Mapping the Product Range of Interdental Brushes: Sizes, Shapes, and Forces.

PURPOSE: Preventive dentistry aims to improve oral hygiene, including the use of interdental cleansing aids. Clear and simple classifications may positively impact patient communication and motivate oral health behaviour. To date, there is no comparative analysis of interdental brush classifications and sizes. MATERIALS AND METHODS: A total of 2320 interdental brush samples by 24 manufacturers was examined regarding their passage hole diameter (PHD) according to the ISO standard for interdental brushes (ISO16409:2016), and their current classifications were evaluated. Inter- and intrarater reliability of the ISO size classification were determined based on 20 raters and 10 interdental brushes. The insertion force for these interdental brushes was analysed in vitro. RESULTS: Excellent intra- and interrater reliability was achieved (intraclass correlation coefficient (ICC) ≥ 0.973) overall, although greater variance was observed for bigger brush sizes. Insertion forces varied depending on size and form of the brushes, amounting to 1.58 N (SD = 1.27 N) for cylindric and tapered brushes, and to 2.31 N (SD = 0.81 N) for waist-shaped brushes. The size range of commercially available products was 0.6-5.2 mm PHD, 90% presenting with a PHD ≤ 2.0 mm. Size intervals were unsystematic. The ISO size was indicated by 33% of all manufacturers, the exact PHD by 25%. CONCLUSIONS: The determination of the PHD is a reproducible instrument for most brushes currently on the market. In vitro, forces developed based on this classification are mostly moderate, thus unlikely to cause periodontal trauma. Given the discontinuous range and unclear labelling of available products, the development of a simplified classification system by usage of the PHD may benefit the practitioner and patient alike by contributing to improve oral hygiene behaviours.

New experimental setup for the measurement of cleaning efficacy and force of interdental aids in 3D-reproduced interdental areas.

BACKGROUND: Interdental rubber picks (IRP) have become a frequent and convenient alternative for interdental cleaning. However, only little evidence exists supporting the effectiveness of newer designs available on the market. Therefore, a new in vitro model was evaluated to measure the experimental cleaning efficacy (ECE), as well as the force needed for insertion and during the use of IRP, with high reproducibility. METHODS: Five different sizes of commercially marketed IRP with elastomeric fingers (IRP-F) (GUM SOFT-PICKS® Advanced, Sunstar Deutschland GmbH, Schönau, Germany) or slats (IRP-S) (TePe EasyPick™, TePe D-A-CH GmbH, Hamburg, Germany) were tested. Interdental tooth surfaces were reproduced by a 3D-printer (Form 2, Formlabs Sommerville, MA, USA) according to human teeth and matched to morphologically equivalent pairs (isosceles triangle, concave, convex) fitting to different gap sizes (1.0 mm, 1.1 mm, 1.3 mm). The pre-/post brushing situations at interdental areas (standardized cleaning, computer aided ten cycles) were photographically recorded and quantified by digital image subtraction to calculate ECE [%]. Forces were registered with a load cell [N]. RESULTS: IRP-F have to be inserted with significant higher forces of 3.2 ± 1.8 N compared to IRP-S (2.0 ± 1.6 N; p < 0.001) independent of the size and type of artificial interdental area. During cleaning process IRP-S showed significantly lower values for pushing/pulling (1.0 ± 0.8 N/0.5 ± 0.4 N) compared to IRP-F (1.6 ± 0.8 N/0.7 ± 0.3 N; p < 0.001) concomitant to significantly lower ECE (19.1 ± 9.8 vs. 21.7 ± 10.0%, p = 0.002). Highest ECE was measured with largest size of IRP-F/IRP-S independent the morphology of interdental area. CONCLUSIONS: New interdental cleaning aids can be tested by the new experimental setup supported by 3D printing technology. Within the limitations of an in vitro study, IRP-F cleaned more effectively at higher forces compared to IRP-S.