This is a controlled, randomized, single-blinded, multicenter, prospective clinical study.

In addition to the standard periodontal treatment procedure on all teeth that need to be treated, the 4 teeth with the deepest pockets (between 4 and 6 mm) will be randomized to either PERIOSYAL® FILL and oral hygiene or oral hygiene alone.

The pocket depth will be measured at six sites around each tooth, and only the deepest pocket sites of each tooth will be taken into account.

This is a controlled, randomized, single-blinded (independent Blinded Evaluator), multicenter, prospective clinical study.

Each subject will receive the standard periodontal treatment procedure on all teeth that need to be treated. The usual cares are scaling and root planing (SRP), and chlorhexidine, and instructions to oral hygiene (proper brushing techniques twice a day, proper flossing technique daily, and prevention : sugar intake, alcohol consumption, fluoride level).

Two other optional treatment sessions with SRP could be performed, if deemed necessary by the Treating Investigator. Those optional SRP session could only be performed after all study-related clinical assessement.

The pocket depth of every teeth will be measured at six sites around each tooth, and only the deepest pocket sites will be taken into account. The 4 teeth with the deepest pockets will be included in the study and randomized to either PERIOSYAL® FILL and oral hygiene or oral hygiene alone.

Inclusion Criteria:

• Men or women, aged between 25 and 60 years
• Patients with at least 20 natural teeth
• Patient with periodontitis confirmed by a X-ray diagnosis, and having at least 4 teeth with periodontal pockets with probing depth between 4 and 6 mm
• Willing to understand and comply with study requirements and to sign informed consent

Exclusion Criteria:

• Patient with an active smoking status
• Patient with an antibiotic therapy within the previous 4 weeks
• Need for continuous medical treatment within 2 weeks prior to enrollment
• Ongoing inflammatory state or a systemic illness that may affect the oral cavity
• Patient with hypofunction in saliva productions (e.g. Sjögren Syndrome with Xerostomia)
• History of active chronic debiliating systemic disease, including insulin or non-insulin dependent diabetes
• Patients with bleeding disorders
• History of allergies to gram positive bacterial proteins
• History of hypersensitivity and/or idiosyncrasies to any of the test compounds, e.g. hyaluronic acid or other device compounds
• History of multiple severe allergies, history of anaphylactic shock
• History of connective tissue disease (rheumatoid arthritis, scleroderma, systemic lupus erythematosus) or of any other autoimmunity disease
• History of herpetic lesion or lichen planus
• Pregnant or breast feeding women, or female subjects of childbearing potential who did not intend to practice medically acceptable method of contraception
• Participation in another clinical study in the previous 3 months