Fluoride is widely recognized for reducing the prevalence of Dental caries. Therefore, either studies aimed to enhance its beneficial effects or to reduce its detrimental effects continues to be relevant. Such studies can benefit from improvements in the techniques employed for the analysis of fluoride. In addition, meaningful international studies in this field can only be conducted if standardized methods for measuring the levels, ingestion and concentrations of fluoride, are available. Currently available fluoride measurement techniques are not standardized and a universal standard for fluoride determination has not been established. Although a variety of techniques are available, none have been accepted for universal use. The current project Aims to collaborate with established analytical laboratories to develop standard, global methods for analyzing fluoride in different types of samples. [unreadable] [unreadable] In order to develop these standard, global methods for fluoride analysis, the Fluoride Laboratory at the Oral Health Research Institute proposes to collaborate with six, additional, well-established laboratories that are currently conducting fluoride analyses. The proposed collaboration will include the analysis of the fluoride content of a series of 180 biological and environmental samples using the methods in current use in each laboratory. Results of these analyses and descriptions of the analytical procedures used will be collected and distributed from each laboratory to all collaborators. A plan will be then developed to resolve any differences in results and to identify preferred analytical procedures in a meeting of all collaborators at the Oral Health Research Institute. Analyses of another series of biological samples by all laboratories using the preferred analytical methods will be then conducted and, finally a scientific paper reviewing the data collected and the preferable analytical procedures will be developed for publication. [unreadable] [unreadable] The proposed investigation will provide an opportunity for seven recognized laboratories to collaborate in order to reach consensus about detailed protocols that will identify and describe gold standard techniques for fluoride analysis of specific types of samples. The proposed study will provide an opportunity to resolve discrepancies that currently make it difficult to compare the results of the many studies dealing with fluoride analyses.