Biomaterials and bone tissue engineering for the reconstruction of jawbone atrophy

Bone tissue engineering by bone grafting is a surgical procedure that replaces missing bone with material from the patient’s own body, using an artificial, synthetic, or natural substitute. Large bone defects and poor bone healing require augmentation to facilitate new bone formation. Long-term prognosis is adversely affected by inadequate bone volume; thus, an adequate three-dimensional amount of bone at the site of implant placement is essential for successful implant therapy. Bone formation after grafting is characterized by three types of bone growth: osteogenesis, osteoinduction, and osteoconduction. Osteogenesis occurs when vital osteoblasts originate from the bone graft material and contribute to new bone growth. Osteoinduction involves the stimulation of osteoprogenitor cells to differentiate into osteoblasts to begin new bone formation. Osteoconduction occurs when the bone graft material serves as a scaffold for new bone growth that is perpetuated by the native bone. Osteoblasts from the margin of the defect that are being grafted use the bone graft material as a framework to spread and generate new bone. A bone graft material is osteoconductive and osteoinductive, and will not only serve as a scaffold for currently existing osteoblasts, but will also trigger the formation of new osteoblasts, thereby, at least theoretically promoting faster integration of the graft. Numerous methods have been used in Guided Bone Regeneration (GBR). One of the most common techniques involves harvesting and implantating fresh autogenous bone grafts taken from the same patient. However, this is an expensive procedure that requires hospitalization, and has a potential risk of donor site morbidity. To avoid such complications, clinicians have developed the use of biomaterials as substitutes for alveolar bone. Other types of grafts available for the maxilla and mandible include allogeneic, alloplastic, and xenogeneic ones. Autografts are the only grafts that provide osteoinductivity; unfortunately, autografts often have unpredictable resorption, morbidity at the donor site, and limited bone availability, which has stimulated research to find new alternative, for bone tissue engineering.