European Organization for Caries Research Workshop: Methodology for Determination of Potentially Available Fluoride in Toothpastes

Abstract

Toothpastes are the most universally accepted form of fluoride delivery for caries prevention. To provide anti-caries benefits, they must be able to release fluoride during the time of tooth brushing or post brushing into the oral cavity. However, there is no standard accepted procedure to measure how much fluoride in a toothpaste may be (bio) available for release. The European Organization for Caries Research proposed and supported a workshop with experts in fluoride analysis in toothpastes and representatives from industry. The objective of the workshop was to discuss issues surrounding fluoride analysis in toothpaste and reach consensus on terminology and best practices, wherever the available evidence allowed it. Participants received a background paper and heard presentations followed by structured discussion to define the problem. The group also reviewed evidence on the validity, reliability and feasibility of each technique (namely chromatography and fluoride electroanalysis) and discussed their strengths and limitations. Participants were able to reach a consensus on terminology and were also able to identify and summarize the advantages and disadvantages of each technique. However, they agreed that most currently available methods were developed for regulatory agencies several decades ago, utilizing the best available data from clinical trials then, but require to be updated. They also agreed that although significant advances to our understanding of the mechanism of action of fluoride in toothpaste have been achieved over the past 4 decades, this clearly is an extraordinarily complex subject and more work remains to be done.

Chemically Soluble Fluoride in Na₂FPO₃/CaCO₃-Based Toothpaste as an Indicator of Fluoride Bioavailability in Saliva during and after Toothbrushing

“…However, fluoride must be chemically soluble in any toothpaste formulation to be released in the oral cavity during toothbrushing and to interfere with the physicochemical process of caries, either reducing demineralization of sound enamel-dentine mineral structure or enhancing remineralization of incipient caries lesions [Cury and Tenuta, 2008;Cury and Tenuta, 2009;Cury and Tenuta, 2014]. Based on this premise and the necessity of research to evaluate the relationship between the concentration of soluble fluoride present in toothpaste and the concentration found in saliva during and after brushing [Martinez-Mier et al, 2019], this study was done with Na 2 FPO 3 /Ca-CO 3 -based toothpaste. For this research, the brand of toothpaste was fixed (Table 1) and the variable under study was the concentration of TSF (ion FPO 3 2-+ ion F) in the toothpaste, which was obtained by standardized time of accelerated aging [Tabchoury and Cury, 1994].…”

“…A toothpaste with Na 2 FPO 3 /Ca is usually formulated with 1,450 μg F/g, close to the total maximum fluoride (0.15%) allowed for most legislations of the world [MERCOSUL, 2002;European Union, 2008]. As Na 2 FPO 3 /Ca toothpaste may not maintain enough chemically soluble fluoride during its expiry time to be effective on caries reduction, it is necessary to have a methodology to estimate whether fluoride is bioavailable in the toothpaste formulation [Martinez-Mier et al, 2019].…”

“…Analytical laboratorial methods are used to determine total fluoride (TF; soluble + insoluble) and total soluble fluoride (TSF; F ion + FPO 3 2ion) in toothpastes [Martinez-Mier et al, 2019]. The determination of TF concentration in a toothpaste is important to check whether it is in agreement with the local legislation of each country, but in terms of its therapeutic anti-caries effect the most important determination is the TSF concentration.…”

Identification and Analysis of the Fluoride Concentration in Toothpastes Intended for Children

“…Toothpastes can be defined as creams or gels consisting of different chemical substances that facilitate the removal or disorganization of the dental biofilm and allow the supply of fluoride to act in the demineralization and remineralization of the dental substrate [15,16]. For this, the minimum According to results of the present study, this condition does not fit the toothpastes identified in the capital of Alagoas, since most toothpastes found for marketing have absence or low fluoride concentration, according to manufacturers' data.…”

Evaluation of free and total fluoride concentration in mouthwashes via measurement with ion-selective electrode

“…. The participants of European Organization for Caries Research Workshop, which was held to discuss the issues related to the methodology for determination of potentially available fluoride in toothpastes, have emphasized the necessity of developing methods measuring fluoride bioavailability[28]. The development of techniques providing the assessment of free fluoride in mouthwashes is also required.…”