Oral hygiene products containing metals, such as zinc chloride mouthwash, are considered by some specialists to be among the most effective treatments for halitosis. The scientific rationale behind these products is that the metal molecules react with sulfur molecules in the breath-the offensive smelling sulfur compounds produced by oral bacteria-creating an entirely new chemical structure that does not smell bad. Metals, typically zinc or copper, are often combined with essential oils such as eucalyptus oil or thymol in oral care products.
Clearly, zinc and other metals only have the ability to neutralize bad breath temporarily. They don’t change the conditions in the mouth, and they don’t have any activity against the odor-producing bacteria themselves, therefore, once all of the metal has reacted with sulfur, or been rinsed from the mouth, the bad odor associated with halitosis returns. Even the essential oils, many of which have some antibacterial activity, are present in insufficient quantities to make a lasting difference. Although products such as zinc chloride mouthwash have been reported to freshen the breath for several hours in some cases, they should be considered among the many products that mask the problem, rather than those that solve it.
In fact, some controlled studies that compared the results of regular use of chemical mouthwashes, products containing metals, and those containing essential oils, found little difference between the three. Other studies found that products such as zinc chloride mouthwash were not as good as antibacterial chemicals over the long term, though they may well have fewer adverse side effects to worry about. In the end, reactive metals such as copper and zinc may indeed neutralize bad breath but they are only part of the solution.
A sensible approach to halitosis involves good oral hygiene including regular tooth and tongue cleaning, yearly or twice yearly visits to the dentist, and treatment for any dental or gum disease. If the problem persists, products that neutralize bad breath can be helpful in the short term while a more permanent solution is sought. Ultimately, the aim is to reduce the population of anaerobic odor-producing bacteria living in the mouth to levels that don’t result in detectable odor. Zinc chloride mouthwash will not produce the desired end result if not combined with other antibacterial measures.