Toothpaste formulations with same fluoride source lead to differing intraoral fluoride concentrations over time

The study is published in the Journal of Dentistry.

Charles R.Parkinson and associates from the GSK Consumer Healthcare, Weybridge, Surrey, United Kingdom conducted this randomised, controlled, analyst blind, crossover study aimed to evaluate and compare salivary fluoride and calcium ion concentration over 60 min following brushing with an assigned treatment and following an orange juice (OJ) or deionised (DI) water rinse 60 min post-brushing.

Study treatments, both containing 1150 ppm fluoride as NaF and 5% w/w KNO3, were the Test (including 1.2 % w/w cocamidopropyl betaine) and Comparator (including tetrasodium pyrophosphate and sodium lauryl sulphate) toothpastes. Twenty nine participants were randomised to treatment.

The following findings were drawn-

a. A sharp increase in salivary fluoride ion concentration immediately post-brushing with either toothpaste decreased over time.

b. Fluoride concentration following Test toothpaste use was numerically higher than the Comparator at all timepoints, with a significant difference from 10 min post-brushing (p < .05).

c. Following the 60 min rinse, there were no significant differences between the Test or Comparator + OJ groups in salivary fluoride concentration but the Test + DI water group was significantly lower than Test (p < .001) or Comparator (p < .001) + OJ groups.

d. A reduction in salivary calcium ion concentration was seen immediately post-brushing and after the OJ rinse with both toothpastes.

e. Significant differences were observed in favour of the Test toothpaste at all timepoints (p < .05) and for Test and Comparator + OJ group (p < .001) compared with Test + DI water rinse.

f. Both treatments were generally well-tolerated.

Therefore, the authors concluded that "toothpaste formulations with identical declared fluoride concentrations and the same fluoride source give rise to differing intraoral fluoride concentrations over time, which are potentially related to different formulation excipient effects."