Polynucleotide + Hyaluronic Acid Gel With Xenogeneic Graft for Intrabony Periodontal Defects

This controlled, randomized, parallel-group clinical study aims to compare open-flap debridement alone with its association with xenogeneic bone graft or xenogeneic bone graft plus gel containing polynucleotides (PN) and hyaluronic acid (HA) in the surgical treatment of intrabony defects in patients with periodontitis (stages III or IV, grades B or C), based on clinical, immunologic, radiographic/tomographic parameters and patient-centered outcomes. The sample size was calculated using the primary variable clinical attachment level (CAL), considering a mean difference of 1 mm between the experimental groups as the minimum value and a standard deviation of 0.91. Considering β = 80% and α = 5%, the required sample size was 18 patients for each experimental group, with each patient contributing a single defect. Considering a dropout of 20%, the number was increased to 22 patients per experimental group, making a total of 66 patients. Patients who meet the inclusion criteria will be randomly assigned to one of three experimental groups (n=22) in a 1:1 allocation ratio: Group C (Control), including intrabony defects treated with open flap debridement alone; Group XENO, including open flap debridement associated with xenogeneic bone grafting; and Group R-XENO, including open flap debridement associated with xenogeneic bone grafting and a PN/HA-containing gel. Randomization will be performed using software, which will identify each participant by a numerical code. Group allocation will be carried out on the day of surgery by the study coordinator. Surgical treatment: After local anesthesia using an infiltration or nerve block technique with a sterile injectable solution of 2% mepivacaine hydrochloride (20 mg/mL) and 1:100,000 epinephrine (10 µg/mL), intrasulcular incisions will be made on the buccal and lingual/palatal aspects using a 15C surgical blade (Stainless Steel Surgical Blades, Swann-Morton®, Sheffield, England), extending one tooth mesially and one tooth distally to the tooth associated with the defect. A full-thickness flap will be carefully elevated on the buccal and lingual/palatal sides to expose 2 to 3 mm of the alveolar crest. Meticulous debridement of the defect will be performed, along with the removal of subgingival biofilm and calculus using ultrasonic combined with manual instruments, followed by irrigation with sterile saline solution. The defects will be filled as follows: with blood clot only in the group C; with xenogeneic bone graft (Geistlich Bio-Oss®, Geistlich Pharma AG, Wolhusen, Switzerland) in the XENO group; and with xenogeneic bone graft (Geistlich Bio-Oss®) plus PN/HA-containing gel (REGENFAST®, Geistlich Pharma AG, Wolhusen, Switzerland) in the R-XENO group. Primary soft tissue closure was achieved by interrupted mattress suture technique with non-resorbable monofilament polyamide 5-0 sutures (Soft Blue®, Techsuture, Bauru, SP, Brazil). Outcome assessment will be conducted at predefined time points. The primary outcome is clinical attachment level (CAL). Secondary outcomes include probing depth (PD); radiographic and tomographic measures of bone fill and defect resolution; quantitative analysis of biomarkers related to tissue neoformation (PDGF-BB, VEGF, BMP-2); early wound healing assessed by standardized indices; and patient-reported outcomes, including pain perception and oral health-related quality of life.