A randomised clinical in situ study to evaluate the effects of novel low abrasivity anti-sensitivity dentifrices on dentine wear.

OBJECTIVES: To compare the abrasive wear on human dentine in an in situ model associated with use of an experimental low abrasivity anti-sensitivity dentifrice containing 1% alumina and 5% sodium tripolyphosphate (STP) with an experimental ultra-low abrasivity non-alumina 5% STP dentifrice, a higher abrasivity daily-use whitening dentifrice, and water as controls. METHODS: This was a single-centre, single-blind, randomised, split-mouth, four-treatment, two-period, crossover in situ study in 29 healthy subjects. Subjects wore bilateral lower buccal appliances, each fitted with four dentine specimens. Study treatments were applied ex vivo (three times daily). Dentine loss was measured by non-contact profilometry after 5, 10 and 15days' treatment. RESULTS: All 29 subjects were included in the efficacy analysis. Significantly less dentine loss was associated with brushing with the low and ultra-low abrasivity dentifrices than with the higher abrasivity dentifrice at all timepoints (p<0.01). Brushing with ultra-low abrasivity dentifrice or water resulted in statistically significantly less dentine loss compared with brushing with the low abrasivity dentifrice at all timepoints (p<0.05). Dentine loss after brushing with ultra-low abrasivity dentifrice was not significantly different from brushing with water. CONCLUSIONS: The degree of dentine loss observed in this in situ model reflected the abrasivity of the study dentifrices. Brushing with low or ultra-low abrasivity STP-containing anti-sensitivity dentifrices resulted in significantly less dentine loss (equating to dentine wear) than with a higher abrasivity daily-use whitening dentifrice.

Fluoride gel supplemented with sodium hexametaphosphate reduces enamel erosive wear in situ.

OBJECTIVE: This study evaluated the effect of fluoride gels, supplemented or not with sodium hexametaphosphate (HMP), on enamel erosive wear in situ. METHODS: Twelve healthy volunteers wore palatal appliances containing four bovine enamel discs. Subjects were randomly allocated into four experimental phases (double-blind, crossover protocol) according to the gels: Placebo (no fluoride or HMP), 1% NaF, 2% NaF, and 1% NaF+9% HMP. Enamel discs were selected after polishing and surface hardness analysis, and treated only once with the respective gels prior to each experimental phase. Erosion (ERO) was performed by extra-oral immersion of the appliance in 0.05M citric acid, pH 3.2 (four times/day, five minutes each, 5 days). Additional abrasion (ERO+ABR) was produced on only two discs by toothbrushing with fluoridated dentifrice after ERO (four times/day, 30s, 5 days). The specimens were submitted to profilometry and hardness analysis. The results were analyzed by two-way ANOVA and the Student-Newman-Keuls test (p<0.05). RESULTS: The 1% NaF+9% HMP gel promoted significantly lower enamel wear for ERO compared to the other groups, being statistically lower than 1% NaF and Placebo for ERO+ABR. Similarly, the lowest values of integrated lesion area were found for 1% NaF+9% HMP and 2% NaF, respectively, for ERO and ERO+ABR. CONCLUSION: The addition of HMP to the 1% NaF gel promoted greater protective effect against ERO and ERO+ABR compared to the 1% NaF gel, achieving similar protective levels to those seen for the 2% NaF gel. CLINICAL SIGNIFICANCE: Gel containing 1% NaF+9% HMP showed a high anti-erosive potential, being a safer alternative when compared to a conventional 2% NaF gel.