This study is intended to evaluate the efficiency of graftless maxillary sinus augmentation with concentrated growth factor (CGF) utilizing "dynamic implant valve approach" (DIVA) system.

Crestal bone deficiency in the posterior maxilla may present a therapeutic challenge when dental implants are required. Sufficient bone volume is necessary for the long term survival of the implant .

The two most used surgical techniques are the crestal and the lateral window. The latter was first described by Tatum and subsequently, Boyene and James in 1980 . In the original technique, after fracturing the sinus floor, an implant was placed and submerged during the healing phase. The crestal osteotome technique is less invasive and was first described by Summers in 1994 . In this technique, a set of osteotomes is used to prepare the implant site, thereby allowing bone preservation.

Since the sinus augmentation was describes, bone grafts have been the mainstay of treatment. Variable bone grafts, such as autografts, allografts, xenografts, alloplasts, or combinations of different graft materials, have been used widely with similar results . Nonetheless, successful bone augmentation in the maxillary sinus, without bone grafting, have been reported in human and animal studies.

In 2011, Dong-Seok et al described sinus augmentation through a lateral window approach, using a fibrin rich block with concentrated growth factor (CGF). The researchers showed successful new bone formation in the sinus, with a success rate of 98% and no major complications .

Graftless Sinus augmentation relies on bioactive mediators that stimulate cell proliferation, matrix remodeling, and angiogenesis. CGF is one of the latest developments in this field, and is produced by processing blood samples with a special centrifuge device. It contains several mediators - platelet-derived growth factor (PDGF), transforming growth factor-b1 (TGF-b1) and b2 (TGF-b2), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), and insulin-like growth factor (IGF). Because CGF is a dense fibrin matrix, richer in growth factors than other preparations, it has proved to have a better regenerative capacity and versatility .

As for the application of CGF, the introduction of the "dynamic implant valve approach" (DIVA), a minimally invasive approach procedure, enables the use of a closed bone augmentation technique. The implant was designed with an internal sealing screw that might serve as drug delivery system via its channel.

In this study, a graftless maxillary sinus augmentation with CGF will be performed utilizing DIVA system, and the bone formation will be periodically measured using panoramic X-ray and cone beam computerized tomography (CBCT).

In addition, in vitro cumulative release of selected growth factors of the CGF will be analyzed. The total quantity of growth factors will be checked using ELISA kits.

Inclusion Criteria:

• No medical history of diseases involving bone metabolism
• Patients that are treated by a prostodontist
• Healthy oral cavity and sinuses, and good oral hygiene
• No bone pathology demonstrated by X-ray
• Residual sub-antral bone of at least 4mm as demonstrated by computerized tomography (CT)
• The patient does not participate in another clinical study
• The patient can read and understand the informed consent

Exclusion Criteria:

• Medical history of a disease affecting bone metabolism (Diabetes Mellitus, heart disease, renal failure, osteoporosis)
• Medical treatment that can affect bone metabolism (such as Bisphosphonates)
• Patients treated with anticoagulants (such as Coumadin, Pradaxa)
• Personal history of chemotherapy or radiotherapy
• Patients with maxillary sinus pathology
• Patients lacking a prostodontic treatment plan
• Pregnant women