The aim of the present study is to clinically and radiographically compare the efficacy of recombinant human platelet-derived growth factor (rhPDGF), Leukocyte-Platelet Rich Fibrin (L-PRF) and Enamel Matrix Derivatives (EMD) in intrabony defects following minimally invasive non surgical peridoontal therapy (MINST).

This study will be designed as a randomized clinical trial of 12-month duration. A total of 88 patients (each with a single infrabony defect) will be recruited and randomly equally distributed into 4 groups: an experimental group treated with MINST and rhPDGF, a second group treated with MINST + L-PRF, a third group treated with MINST and EMD and and a control group treated with MINST alone.

Each defect will be treated with an ultrasonic scaler with dedicated thin tips for supra- and subgingival debridement associated with hand instrumentation under local anesthesia. Caution will be taken to preserve the stability of soft tissues. Following MINST experimental and control sites will be randomly chosen. The test sites will be treated by inserting a collagen plug soaked for at least 15 minutes in a 1.5cc solution containing hPDGF-BB. In the second group the infrabony defects will be treated with MINST and L-PRF. In the third group the infrabony defects will be treated with MINST and EMD. The control group will be treated with MINST alone.

Pre- and post-treatment clinical measurements were performed by an examiner blinded to the treatment modalities using a graded periodontal probe (HuFriedy UNC 15). Before the treatment and at 6 and 12 months post-treatment, all patients were examined by measuring the clinical attachment level, probing depth, gingival recession, full-mouth plaque score and bleeding on probing.

Standardized radiographs of selected study sites will be taken at baseline and at the 6 and 12 months follow-up visits using the long-cone technique with a customized holder and a thermoplastic occlusal reference to allow reproducible positioning. All radiographs will be analysed by a dedicated dental software (Carestream Dental LLC Atlanta, GA, USA) to make linear measurements. The defect bone level (DBL), the defect angle (DA), the intra- and suprabony components of the defect and the radiographic defect area (RDA) will be evaluated.

Inclusion Criteria:

• Patients with a diagnosis of periodontitis stage III or IV (grades A to C),
• non-smokers or former smokers who quit at least 1 year ago, and
• had not received any periodontal treatment in the 3 months prior to recruitment;
• Presence of at least 1 Infrabony defect (PPD ≥ 5 mm with infrabony defect depth of ≥3mm at screening radiograph);
• One and two wall infrabony defects at screening radiograph and periodontal charting.
• Signed informed consent.

Exclusion Criteria:

• Presence of uncontrolled systemic diseases that could affect treatment outcomes such as diabetes mellitus with an HbA1C>7%, rheumatoid arthritis or any form of immunosuppression;
• Subjects requiring antibiotic prophylaxis;
• 3-wall infrabony defects;
• Patients that had received systemic or local delivery of antibiotic therapy 6 weeks before enrollment;
• Presence of furcation defect;
• Chronic intake of NSAIDs or steroids, currently;
• Patients undergoing orthodontic treatment, having removable prosthetic appliances, pregnancy, tumors of the oral cavity or the presence of any psychiatric condition that could affect participation.