Bahaviour of amine fluorides in toothpastes using teeth brushing models

In elmex® and meridol® toothpastes, a well characterised amine fluoride (Olaflur®) is used as source of fluoride in order to provide protection from caries. Up to now, data about the stability of these amines in the presence of the oral microflora are lacking. Objective: To investigate how contents of amines in toothpaste are influenced by tooth brushing and whether incubation of salivary slurry and rinsings collected after tooth brushing influences microbiological activity with respect to potentially modifying amine contents. Methods: Amine profiles and contents were characterized by LC/MS in the original toothpaste and after teeth brushing in slurry and rinsings collected. To simulate worst case conditions, salivary slurry was incubated at 37°C, 2h. Results: In toothpaste samples (n=31), tertiary amine contents were found to range from 8.4 to 35.9 mg/g and those of secondary amines from 39 to 197 µg/g. After teeth brushing, mean tertiary amine content corrected for dilution in the slurry was diminished down to about one third of the original amount. Secondary amine content, only about 1/1000 of tertiary amines, was reduced by one third. After slurry incubation, mean contents of tertiary amines were found enhanced by 39%, most probably by liberation from toothpaste particles, whereas secondary amine contents remained constantly low. Conclusion: Teeth brushing markedly reduces amine contents in toothpaste when comparing original contents in toothpaste with contents in teeth brushing slurry and rinsings. This indicates that amines remain fixed in the oral cavity. Secondary amines are less retained in the oral cavity than tertiary amines. There is no influence on secondary amine contents after 2 hrs incubation at 37°C of collected teeth brushing slurry and rinsings. The results clearly show that there is no influence of microbiological metabolism on secondary amine contents.

Work sponsored by GABA international