Efficacy of combined oral hygiene devices for interproximal plaque removal: an in vitro study

BACKGROUND: This study compared interproximal plaque removal rates when oral hygiene devices were used with a manual toothbrush. METHODS: Artificial plaque was applied to the mesial interproximal surface of a lower left first molar mounted on a jaw model within a simulator. Removal was compared among 10 groups, including toothbrush alone (TB) and combinations of single-tufted brushes (Tuft), interdental brushes (IDB), and dental floss (string floss [SF] or holder-type floss [HF]). Five dental professionals performed the procedures. Pre- and post-cleaning images were analyzed to determine removal rates. Statistical analysis was conducted using a linear mixed-effects model with Tukey's post-hoc test. RESULTS: The estimated marginal mean (EMM) for the TB group was 0.44 (95% confidence interval [CI]: 0.37-0.50). All combinations achieved significantly higher removal rates (p < 0.001). The TB, IDB, and SF combination achieved the highest EMM (0.93; 95% CI: 0.87-0.99). No significant differences were observed among the three SF combinations; however, all three demonstrated significantly higher rates than other protocols (p < 0.001). CONCLUSIONS: Adjunctive devices significantly improve interproximal plaque control compared to toothbrushing alone. Under the conditions of this experimental model, the combinations that included string floss demonstrated the highest efficacy for physical plaque removal. Further studies are needed in different anatomical settings and broader user populations.