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

Abstract 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.