antimicrobial action, should be
able to dissolve the necrotic pulp remnants, should inactivate the endotoxins.
6. 1) MANUAL AGITATION TECHNIQUE
The simplest of all mechanical activation techniques is the manual irrigant
agitation, which can be performed with different systems.
The easiest way to achieve this effect is moving vertically and passively the
endodontic file within the root canal.
The file promotes the irrigant penetration and reduces the presence of air
bubbles in the canal space9 ,but does not improve the final cleaning
7. A) SYRINGE IRRIGATION WITH
NEEDLES/CANNULAS:
The technique involves dispensing of an irrigant into a canal through
needles/cannulas of variable gauges, either passively or with agitation.
The latter is achieved by moving the needle up and down the canal
space.
Irrigation tip gauge will largely determine how deep an irrigant can
penetrate into the canal.
A 21-gauge tip can reach the apex of an ISO size 80 canal, a 23-gauge
tip can reach a size 50, a 25-gauge tip can reach a size 35 canal, and a
30-gauge tip can reach the apex of a size 25 canal.
,Open-ended tips express irrigant out the end toward the apex and
consequently increase the apical pressure within the canal.
Closed-ended irrigant tips are side-vented and thus create more
pressure on the walls of the root canal and improve the hydrodynamic
activation of an irrigant and reduce the chance of apical extrusion
8. B)ROTARY BRUSHES:
Brushes are not directly used for delivering an irrigant into the canal spaces.
They are adjuncts that have been designed for debridement of the canal walls
or agitation of root canal irrigant.
They might also be indirectly involved with the transfer of irrigants within the
canal spaces.
Recently, a 30- gauge irrigation needle covered with a brush (NaviTip FX;
Ultradent Products Inc., South Jordan, UT) was introduced commercially.
NaviTip Fx is a 30-gauge irrigation needle covered with a brush was
introduced commercially by Ultradent company.
The Endobrush could not be used to full working length because of its size,
which might lead to packing of debris into the apical section of the canal
after brushing
9. C)MANUAL DYNAMIC AGITATION:
An irrigant must be in direct contact with the canal
walls for effective action. Its often difficult for the
irrigant to reach the apical portion of the canal
because of the so-called vapor lock effect.
The gently moving well-fitting gutta-percha master
cone up and down in short 2 to 3 mm strokes
(manualdynamic irrigation) within an instrumented
canal can produce an effective hydrodynamic effect
and significantly improve the displacement and
exchange of any given reagent
10. 2)MACHINE ASSISTED AGITATION
TECHNIQUE:
A)ROTARY BRUSHES:
i) Ruddle brush and canal brush come under this.
A rotary handpiece-attached microbrush has been used by ruddle to
facilitate debris and smear layer removal from instrumented root canal.
The brush includes a shaft or shank and a tapered brush section. During
debridement phase, microbrush rotates at about 300 rpm.
ii) Canal Brush is another endodontic microbrush that has recently been made
commercially available.
This highly flexible microbrush is molded entirely from polypropylene and might
be used manually with a rotary action.
A) Ruddle Brush
B) Canal brush
11. B)CONTINUOUS IRRIGATION DURING
ROTARY IRRIGATION:
(i) The Quantec-E irrigation system (Sybron Endo, Orange, CA) is a self
contained fluid delivery unit which is attached to the Quantec-E Endo
System .
It consist of a pump console, two irrigation reservoirs, and tubing which
provide continuous irrigation during rotary instrumentation.
(ii) The Self adjusting file(SAF) system is a shaping and cleaning system
designed for minimally invasive endodontic treatment.
It is operated with the specific handpiece head (RDT ,ReDent) and an
irrigation pump(VATEA pump) that allows continuous flow of irrigant
through the hollow file .
It is available in two diameter:1.5-2.0.
Both are extremely compressible.
