The purpose of this clinical study is to evaluate the safety and efficacy of treating periodontal disease with the STERIFY GEL medical device in combination with SRP procedure, in terms of periodontal pocket healing. Efficacy will be compared with the use of the nonsurgical SRP technique alone, which is considered a gold standard treatment for periodontitis, with the aim of observing improved results when using the STERIFY GEL device.

The study is prospective, split-mouth.STERIFY GEL will be administered into the periodontal pockets of one or two segments of patients undergoing whole-mouth extended SRP, with the contralateral segments serving as controls (split-mouth), in a single session.

The purpose of the study is to test the safety and efficacy of STERIFY GEL in promoting healing of periodontal pockets following SRP, compared with treatment with SRP alone. With specific visco-elastic and mucoadhesive properties, STERIFY GEL easily penetrates into the deepest and hard-to-reach areas of periodontal and peri-implant pockets, adhering to the gingival tissue and alveolar bone, providing complete coverage of the pockets. The effect of STERIFY GEL is promoted by a physical mechanism of action. After SRP, the gel is applied into the gingival pocket, where it acts primarily as a filler to restore volume, physically preventing bacteria from entering and reinfecting the pocket. STERIFY GEL can thus mechanically protect treated pockets and bone defects, promoting tissue healing. The occluding action at the level of periodontal and peri-implant gingival pockets, in synergy with the accessory action of hydroxytyrosol, nisin, and magnesium ascorbyl phosphate, prevents bacterial recolonization and promotes subsequent tissue regeneration.

Although SRP surgery is considered a gold standard treatment for periodontitis, it may in some cases be insufficient to decontaminate the pocket allowing bacteria to recolonize the tissues promoting new inflammation that can worsen the clinical picture.STERIFY GEL may find useful application in cases of moderate to severe chronic periodontal disease as an adjunctive treatment following SRP to improve and accelerate healing parameters and prevent recurrent inflammation and infection.In addition, antimicrobial control action prevents antibiotic use and the risk associated with antibiotic resistance.Such control of periodontal disease also allows for the maintenance of patients who cannot undergo surgical treatment (e.g., patients on bisphosphonate therapy, defected etc.).

Inclusion Criteria:

• Patients with grade III and IV chronic periodontal disease according to the European Federation of Periodontology classification involving at least two sites
• Adherence to the study and signing of informed consent
• Major age- Participants with a minimum of 6 teeth with periodontal pocket depth greater than 5mm- Participants with at least 20 teeth

Exclusion Criteria:

• Established hypersensitivity to one or more components of the device- Pregnancy or lactation- Heavy smoker (more than 9 cigarettes per day)- Concomitant dental disease, except periodontitis, or planned treatment that may interfere with the study or study procedure, such as dental surgery or tooth implantation- Diabetes mellitus, rheumatoid arthritis, or other chronic diseases that may affect disease or treatment
• Aggressive periodontitis
• History of radiation or chemotherapy
• Autoimmune mucosal diseases
• Mental illnesses
• Parafunctions such as bruxism
• Use of antibiotics in the past 3 months
• Periodontal surgeries in the past 12 months in the areas covered by the study