Surfactants : Surface tension of liquids - Courtesy ROOTS
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From: "George Chatzipetros"
Sent: Saturday, June 10, 2006 3:37 AM
Subject: [roots] surfactants
Can anyone enlighten me as to what is the ideal ratio of mixing alcohol with hypochlorite to reduce
its surface tension? - George
No need to mix it, just drop it onto the hypo. when it is in the canal and it will appear to be
'sucked 'up the canal. - Stephen Day.
"ideal" and "irrigant" aren't two words commonly used in the same sentence ;-))) Everyone seems to have
their own recipe. Of course certain rules do apply, just attempting a bit of tongue in cheek humor.
peronally, I think a "couple drops per squeeze" is ideal ;-) - Kendel
what kinda alcohol? Ethanol. whisky??? beer?? and who sucks it up? - ananya
I use 100%, anhydrous ethanol. You may have to get it from a pharmacy. One drop is into the bleach
flooded chamber is good - Arturo
Does anybody pre-mix, the ethanol into the bleach syringe? - Simon Bender
Good question. Don't know if it would inactivate the naocl after a period of time? Once you add the etoh
to the naocl it bubbles like hell under the scope. Would be nice to have it together though - Arturo
When you add 100% ethanol to Sodium Hypochlorite you are reducing the surface tension of the irrigant.
Surface tension is typically measured in dynes/cm, the force in dynes required to break a film of length 1 cm.
Equivalently, it can be stated as surface energy in ergs per square centimeter. Water at 20°C has a surface
tension of 72.8 dynes/cm compared to 22.3 for ethyl alcohol and 465 for mercury.
If you add anhidrous ethanol to water you can reduce it’s surface tnsion from 72.8 dynes /cm to 22.3 dynes
per square centimeter.
In the bacteriology literature of the 70’s (hospital disinfection) it was shown that a mixture of NaOCL2
with ethanol was sporicidal to Bacillus subtillis spores. The mixture was active for a couple of hours.
Recently Dr. Buck .. Dr. Eleazer ‘s resident when he was still in Lousville showed that Sodium Hypochlorite
with Ethanol detoxifies endotoxin (Buck RA, Cai J, Eleazer PD, Staat RH, Hurst HE. Detoxification of endotoxin
by endodontic irrigants and calcium hydroxide. J Endodon 2001;27:325-327) as much as Calcium hydroxide.
Whereas Ethanol 95% alone or Sodium Hypochlorite alone were not effective.
I discussed the surface tension of Sodium Hypochlorite an its surface tension reduction in my presentation
in SUMMIT 1 ....... the golden days of ROOTS ;-) - Benjamin Schein
Thanks Ben. Good explanation - Randy
Surely not during the time taken to clean and shape - say an hour or two? - Simon
Simon, There is one paragraph on surfactants in a recent review of root canal irrigants from the JOE.
I don't agree with everything in this article but I'm posting it since it does have some comments on surfactants.
The paragraph is on pg 395, second to last paragraph of the article. - Randy Hedrick
One other idea that keeps returning is the notion that reducing surface tension by adding wetting agents would
improve the effectiveness of irrigants, as they would reach better into dentinal tubules and accessory canals
(169, 170). In the original study that showed a better penetration of liquids with reduced surface tension into the
root canal systems of extracted molars, it was not mentioned whether these teeth were dry or had been kept in a moist
environment (169). In situ root canals and adjacent dentin walls are liquidfilled (171), and surface tension of
liquids to be introduced thus plays a minor role in this environment. The infiltration of dentin by chemical moieties
from aqueous solutions occurs via diffusion rather than direct liquid exchange (172). Therefore, it may not
come as a surprise that reducing surface tension in irrigants does not influence their capacity to remove the smear
layer (143), nor does it enhance their antibacterial efficacy in the root canal (173). Moreover, reducing the surface
tension in solutions used during instrumentation may actually cause an increased penetration of smear material into
the dentinal tubules (174).
Finally, it should be mentioned that the irrigating concepts presented here are aimed at obtaining a clean root canal
system that is ideally prepared for the classic filling technique, using guttapercha and a sealer. In the future,
other ways to fill root canal systems may evolve and/or be established, such as the use of resinbonded
systems (175), bioactive materials (176), or even the attempt to regenerate pulp tissue in necrotic cases (177).
Although radical changes in the irrigating concept are not likely to occur, the specific needs for irrigants when such
alternative attempts are followed are yet to be delineated.