J Korean Acad Oral Health.  2015 Jun;39(2):81-87. 10.11149/jkaoh.2015.39.2.81.

Evaluation of fluoride bioavailability in toothpastes

• Ko HY
• Kang SM
• Kwon HK
• Kim BI

• KMID: 2321512
• DOI: http://doi.org/10.11149/jkaoh.2015.39.2.81

Abstract

OBJECTIVES
The aims of this study were to determine the total fluoride concentration and bioavailable fluoride concentration in different toothpastes, based on a newly suggested method by the International Organization for Standardization (ISO), and to compare the measured concentrations with the concentrations written on the packaging.
METHODS
The concentrations of total fluoride (TF) and bioavailable fluoride (BF) were measured in six toothpastes. For the TF measurement, 1 g of each toothpaste was mixed with dipotassium hydrogen phosphate (K2HPO4), and hydrogen chloride (HCl) was placed. After 24 hours, the samples were centrifuged and total ionic strength adjustment buffer (TISAB) solution was added. For the BF measurement, the toothpaste was mixed with K2HPO4 for only 1 minute. The samples were centrifuged, and then HCl was placed and allowed to stand for 24 hours. The TISAB solution was added subsequently. The concentration of fluoride ions was measured using a fluoride ion-selective electrode and calculated against a standard curve.
RESULTS
The six toothpastes were composed of different fluoride compounds and abrasives. The measured TF concentration ranged from 624.99 ppm to 1,353.00 ppm, and the similarity to the declared fluoride concentration ranged from 53.48% to 93.31%. The measured BF concentration ranged from 587.61 ppm to 1,360.05 ppm, and the similarity to the expected fluoride concentration ranged from 41.97% to 93.80%. Two samples were clearly separated when the samples were centrifuged, whereas the remaining four samples had unclear supernatants. The clearly separated toothpastes (i.e., toothpastes 5 and 6) had BF concentrations that were similar to or lower than the declared fluoride concentrations and the measured TF concentrations. However, the unclearly separated toothpastes showed inconsistent relationships between the measured TF and BF concentrations.
CONCLUSIONS
The measured TF and BF concentrations of the six toothpastes did not reach the expected fluoride concentration. This finding resulted from the different compositions and forms of the toothpastes. Therefore, the properties of toothpastes need to be considered when measuring their fluoride concentrations.

Keyword

Fluoride; Toothpaste; Bioavailabilit; Standards

MeSH Terms

Biological Availability*
Fluorides*
Hydrochloric Acid
Hydrogen
Ion-Selective Electrodes
Ions
Osmolar Concentration
Product Packaging
Toothpastes*
Fluorides
Hydrochloric Acid
Hydrogen
Ions
Toothpastes

Figure

• 

  Fig. 1. Percentages of similarities between the expected fluoride and the measured total fluoride (dark bars) and also between the expected fluoride and the measured bioavailable fluoride (light bars) of the toothpastes.

Reference

References

1. Glass RL. First International Conference on the Declining Prevalence of Dental Caries. J Dent Res. 1982; 61:1304–1383.

2. Petersen PE, Lennon MA. Effective use of fluorides for the prevention of dental caries in the 21st century: the WHO approach. Community Dent Oral Epidemiol. 2004; 32:319–321.

3. Ripa LW. A critique of topical fluoride methods (dentifrices, mouth-rinses, operator-, and self-applied gels) in an era of decreased caries and increased fluorosis prevalence. J Public Health Dent. 1991; 51:23–41.

4. Glass RL. Caries reduction by a dentifrice containing sodium mono-fluorophosphate in a calcium carbonate base. Partial explanation for diminishing caries prevalence. Clin Prev Dent. 1981; 3:6–8.

5. Marinho VC, Higgins JP, Sheiham A, Logan S. Fluoride toothpastes for preventing dental caries in children and adolescents. Cochrane Database Syst Rev. 2003; CD002278.

6. Wong MC, Clarkson J, Glenny AM, Lo EC, Marinho VC, Tsang BW, et al. Cochrane reviews on the benefits/risks of fluoride toothpastes. J Dent Res. 2011; 90:573–579.

