Voilà un constat qui jette un pavé dans la mare et remet en question l'utilisation du fluor par voie topique.

Les auteurs de cette étude ont déposé sur des plaques d'émail un biofilm, afin de mesurer à quelle profondeur de celui-ci, pénètrent les ions de fluors censés protéger les dents.

En portant l'expérience sur des périodes correspondant soit à la durée du brossage moyen (2 min.) et jusqu'à 30 minutes, les chercheurs ont constaté que la pénétration du fluor se limite aux zones les plus superficielles du biofilm.

Les chercheurs ont également observé que l'émail sous-jacent n'en récupère que d'infimes quantités !!
Quel est donc l'intérêt du fluor  ??

Abstract original de la publication :

J Dent Res. 2005 May;84(5):451-5.
“Penetration of fluoride into natural plaque biofilms.”
Watson PS, Pontefract HA, Devine DA, Shore RC, Nattress BR, Kirkham J, Robinson C.
Division of Oral Biology, Leeds Dental Institute, Clarendon Way, Leeds, LS29LU,UK.

Caries occurs at inaccessible stagnation sites where plaque removal is difficult. Here, the penetration through plaque of protective components, such as fluoride, is likely to be crucial in caries inhibition. We hypothesized that topically applied fluoride would readily penetrate such plaque deposits. In this study, plaque biofilms generated in vivo on natural enamel surfaces were exposed to NaF (1000 ppm F-) for 30 or 120 sec (equivalent to toothbrushing) or for 30 min. Biofilms were then sectioned throughout their depth, and the fluoride content of each section was determined with the use of a fluoride electrode. Exposure to NaF for 30 or 120 sec increased plaque fluoride concentrations near the saliva interface, while concentrations near the enamel surface remained low. Fluoride penetration increased with duration of NaF exposure. Removal of exogenous fluoride resulted in fluoride loss and redistribution. Penetration of fluoride into plaque biofilms during brief topical exposure is restricted, which may limit anti-caries efficacy.