Abstract
<title>Abstract</title> <p>Background/Objectives: The "Clean and Seal" protocol, combining a sodium hypochlorite (NaOCl)/amino acid solution with cross-linked hyaluronic acid (xHyA) as adjuncts to non-surgical periodontal therapy, has shown promising results in preliminary studies. However, evidence remains limited regarding its effectiveness in residual pockets exceeding the "critical probing depth" threshold. This randomized controlled trial aimed to evaluate the clinical effectiveness of scaling and root planing (SRP) alone, SRP combined with NaOCl/amino acids, and SRP combined with NaOCl/amino acids and xHyA in residual pockets with probing depth (PD) ≥ 5 mm at 3 months following Step 2 periodontal therapy. Methods: Sixty patients with 161 residual pockets (PD ≥ 5 mm) were randomly allocated to three groups: Control (SRP alone, n=20, 40 pockets), NaOCl (SRP + NaOCl/amino acid solution, n=20, 41 pockets), and NaOCl + xHyA (SRP + NaOCl/amino acids + cross-linked hyaluronic acid, n=20, 47 pockets). PD, clinical attachment level (CAL), and bleeding on probing (BOP) were recorded at baseline and 3 months. Non-parametric statistical tests were used for within- and between-group comparisons. Results: All groups showed statistically significant improvements in PD, CAL, and BOP from baseline to 3 months (p < 0.001). The NaOCl + xHyA group demonstrated significantly greater PD reduction (3.29 mm) and CAL gain (3.15 mm) compared to both the Control (2.11 mm; 2.23 mm) and NaOCl-only groups (2.54 mm; 2.54 mm) (p < 0.001). No significant differences were found between the Control and NaOCl-only groups for PD or CAL (p = 0.975), or between any groups for BOP at 3 months (p = 0.163). Conclusions: Within the limitations of this study, it can be concluded that the protocol combining NaOCl/amino acids and xHyA, provided superior clinical outcomes compared to SRP alone or SRP with NaOCl/amino acids alone in deep residual pockets.. Trial registration: ClinicalTrials.gov NCT07474272.</p>