Viadent usage and oral leukoplakia: A spurious association

Oral rinse and toothpaste products (Viadent) containing Sanguinaria extract have been shown through extensive clinical trials to be effective against plaque build-up and gingivitis. To establish safety, a comprehensive resear ch program was conducted, including a series of clinical studies and a numb er of animal studies to evaluate acute, subchronic, and chronic toxicity, a nd the potential for irritation of mucosal tissues. In 1990 and 1993, an Ex pert Panel reported on reviews of these data and concluded that Viadent pro ducts are safe for their intended use. Despite the large database of inform ation to support the safety of Viadent products, Damm et al. (1999) recentl y raised the possibility that their usage may be causally associated with d evelopment of oral leukoplakia. However, a critique of this recent report s hows that it does not fulfil criteria for establishing causation. In partic ular, the study does not show that exposure to Viadent preceded the onset o f leukoplakia, it does not demonstrate dose-response or biological plausibi lity, and it suffers from selection and information bias and from potential confounding. Furthermore, upon critical evaluation, the Damm et al. (1999) report on a case-series is inconsistent with the weight of available clini cal evidence showing that Sanguinaria extract-containing oral health care p roducts cause no cytotoxic or significant irritant effects in the oral muco sa in human studies of up to 6 months duration. The animal data similarly d o not support a causal association between Viadent usage and oral leukoplak ia in humans. These data demonstrate that Sanguinaria extract and whole Via dent formulations are without significant irritation potential and have no effects on the ol al mucosa, even in studies with life-long dietary exposur e to Sanguinaria extract. The mutagenicity and genotoxicity data do not ind icate that Sanguinaria extract or its components are genotoxic in vivo. The results of 2 GLP compliant rat oncogenicity studies provide no evidence of any carcinogenic effect of Sanguinaria extract. In conclusion, the availab le clinical and animal data provide no support for and in fact argue strong ly against the hypothesis that the use of Viadent toothpaste and/or oral ri nse products may be causally associated with the development of leukoplakia in humans. (C) 1999 Academic Press.