No abstract

A critical size bone defect may arise due to severe trauma or tumors where a large portion of the bone is removed. In some instances, autografts cannot be used for filling such large defects. Allografts may be used to reconstruct large bone defects, but these grafts may not incorporate in the healing response. Consequently, it is still a challenge for reconstructive surgery to reconstruct large bone defects. A variety of treatment strategies have been progressed to promote the healing response and close the bone defects. Micro and nano particles (MNPs) technology is a newer option than traditional grafts, which may defeat many limitations of the bone graft usage. However, there are still no well approved treatment strategies to override all the expected requirements. Due to the existence of variety strategies for treatment of critical size bone defects, this impartial review, highlights on the techniques and strategies that have been accomplished to anatomize the complicated treatment problems of large bone defect healing, the limitations of therapeutic relevant biodegradable materials, and service the regeneration of large bone defects.

Objective: The purpose of this review article is to illustrate the current state of development of bone graft substitutes that could be used for bone defect regeneration, as well as to analyze their efficacy for clinical use. Methods: An electronic search of the PubMed, was performed for articles written in English. The focused question was "ideal graft substitute material to choose in clinical practice"?. The searches were limited to articles including: bone graft, bone defect scaffold, bone substitutes, and bone regeneration. An attempt was made to identify clinical studies. During the data collection, the data were extracted from the studies including scaffold material, properties and advantages of bone substitutes, as well as clinical results if the study has been provided clinically. Results: In spite of several acceptable scaffold options available for bone regeneration, these options still need to bridge the gap between research and clinical practice. There is little information available about the cellular basis for bone regeneration in humans. Several problems limit the broad usage of such options, including lack of randomized controlled human studies, and dubious long term results. Conclusion:The studies should be nurtured and monitored by a combination of clinical experience. Future trends may focus on the effective combinations of osteoinductive materials, osteoinductive growth factors and cell-based tissue regeneration tactics using composite carriers. There is no single ideal graft material to choose in clinical practice, therefore researches are ongoing in all relevant fields, to establish modern bone regeneration protocols that may lead to the innovation of ideal graft substitutes.