Influence of temp

Influence of temperature and concentration on
the dynamic viscosity of sodium hypochlorite in
comparison with 17% EDTA and 2% chlorhexidine
gluconate: An in vitro study
Journal of Conservative Dentistry | Jan-Feb 2014 | Vol 17 | Issue 1
PRESENTED BY:
DR.ANUBHUTI
GUIDED BY:
DR.RAHUL MARIA

INTRODUCTION
Endodontic success relies upon the complete
chemo mechanical debridement of the radicular
pulp space.
Mechanical instrumentation alone does not result
in complete elimination of intra-radicular
microorganisms
JCD JAN-FEB 2014 VOL 17/ISSSUE 1 2

The three most important attributes for an
endodontic irrigant are its
Tissue
dissolution
ability
Anti -microbicity Ability to
remove the
smear layer

1. Allows
penetration
of irrigants
into dentinal
tubules.
2. Enhances
penetration
and
adhesion of
sealer to
dentin.
3. Filling
materials
adapt better
to the canal
wall.
4. Reduces
coronal
and apical
leakage.
N.B: The small
particles of the
smear layer are
primarily
inorganic.
(Walton)
Advantages of smear layer removal
(Walton & Weine)

5
Irregular surface and may
retain cellular debris.
Tubules coated with the
smear layer
Pathways of cohen 86th
edition. Page no:197
SEMs from the canal system of a mandibular molar
Cellular fragment and a small
vessel-like structure
remain
All cellular debris has been
removed by the action of
5.25% NaOCl
The tubules
are clean and open. No smear
was formed.

1. Facilitate the mechanical action of endodontic
hand or rotary files
2. Increase cutting efficiency → better removal of
debris
3. Reduce torque → the files and reamers are less
likely to break (Weine)
Functions of lubricants

Saline
sodium hypochlorite (NaOCl)
Chlorhexidine (CHX)
Iodine potassium iodide (IKI)
Hydrogen peroxide (H2O2),
MTAD
Citric acid (CA)
EDTA (lubricant, decalcifying and chelating agent)
Types of irrigants

The three most commonly used
endodontic irrigants
Sodium
hypochlorite
(NaOCl),
chlorhexidine
gluconate
(CHX)
Ethylene
diamine
tetraacetic acid
(EDTA).

One of the most essential parameters related to fluid flow
characteristics is its dynamic viscosity, which is the
resistance exhibited by a fluid while it is being deformed by
tensile or shear stresses.
The lesser the viscosity, the easier is the fluid movement

In any type of flow, layers of fluid
move at different velocities, and the
resulting dynamic viscosity arises
due to the shear stress required to
oppose the applied force
Temperature is one of the
primary influencing
variables affecting fluid
viscosity

The purpose of this study was to assess the
influence of temperature (25°C, 45°C, and 60°C)
and concentration (1.25%, 2.6%, and 5.25%) on
the dynamic viscosity of NaOCl in comparison
with 17% EDTA (25°C) and 2% CHX (25°C).

MATERIALS AND
METHODS
It was performed using a rotational digital Viscometer
(Brookfield LVDV-II PRO, Middleboro, USA) with an
enhanced UL adapter, which facilitates the
measurement of low viscosity fluids.
Measurement of dynamic viscosity

The measurement of
viscosity was performed
using a water bath
maintained at constant
temperature using a
calibrated thermostat.

The dynamic viscosity of NaOCl was
assessed at three concentrations
1.25%
2.6%
5.25%

25°C
45°C
60°C
The role of temperature on dynamic viscosity was further
evaluated for each of the above mentioned concentrations at
three temperature variants

To warm NaOCl , syringes are filled with NaOCl
are placed in 60-70 C (140 F) Water bath.
18Nisha Garg 2nd edition page no 213

Saline (0.9%) was used
as the control at 25°C to
validate the procedure.

EDTA (17%) and CHX (2%)
were assessed for viscosity
measurements at 25°C.

Calculation of mean values and standard deviation were then performed for the ten
viscosity values.
The procedure was then repeated ten times for each solution for each group and
each concentration.
The dynamic viscosity measurements (μ) were recorded.
An appropriate spindle corresponding to low viscosity fluids was selected, and a
fluid volume of 100 mL was used at a constant speed of 100 rpm.

