Strontium-Fluoride Toothpaste Affects Enamel F and Sr Level in vivo

Objectives: The aim of the study has been to assay F and Sr contents in the superficial layer of healthy enamel following the use of experimental, synthetic hydroxyappatite toothpastes supplemented with F and Sr ions. Methods: Two types of toothpaste were used – a synthetic hydroxyappatite toothpaste supplemented with strontium ions (250 ppm) and the same toothpaste supplemented with fluoride (1000 ppm). Healthy volunteers aged 20-30 years who brushed the teeth with these toothpastes for 6 months, twice daily for about 2 minutes, took part in the study. F and Sr enamel contents was determined at 2, 4 and 6 months – Brudewold's abrasion method was used to sample enamel from labial surface of the central incisors. Fluoride contents in the enamel was assayed using ionoselective fluoride electrode and by determining calcium contents through atomic spectrophotometry, whereas Sr contents was assayed through atomic absorption spectrometry with electrothermic atomisation plus calcium contents determination. Results: There was statistically significant increase in fluoride contents (p <0.1) in both groups, though mean increase in F contents after 2, 4 and 6 months was higher in the „Sr+F” group. There were no significant differences in Sr enamel contents between the two groups at 6 months. Conclusion: Sr supplementation of fluoride toothpastes may increase the uptake of F by the superficial layer of healthy enamel in vivo.