A New Anti-Halitosis Mouthrinse
A Pilot Study Of The Effectiveness and Substantivity Of A New Anti-Halitosis Mouthrinse.
A cysteine challenge test was used to measure the effectiveness of an anti-halitosis mouthrinse (AHM) over a six-hour period. AHM was shown to provide a sustained and effective anti-halitosis effect over the entire 6 hours.
The cysteine challenge test is a severe in vitro test for mouthrinse effectiveness. A cysteine rinse was administered hourly over 6 hours to 5 volunteers after an initial 60 second rinse with AHM. A 71.4% reduction in volatile sulfur compounds (VSC’s) was achieved at 6 hours post-rinse. Conclusion: AHM was shown to provide a consistent, sustained and extremely effective reduction in VSC concentrations for at least 6 hours in human volunteers.
Americans spent over $700 million on mouthwash products and another $625 million on breath mints and other mouth fresheners in the year 2000 (1). It has been estimated that 20% to 60% of the population suffer from chronic halitosis (2,3). Roughly 70% report having occasional “morning breath.” Most cases of halitosis originate in the oral cavity (85%), primarily from VSC’s released by bacteria on the posterior dorsum of the tongue (4,5). Anaerobic gram-negative bacteria on the tongue and in deep periodontal pockets process protein by bacterial putrefaction. The protein is first ingested and then broken down into amino acids, cysteine and cystine are processed, foul-smelling VSC’s (hydrogen sulfide and methyl mercaptan) are released and are perceived as halitosis (6). Other gases make minor contributions to the overall halitosis odor. These have been identified as putricine (decaying meat), cadaverine (rotting corpses), skatole (feces), and isovaleric acid (sweating feet). When these are mixed in small amounts with the primary VSC’s hydrogen sulfide (rotten eggs), methyl mercaptan (feces) and dimethyl mercaptan in the oral cavity, a very foul breath can be produced (1).
The commercially available mouthwashes use combinations of essential oils and alcohol or oil-water-cetylpyridinium chloride with alcohol to “kill germs” that cause bad breath. Once the initial bacteria are killed they return to their prior level within minutes so any anti-halitosis effects are temporary. Also, the long-term effects of alcohol tend to dry the oral tissues and create a better environment for the overgrowth of odor producing anaerobes. Chlorhexidine is the “gold standard” of antibacterial mouthwashes, which is effective against supragingival plaque bacteria for up to 8 hours. It would be a good anti-halitosis treatment if the side effects of staining, taste alteration and oral ulcerations could be negated. Since eliminating bacteria in the oral cavity could lead to the overgrowth of undesirable species such as candida albacans, a different strategy has been developed to combat halitosis. It involves the long-term suppression of the odor-causing gram-negative anaerobic bacteria population on the tongue rather than their elimination (1).
AHM uses this newer strategy to combat halitosis. The first active ingredient is highly oxidizing sodium chlorite (600ppm of chlorite ion). It oxidizes the sulfides of the VSC’s to non-odorous sulfates and raises the oxidation/reduction ration of the saliva toward the more oxidizing state. This suppresses the overgrowth of the anaerobic bacteria on the tongue. The other active ingredient zinc acetate (300 ppm of zn ion) oxidizes the VSC’s and creates a more oxygen rich oral environment, but also interferes with the proteolytic activities of the anaerobic bacteria. A mouthwash containing just the sodium chlorite ion (600 ppm) was tested and was found to be effective for less than two hours. Another mouthwash containing zinc ion (300 ppm) was the active ingredient showed effectiveness to 4 hours. When combined, a synergy was created which extended the anti-halitosis effects past 6 hours (6).
A factory calibrated halimeter (Interscan model RH-17K) was used to measure the VSC’s (parts per billion of hydrogen sulfide and methyl mercaptan) in the oral air of five volunteers (7). These volunteers were screened for age (18 to 75), positive medical histories that revealed drug or alcohol use or other conditions that in the opinion of the investigators would interfere with the study. Pregnant or lactating females were not selected. Volunteers had to submit to a dental screening process. Only volunteers with a well-restored generally intact dentition (minimum 16 teeth with at least 4 molars) with no removable prostheses and healthy periodontal status with no active oral pathology were accepted. They were then tested for a positive response to the cysteine challenge test (between 500 and 2000ppb VSC halimeter reading at 3 and 5 minute post rinse). They were asked to refrain from any oral hygiene procedures, and have no food, drink or tobacco products 12 hours prior to and during the 6 hour trials. A 6ml 5mM cysteine rinse (pH 6.5) was swished for 30 seconds and expectorated (8). A halimeter reading was taken, using the manufacturer’s protocol of adjusting the machine to 0 ppb, then inserting a disposable straw attached to the inlet hose one and a half inches into the oral cavity and sampling the concentration of VSC’s in the passive oral air. The volunteers held their breath for 15 seconds while the reading was taken. Readings were made at 3 and 5 minute intervals post-rinse and recorded. Twenty minutes later, a 12 ml de-ionized water rinse was swished for 60 seconds to serve as the control rinse and another 3 and 5 minute reading was taken. A cysteine rinse was administered and recorded at the same 3 and 5 minute intervals at 40 minutes, 60 minutes, then hourly out to 360 minutes. All of the volunteers showed a positive response to the cysteine challenge with no VSC reduction from the water rinse (fig. 1).
The next test was run with the volunteers rinsing with 12 ml of the mouthwash formula for 60 seconds and readings taken after the cysteine challenge at 40 min, 60 min, and then hourly intervals to 360 minutes (fig. 2).
Results and Discussion
The baseline reading for the group was in the 83 ppb range, which was well below the threshold of 200 ppb of patients suffering from detectable halitosis. When a water rinse was given as a control, there was no change in the high VSC reading of subsequent cysteine challenges (fig. 1). The test that was then given with the test mouthrinse showed a significant reduction in VSC levels with each cysteine challenge all the way to the 6 hour limit of the study (fig. 2).
The test mouthrinse showed a reduction in halitosis-causing VSC’s, (hydrogen sulfide and methyl mercaptan) from the first challenge at 20 minutes to the end of the trial at 6 hours. A reduction in VSC levels of over 70% at six hours indications a substantial anti-halitosis effect for this mouthwash. With these pilot study results, further large-scale clinical trials are indicated to test the mouthwash results out to 12 hours, effect on morning breath levels after night-before rinsing as well as trials using organoleptic judges combined with halimeter VSC measurements.
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