Improved plaque-induced gingivitis in students using calibrated interdental brushes: results of a 3-month multicenter educational intervention

: Objective: To evaluate the short-term clinical impact of daily use of calibrated interdental brushes (IDBs) on gingival bleeding among dental and dental hygiene students within academic curricula. Methods: A prospective cohort of 117 students from three Italian universities was followed over three months. All participants received personalized training and calibrated interdental brushes matched to their interdental spaces. The primary outcome was the percentage of interdental sites exhibiting bleeding on interdental brushing (BOIB), assessed at baseline (T0), one month (T1), and three months (T2). Adherence was self-reported. Statistical analyses included Wilcoxon tests, multivariate regression, and adjusted ANCOVA models. Results: Median bleeding scores decreased from 50.0% [IQR: 26.9-69.2] at baseline to 15.4% [IQR: 3.8-30.8] at one month and further to 11.5% [IQR: 0.0-26.9] at three months (p < 0.001). Regular interdental brush users showed a 15 to 16 percentage point greater reduction in bleeding compared to occasional users (p < 0.001). Dental hygiene students had significantly lower baseline bleeding scores than dental students, but both groups experienced comparable benefits from the intervention. Adjusted analyses confirmed a sustained beneficial effect of regular interdental brushing. Initial weak and transient correlations between behavioral factors and bleeding likely reflect multifactorial influences and variable adherence. Conclusions: Daily use of calibrated interdental brushes produces a rapid, significant, and sustained reduction in gingival bleeding among dental students. Systematic integration of this protocol within dental education programs is feasible and effective, promoting early adoption and maintenance of essential preventive oral health behaviors.