Impact of toothbrush type and periodontal phenotype on root coverage stability: A 6‐year observational follow‐up of a randomized clinical trial

BACKGROUND: This 6-year observational follow-up of a randomized, parallel-arm clinical trial evaluated the association between toothbrush type and periodontal phenotype on the long-term stability of the gingival margin (GM) following coronally advanced flap (CAF) surgery. METHODS: Thirty-one of the original 60 subjects were reevaluated after 6 years. Treated gingival recessions were allocated to manual or oscillating-rotating toothbrush use. Periodontal phenotype was qualitatively assessed at baseline using a color-coded probe. Recession depth (RD), mean root coverage (mRC), and complete root coverage (CRC) were recorded over time and compared between groups. Data were analyzed using random-intercept models and non-parametric tests (α = 0.05). RESULTS: GM relapse occurred in both groups. Loss of CRC occurred earlier in the manual toothbrush group (6 months) than in the oscillating-rotating group (2 years). At 6 years, both groups showed a significant reduction in CRC (manual: 58.8%, p < 0.001; oscillating-rotating: 57.1%, p < 0.001), with no statistically significant differences between toothbrush types. Periodontal phenotype and oscillating-rotating toothbrush use, assessed at the 6-year time point, were associated with greater GM stability. CONCLUSIONS: Within the limitations of this 6-year follow-up, CAF surgery in thin and medium periodontal phenotypes was associated with gingival recession recurrence over time, while oscillating-rotating toothbrush use was associated with delayed GM breakdown.