The 0.5mm file compressed to the dimension of 20 K file and 2.0mm file
compressed to the dimension of 35 K file
12. SONIC ACTIVATED IRRIGATION
The endo activator system uses safe, non- cutting
polymer tips in an easy to use subsonic handpiece
to quickly and vigorously agitate irrigant solutions
during endodontics therapy.
When comparing sonic with ultrasonic activation
system results are controversial.
The difference lies in the oscillating movements:
sonic devices range from 1500 and 6000 Hz.
Examples: Endosonor and EndoSoft ESI
inserts,IrriSafe, the EndoActivator System, and the
Vibtinge sonic syringe.
Inadvertent cavitation of root canals is not
observed with sonic instrument.
13. ULTRASONIC INSTRUMENTS
Instruments used in the handpieces that move near or faster than the speed
of sound range from standard K type files to special broach like instruments.
Sonic treatment: the term refers to sound waves in the region 16 hZ up to
20kHz whereas ultrasonic waves ranges from 20kHz to 1Ghz.
14. MECHANISM
These are based in three mechanisms of action:
CAVITATION
PRODUCTION OF
HEAT
ACOUSTIC
MICROSTREAMING
15. CAVITATION
Ultrasonic waves in the presence of liquids results in massive oscillation with regions of
high and low pressure. This phenomenon is known as cavitation.
The result includes bubble formation within the liquid, as well as turbulent fluid
currents.
The microbubbles created may be empty, or may contain gas or vapor.
With the use of sodium hypochlorite, it is possible to achieve a warming effect above
the boiling point of 40°C, which leads to the formation of the Na+ cation, the
hypochlorite anion ClO, as well as the formation of NaOH, ClOH, C12, O, or NaCl
(van der Sluis et al., 2006).
These highly reactive elements may be the reason for the observation that the
antibacterial effect of ultrasound in the presence of water is relatively weak (Ahmad et
al., 1990), but is much stronger with typical endodontic irrigating solutions, providing a
large antibacterial effect (Cameron, 1987; Huque et al., 1998).
16. PRODUCTION OF HEAT
With the application of high acoustic pressure, the microbubbles enlarge until they
eventually implode, creating strong local pressure waves as well as a rise in temperature
(heat).
In comparison, the instruments designed for use in the dental practice are too weak to
create large cavitation effects.
For this reason, the effect has been considered by numerous authors as too mild and
thus ineffective (Ahmad et al., 1987b, 1988; Walmsley 1987; Lumley et al., 1988).
17. ACOUSTIC MICROSTREAMING
Most important and effective is the third mechanism of action: acoustic
microstreaming.
Within the sonic field, there is an interaction between the sonic file oscillations and the
irrigating solution, which leads to motion within the fluid, the so-called “eddy current.”
This current flows from the coronal end of the root canal toward the apical area and
exhibits the typical nodes and antinodes; it is strongest at the tip (van der Sluis, 2006).
Due to the higher level of energy, the eddy currents that are created elicit
hydrodynamic shear stresses, which have been demonstrated in many studies (Ahmad
et al., 1987a, b, 1992; Lumley et al., 1991; Walmsley et al., 1992, Roy et al., 1994).
Contact of the sonic or ultrasonic probe with the internal surface of the root canal
reduces acoustic microstreaming by interrupting the continuous motion of the wave, but
does not eliminate it completely.
18. ULTRASONIC HANDPIECES
Ultrasonic endodontics is based (at 20-25 Khz) activates an endodontic file
resulting in the three dimensional activation of file in the surrounding
medium.
Ultrasonic handpieces use k files as a canal instrument. Before a size 15 file
can fully function, however the canal must be enlarged with hand instruments
to at least size 20.
19. TYPES OF ULTRASONIC IRRIGATION
Simulatenous Ultrasonic Irrigation
• The file is intentionally bought in contact
with the canal walls
Passive Ultrasonic Irrigation
• In passive ultrasonic irrigation the file
never touches the canal walls
20. PASSIVE ULTRASONIC IRRIGATION(PUI)
First described by Weller et al.
The term, passive is related to the noncutting action of the ultrasonically
activated file.
