Hyaluronic Acid and Octenidine Gel as an Adjunct to Non-surgical Periodontal Treatment

Inclusion Criteria: * Male or female aged 18 and above * Engaged patients presenting with a Full Mouth Plaque Score (FMPS) of ≤ 20% within the 6 weeks prior to enrolment, or exhibiting a ≥ 50% reduction in plaque score from the initial screening visit. * Periodontitis stage III/IV (grades A to C) with at least one site per quadrant with PPD ≥5mm, bleeding on probing and attachment loss ≥5mm * Willing to sign informed consent and comply with study procedures Exclusion Criteria: * Know hypersensitivity and/or allergy to any of the product's component (as per user leaflet) * Self-reported pregnancy or lactation * Smoking (current or in past 5 years), including e-cigarettes/vaping * Medical history including diabetes mellitus or other serious medical/ psychiatric conditions or transmittable diseases that according to the investigator may increase the risk associated with study participation * History of conditions requiring prophylactic antibiotic coverage prior to invasive dental procedures or/and systemic antibiotic therapy during the 3 months preceding the baseline evaluation * In chronic treatment with anti-inflammatory (including corticosteroids), anticoagulants/antiplatelets (including aspirin), immunosuppressants or other medication that can severely impact wound healing * History of alcohol or drug abuse * Subgingival professional mechanical plaque removal (excluding not-extensive subgingival debridement as judged by the examining clinician) and/or surgical periodontal treatment within the last 12 months * Other severe acute or chronic medical or psychiatric condition or psychological disorder, including limited mental capacity or language skills such that study information could not be understood, informed consent could not be obtained, or simple instructions could not be followed, or any additional conditions which, in the judgement of the investigator, would make the subject inappropriate for entry into this trial