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allied_______________ international 4525 Hiawatha Avenue Minneapolis Minnesota 55406 U.S.A. laboratories Chris Christopfel, PhD |
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May 1, 1996
Introduction The immediate noticeable manifestation of halitosis is caused by the presence of volatile sulfur compounds, especially hydrogen sulfide (H2S), volatile organic acids and volatile amines in the breath. The major cause of malodor being the volatile sulfur compounds which have intensely unpleasant odors even at very low concentrations. These compounds are produced by the action of micro-organisms on proteins that contain the sulfur-containing amino acids cysteine and methionine. One mechanism by which the “Stabilized Chlorine Dioxide” containing mouthrinse products are purported to eliminate halitosis is by oxidation of the odoriferous volatile sulfur compounds into non-volatile, non-odoriferous molecules such as the corresponding sulfates, sulfonates and sulfones. Therefore, one possible experimental procedure to evaluate the effectiveness of a given brand of “Stabilized Chlorine Dioxide” based mouthrinse is to test its effectiveness of oxidizing volatile sulfur compounds.
Experimental Procedures
Hydrogen sulfide gas in nitrogen and air at concentration
of about 400-500 ppb was bubbled through a fine glass frit into
60 mL of an aqueous sample that was to be tested for its ability
to decrease the concentration of H2S in the gas stream.
The gas stream emerging from the test sample was directed into
a halimeter (Interscan Corp) which measures the H2S
concentration of the gas stream.
The sample of Oxyfresh New Fresh Flavor Mouthrinse
used in all of these experiments was a production sample (Lot
#04661) taken before the peppermint oil was added. It was tested
without the peppermint oil to eliminate any possibility that the
volatile mint component could interfere with the electrochemical
measurement of the hydrogen sulfide by the Halimeter.
In this experiment H2S concentrations
were recorded after 1, 2, 3, 4 and 5 minutes after the gas flow
through the mouthrinse samples commenced.
[Note: The experimental procedure used in this study
is a slightly modified variation of a procedure that was generously
provided by Dr. Manny Shaw of Interscan Corp]
Results
The numbers in the table below all have units of
parts per billion (ppb) H2S. Also, they are the average
of five readings taken after 1, 2, 3, 4 and 5 minutes.
Clearly, all of the products tested reduced the hydrogen
sulfide (H2S) level significantly below that of a water
control.
The Oxyfresh New Mouthrinse product is more effective
in these studies than the Retardex Oral Rinse even though the
“Stabilized Chlorine Dioxide” level in the Oxyfresh
product (628 ppm) is significantly lower that that in the Retardex
Oral Rinse (980 ppm).
[Editorial Comment: This is the result of a synergistic
effect with the other ingredients in the Oxyfresh formulation.
It is conventional wisdom in the medical profession that the
best dosage level of an active ingredient is the lowest effective
dosage. More is not necessarily better.]
Although ProFresh exhibited more hydrogen sulfide
reduction, it does not necessarily follow that it is better than
the Oxyfresh product as a mouthrinse. Under conditions of actual
use, it is not impossible that the difference between the two
would be insignificant. The experiments performed in this study,
while useful and informative, do not reproduce the conditions
of actual use. The experiments performed in this study used contact
times with H2S gas with the mouthrinse products of
a second or less. These conditions could magnify the difference
between the ProFresh and Oxyfresh mouthrinse products. In a study
with contact times of one minute, as recommended on
the Oxyfresh bottle, the difference may be attenuated
to insignificance. [Editorial Comment: It should be noted that ProFresh contains free chlorine dioxide
in addition to the stabilized form. Oxyfresh,
in previous research, has evaluated and rejected the use of free
chlorine dioxide for the following reasons:
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