Major approaches and clinical outcomes of bone regeneration for dental implants: a systematic review

Abstract
Introduction: In the last decades, the number of dental implant procedures has increased in the world, with about 1.0 million dental implants per year. When a tooth is lost in the posterior region of the maxilla, there is a natural resorption of the alveolar process. There are several surgical techniques that can be used to reconstruct the atrophic alveolar ridge. Objective: A systematic review was carried out to present the key considerations of bone regeneration and bone, cellular and molecular grafts for adequate bone formation for successful dental implants. Methods: The present study followed a systematic review model, following the rules of systematic review – PRISMA. The search strategy was performed in the PubMed, Cochrane Library, Web of Science and Scopus, and Google Scholar databases. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: The total of 132 articles were found. A total of 74 articles were fully evaluated and 31 were included in this study. Normal bone formation and tissue repair involve coordinated interaction between bone-forming cells and biological signals. TNF-α stimulates bone and cartilage resorption and inhibits collagen and proteoglycan synthesis. IL-1 induces the expression of a wide variety of cytokines. LIF and IL-6 are two such molecules that are known to stimulate the differentiation of mesenchymal progenitor cells into the osteoblastic lineage. The bioactivation of the dental implant surface with FRP has been described and discussed by the scientific community as a surface treatment for the stimulation and acceleration of the osseointegration process, as well as to achieve greater primary stability to the implant. The combination of FRP and Bio-Oss® has been studied with good clinical results, reducing healing time from 180 days to approximately 106 days. The use of bone grafts significantly improves the residual alveolar ridge regardless of the membrane used. Furthermore, implants placed in fresh extraction sockets with and without elevation of the mucoperiosteal flap can be successfully performed with augmentation procedures.