The aim of the present investigation will be evaluate the healing of periodontal intraosseous defects following Minimally Invasive Non Surgical Debridement (MINSD) and application of a hyaluronic acid-based gel, compared to MINSD alone.

A total of 22 patients will be enrolled, selected by inclusion and exclusion criteria and randomly divided in two groups: hyaluronic acid group (HA) and no-hyaluronic acid group (No-HA).

The objective of the study will be compare the healing of periodontal intraosseous defects following treatment with Minimally Invasive Non Surgical Debridement (MINSD) and application of hyaluronic acid (HA) compared to MINSD alone.

Twenty-two patients with intraosseous periodontal defects will be randomly assigned to treatment with MINSD and application of a hyaluronic acid-based gel (HA Group) or MINSD alone (No-HA Group).

Primary outcome will be "Probing Depth" (PD), while the secondary outcomes will be "Clinical Attachment Level" (CAL) gain, "Gingival Recession" (GR) and "Radiographic Defect Angle" (RDA).

After local anesthesia, in HA group MINSD will be performed using an ultrasonic scaler with fine tips and micro-curette; then, a hyaluronic acid-based gel will be applied to the intraosseous periodontal pockets.

In the No-HA group, only subgingival mechanical debridement (MINSD) will be performed with an ultrasonic scaler with fine tips and micro-curette.

Finally, a polishing paste will be applied to the supra-gingival level in both groups using a rubber cup. Patients of both groups will be recalled every month for professional oral hygiene and, after 6 months, all measurements will be repeated and the final evaluation will be carried out.

Inclusion Criteria:

• Patients diagnosed with periodontitis;
• Age ≥ 18 years old;
• Presence of at least 10 teeth per arch;
• Presence of at least two teeth with Probing Depth (PD) ≥ 5 mm per quadrant;
• Presence of at least one intraosseous pocket;
• Single-rooted and multi-rooted teeth.

Exclusion Criteria:

• Patients with systemic diseases;
• Prolonged antibiotic or anti-inflammatory treatment within 4 weeks prior to periodontal therapy;
• Pregnant or lactating;
• Tobacco smokers (≥ 10 cigarettes per day);
• Multi-rooted teeth with furcation involvement;
• Third molars.

Only patients will be unaware of the type of treatment performed, with prior written informed consent. So, they will be divided in the two groups of study after a process of randomization