The Influence of Interdental Brushes and Toothpaste On Approximal Enamel and Dentine Abrasion - A Laboratory Study

To investigate the approximal abrasive enamel and dentine wear using interdental brushes (IDBs) with and without toothpaste in a novel standardised in-vitro set-up.

Seventy-two bovine enamel and 72 dentine specimens were prepared and randomly allocated into 12 groups (odd group: dentine; even group: enamel). The specimens were brushed with three IDB types of ISO 2 (Curaprox (CPS09, groups 1-4), Elmex (size 2, groups 5-8) and Circum (Circum 2, groups 9-12)) with artificial saliva or toothpaste slurry (Colgate Total Original). A custom-made brushing device simulated interdental brushing for 1 h on dentine (7,200 strokes) and 6 h on enamel (43,200 strokes). Wear was assessed using a contact profilometer, and electron microscopy images were taken. Kruskal-Wallis and Mann-Whitney tests were used for statistical analysis.

The combination of IDBs with artificial saliva resulted in enamel and dentine wear below the detection limit, similar to the enamel wear when toothpaste was used. Dentine specimens showed significant abrasive wear, which was influenced by the IDBs' design as follows: Curaprox (median ± interquartile range (IQR): 8.6 ± 1.0 µm), Circum (9.7 ± 2.9 µm), and Elmex (18.8 ± 9.1 µm). The difference in wear between Curaprox and Circum was not statistically significant (P = 1). However, the increase in the wear of Elmex compared with that of the other IDBs was significant (P 0 0.001).

The use of IDBs with toothpaste may cause statistically significant dentine wear and should not be recommended in combination. Appropriate instructions are essential.