App-supported powered toothbrushing during non-surgical periodontal therapy in stage III–IV periodontitis: a secondary analysis of a randomized controlled trial

BACKGROUND: Adequate plaque control is essential for successful non-surgical periodontal therapy (NSPT). App-supported powered toothbrushes (PT) may improve oral hygiene behaviour, but evidence of additional clinical benefit during NSPT in advanced periodontitis is limited. This secondary analysis of a prospectively registered four-arm randomized controlled trial compared an app-supported PT with an identical PT without app support. METHODS: Forty-four patients with generalized stage III-IV periodontitis were randomly assigned within the powered-toothbrush stratum to an app-supported PT (TPB, n = 23) or an identical PT without app support (CPB, n = 21) and analysed by intention-to-treat; missing data due to dropout (TPB/CPB: n = 4/n = 3) were handled using last observation carried forward. All patients received standardized NSPT. Clinical parameters were assessed at baseline (T1) and after 5-6 months (T6). ΔGBI was the registered primary outcome of the four-arm trial; ΔPPD (T6-T1), a prespecified secondary clinical outcome, was the principal outcome of this two-arm analysis. Questionnaire-based oral hygiene motivation was assessed at T1 and T6. RESULTS: For the registered primary outcome, ΔGBI did not differ significantly between groups (CPB: -7.12 ± 18.73%; TPB: -9.28 ± 16.91%; p = 0.573). Both groups showed significant reductions in mean PPD (CPB: -0.59 ± 0.57 mm; TPB: -0.67 ± 0.66 mm; both p < 0.001), with no significant between-group difference in ΔPPD (mean difference: -0.08 mm, 95% CI - 0.45 to 0.29; p = 0.832). CAL improved significantly in CPB only, whereas GR increased more in TPB (p = 0.011). No significant between-group differences were observed for CAL, PCR, GBI, or PPD distribution. During the post-treatment phase, both groups showed further improvements without intergroup differences. Questionnaire outcomes revealed no significant between-group differences after correction for multiple testing, although motivation for interdental cleaning improved significantly within TPB (p = 0.002). CONCLUSIONS: App support did not provide additional clinical benefit over powered toothbrushing without app support during NSPT. Descriptive, non-significant trends toward more favourable post-treatment changes suggest a potential role in behavioural support and maintenance, potentially requiring integration of professional guidance. TRIAL REGISTRATION: The fourarm randomized controlled trial was prospectively registered in the German Clinical Trials Register (DRKS00031539) on May 4, 2023. The present study reports a secondary analysis of its two poweredtoothbrush arms.