In vitro effect of fluoride gels supplemented with nano-sized sodium trimetaphosphate on enamel erosive wear.

Objective: To assess the protective effect of fluoride (F) gels supplemented with micrometric or nano-sized sodium trimetaphosphate (TMPmicro and TMPnano, respectively) against enamel erosion in vitro.

Methods: Bovine enamel blocks (n = 140) were selected according to their surface hardness, and randomly divided into seven groups (n = 20/group), according to the gels tested: Placebo (without F/TMP), 4,500 μg F/g (4500F), 9,000 μg F/g (9000F), 4500F plus 2.5 % TMPnano (2.