Dec. 27, 2001 COLUMBUS, Ohio - A new study suggests that an old formulation of a particular brand of dental products has left its legacy in patients' mouths in the form of potentially precancerous lesions.
Sanguinarine, a natural anti-bacterial agent, was once a key ingredient in the Viadent line of toothpastes and mouth rinses. Researchers suspect that sanguinarine causes the formation of white lesions, called oral leukoplakia.
The current study suggests that users of the former Viadent formulation were eight to 11 times more likely to develop leukoplakia than were those who had never used the product.
While leukoplakia often causes no symptoms and may disappear, it can also sometimes lead to oral cancer, said Carl Allen, a study co-author and a professor of oral pathology and dentistry at Ohio State University.
"We're seeing patients who used the old formulation of Viadent develop lesions two, three, four, even five years after they stopped using the product," he said.
The study appears in a recent issue of the journal Epidemiology. Allen conducted the study with Ana Karina Mascarenhas, an associate professor of health policy and health services research at Boston University's School of Dental Medicine and John Loudon, a dentist with the Australian government.
In the late 1990s, dentists began noticing and questioning a higher-than-usual occurrence of leukoplakia in an unusual place - between the gums and upper cheek, an area called the maxillary vestibule. Leukoplakic lesions usually tend to form on the tongue and cheeks, Allen said.
Leukoplakia affects about 1 to 5 percent of the U.S. adult population. A study conducted in 1999 by another team of dental researchers found that 84 percent of 88 patients who had used Viadent products had developed oral leukoplakia. Viadent is manufactured by Colgate Oral Pharmaceuticals, a subsidiary of the Colgate-Palmolive Company.
In the current study, Allen and his colleagues examined records of 148 patients diagnosed with leukoplakia from January 1997 through December 1998. They asked each patient to fill out a questionnaire regarding their use of Viadent products as well as the use of tobacco and alcohol consumption. Frequent drinking and tobacco use are linked to the development of oral leukoplakia. The researchers also asked each subject to either come in for a checkup or for permission to examine individual patient records. For comparison, the study included 148 patients without signs of leukoplakia.
Patients who had used Viadent products were 9.7 times more likely to have developed the white lesions.
"The risk of developing leukoplakia was greater for Viadent users, regardless of the combination of products used," Allen said.
Risk of developing oral leukoplakia also increased with age. Risk increased two-and-a-half times with increased daily use of Viadent products - that is, the more often a person used the product each day, the more likely he was to develop lesions. Risk was highest in patients who had used both toothpaste and mouth rinse, followed by users of the rinse only. Toothpaste users had the lowest risk.
Patients with leukoplakia should be alert for oral cancer.
"The sanguinarine-related leukoplakic lesions are usually asymptomatic and the majority aren't precancerous, but they could undergo malignant transformation at some point," Allen said. "We do see a small percentage of biopsies with definite precancerous changes. These should be removed completely.
"If a lesion is identified, then a biopsy is needed," Allen said. "Patients with oral leukoplakia should get a thorough oral examination at least every six months with an oral surgeon or an oral pathologist - someone who is familiar with leukoplakia."
"At the time that we conducted the study, we looked at the active ingredients in many other brands of mouth rinses and toothpastes," he said. "We determined that Viadent was the only brand at the time that contained sanguinarine."
Since then, other brands of toothpaste containing sanguinarine have come on to the market. While Colgate has since replaced sanguinarine in its Viadent products with another anti-bacterial agent, Allen warns people to watch out for the ingredient in other brands of dental products.
"I'd be concerned if sanguinarine was the active ingredient in my toothpaste or mouth wash," he said. "There are a lot of folks who think that if something is natural, it must be good for them. That's not always the case."
Although Colgate changed the formula of Viadent, Allen said he and his colleagues still see patients with leukoplakia related to sanguinarine use.
"Many lesions persist even once a person stops using Viadent," Allen said. "We've also seen people develop new lesions after they had stopped using the product."
The research was supported by a grant from the American Cancer Society.
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