The goal of this clinical trial is to learn if using sodium hypochlorite/amino acid gel, with or without cross-linked hyaluronic acid, as an addition to standard non-surgical periodontal therapy works to treat periodontitis in adults. It will also learn about the safety of these treatments. The main questions it aims to answer are:

Does the adjunctive treatment reduce bleeding on probing, plaque index, and periodontal pocket depth?

What medical or dental problems do participants have when receiving these treatments?

Researchers will compare:

Standard non-surgical periodontal therapy alone

Standard therapy plus sodium hypochlorite/amino acid gel

Standard therapy plus sodium hypochlorite/amino acid gel and cross-linked hyaluronic acid ("Clean and Seal" protocol)

Participants will:

Receive their assigned treatment during one clinical session per the study protocol

Have clinical measurements taken before treatment and at three months after treatment

Be monitored for any dental or medical adverse events related to the procedures

Detailed Description

This study is a randomized controlled clinical trial designed to evaluate the effectiveness of adjunctive therapies in the non-surgical treatment of periodontitis. The trial compares three groups:

Standard non-surgical periodontal therapy (scaling and root planing with oral hygiene instruction).

Adjunctive sodium hypochlorite/amino acid gel applied before mechanical debridement.

Adjunctive sodium hypochlorite/amino acid gel followed by cross-linked hyaluronic acid ("Clean and Seal" protocol) after mechanical debridement.

The study aims to assess whether the use of these adjunctive treatments provides additional clinical benefits beyond standard therapy, measured through periodontal parameters such as plaque index (PI), bleeding on probing (BOP), probing pocket depth (PPD), clinical attachment level (CAL), and gingival recession (GR).

Participants will be recruited from patients attending a dental clinic in Antwerp, Belgium. Randomization will be conducted at the time of enrollment using a pre-defined allocation scheme implemented in Microsoft Excel. Treatments will be performed by qualified dental professionals under standardized clinical conditions. Clinical measurements will be collected before intervention and at three months post-intervention by a calibrated examiner.

The trial is designed to provide robust clinical evidence regarding the efficacy and safety of sodium hypochlorite/amino acid gel alone and in combination with cross-linked hyaluronic acid as adjuncts to conventional non-surgical periodontal therapy. Findings may inform future clinical practice and contribute to optimizing non-surgical treatment protocols for periodontitis.

Inclusion Criteria:

• Localized periodontal pocket with a probing depth ≥ 6 mm and a clinical - attachment loss of > 3 mm (periodontitis stage III or IV; classification of the European Federation of Periodontology and American Academy of Periodontology);
• Patients who signed the written informed consent and is willing to cooperate;
• Bleeding on probing in more than 30% of the sites.

Exclusion Criteria:

• Medical history likely to affect periodontal status and/or to compromise treatment outcomes;
• Patients who received antibiotic and/or anti-inflammatory treatments the last 6 months
• Patients who received immunosuppressors treatments the last 6 months;
• Patients who received any periodontal therapy for the last 6 months;
• Pregnant or lactating women;
• Smokers smoking more than 10 cigarettes per day.

Individual participant data (IPD) from this study will not be shared due to the small sample size and the sensitive nature of patient-level clinical measurements. Sharing such data could risk participant confidentiality and privacy. Additionally, the study is investigator-initiated, and resources for secure anonymization, storage, and controlled access for external researchers are not available at this time.

Not applicable; all procedures are open-label.