Beyond Routine Subgingival Instrumentation: An Evidence-Based Framework for Individualized Supportive Periodontal Therapy in Periodontitis Patients

Background: Supportive periodontal therapy (SPT) is essential for maintaining periodontal stability after active treatment of periodontitis. Although subgingival instrumentation is a well-established component of active periodontal therapy, its routine repetition during maintenance visits remains clinically debated. Evidence supporting instrumentation during disease resolution cannot be directly extrapolated to all patients receiving long-term supportive care. Aim: This narrative review critically evaluates current evidence regarding routine versus selective subgingival instrumentation during SPT and proposes an evidence-based framework for individualized periodontal maintenance. Methods: A targeted narrative synthesis of randomized and prospective clinical studies, systematic reviews, consensus reports, and evidence-based periodontal guidelines was undertaken. Particular attention was given to probing pocket depth, clinical attachment level, bleeding on probing, residual pockets, microbiological outcomes, risk factors, and patient adherence. Evidence synthesis: Available comparative evidence does not demonstrate a consistent additional benefit of routine subgingival instrumentation for every periodontally stable patient. A two-year randomized trial (Angst et al., 2019) found comparable overall maintenance with or without routine subgingival instrumentation, whereas a more recent randomized trial (Isola et al., 2026) reported additional improvements in bleeding-related and residual-pocket outcomes when subgingival instrumentation was included. These apparently divergent findings support context-dependent rather than universal treatment decisions. Conclusions: SPT should move from automatic procedure-based protocols toward individualized, risk-based care. Subgingival instrumentation remains an important therapeutic tool, but its use during maintenance should be guided by current disease activity, residual pocket characteristics, patient-level risk factors, and longitudinal stability.