Dentifrices with fluoride and trimetaphosphate on erosion enamel

Objective: This in situ study was to evaluate the effect of toothpastes with different fluoride concentrations, combined or not with sodium trimetaphosphate (TMP) on erosion (ERO) and erosion followed by abrasion (ABR). Method: A double-blind, crossover study 15 volunteers were selected randomly divided into 5 groups according to the treatments: placebo, 1,100 μg F/g, 1,100 μg F/g + 3%TMP, 500 μg F/g + 3%TMP and 5,000 μg F/g. Palatal appliances containing 4 enamel blocks were submitted to acid challenge with drink (Coca-Cola^TM, pH 2.6) for 5 minutes, four times a day for seven days. And then immersed in a suspension of dentifrice/deionized water for 15 seconds. After erosion, 2 blocks were subjected to abrasion by brushing for 15 seconds. At the end of the experiment the enamel wear (µm) and surface hardness (Knoop) was determined. The results were submitted to analysis of variance followed by Student-Newman-Keuls test (p <0.05). Result: The wear observed in ERO was lower than that seen in the wear ERO + ABR in all groups. There was less wear (µm) for the 500 µg F/g + 3%TMP and 5,000 µg F/g groups. The  500 µg F/g + 3%TMP group had lower values wear when compared to 1,100 µg F/g and 1,100 µg F/g + 3%TMP groups in both challengers (p<0,05). Regarding the hardness the 5,000 µg F/g group presented highest hardness value when compared to the others (p < 0.05). Conclusion: The addition of TMP to a dentifrice with 500 µg F/g reduces the wear of the enamel as a dentifrice having a fluoride concentration 10 times higher (5,000 µg F/g) although dentifrice 5000 µg F/g having obtained the highest hardness values among the groups, the wear observed in ERO was lower than that seen in the wear ERO + ABR in all groups.