Objectives: The objective of this study was to evaluate the efficacy of four different side-to-side toothbrushes and the impact of various brushing parameters on noncontact biofilm removal in an adjustable interdental space model.
Materials and methods: A three-species biofilm, consisting of Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus sanguinis, was formed in vitro on protein-coated titanium disks using a flow chamber combined with a static biofilm growth model. Subsequently, the biofilm-coated disks were exposed to four different powered toothbrushes (A, B, C, D). The parameters distance (0 and 1 mm), brushing time (2, 4, and 6 s), interdental space width (1, 2, and 3 mm), and toothbrush angulation (45° and 90°) were tested. The biofilm volumes were determined using volumetric analyses with confocal laser scanning microscope (Zeiss LSM700) images and Imaris version 7.7.2 software.
Results: The median percentages of simulated interdental biofilm reduction by the tested toothbrushes ranged from 7 to 64 %. The abilities of the analyzed toothbrushes to reduce the in vitro biofilm differed significantly (p < 0.05). Three of the tested toothbrushes (A, B, C) were able to significantly reduce a simulated interdental biofilm by noncontact brushing (p ≤ 0.005). The brushing parameters and their combinations tested in the experiments revealed only minor effects on in vitro interdental biofilm reduction (p > 0.05).
Conclusions: A three-species in vitro biofilm could be altered by noncontact brushing with toothbrushes A, B, and C in an artificial interdental space model.
Clinical relevance: Certain side-to-side toothbrushes demonstrate in vitro a high efficacy in interdental biofilm removal without bristle-to-biofilm contact.
Keywords: Biofilm; Hydrodynamic effect; Interdental; Oral hygiene; Preventive dentistry; Side-to-side toothbrush.