Estimation of dynamic viscosity of various
irrigants at room temperature -.(Groups 1-6)
0.9% of saline was used as the control at 25°C to ensure the validity of the experimental procedure.
The same procedure was repeated at room temperature using freshly prepared solutions of 17%
solution of EDTA and 2% CHX.
The dynamic viscosity measurements were then recorded.
Serial dilutions of 2.6% and 1.25% NaOCl were prepared from a 5.25% stock solution of NaOCl using
distilled water at room temperature (25°C).

GROUP IRRIGANT TEMPERATURE
I 0.9% Saline 25°C
II 2% CHX 25°C
III 17% EDTA 25°C
IV 1.25% NaOCl 25°C
V 2.6% NaOCl 25°C
VI 5.25%NaOCl 25°C

Estimation of dynamic viscosity of NaOCl (1.25%, 2.6%,
and 5.25%), at varying temperatures – (Groups 4a, 4b;
5a, 5b and 6a, 6b
GROUP IRRIGANT TEMPERATURE
IV a 1.25% NaOCl 45°C
IV b 1.25% NaOCl 60°C
V a 2.6% NaOCl 45°C
V b 2.6% NaOCl 60°C
VI a 5.25%NaOCl 45°C
VI b 5.25%NaOCl 60°C

Kolmogorov-.
Smirnov and
Shapiro Wilk
tests
one-way
ANOVA
independent
sample T-test
The tests used for the statistical
analysis were

RESULTS
The normality tests
Kolmogorov- Smirnov and
Shapiro Wilk test results
suggested that the data
followed a normal
distribution.
Therefore, to analyze the data,
parametric tests were
employed.

One-way ANOVA analysis of the various tested irrigants
at room temperature showed significant differences
amongst the groups 1-6.
Intergroup analysis using independent samples T test
showed that all the tested samples were significantly
different from each other, except between 2% CHX
(Group 2) and 1.25% NaOCl (Group 4).
These results indicate that at room temperature, the
least viscous irrigants are 2% CHX and 1.25% NaOCl

Viscosity
statistically
increased with
NaOCl
concentration
and decreased
with increasing
temperature.
Thus, amongst
the tested NaOCl
groups, 5.25%
NaOCl at room
temperature was
significantly the
most viscous (μ
=1.5300 Cps)
while 1.25%
NaOCl at 60°C
was significantly
the least viscous
(μ =1.1800 Cps).

DISCUSSION
The effect of viscosity on fluid
dynamics is related to its flow
pattern, which is primarily of two
types, a laminar flow when the fluid
velocity is low resulting in a smooth
sliding of adjacent fluid layers
and a turbulent flow
exhibiting erratic
patterns due to the
mixing of the
adjacent layers

The laminar and turbulent
flows have an effect on a
dimensionless quantity
namely the Reynolds
number (Re), represented by
the formula
Where (ρ) is the fluid density (kg.m-3),
(μ) is the fluid dynamic viscosity (Pa.s),
(ν) is the average fluid velocity(m.s-1), and
(D) is the characteristic Domain diameter (m).

When the value of the Reynolds
number is less than 2,300, it
indicates a laminar flow,
values greater than 4,000 refer
to a turbulent flow. Values in
the range of 2300-4000 indicate
a transient flow

The most
recommended
irrigation regimen
employs a
combination of
5.25% NaOCl
followed by a final
rinse with 17% EDTA

The poor efficiency of 5.25% NaOCl
and 17% EDTA in removing the smear
layer in the apical third of root canals
could be attributed to their high
viscosity

One of the effective
ways of improving the
efficiency of NaOCl is
by increasing its
temperature.

Thus, the desired irrigant requisites can be achieved by heating low concentration
solutions of NaOCl (1.25%) to 60°C for enhanced irrigation dynamics
This is also associated with a reported increase in bactericidal efficacy that is
almost doubled for every 5°C elevation in temperature.
On heating, there is thermal agitation of the irrigant molecules, which enhances its flow
properties.

