Influence of the relative enamel abrasivity of toothpastes (REA value) on the wear of eroded enamel

Eroded enamel is more susceptible to abrasion than healthy one. The present study aims to determine the impact of toothpaste abrasiveness (REA-value) and brushing force on enamel wear after erosion. 140 enamel samples from bovine teeth were divided into seven groups (N = 20). Each group was assigned a different toothpaste with varying levels of abrasiveness (groups 1+2: Candida Parodin (REA 2), groups 3+4: Candida Multicare (REA 9), and groups 5+6: Candida White Micro Crystals (REA 19)). The samples were first exposed to a citric acid solution (pH 2.60; 2 min) to simulate an erosive attack and then subjected to brushing with the assigned toothpaste using an automatic brushing machine at 1- and 2-N brushing force. Samples of group 7 were left unbrushed and served as the control group. The erosive/abrasive cycling was repeated 10 times. Enamel wear was measured profilometrically. Higher erosive/abrasive wear was observed in all toothpaste groups compared to the control. In all toothpaste groups, erosive/abrasive wear was significantly higher at 2-N brushing force than 1 N (P < 0.05). At 1-N and 2-N force, Candida Parodin showed lower enamel wear than Candida Multicare and Candida White Micro Crystals. The results showed that toothpastes with higher REA values result in greater abrasion of eroded enamel, but only up to a certain value. Eroded tooth structure is more prone to abrasion at higher contact pressure, but REA value has a greater influence. Patients with erosion should use toothpaste with low REA value and avoid excessive contact pressure.