Mouthwashes work but may stain teeth for a while

NEW YORK (Reuters Health), Oct 10 - Over-the-counter mouthwashes really do kill bad breath, although some may stain the tongue and teeth, at least temporarily, according to the first systematic review of the effectiveness of these products.

The findings are published in the Cochrane Library, a publication of the Cochrane Collaboration, an international organization that evaluates medical research.

Bad breath, or halitosis, is caused by the breakdown of bacteria in the mouth, producing foul-smelling sulfur compounds. This is the same compound that makes rotten eggs smell bad. Antibacterial mouthrinses are widely used to treat bad breath, despite some uncertainty about their effectiveness.

Zbys Fedorowicz, from the Ministry of Health in Bahrain, Awali, and colleagues reviewed five randomized controlled studies that compared various over-the-counter mouthrinses to placebo in a total of 293 adults over the age of 18 with bad breath.

They found evidence that compared with placebo and as judged by the human nose, mouth rinses containing antibacterial agents such as chlorhexidine and cetylpyridinium do markedly reduce levels of odor-causing bacteria on the tongue, while those containing chlorine dioxide and zinc neutralize foul-smelling sulfur compounds.

"We found that antibacterial mouthrinses, as well as those containing chemicals that neutralize odours, are actually very good at controlling bad breath," Fedorowicz noted in a written statement.

However, the investigators also found that mouthrinses containing chlorhexidine "resulted in noticeable but temporary staining of the tongue and teeth" and also can temporarily alter taste sensations.

Last Updated: 2008-10-10 13:00:53 -0400 (Reuters Health)

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