Analysis of fluoride levels retained intraorally or ingested following routine clinical applications of topical fluoride products.

A variety of topical fluorides is now used clinically for the prevention and control of dental caries. It is essential for the dental profession to be fully aware of the relative retention rates of fluoride in saliva and thus its contact with the teeth. These may vary following the use of the different categories and concentrations of agents available and with different methods of use. It is also important to be aware of the amounts of fluoride ion ingested following use of the more concentrated forms and of the resultant elevation in total blood fluoride levels. These parameters were investigated in a series of experiments involving human volunteer subjects using a variety of topical fluoride materials commercially available in Australia. Fluoride mouthrinses appeared to provide the highest salivary retention rates per dose of all forms of topical fluoride. Ingestion rates from concentrated gels were acceptable when effective evacuation methods were applied. The use of custom-made trays resulted in a reduction in amounts of fluoride ion ingested, though simple self-application by toothbrush of smaller quantities proved to be an effective alternative in terms of amount of fluoride ion retained in saliva per amount applied and ingested. None of the concentrated gels used resulted in elevations in total blood fluoride levels which were of concern in adults. It is acknowledged that salivary retention rates of fluoride ion do not necessarily reflect the caries inhibitory effects of topical fluorides. However, these data provide some indication of possible advantages of some products and methods of application over others.