“…Extensive studies have been carried out into how to maintain the residual alveolar ridge by decreasing alveolar bone resorption or accelerating new bone formation. Although some methods [8][9][10]15,18,25,27,28,30,34,37,38 , such as allografts, autografts, osteoinduction by cytokines or growth factors, osteopromotion by the guided bone regeneration technique and immediate dental implants, can promote bone formation, secondary lesions, immunologic rejection and poor long-term results of these treatments limit their clinical applications.…”