Bone regeneration following injury is initiated by inflammatory signals and occurs in association with infiltration by sensory nerve fibers. Together, these events are believed to coordinate angiogenesis and tissue reprogramming, but the mechanism of coupling immune signals to reinnervation and osteogenesis is unknown. Here, we found that nerve growth factor (NGF) is expressed following cranial bone injury and signals via p75 in resident mesenchymal osteogenic precursors to affect their migration into the damaged tissue. Mice lacking Ngf in myeloid cells demonstrated reduced migration of osteogenic precursors to the injury site with consequently delayed bone healing. These features were phenocopied by mice lacking p75 in Pdgfra ⁺ osteoblast precursors. Single-cell transcriptomics identified mesenchymal subpopulations with potential roles in cell migration and immune response, altered in the context of p75 deletion. Together, these results identify the role of p75 signaling pathway in coordinating skeletal cell migration during early bone repair.

Bone and cartilage regeneration is an area of tremendous interest and need in health care. Tissue engineering is a potential strategy for repairing and regenerating bone and cartilage defects. Hydrogels are among the most attractive biomaterials in bone and cartilage tissue engineering, mainly due to their moderate biocompatibility, hydrophilicity, and 3D network structure. Stimuli-responsive hydrogels have been a hot topic in recent decades. They can respond to external or internal stimulation and are used in the controlled delivery of drugs and tissue engineering. This review summarizes current progress in the use of stimuli-responsive hydrogels in bone and cartilage regeneration. The challenges, disadvantages, and future applications of stimuli-responsive hydrogels are briefly described.

The pain associated with bone fracture is mediated by somatosensory neurons, which also appear to be required to initiate bone regeneration. To characterize neuroanatomical circuitry mediating skeletal nociception and regeneration, we profiled dorsal root ganglia (DRG) neurons innervating murine bones using single-cell transcriptomics before and after fracture. CGRP ⁺ and Aβ-Field LTMR neurons were the most represented classes of bone-innervating neurons. Dynamic changes in sensory neuron response to injury reflected the phasic nature of bone repair, including expression of morphogens such as Tgfb1 , Fgf9 , and Shh . Innervation loss resulted in poor bone repair and was associated with defective mesenchymal cell proliferation and osteodifferentiation. Finally, we identified fibroblast growth factor 9 (FGF9) as a major regulator of fracture repair that could be leveraged to promote bone repair.

Aim: In this study, we aimed to describe a multimedia-supported manikin system, compare the new manikin with the traditional manikin and evaluate its effectiveness in preclinical dentistry training.Methods: A total of 150 students participated in this study. Amongst these students, 71 in the 2015-year group used traditional manikins (Group TM) for preclinical training courses (endodontics training courses and prosthodontics training courses), and 79 in the 2016-year group used manikins with a multimedia system (Group MM). The scores of the training courses between the two groups were compared. A questionnaire survey was used to collect opinions of the students in Group MM on their experience of using the multimedia-supported manikin system in the preclinical training.Results: In the endodontics training courses, the scores of Group MM were higher than those of Group TM, but there was no significant difference (P = 0.379 > .05). However, the scores of prosthodontics training courses in Group MM were significantly higher than those in Group TM (P = 0.018 < .05). The questionnaire results indicated that the students in Group MM were satisfied with the device in usability, clarity, effectiveness and improvement in operation proficiency.Conclusions: In the groups studied, for preclinical dental training, the multimedia-supported manikin system was a good alternative to traditional manikin in preclinical dentistry training.

A residual dog-ear arising from the traditional Limberg flap transposition sometimes influences the cosmetic outcomes, and the Limberg flap with a subcutaneous pedicle is an innovation applicable to a variety of facial defects and free from the dog-ear. To investigate the outcome of the subcutaneous pedicle Limberg flap for the reconstruction of medium-sized facial skin defects. From August 2002 to June 2004, the subcutaneous pedicle Limberg flap was designed to repair facial skin defects in 17 patients (19 flaps), and the size of the lesions ranged from 2.0 x 1.9 cm to 5.0 x 4.5 cm. All flaps survived with primary healing postoperatively. The patients were followed up from 1 to 22 months, and functionally and cosmetically satisfactory outcomes were achieved. This subcutaneous pedicle Limberg flap provides a competitive repair alternative for the treatment of medium-sized skin defects in the face.