Over-the-counter mouthrinses really do put a stop to bad breath. The first systematic review on the effectiveness of mouthrinses shows that they play an important role in reducing levels of bacteria and chemicals that cause mouth odours. Pick which one you use though, because some can temporarily stain your tongue and teeth, warns this new review from The Cochrane Library.
Bad breath is a very common complaint affecting around half the population in developed countries. The smell is generated by bacteria that accumulate on the tongue and produce sulphur compounds including hydrogen sulphide. This is the same compound that makes rotten eggs smell bad. To combat this, mouth rinses are classified in two categories, those that kill the bacteria producing the sulphur compounds and those that neutralise or mask the odour of these compounds. Antibacterial mouthrinses are widely used to treat bad breath, despite some uncertainty about their effectiveness.
"We found that antibacterial mouthrinses, as well as those containing chemicals that neutralise odours, are actually very good at controlling bad breath,' says lead researcher, Zbys Fedorowicz, who works at the Ministry of Health in Bahrain.
Although the different mouthrinses had similar effects on odours, the researchers point out that products containing chlorhexidine resulted in noticeable but temporary staining of the tongue and teeth, and also can temporarily alter taste sensations.
The review, carried out by a team of Cochrane Researchers, included the results of five separate trials involving 293 participants. The team found that mouthrinses employing antibacterial agents such as chlorhexidine and cetylpyridinium were significantly more effective than placebos in reducing mouth odours, as judged by human noses. Mouthrinses containing chlorine dioxide and zinc were more effective in neutralising odour compounds.
Researchers also noted that more studies are needed to compare the effectiveness of different mouthrinses in treating bad breath. And they say that despite the growing trend for electronic assessment of mouth odours, the human nose should remain the gold standard.
"There's no substitute for a human nose when it comes to sniffing out bad breath," says Fedorowicz.