Bone development involves the aggregation of mesenchymal stem cells into mesenchymal condensations, which is partly similar to tooth development but without the epithelial invagination. Bone has a high potential for endogenous self-repair.There are two types bone formation: intra-membranous and endochondral. In endochondral bone formation, the mesenchymal condensations first undergo chondrogenesis and then ossification to form cartilage and bone. During adulthood, bone possesses the intrinsic capacity for regeneration throughout life. In most bone injuries or fractures, the damaged bone tissue can be functionally regenerated by the local cells. However, when the fractures are serious such as large bone defects created by trauma, infection, tumour resection, and skeletal abnormalities enough that self-healing cannot repair, an adequate supply of stem cells such as bone marrow stem cells is required for efficient bone regeneration. Oral MSCs seem to be ideal candidates for bone regeneration. Due to the population ageing, human diseases with impaired bone regeneration are on the rise.
Current strategies to facilitate one healing include various biomolecules, cellular therapies, biomaterials and different combinations of these. Animal models for testing novel regenerative therapies remain the gold standard in pre-clinical phases of drug discovery and development. For usage of animal models for human bone regeneration skeletal characteristics of the selected animal species should considered seriously; a suitable animal model should be studied which basically mimics the intended clinical indication; and all the cell based approaches should be specifically studied.