Antierosive Potential of Fluoride Toothpaste Associated With Aminomethacrylate Copolymer

Objectives: This study aimed to evaluate if the aminomethacrylate copolymer could potentiate the protective potential of sodium fluoride in toothpaste formulations against enamel initial erosion.
Methods: Polished bovine enamel specimens were divided into five treatments: ultra-pure water (negative control - NC), toothpaste without active agent (placebo- PL), experimental toothpaste with aminomethacrylate (AMC 4% - AMC), toothpaste with sodium fluoride (NaF 1450 ppm F^- - F), and toothpaste with sodium fluoride + aminomethacrylate (NaF+AMC - AMC+F). The specimens were immersed in human saliva (1 h) to allow acquired pellicle formation. Then, an erosive/rehardening cycling was performed with exposure to 0.3% citric acid (natural pH - 5 min), human saliva (30 min), treatment with toothpaste slurries (120 s), human saliva (30 min), and 0.3% citric acid (5 min). All the steps were performed under agitation (30 rpm). Knoop surface microhardness (KN) was assessed in four moments: KNinitial (sound enamel), KNE1 (after the first acid exposure), KNT (after the treatment), and KNE2 (after the second acid exposure). Rehardening (Re) and protective (Prot) potential were assessed with the following formulas: %Re = [(KN_T-KN_E1) / (KN_E1)] x 100 and %Prot = [(KN_E2-KN_E1) / (KN_E1)] × 100. The data were analyzed by One-Way ANOVA and Tukey tests (5%).
Results: The mean ± standard deviation values and results of Tukey’s test for %Re were: NC (3,11±4,09)a; PL (1,78±3,51)a; AMC (5,59±3,08)a; F (7,53±9,17)a; AMC+F (20,23±7,10)b. For %Prot were: NC (-50,68±5,27)a; PL (-51,65±3,74)a; AMC (-41,21±8,47)b; F (-34,10±5,99)b; AMC+F (-19,80±7,95)c.
Conclusions: It was concluded that the addition of aminomethacrylate copolymer in the experimental fluoride toothpaste increased the enamel rehardening and the protective potential of the sodium fluoride against enamel initial erosion.