NaOCl is the most recommended endodontic
irrigant due to its tissue dissolution ability,
which is a function of its concentration,
available surface area of the involved tissue,
exposure time, variations in temperature,
surface tension, and volume of the irrigant.

NaOCl- Concentrations

Ethylene-Diamine-Tetra-Acetic acid
17% ,disodium salt ,pH 7
C10H16N2O8

Nygaard-Østby first
suggested the use of EDTA
for cleaning and widening
canals.
Later, Fehr and Nygaard-
Østby introduced EDTAC (N-
OTherapeutics Hd, Sweden),
quaternary ammonium
bromide, used to reduce
surface tension and
increase penetration

Chelating Agents
Chelate react with calcium, so their action is
to react with calcium ions and substitute it
by sodium ions which can bind to dentin to
give soluble salt used to enlarge narrow
curved and calcified canals and also aids in
the removal of Smear Layer(inorganic part)

Basic purpose of chelating agents
Lubrication Emulsification
Holding
debris in
suspension

CHELATORS AVAILABLE IN :
AVAILABLE
IN
VISCOUS
FORM
RC PREP
AQUEOUS
FORM
EDTA
42
JCD JAN-FEB 2014 VOL
17/ISSSUE 1

Tublicid
File-
Eze
RC
Prep
17/ISSSUE 1
4
3
Types of Chelating Agents
EDTA
EDTAC
In all of EDTA is the
active ingredient

VARIATIONS

It has NO
antibacterial
activity
Used in
concentration of
17%
Optimal working
time 15 minutes
(Goldberg and
Abramovich)
removal of Smear
Layer(inorganic part) in less than
1 min if the fluid is able to reach
the root canal wall surfaces
5

Indication of EDTA
The best use of chelating agents is to
aid and simplify preparation for very
sclerotic canals after the apex has
already been reached with a fine
instrument.

Contraindications of EDTA
1)A ledged or blocked canal: If a sharp instrument is forced
or rotated against a wall softened by the chelate, a new but
false canal will be started.
2) Curved canals once the larger-sized instruments (size 30 or
greater) are being used. These instruments are not as flexible
as the smaller sizes and may produce root perforation.
17/ISSSUE 1
47

* Chelating agents are placed in the orifice of a
canal to be enlarged on the flutes of the enlarging
instrument or by plastic syringe.
EDTA reacts with glass, so glass syringes of that
material may not be used.
17/ISSSUE 1
48

Precaution
EDTA will remain active within the canal for 5
days if not inactivated. If the apical constriction
has been opened, the chelate may seep out &
damage the periapical bone. For this reason, at
the completion of the appointment, the canal
must be irrigated with NaOCl to inactivate EDTA.

Goldberg and Abramovich have
shown that EDTAC increases
permeability into dentinal tubules,
accessory canals, and apical
foramina
JCD JAN-FEB 2014 VOL 17/ISSSUE 1
5
0

Developed by Stewart and
others in 1969, RC-Prep is
composed of EDTA and urea
peroxide in a base of Carbowax.
It is not water soluble.
Its popularity, in combination with
sodium hypochlorite, is enhanced by
the interaction of the urea peroxide in
RC-Prep with sodium hypochlorite,
producing a bubbling action thought to
loosen and help float out dentinal
debris.

• Zubriggen et al., however, reported that a residue
of RC-Prep remains in the canals in spite of
further irrigation and cleansing.
• This led to the question of the effect of RC-Prep
residue on apical seal.
• Cooke et al. showed that RC-Prep allowed
maximum leakage into filled canals—over 2.6
times the leakage of the controls

Disadvantage of EDTA
• Deactivation of NaOCl by reducing the
available chlorine. -Walton

EDTA is employed as a final rinse due to
its ability to remove the inorganic
component of smear layer and is
recommended in a concentration of
17% for a period of one minuteJCD JAN-FEB 2014 VOL 17/ISSSUE 1 55

CHX has potent
antimicrobial ability,
especially against E.
faecalis
It is highly effective in
reducing intra-radicular
microbes in teeth with
apical periodontitis and is
recommended in a
concentration of 2% as a
final rinseJCD JAN-FEB 2014 VOL 17/ISSSUE 1 59

