Periodontitis is a complex multifactorial inflammatory disorder of periodontium, which occurs due to accumulations of microorganism that lead to gradual damage of periodontal tissues resulting in the creation of periodontal defects and recession of gingiva. This leads to the initiation of bone resorption forming bone defect known as periodontal pocket (PP). PP could be treated by surgical and non-surgical procedures. Non-surgical treatment or initial periodontal treatment (IPT) aims to remove irritant factors of periodontal disease. Surgical procedure has to be applied if inflammation persists after non-surgical procedures. One of the most common surgical procedures used for treatment of PP is an open flap debridement (OFD) which aims to remove infection and inflamed tissue, and to establish the appropriate biological situations essential for periodontal regeneration. However, the regeneration of tissues damaged by periodontitis could not be accomplished by OFD alone. Some autologous products that can be used in regenerative periodontal treatment include: ABG, autologous soft tissue graft and autologous platelet concentrates (APC).

ABGs consist of live osteoblasts, osteoprogenitor stem cells and all the three components for tissue engineering, i.e, scaffold, cells, and signaling molecules. Among the several available regeneration substances, only ABG involves osteoconductive, osteoinductive, and osteogenic properties. Due to their favorable characteristics, ABGs have been regarded as the "gold standard", and the most successful material that can be used in periodontal regeneration surgery. Despite being quite effective, ABGs have some drawbacks, including limited donor locations, insufficient bone amount, another site surgery, the possibility of some unexpected bone resorption and donor site morbidity, which includes pain, infection, sensory loss, and bleeding. Because of these shortcomings, the use of other autologous products such as autologous platelet concentrates (APC ; PRF, CGF) has become needed.

PRF is a second-generation autologous platelet concentrate as it is a natural concentrate prepared directly by taking blood from the patient without adding any anticoagulant. PRFs were firstly introduced in 2001 with the aim of simplifying the platelet-rich plasma (PRP) preparation protocol and overcoming its drawbacks. It is inexpensive, time saving, and it does not require chemical alteration in collected blood. Literature showed that the PRF membrane could stay intact and release continuously large quantities of growth factors slowly for at least 1 week, due to its fiber network scaffold. PRF shows effective outcomes in the surgical management of periodontal intra-bony and furcation defects which lead to noticeable improvement of PD and CAL. Some other dental applications are socket preservation after extraction, root covering procedure, third-molar surgery, alveolar ridge preservation, guided tissue regeneration and sinus elevation. Furthermore, PRF has the ability to enhance osseointegration of implants and can be used with grafting materials as natural resorbable membrane as an alternative to collagen membrane in managing periodontal and peri-implant defects. Nevertheless, the PRF membrane has fast biodegradability (up to 14 days). However, PRF has some limitation, as it required to be used as quickly as possible after preparation. Recently, researchers developed new products of the PRF that aim to improve the properties of PRF and obtain a better autogenous biological material by changing the centrifuge time and speed (Injectable-PRF, Advanced-PRF and CGF).

CGF is an advanced second-generation platelet concentrate, which consists of diverse growth factors that stimulate and accelerate bone formation and soft and hard tissue healing. CGF can also improve the quality of the produced new bone. CGF was firstly introduced by Sacco in 2006 as a recent improved formulation of PRF which contains high amount of growth factors and can be used successfully in regenerative treatments. It has a different preparation protocol by alternating and controlling centrifugation speeds manually or by using a special centrifuge machine, which permits the formation of a considerably larger and firmer fibrin matrix which is more abundant in growth factors compared to those observed in PRP and classic PRF. He et al26 reported that the three-dimensional fiber network scaffold of CGF could help in releasing growth factors gradually for a period between 7-10 days.

So, according to recent findings in the literature, the hypothesis of this study was that the treatment of periodontal intrabony defects by using OFD in combination with autologous products (PRF, CGF and ABG) would lead to effective outcomes compared to OFD alone. Therefore the aim of this randomized controlled clinical study was to evaluate the effects of different autologous products (PRF, CGF and ABG) on the treatment of periodontitis patients who have intrabony pockets and to compare between their efficiency clinically and radiographically.