DENTAL practitioners have been telling their patients for many decades to floss daily, and they have been doing so for good reasons. A patient visited my clinic with a mouth filled with decayed teeth and swore that while he brushed “more or less regularly,” he never flossed but claimed to use mouth rinse often. In fact, he said he was not sure what flossing entailed. The benefits of flossing are real – they are not a myth.

To say or imply that a mouth rinse can replace floss is false and misleading. Mouthwash is no substitute for dental floss. Some years ago in the United States, a federal judge ruled against a popular mouth rinse advertisement campaign, calling it false, misleading, and a public health risk. Judge Denny Chin said in a written ruling that he expected to order Pfizer Inc. to stop claiming that its product is as effective as floss at reducing plaque and gingivitis between teeth.

The ruling came after McNeil-PPC Inc., a subsidiary of Johnson & Johnson, filed a lawsuit stating that false claims in the advertising campaign posed an unfair threat against its sales of dental floss.

There was an advertisement in print that featured a bottle of mouth rinse balanced on a scale opposite a floss container. This ad stated: “This mouth rinse (name withheld) is clinically proven to be as effective as floss at reducing plaque and gingivitis between the teeth.” The campaign also featured a television commercial titled “Bing Bang.” In it, the commercial announced that this mouth rinse is as effective as floss and that clinical tests proved it, though it did add that there is no replacement for flossing.

Substantial evidence demonstrates that flossing is important in reducing tooth decay and gum disease and that it cannot be replaced by rinsing with mouthwash. Most related companies base their advertising campaigns on emphasising that dental professionals should continue to recommend daily flossing and caution that they are not suggesting mouth rinse should be used instead of floss.

The judge said the company based its findings on two flawed studies of people with mild to moderate gingivitis who did not use floss properly. The studies, he added, proved only that this popular mouth rinse is “as effective as improperly used floss.”

Gingivitis, which is estimated to affect some seventy-five percent of the world’s population, causes inflamed, swollen, and sometimes bleeding gums. It can precede periodontitis, a less common inflammation that develops in deeper tissues and oftentimes leads to tooth loss.

It should be noted that 87 percent of consumers floss either infrequently or not at all, despite frequent warnings from dentists and dental hygienists to do so. The judge said Pfizer had received complaints about its advertising, including one from a dental professional who said he was “aghast” to hear of the company’s claims and another who said the claims “can set back years of progress by the ethical dental profession in convincing patients that flossing is essential for their oral health.”

Flossing provides benefits that no mouth rinse can, including the ability to remove plaque below the gum line and to dislodge pieces of food trapped between teeth. While most mouth rinses are powerful oral antiseptics—which clearly have their benefits—they could never replace dental floss. It is highly troubling that any mouth rinse manufacturer would take the position that a mouth rinse can replace floss.