Hyaluronic Acid and Polynucleotides for Supra-bony Defects

Inclusion Criteria: * Systemically healthy males and females ≥18 years old * Stage III or IV periodontitis (Papapanou, Sanz et al. 2018) * Presence of supra-bony periodontal defects (i.e., defects where the base of the pocket is located coronal to the alveolar crest and characterized by a predominantly horizontal pattern of tissue destruction) confirmed clinically and radiographically at a minimum of two and a maximum of four adjacent teeth and with a probing pocket depth (PPD) \> 5 mm, following non-surgical periodontal therapy (NSPT). If \>4 adjacent teeth exhibited the above clinical and radiographic conditions, the four adjacent teeth showing the greatest overall loss of periodontal attachment were included. Wisdom teeth and second molars will not be considered for the study. If defect presents with an intrabony component, this should be ≤2 mm. * Non-surgical periodontal treatment (step 1 and 2) completed within the previous 4 months * Full-mouth bleeding score (FMBS) and full-mouth plaque score (FMPS) ≤20% Exclusion Criteria: * Teeth with degree III mobility * Multi-rooted teeth with grade ≥2 furcation involvement * Heavy smokers (≥10 cigarettes a day) * Untreated caries or endodontic lesions or abscesses on the teeth involved in the surgery * Previous periodontal surgery in the area selected for the study * History of conditions requiring prophylactic antibiotic coverage prior to invasive dental procedures (e.g., mitral valve prolapse, artificial heart) * Antibiotic or anticoagulant therapy during the month preceding the baseline exam. * History of alcohol or drug abuse * Medical history that includes uncontrolled diabetes or hepatic or renal diseases, or other serious medical conditions that can have a negative impact on the periodontal condition * In treatment with medications that can severely affect bone metabolism and blood clot formation (e.g., anticoagulants, long-term corticosteroids, bisphosphonates, immunosuppressants) * Self-reported pregnancy or lactation.