Polynucleotides and Hyaluronic Acid (PN-HA) mixture showed several effects in modulation of healing process. The aim of this study was to assess the safety and clinical performance of PN-HA alone or in association with Deproteinized Bovine Bone Mineral (DBBM) with papillary preservation flaps (PPF) in the treatment of residual pockets. A total of 43 patients with 55 infra-bony defects were recruited; 30% were smokers. The mean baseline Probing Depth (PD) was 7.7 ±1.9 mm with a corresponding mean recession (Rec) of 1.9± 1.3 mm. The depth of infra-bony defect at the surgical measurement was 5.2±2.1 mm. DBBM was applied at 56% of the defects considered as not-containing based on clinical judgment. Healing was uneventful at all sites. After one year, PD reduction was 4.4±1.8 mm with a Rec increase of 1.0 ±0.8 mm. Detected bone fill at x-ray was 3.5 ± 1.9mm. The multilevel analysis showed that absence of smoking habits was associated with improved PD reduction (P =0.026) and bone gain (P= 0.039). PN-HA mixture is a safe product for periodontal surgery and seems to promote clinical benefit in the treatment of residual pockets associated to infra-bony defects.