The application of virtual reality has become increasingly extensive as this technology has developed. In dental education, virtual reality is mainly used to assist or replace traditional methods of teaching clinical skills in preclinical training for several subjects, such as endodontics, prosthodontics, periodontics, implantology, and dental surgery. The application of dental simulators in teaching can make up for the deficiency of traditional teaching methods and reduce the teaching burden, improving convenience for both teachers and students. However, because of the technology limitations of virtual reality and force feedback, dental simulators still have many hardware and software disadvantages that have prevented them from being an alternative to traditional dental simulators as a primary skill training method. In the future, when combined with big data, cloud computing, 5G, and deep learning technology, dental simulators will be able to give students individualized learning assistance, and their functions will be more diverse and suitable for preclinical training. The purpose of this review is to provide an overview of current dental simulators on related technologies, advantages and disadvantages, methods of evaluating effectiveness, and future directions for development.

Histone arginine methylation, which is catalyzed by protein arginine methyltransferases (PRMTs), plays a key regulatory role in various biological processes. Several PRMTs are involved in skeletal development; however, their role in the osteogenic differentiation of mesenchymal stem cells (MSCs) is not completely clear. In this study, we aimed to elucidate the function of PRMT3, a type-I PRMT that catalyzes the formation of ω-mono- or asymmetric dimethyl arginine, in MSCs osteogenesis. We found that PRMT3 promoted MSCs osteogenic commitment and bone remodeling. PRMT3 activated the expression of miR-3648 by enhancing histone H4 arginine 3 asymmetric dimethylation (H4R3me2a) levels at promoter region of the gene. Overexpression of miR-3648 rescued impaired osteogenesis in PRMT3-deficient cells. Moreover, administration of Prmt3 shRNA or a chemical inhibitor of PRMT3 (SGC707) caused an osteopenia phenotype in mice. These results indicate that PRMT3 is a potential therapeutic target for the treatment of bone regeneration and osteopenia disorders.

Tissue inflammation is an important problem in the field of human adipose-derived stem cell (ASC)-based therapeutic bone regeneration. Many studies indicate that inflammatory cytokines are disadvantageous for osteogenic differentiation and bone formation. Therefore, overcoming inflammation would be greatly beneficial in promoting ASC-mediated bone regeneration. The present study aims to investigate the potential anti-inflammatory role of Prostaglandin G/H synthase 1 (PTGS1) during the osteogenic differentiation of ASCs. We performed TNFα treatment to investigate the response of PTGS1 to inflammation. Loss- and gain-of-function experiments were applied to investigate the function of PTGS1 in the osteogenic differentiation of ASCs ex vivo and in vivo. Western blot and confocal analyses were used to determine the molecular mechanism of PTGS1-regulated osteogenic differentiation. Our work demonstrates that PTGS1 expression is significantly increased upon inflammatory cytokine treatment. Both ex vivo and in vivo studies indicate that PTGS1 is required for the osteogenic differentiation of ASCs. Mechanistically, we show that PTGS1 regulates osteogenesis of ASCs via modulating the NF-κB signaling pathway. Collectively, this work confirms that the PTGS1-NF-κB signaling pathway is a novel molecular target for ASC-mediated regenerative medicine.