7. Bibby BG. A test of the effect of fluoride-containing dentifrices on dental caries. J Dent Res. 1945; 24:297–303.

8. Kyes FM, Overton NJ, McKean TW. Clinical trials of caries inhibitory dentifrices. J Am Dent Assoc. 1961; 63:189–193.

9. Ericsson Y. Fluorides in dentifrices. Investigations using radioactive fluorine. Acta Odontol Scand. 1961; 19:41–77.

10. van Loveren C, Moorer WR, Buijs MJ, van Palenstein Helderman WH. Total and free fluoride in toothpastes from some non-established market economy countries. Caries Res. 2005; 39:224–230.

11. Kim J-H, Jeong S-S, Choi C-H, Hong S-J. Fluoride concentration of commercial dentifrices and effect of fluoride containing dentifrices on artificial enamel caries. Journal of Korean academy of oral health. 2006; 30:56–66.

12. Hong S-J, Park Y-N, Jeong S-S, Ha M-O, Choi C-H, Lee K-H. Fluoride concentration of commercial dentifrices for children in Korea. Journal of Korean academy of oral health. 2008; 32:143–151.

13. ISO. ISO 11609:2010 Dentistry-Dentifrices-Requirements, test methods and marking. Geneva: ISO;2010.

14. Lefkoff MH, Beck FM, Horton JE. The effectiveness of a disposable tooth cleansing device on plaque. J Periodontol. 1995; 66:218–221.

15. Keyes PH. The infectious and transmissible nature of experimental dental caries. Findings and implications. Arch Oral Biol. 1960; 1:304–320.

16. Tenuta LM, Cury JA. Fluoride: its role in dentistry. Braz Oral Res. 2010; 24(Suppl 1):9–17.

17. Carrera CA, Giacaman RA, Munoz-Sandoval C, Cury JA. Total and soluble fluoride content in commercial dentifrices in Chile. Acta Odontol Scand. 2012; 70:583–588.

18. White DJ. Reactivity of fluoride dentifrices with artificial caries. III. Quantitative aspects of acquired acid resistance (AAR): F uptake, retention, surface hardening and remineralization. J Clin Dent. 1991; 3:6–14.

19. Hattab FN. Analytical methods for the determination of various forms of fluoride in toothpastes. J Dent. 1989; 17:77–83.

20. Gleisner H, Einax JW, Mores S, Welz B, Carasek E. A fast and accurate method for the determination of total and soluble fluorine in toothpaste using high-resolution graphite furnace molecular absorption spectrometry and its comparison with established techniques. J Pharm Biomed Anal. 2011; 54:1040–1046.

21. Biemer TA, Asral N, Sippy A. Ion chromatographic procedures for analysis of total fluoride content in dentifrices. Journal of Chromatography A. 1997; 771:355–359.

22. Pessan JP, Toumba KJ, Buzalaf MA. Topical use of fluorides for car- ies control. Monogr Oral Sci. 2011; 22:115–132.

23. Benzian H, Holmgren C, Buijs M, van Loveren C, van der Weijden F, van Palenstein Helderman W. Total and free available fluoride in toothpastes in Brunei, Cambodia, Laos, the Netherlands and Suriname. Int Dent J. 2012; 62:213–221.

24. Conde NC, Rebelo MA, Cury JA. Evaluation of the fluoride stability of dentifrices sold in Manaus, AM, Brazil. Pesqui Odontol Bras. 2003; 17:247–253.

25. Stookey GK, DePaola PF, Featherstone JD, Fejerskov O, Moller IJ, Rotberg S, et al. A critical review of the relative anticaries efficacy of sodium fluoride and sodium monofluorophosphate dentifrices. Caries Res. 1993; 27:337–360.

26. de Freitas JF. Fluoride stability in toothpastes. Aust Dent J. 1984; 29:30–35.

27. Hattab FN. The state of fluorides in toothpastes. J Dent. 1989; 17:47–54.

28. Patil VH, Anegundi RT. An in vitro assessment of fluoride uptake by tooth enamel from four different fluoride dentifrices. Eur Arch Paediatr Dent. 2014.

29. ADA. Acceptance Program Guidelines: fluoride-containing dentifrices. Chicago: Council on Scientific Affairs;2005.

30. Gaffar A, Polefka T, Afflitto J, Esposito A, Smith S. In vitro evaluations of pyrophosphate/copolymer/NaF as an anticalculus agent. Compend Suppl. 1987; S242–250.