PUI should be introduced in the canal once the root canal system has a final
apical size and taper.
A fresh solution of irrigant should be introduced, and a small file or smooth
wire(eg. #15) is ultrasonically activated.
Using this noncutting approach the potential to create aberrant shapes within
the root canal is reduced to minimum
21. NEGATIVE APICAL PRESSURE IRRIGATION
Irrigant is delivered into the access chamber and a very fine needle
connected to the dental unit’s suction device is placed into the root canal.
Excess irrigant from the access cavity is then transferred apically and
ultimately removed via suction.
First, a macrocannula, equivalent to an ISO size #55, .02 taper instrument,
removes coronal debris.
Subsequently, a microcannula, equilvalent to a size #32, .02 taper, removes
particles lodged close to WL.
Such a system is commercially available (Endovac, Discus Dental) and may
prove a valuable adjunct in canal disinfection.
22. One of the main characterstics of the system is
safety.
Various studies have shown that Endovaac prevents
irrigant extrusion.
Another, device that makes use of pressure suction
technology is the RinsEndo system.
It aspirates the delivered rinsing solution into a
irrigation needle that is placed close to the WL and
at same time activates the needle with oscillations
of 1.6 Hz amplitude.
23. SAFETY IRRIGATOR
The safety irrigator is an irrigation/ evaculation system that
apically delivers the irrigant under positive pressure through
a thin needle containing a lateral opening and evacuates the
solution through a large needle at the root canal orifice.
The safety irrigator features a large coronal evacuation
tube, enabling the user to irrigate and evacuate
simultaneously safely.
It fits any standard Luer- lock syringe.
Designed to limit hypochlorite accidents.
This needle is assembled with negative pressure syringe and
comes with side vented irrigating needle.
24. GENTLE WAVE SYSTEM
The Gentlewave system was introduced by the United States in 2016.
The device is composed of a console, and so called procedure instrument, which is a single
use tip attached to a handpiece and a central unit that contains three individual irrigation
solution containers, one waste canister, a degassing system, and a pressure generator.
The system delivers an energized flow of irrigation solutions from the central unit to the
procedural instrument.
According to the manufacturer, the fluid stream entering the tooth creates a shear force,
which in turn causes hydrodynamic cavitation.
The implosion of micro-bubbles then creates an acoustic field of broadband frequencies,
which travels through the fluid into the root canal system.
The programmed irrigation regimen begins with 3% NaOCl followed by 8% EDTA, with a rinse
of distilled water in between and at completion.
The fluid within the root canal space is continuously collected and removed from the
chamber through a five-point vented suction system built in the sealing lid of the procedural
instrument.
25. The studies investigating cleaning
and disinfection of the root canal
system concluded that GW irrigation
results in a faster dissolution rate
than other systems, that can clean
canals efficiently with minimal
instrumentation and can reduce
residual debris and promote better
penetration into dentinal tubules
compared with needle irrigation.
26. LASER ACTIVATED IRRIGATION
Lasers are widely used in dentistry and include a diode, Nd:YAG, erbium and
CO2 , which produces radiation in both the near and far infrared
electromagnet spectrum.
The Er:YAG laser wavelength (2940 nm) has the highest absorption in water
and high affinity to hydroxyapatite, which makes it suitable for use in root
canal treatment.
Laser energy may be used to activate irrigant solutions in different ways, for
example at a molecular level, as in photo-activated disinfection (PAD) or at a
bulk flow level as in laser-activated irrigation (LAI).
The mechanism of action is based on the generation of a secondary cavitation
effect with expansion and the successive implosion of fluids.
27. PIPS
Erbium laser technique that uses photon-induced photoacoustic
streaming (PIPS) of irrigants.
In this technique, the laser tip is placed into the coronal access
opening of the pulp chamber only and is kept stationary without
advancing into the orifice of the canal.
The use of a tapered and stripped tip with specific minimally
ablative laser settings is required: low energy (20 mJ), pulse
repetition rate (15 Hz), and short pulse duration (50 μs).
