Platelet-rich Fibrin and Autogenous Bone vs Membrane and Autogenous Bone in Intrabony Defects

This is a prospective, randomized and controlled clinical trial designed to evaluate the clinical and radiographic outcomes 12 months after two treatment modalities of IBDs: PRF + ABG into defects in the test subjects( TS); membrane + ABG in the control subjects ( CS). The patients enrolled exhibit unfavourable IBDs and all experimental sites will be accessed with a simplified papilla preservation flap ( SPPF) procedure. The filling material (ABG) is common to both treatments: therefore, the investigation will focus on the addictive effect of PRF used in place of MEMBRANE. MEMBRANE is chosen as the active control ( AC) as it is currently considered as the biological "gold standard" agent for the treatment of IBDs.

A non-inferiority trial ( NIT) is designed to prove that using PRF instead of MEMBRANE could achieve a similar result, reducing the treatment's cost and allowing the clinicians to use autogenous material only.

An AC (comparator) is present, but the investigators do not include a third experimental arm, a group of IBDs treated using Open Flap Debridement ( OFD) alone, as it is widely accepted in NITs.

The estimate of the AC effect vs. placebo is assumed from a recent meta-analysis, by the Lower Bound of a 95% Confidence Interval ( CI) of the mean of MEMBRANE + ABG, while an OFD estimate from the corresponding 95%.. The difference between estimates is set as the added benefit of the AC and as a ground for the assay sensitivity.

44 patients affected by moderate-to-severe chronic periodontitis, will be selected for the study. Each patient will participate in the study with a single experimental site. The participants will receive verbal and written information and they will sign a consent form approved by the Ethical Committee of the G. DAnnunzio University of Chieti - medical faculty. The study protocol is in accordance with the Declaration of Helsinki of 1975, revised in Tokyo in 2004. Four months before the surgical treatment, all 44 patients will undergo SRP by ultrasonic instruments and hand curettes and motivational instructions on oral home care.

Non-inferiority margin. A reliable estimate of the expected clinical attachment level ( CAL) gain from an MEMBRANE+ ABG treatment is drawn from a recent meta-analysis, reporting on 548 IBDs in 434 patients.

By literature, CAL gain obtainable by OFD surgical treatments alone is 2.47 mm. The differential effect of using MEMBRANE amounts about 1 .

Each defect will be assigned a defect number and will be randomly allocated to one of the two treatment regimens. Assignment will be performed by a custom made computer-generated table. To conceal allocation, opaque envelopes will be assigned to the specific experimental site and will be opened during surgery Preoperative and 3- 6- 12-months postoperative intraoral standardized radiographs will be taken by the paralleling technique using an individual film-holder device consisting of a bite block rigidly connected to an acrylic dental splint to achieve identical film placement at each evaluation. Pre- and postoperative radiographs will be evaluated by two experienced clinicians who will be masked with respect to the provenience of the radiographs and the clinical measurements. The positions of alveolar crest level and of the bottom of the defect distance and will be marked by a pencil on the radiographs and bottom of the defect will be measured by a millimeter grid. Linear distances between the most coronal interproximal alveolar crest level and the bottom of the defect will be obtained by counting the walls