Background: Virtual reality (VR) dental simulators are currently used in preclinical skills training. However, with the development of extended reality technologies, the use of mixed reality (MR) has shown significant advantages over VR. Objective: This study aimed to describe the research and development of a newly developed MR and haptic–based dental simulator for tooth preparation and to conduct a preliminary evaluation of its face validity. Methods: A prototype of the MR dental simulator for tooth preparation was developed by integrating a head-mounted display (HMD), special force feedback handles, a foot pedal, computer hardware, and software program. We recruited 34 participants and divided them into the Novice group (n=17) and Skilled group (n=17) based on their clinical experience. All participants prepared a maxillary right central incisor for an all-ceramic crown in the dental simulator, completed a questionnaire afterward about their simulation experience, and evaluated hardware and software aspects of the dental simulator. Results: Of the participants, 74% (25/34) were satisfied with the overall experience of using the Unidental MR Simulator. Approximately 90% (31/34, 91%) agreed that it could stimulate their interest in learning, and 82% (28/34) were willing to use it for skills training in the future. Differences between the 2 study groups in their experience with the HMD (resolution: P=.95; wearing comfort: P=.10), dental instruments (P=.95), force feedback of the tooth (P=.08), simulation of the tooth preparation process (P=.79), overall experience with the simulation (P=.47), and attitude toward the simulator (improves skills: P=.47; suitable for learning: P=.36; willing to use: P=.89; inspiring for learning: P=.63) were not significant. The Novice group was more satisfied with the simulator’s ease of use (P=.04). There were significant positive correlations between the overall experience with the simulation and the HMD’s resolution (P=.03) and simulation of the preparation process (P=.001). Conclusions: The newly developed Unidental MR Simulator for tooth preparation has good face validity. It can achieve a higher degree of resemblance to the real clinical treatment environment by improving the positional adjustment of the simulated patients, for a better training experience in dental skills.

Mesenchymal stem cells (MSCs) are a reliable resource for bone regeneration and tissue engineering, but the molecular mechanisms of differentiation remain unclear. The tumor antigen 15-leucine-rich repeat containing membrane protein (LRRC15) is a transmembrane protein demonstrated to play important roles in cancer. However, little is known about its role in osteogenesis. This study was to evaluate the functions of LRRC15 in osteogenic differentiation of MSCs. Osteogenic-induction treatment and the ovariectomized (OVX) model were performed to investigate the potential relationship between LRRC15 and MSC osteogenesis. A loss-of-function study was used to explore the functions of LRRC15 in osteogenic differentiation of MSCs in vitro and in vivo. NF-κB pathway inhibitor BAY117082, siRNA, nucleocytoplasmic separation, and ChIP assays were performed to clarify the molecular mechanism of LRRC15 in bone regulation. Our results first demonstrated that LRRC15 expression was upregulated upon osteogenic induction, and the level of LRRC15 was significantly decreased in OVX mice. Both in-vitro and in-vivo experiments detected that LRRC15 was required for osteogenesis of MSCs. Mechanistically, LRRC15 inhibited transcription factor NF-κB signaling by affecting the subcellular localization of p65. Further studies indicated that LRRC15 regulated osteogenic differentiation in a p65-dependent manner. Taken together, our findings reveal that LRRC15 is an essential regulator for osteogenesis of MSCs through modulating p65 cytoplasmic/nuclear translocation, and give a novel hint for MSC-mediated bone regeneration.

Background: Bone defects are a common clinical condition that has gained an increasing amount of attention in recent years. Causes of bone defect include tumors, inflammation, and fractures. Bone tissue engineering is a novel treatment of bone defect, and human mesenchymal stem cells (hMSCs) are the ideal seed cells for bone tissue engineering due to their multi-lineage differentiation potential and immunogenicity. The laminin α2 (LAMA2) gene encodes the α2 subunit of laminins. Mutations in this gene have been reported to cause muscular dystrophy, but thus far no studies have elucidated the role of LAMA2 in the fate choices of MSCs. Here, we aimed to investigate the critical role of LAMA2 in the osteogenesis and adipogenesis of mesenchymal stem cells (MSCs).Methods: We investigated LAMA2 function in osteogenic and adipogenic differentiation of MSCs in vitro and in vivo through loss- and gain-of-function experiments. In addition, molecular mechanism was clarified by Western blot and siRNA.Results: Our results demonstrated that LAMA2 was a critical regulator for fate commitment of MSCs. Both in vitro and in vivo studies indicate that LAMA2 inhibits osteogenesis and promotes adipogenesis.Mechanistically, we found that LAMA2 regulated osteogenesis and adipogenesis of MSCs by modulating the hedgehog signaling pathway.Conclusions: The present work confirms that LAMA2 is a new molecular target for MSC-based bone regeneration.