The difference in laser penetration and bacterial killing is attributed
to the difference in the degree of absorption of different
wavelengths of light within the dentin.
28. PHOTOACTIVATED DISINFECTION
Photodynamic therapy (PDT) or light-activated therapy (LAT) may have
endodontic applications because of its antimicrobial effectiveness.
In principle, antimicrobial photodynamic therapy (APDT) is a two-step
procedure.
•Step 1:
Photosensitisation of
infected tissue
•Irradiation of
photosensitized tissue
29. ANTIBACTERIAL NANOPARTICLES
Nanotechnology is the science conducted at the nanoscale, using particles about 1
to 100 nm.
Nanoparticles in endodontics are being developed for their efficient disinfection of
root canals, due to the broad-spectrum antibacterial activity.
The nanoparticles evaluated in endodontics include Chitosan (CS-np), zinc oxide
(ZnO-np), and silver (Ag-np) nanoparticles
CS-np have been widely studied and appear to be effective against monospecies
(E. faecalis) and multispecies biofilms, even in the presence of tissue inhibitors,
and it has been attributed to their ability to disrupt the cell wall.
Silver nanoparticles are also being evaluated for use as root canal disinfecting
agents.
In gel and liquid form, such nanoparticles have been shown to be able to kill and
disrupt E. faecalis biofilm.
30. Bioactive glass (SiO2 -Na2O-CaO-P2O5 ) is another revolutionary introduction
in the field of nanotechnology.
The antimicrobial effect of bioactive glass is due to its ability to maintain an
alkaline environment over a period of time.
When used in root canals, bioactive glass was found to kill bacteria, but the
mechanism of action was not pH related and dentin did not seem to alter its
effect.
It is recently being researched for its use for endodontic regeneration in
which diseased or necrotic pulp tissues are removed and replaced with
healthy pulp tissues to revitalize teeth.
31. HEALOZONE
Ozone, in the gaseous or aqueous phase, is a powerful and reliable
antimicrobial agent against bacteria, fungi, protozoa, and viruses.
The mechanism of action is based on the destruction of cell walls and
cytoplasmic membranes of bacteria and fungi by the oxidant potential
of the ozone.
During this process, ozone attacks glycoproteins, glycolipids, and other
amino acids and inhibits the enzymatic control system of the cell with
an increase of the membrane permeability leading to immediate
functional cessation.
The ozone molecules then readily enter the cell and effectively kills
microorganisms.
It is applied to oral tissues in the following forms: ozonated water,
ozonated olive oil, and oxygen/ozone gas.
32. WATER PREPARATIONS
Super-oxidized water, also called electrochemically activated water or potential
oxidative water, is effectively saline that has been electrolyzed to form
superoxidized water, hypochlorous acid, and free chlorine radicals.
It is commercially available as Sterilox (Sterilox Technologies, Radnor, PA, USA).
This solution is nontoxic to biologic tissues, yet able to kill microorganisms.
The solution is generated by electrolyzing saline solution—a process no different
from that used in the commercial production of NaOCl.
The difference, however, is that the solution accumulating at the anode is
harvested as the anolyte and at the cathode as the catholyte.
These solutions display properties that are dependent upon the strength of the
first saline solution, the applied potential difference, and the rate of generation.
Anolyte and catholyte solutions generated from one such technology (Radical
Waters Halfway Johannesburg, South Africa) have shown promise as antibacterial
agents against laboratory-grown, single-species biofilm models.
33. CONCLUSION
Various irrigating device have been evolved in order to replace the previous
syringe irrigation.
Clinical studies have described the higher efficacy in effective microbial
count.
Due to the safety factors, capacity of the high volume irrigant delivery and
ease of application the newer irrigation devices may change the insight of
conventional endodontic treatment.
Editor's Notes
The vapor lock phenomenon entails the formation of an air or gas bubble inside a close ended system.
Both these steps have synergistic action in killing the bacteria.
