The Influence of Erosive and Abrasive Effects of Interdental Brushing on Bovine Enamel and Dentine In Vitro

Purpose: To investigate the effects on enamel and dentine caused by erosion with hydrochloric acid (HCl) or abrasion with interdental brushes and toothpaste, and a combined protocol using roughness and profilometry measurements as well as scanning electron microscopy images. Materials and methods: 24 bovine enamel samples and 24 dentine samples were divided into three groups each (groups 1-3: enamel; groups 4-6: dentin; n = 8) and investigated after an abrasion protocol (2 × 10 brushing cycles per day) in groups 1 and 4, a combined protocol (10 brushing cycles, 10 × 2min erosion in HCl, 10 brushing cycles per day) in groups 2 and 5 and an erosion protocol (10 × 2min erosion in HCl) in groups 3 and 6 for 10 days. Profilometry and roughness measurements were registered at baseline, after 5 and after 10 days. Scanning electron microscopy (SEM) images were recorded at baseline and after 10 days. Results: For enamel, the significantly highest substance loss (mean ± SD) after 5 days was observed in the combined group (10.71 ± 0.41 μm), whereas the second highest substance loss was in the erosion-only group (9.16 ± 0.23 μm). In dentin, the highest substance loss after 5 days occurred in the combined group (7.4 ± 0.83 μm), and the second highest substance loss was presented in the erosion-only group (7.26 ± 0.5 μm). After 10 days, the combined group (18.88 ± 0.56 μm) exhibited the highest substance loss in enamel, showing a statistically significant difference compared with the erosion-only and abrasion-only groups (P 0.001, respectively). In dentin, the highest substance loss was observed after 10 days in the erosion-only group (7.96 ± 0.8 μm), exhibiting a statistically significant difference compared to both the combined (P = 0.022) and abrasion-only groups (P 0.001). Conclusion: In all groups, with the exception of abrasion-only groups, enamel substance loss occurred. Thus, measures against erosive and abrasive wear, both alone and combined, have to be implemented, such as comprehensive patient education.