Pocket closure after repeated subgingival instrumentation: a stress test to the EFP guideline for stage III-IV periodontitis

OBJECTIVES: To study the effects of one or two repeated subgingival instrumentations (RSI) in achieving the endpoints of therapy (EoT) in open pockets [residual probing pocket depth (PPD) ≥ 6 mm and PPD 4–5 mm with bleeding on probing (BoP)] after steps I-II of therapy. MATERIALS AND METHODS: Twenty-five patients (3,552 total sites; 1,450 open pockets) with stage III-IV periodontitis received steps I-II of periodontal therapy and were re-evaluated after 4–6 weeks (T1). Residual pockets received RSI at T1 and at 3 months (T2). EoT (PPD < 4 or PPD < 6 BoP-) rate at T1, T2 and 6 months (T3) was computed. The number of needed surgeries and treatment costs were calculated. RESULTS: At T1, 67.6% of open pockets achieved EoT. At residual PPD ≥ 6 mm at T1 (n = 172), one and two RSI resulted in 33.1% and 45.9% of EoT at T2 and T3, respectively. At residual PPD 4–5 mm with BoP at T1 (n = 298), one and two RSI resulted in 66.8% and 72.1% of EoT at T2 and T3, respectively. PPD at T1 predicted EoT after RSI in both cases, while tooth type only in residual PPD 4–5 mm BoP + . At T1, mean number of surgeries per patient and associated costs were significantly higher than after one/two RSI. CONCLUSIONS: RSI may achieve EoT in residual PPD 4–5 mm BoP + and PPD ≥ 6 mm in a considerable number of cases. CLINICAL RELEVANCE: These findings may support the administration of one/two cycles of RSI prior to surgical approach. PROTOCOL REGISTRATION: ClinicalTrials.gov identification number: NCT04826926. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00784-023-05279-6.