Fluoride bioavailability on demineralized enamel by commercial mouth rinses

Abstract

The ability of mouth rinses, available in the international market, to form reaction products on demineralized enamel (bioavailability test) was evaluated in vitro. Nine mouth rinses purchased in Chile were evaluated; eight formulated with NaF (one containing 100 µg F/mL and seven containing 226) and one with Na2FPO3 (226 µg F/mL as ion F). Demineralized enamel slabs (n=15 per mouth rinse) were sectioned; one half was subjected to the assigned mouth rinse treatment for 10 min and the other half was used to obtain baseline data. Loosely bound and firmly bound fluoride formed on enamel were determined with an ion-specific electrode and the values were expressed in µg F/cm2. The concentration of fluoride and the pH of the mouth rinses were previously determined. Concentrations of loosely bound and firmly bound fluoride formed on enamel were independently analyzed by ANOVA and Tukey’s test (α=5%). The loosely bound and firmly bound fluoride concentrations (µg F/cm2) formed ranged from 3.2 to 36.2 and 0.4 to 1.7, respectively. Loosely bound fluoride formed on enamel was significantly more effective in discriminating the effect of different commercial mouth rinses than firmly bound fluoride. Mouth rinses with 226 ppm F as NaF and low pH presented significantly greater bioavailability of fluoride on enamel than those with higher pH or lower NaF concentration. The mouth rinse with Na2FPO3 showed low reactivity. Although further studies are necessary, the findings showed that commercial fluoride-containing mouth rinses have important variations in enamel fluoride bioavailability, which may result in differences on anticaries efficacy.

Essential oil-containing solutions (mouthwashes) preserve dental enamel with releasing low Ca and P concentrations without morphology alterations: an in vitro study

“…Several oral care products such as F-containing mouthrinses have a low pH ( Hellwig and Lussi, 2006 ). The results of this study are in agreement with other investigations on EO- and F-containing mouthrinses ( Zero et al, 2004 ; Delgado et al, 2018 ; Valdivia-Tapia et al, 2021 ) and pH values similar to sports drinks ( Sato et al, 2021 ). The EO-containing solutions investigated in this study showed low pH; however, they needed a small amount of base to be neutralized (low TA) ( Saads Carvalho and Lussi, 2020 ), which represents a low erosive potential for tooth tissues ( Harper et al, 2021 ).…”

Fluoride, pH Value, and Titratable Acidity of Commercially Available Mouthwashes

“…Mouthwashes with 226 ppm sodium fluoride and a low pH presented a better bioavailability than those with a higher pH. 18 There is, however, concern that mouthwashes with a low pH could contribute to erosion. 19 , 20 , 21 , 22 As well as pH value, titratable acidity (TA; “the buffer capacity”) plays an important role in erosion.…”