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Osteoporosis (OP) is an age-related disease of bone metabolism, characterized by bone mass loss and bone microarchitecture deterioration, the poor osteogenesis microenvironment of OP caused hardly repairing of the bone defects. As a dynamic process to fuel cellular renovation, autophagy has been proved to play a vital role in regulating cell differentiation and maintaining bone homeostasis. Traditional bone repairing biomaterials are hardly repairing the bone defects under OP pathological microenvironment. Therefore, it is essential to development novel biomaterials to improve osteoporotic osteogenesis. Compared to biochemical cues, biophysical cues exhibited more advantages in biocompatible and side effects. Herein, inspired by the importance of enhanced autophagic response in osteoporotic environment, we intend to utilize the micro-/nano-structured hydroxyapatite (mnHA) bioceramics as the mimic structure of natural bone tissue to regulate autophagic activity in ovariectomy bone mesenchymal stem cells (OVX-BMSCs), finally promote to bone regeneration in OP condition. The results indicated that mnHA bioceramics promoted cell adhesion and osteogenesis of OVX-BMSCs, and enhanced autophagy level in OVX-BMSCs. In the calvarial defects of OVX-rats, the mnHA scaffold acquired excellent bone repair effect. According to the current findings, regulating the level of autophagy could be a promising strategy for improve osteoporotic osteogenesis in the future.

Tooth defect and loss are common clinical diseases in stomatology. With the extension of life expectancy, there is an increasing demand for tooth tissue and whole tooth regeneration. Compared with traditional oral prosthetic treatment, tooth regeneration has unique advantages and has become one of the hotspots towards oral biomedical treatment. In this review, we discussed the development and challenges of tooth regeneration based on cells and materials, including tooth enamel, dentin, dental pulp, cementum, dentin-pulp complex, and the whole tooth regeneration, in order to provide a comprehensive, up-to-date, illustrative overview of tooth regeneration issues. The mechanisms of the regeneration were also summarized and discussed. Moreover, this review hints the future perspective and research direction of tooth regeneration in the challenging field of regenerative dentistry.