Comparison of the cleaning efficiency between interdental brushes and sticks: a laboratory study

Studies on interdental cleaning have shown an advantage of interdental brushes (IDB) over other interdental care products. Sticks (STK) made of rubber are often recommended as an alternative, as they are considered user-friendly, gentle but nevertheless effective. This laboratory study aimed to compare the cleaning efficiency with the same application force between IDB and STK. Brushes with different geometries and diameters were tested. Two conical STK from two manufacturers of the sizes "XS/S" (0.7-2.6 mm) and "L" (0.9-3.4 mm) were tested. For the IDB, one conical (2.7-3.4 mm), two cylindrical (1.9 and 2.5 mm) and one waisted brush (4-2-4 mm) were assessed. A geometric model with parallel-walled metal blocks (black and coated with titanium oxide) was used. The brushes were tested with one and five cleaning cycles each in horizontal direction. The test surfaces were measured planimetrically for cleaning efficiency by calculating the areas freed from titanium oxide in relation to the maximum cleanable total area. The maximum cleaning efficiency of the IDB was 45% at 1 mm distance with one cleaning cycle and 95% with five cycles. For the sticks, the cleaning efficiency with one cleaning cycle was 30% and 67% with five cycles. At a distance of 2 mm, the maximum cleaning efficiency was 50% with one cleaning cycle and 87% with five cycles for the IDBs and only 10% for the STKs. Taking into account the limitations of this study, the IDBs showed an overall better cleaning efficiency with the same application force, compared to STKs, with the waisted IDB achieving better cleaning efficiency than the conical IDB. In conclusion, STKs can be used in narrow interdental spaces where app opriate, but overall IDBs are more preferable in narrow and wider contact point conditions.