Mouth rinse causes stains?

Mar 10, 2008

It's the hot topic on blogs and even on Amazon.com's forums: Crest's popular alcohol-free Pro-Health Rinse purportedly causes staining.

"After extended use for a month it stained in between my teeth brown. It looked terrible and it cost me a one hundred dollar trip to the dentist to scrape that junk off," wrote one Amazon poster. Another added, "After about a week my teeth had gained an ugly shade of brown that won't go away." Of 109 user reviews of the product on Amazon, 88 people gave the Pro-Health Rinse one star -- the lowest possible rating.

The culprit is apparently cetylpyridinium chloride (CPC), the rinse's active ingredient. CPC is an effective antibacterial that binds to a bacterium's membrane and ruptures it. The debris from the dead bacteria is what can cause the staining. Lifestyle factors -- notably tobacco and red wine -- can exacerbate the problem.

"But only a very small percentage of the audience encounters this problem," said Procter & Gamble spokeswoman Laura Brinker. (Brinker couldn't define how many users constitute a "very small percentage.") Pro-Health Rinse is a good choice for anyone who doesn't want to use an alcohol-based rinse, Brinker said.

"We've sold 82 million units of the rinse in the last three years. It has one of the highest repeat [purchase] rates of any product we sell," she said. Proof positive, in P&G's eyes, that customers are happy with the rinse.

Clinicians and cosmetic dentists contacted by DrBicuspid.com largely back up P&G's assertion. Giovanni Salvi, D.M.D., and a professor in the Department of Periodontology at the University of Berne, Switzerland, recently concluded a six-month study of CPC's effect on plaque and gingivitis. "Very few patients complained about staining" said Dr. Salvi, although he added that a discoloration index was not assessed.

Cosmetic dentists contacted by DrBicuspid.com largely echoed this finding. "I've never heard of CPC being associated with staining" said one. Another: "Many mouth rinses that kill oral bacteria can leave brown stains on teeth, but staining can be easily removed; I don't worry about staining. Besides, I usually recommend the CariFree rinses, because they're great at removing biofilm. The fact that they also don't leave stains is an extra benefit."

Bottom line? "We don't have any plans to change the concentration of CPC [in Pro Health Rinse] or change the labeling," Brinker siad.