Among the biomaterials used, synthetic calcium phosphate ceramics are particularly valuable for bone tissue engineering because they are similar in composition to bone mineral. These ceramics are widely used to repair bone defects in orthopedic, spinal, maxillofacial or dental surgery. Synthetic bone substitutes, in addition to being safe in terms of pathogen transmission, demonstrate bioactivity and osteoconductive properties. These materials are most often made of hydroxyapatite (HA: Ca10(PO4)6(OH)2), tricalcium phosphate beta (β-TCP: Ca3(PO4)2) or consist of mixtures of the two phases (biphasic calcium phosphate, BCP) in variable proportions. The micro and macro-porous properties of BCP permit invasion of biological fluids, cells and tissues.

In 1974, Friedenstein showed that bone marrow (BM) contains osteogenic precursor cells, i.e. mesenchymal stem cells (MSC). These cells (1 / 100,000 nucleated cells in adults) were isolated from BM by their capacity to adhere to treated culture plastic. Mesenchymal stem cells have the ability to renew themselves and are multipotent, capable of developing into a variety of cell types depending on the culture medium in which they are cultured. Many studies have shown that if these cells are seeded and/or cultivated on calcium phosphate ceramic matrices, they can induce bone formation in vivo and regenerate critical size defects.

The purpose of this clinical study therefore is to assess the results of bone regeneration in an edentulus area by using culture expanded autologous mesenchymal stem cells associated with synthetic biphasic calcium phosphate bone substitutes. This randomized controlled trial involving 150 patients should demonstrate equivalent or superior outcomes in terms of bone regeneration.  In the long term, this bone tissue engineering approach should replace autologous bone grafts with a simpler and less invasive technique.