Gum Disease : Anti-Plaque Mouthwashes, Baking Soda

by Food and Drug Administration (FDA)

(Page 3 of 3)

Anti-Plaque Mouthwashes

The use of mouthwashes in the quest for a healthy mouth has a long history. According to Irwin Mandel, D.D.S., professor of dentistry at Columbia University's School of Dental and Oral Surgery, an ancient Chinese text contains the first known recommendation for the use of a mouthwash in the treatment of gum disease: Rinse the mouth with urine.

In the intervening 5,000 years, urine (which from a healthy person is sterile) has been used as a mouthwash in cultures around the world. By lowering the acidity of the mouth it may, says Mandel, help reduce the formation of cavities. But against the periodontal diseases it's unlikely to have an effect.

The modern era of mouthwashes might be said to have begun in 1920. It was then that Listerine, which had already been sold for more than 40 years as a general antiseptic, was first marketed as a remedy for bad breath. A new advertising campaign for the product introduced the American public to the term "halitosis" and its social undesirability. The pitch was so successful it is now considered a classic. Such promotional activities no doubt contributed to what Mandel describes as a longstanding "disdain" of mouthwashes by members of the dental and scientific communities. This view was further reinforced by a widely held assumption that any effect mouthwashes had against oral bacteria was only temporary. In the early 1980s, however, studies began to appear suggesting that some mouthwashes might indeed reduce supragingival plaque and plaque-related gingivitis. There is no evidence that mouthwashes can affect subgingival plaque or periodontitis.

A prescription product (trade name Peridex) containing the antimicrobial chlorhexidine was approved by FDA in 1986 based on studies showing that it reduced gingivitis by up to 41 percent. Chlorhexidine mouthwashes have long been used in Europe, and a 1986 article in The Journal of Periodontal Research called chlorhexidine "the most effective and most thoroughly tested anti-plaque and anti-gingivitis agent known today."

A month later the American Dental Association awarded Peridex its "Seal of Acceptance" — the first ever granted a mouthwash by the ADA. This seal (which can have considerable marketing value and is probably most familiar as a result of its being displayed on many brands of toothpaste) indicated that Peridex had met a series of guidelines established by the ADA for evaluating products making anti-plaque, anti-gingivitis claims.

In 1987 the ADA awarded its second (and so far only other) Seal of Acceptance to a mouthwash for use in the reduction of plaque and gingivitis. This seal went to Listerine, and its manufacturer has since used the ADA seal in promoting the product as a plaque-fighter. FDA, however, has not yet approved Listerine for this use. In fact, FDA has sent letters to the makers of Listerine and several other over-the-counter (OTC) products making anti-plaque claims stating that in its opinion the products are being marketed in violation of the Federal Food, Drug, and Cosmetic Act and are "at risk of regulatory action."

The basis for these letters is that no ingredient for use in an OTC drug product has yet been recognized as safe and effective for the prevention or reduction of plaque or gingivitis in FDA's ongoing evaluation of OTC drug products. FDA therefore considers as unproven claims that a product's ingredients have such effects.

In part, the reason for this stance (and for the difference between the actions of FDA and those of the ADA with respect to Listerine) has to do with timing. Data concerning the claims of the OTC anti-plaque, anti-gingivitis products were not available until after FDA's review of OTC dental products was well under way. Such data have since been submitted and in the case of Listerine, says Jeanne Rippere, a microbiologist in FDA's over-the-counter drug evaluation division, the information is probably much the same as that presented to the American Dental Association and on which the awarding of its Seal of Acceptance was based.

In a continuation of its ongoing OTC drug review, FDA plans to have a panel of non-government experts evaluate ingredients that might be used in OTC drug products making anti-plaque and anti-gingivitis claims. Steps are being taken to facilitate this process, and it may begin within the next year.

What About Baking Soda?

In the late 1970s and early '80s an oral hygiene program known as the Keyes Technique was widely promoted in the United States. Aimed at combatting plaque-related periodontal diseases, the program included not only such conventional advice as frequent professional cleanings, but also the recommendation that patients apply to their gums and brush their teeth with a mixture of salt, hydrogen peroxide, and baking soda.

Laboratory studies showing these agents had some effectiveness against harmful bacteria were the principal basis for this recommendation. But critics pointed out that what worked in the laboratory didn't always work in the mouth. A study by the technique's proponents showed some effectiveness in humans. However, it lacked a control group, so it was impossible to say how the technique compared to more traditional methods of oral hygiene. Furthermore, the subjects in this study had been liberally treated with antibiotics, so it wasn't known if the benefits they had experienced were actually due to the baking soda brushing regimen.

To resolve these issues, dental researchers at the University of Minnesota, led by Larry Wolff, Ph.D., D.D.S., conducted a four-year study involving 171 adults with moderate periodontitis. The study's design enabled the researchers to compare the effectiveness of a baking soda, salt, and hydrogen peroxide mixture with that of ordinary toothpaste. The results, published in the January 1989 Journal of the American Dental Association, showed that while the baking soda mixture did help in the maintenance of oral health it was no more effective than ordinary toothpaste.

Wolff and his colleagues also found that, compared to the patients using ordinary toothpaste, those using the baking soda regimen were three times as likely to stop following their oral hygiene program because it was inconvenient. Overall, they said, there was no evidence that a baking soda brushing regimen "will contribute more toward periodontal health than use of a commercial toothpaste, a toothbrush, and dental floss."

About the Author

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