title: Fluoride availability and stability of Japanese dentifrices.
abstract: The decline of dental caries in the industrialized countries can be attributed to widespread use of fluorides. The Japanese market share of dentifrices containing fluorides has increased from 12% in 1985 to 77% in 2000. For a fluoride dentifrice to be effective in the control of dental caries, an adequate concentration of the fluoride must be soluble. Several Japanese fluoride dentifrices have in their formulations calcium phosphate as an abrasive, which may react with fluoride. This study was designed to evaluate the availability and stability of fluoride in the most consumed dentifrices in Japan. The analyses were made when the dentifrices were purchased (fresh samples) and after one year of storage (aged samples) at room temperature (21.8 +/- 3.6 degrees C). Total fluoride and soluble fluoride was determined using an ion specific electrode. All dentifrices showed similar concentrations of total fluoride in fresh and aged samples in accordance with the Japanese Legislation (content of less than 1,000 ppm F). Some dentifrices, with dicalcium phosphate as abrasive, showed decreasing concentrations of total soluble fluoride and increasing amounts of insoluble fluoride over time. Although most of the Japanese fluoridated dentifrices evaluated in this study contain unstable fluoride, they were found to have sufficient concentrations of soluble fluoride to be effective in preventing dental caries.
authors.affiliation: Department of Preventive and Social Dentistry, Faculty of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil. lhashizume@yahoo.com
authors.forename: Lina Naomi
authors.initials: LN
authors.lastname: Hashizume
authors.forename: Ynara Bosco de Oliveira
authors.initials: YB
authors.lastname: Lima
authors.forename: Yoko
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Jaime Aparecido
authors.initials: JA
authors.lastname: Cury
mesh_terms: D001682:Biological Availability; D002327:Cariostatic Agents / Q000737:chemistry / Q000493:pharmacokinetics*; D003802:Dentifrices / Q000737:chemistry*; D004355:Drug Stability; D005459:Fluorides / Q000737:chemistry / Q000493:pharmacokinetics*; D017736:Ion-Selective Electrodes; D007477:Ions; D007564:Japan; D016014:Linear Models; D012995:Solubility
chemical_list: D002327:Cariostatic Agents; D003802:Dentifrices; D007477:Ions; D005459:Fluorides