This in vitro study was aimed to compare the cleaning efficacy of three toothbrushes with a bristle stiffness determined as hard [H], medium [M], and soft [S].
Methods:
Six samples of each toothbrush were used in this study. All brushes showed an identical bristle field with 40 tufts. Each tuft of [H] and [M] had 44 filaments; [S] had a filament number of 22 per tuft. The cleaning efficacy of the brushes was tested using a standardized method with a custom-made automatic tooth brushing machine. Five modified artificial teeth (43 – 47, Frasaco) were stained with a highly resistant black varnish and coated with titaniumdioxid as plaque substitute. Each brush was used for 10 seconds (simulated tooth brushing of three minutes for the whole mouth) with a load of 2 N. The efficacy on the different tooth surfaces (vestibular, cervical and proximal) was analyzed with Adobe Photoshop CS5 and ImageJ. Statistical testing was accomplished using Kruskal-Wallis- and Mann-Whitney-Test (p<0.05).
Results:
The mean (standard deviation) artificial plaque removal was 33.9 (2.8) [H], 34.1 (3.2) [M], and 43.3 (5.0) [S] on vestibular surfaces and 15.0 (3.5) [H], 16.6 (3.2) [M], and 28.6 (2.1) [S] in the cervical areas. Brush [H] showed a significantly higher efficacy than [M] and [S] (p<0.05) on vestibular surfaces. Furthermore [S] was significantly superior to [H] and [M] in the cervical regions (p<0.05). The efficacy on proximal surfaces 3.02 (1.51) [H], 2.45 (0.56) [M], and 1.85 (0.49) [S] was not significantly different between the three toothbrushes.
Conclusions:
The efficacy of the removal of a plaque substitute on vestibular surfaces increased with higher stiffness of the toothbrush. In contrast, an increasing efficacy on cervical regions was observed with decreasing bristle stiffness.