60
NaOCl + EDTA
 No evidence to support any claims for the
antimicrobial action of EDTA
 Partial inhibition of the action of NaOCl
Grawehr et al. 2003; Zehnder et al. 2005

61
Orange precipitate formed
by mixing chlorhexidine with
sodium hypochlorite.

62
Mixing sodium
hypochlorite
chlorhexidine with
EDTA produces a
white cloud
precipitation.

Australian Dental Journal 1998;43:(4) 63
25-gauge needles were
common place for
endodontic irrigation a
few years ago, they were
first replaced by 27-G
needles, now 30-G and
even 31-G needles are
taking over for routine use
in irrigation

Side vented nedles are used

Flexiglide needle for irrigation also easily
follows curved canals

MTAD
Bio Pure MTAD (Dentsply,
Tulsa, OK) is a mixture of a
tetracycline isomer, an acetic
acid, and Tween 80 detergent
(MTAD)-was designed to be
used as a final root canal
rinse before obturation

Tetracycline has many unique properties of low pH and thus can act as
a calcium chelator and cause enamel and root surface
demineralization
MTAD is effective in removing the smear layer along the whole length
of the root canal and in removing organic and inorganic debris and
does produce any signs of erosion or physical changes in dentine,
Whereas a mixture of 5.25% sodium hypochlorite and 17% EDTA does

In particular, MTAD mixture is effective against E. fecalis, and it is also
less cytotoxic than a range of endodontic medicaments, including
eugenol, hydrogen peroxide (3%), EDTA, and calcium hydroxide paste
Torabinejad et al, showed that the effectiveness of the MTAD was
enhanced when low concentration of NaOCl is used as an intracanal
irrigant before the use of MTAD as a final rinse.
MTAD does not seem to significantly change the structure of the
dentinal tubules

The placement of MTAD with a
cotton- wrapped barbed broach
allows intimate contact of the
solution even in the apical region of
the canals

SEQUENCE OF IRRIGATION

condition irrigant
Necrotic pulp NOCl
Final rinse with chlorhexidine
Vitl pulp exposure NOCl
Final rinse with EDTA
Calcified/sclerotic canal EDTA
NOCl
Infected canal( exudate present) NOCl
Chlorhexidine
Periapical abcess( to establish drainage) Hot water /saline
NOCl
Open apex/apical perforation Chlorhexidine
Curved canals Glyoxide
NOCl
Canals left open for drainage 3% hydrogen peroxide
saline
Re – treatment cases Chlorhexidine
NOCl
Removing smear layer in non-infected cases EDTA/ citric acid
NOCl

CONCLUSION
A concentration of 5.25% NaOCl
and 17% EDTA make these
irrigants significantly viscous at
room temperature.
This higher viscosity would be
detrimental to irrigation
dynamics in the crucial apical
third in terms of tissue
dissolution, smear layer removal,
and antimicrobial ability.

Elevating the temperature of 1.25% NaOCl to 60°C
significantly reduces the viscosity of the irrigant.
This would clinically translate into improved
irrigation dynamics.

ReferencesTorabinejad M, Walton RE. Endodontics principles and
practice. 4th ed. Saunders; 2009. p. 391-404.
Cohen S, Hargreaves KM. Pathways of the pulp. 9th ed.
St. Louis: Mosby; 2006. p. 318-323.
Ingle JI,Bakland LK. Endodontics. 5th ed. BC Decker;
2002. p. 498-505.
Weine FS. Endodontic therapy. 6th ed. St. Louis:
Mosby; 2004. p. 221-226
Haapasalo M, Shen Y, Qian W, Gao Y. Irrigation in
endodontics. Dent Clin N Am. 2010; 54: 291-312.
(Review) JCD JAN-FEB 2014 VOL 17/ISSSUE 1 82

INGLE’S 6TH edition
Pathways of cohen 6th,9th ,13th edition
Textbook of endodontics Anil kohli’s
operative dentistry,2014,39-5,460-468 83

THANK YOU

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