Reimplantation is one of the treatments after removing failed dental implants.In recent years,lower survival rates have been observed in reimplanted implants compared to initial implantations,possibly due to patient factors and site-specific conditions of the failed site.Therefore,in addition to considering the timing of implantation,techniques for soft and hard tissue regeneration,and implant selection,it is important to evaluate the timing and reasons for previous failures as well as the removal methods when perform-ing reimplantation.This review aims to summarize the risk factors affecting the survival rate and discuss treatment strategies for impro-ving outcomes of reimplantation.

Reimplantation is one of the treatments after removing failed dental implants.In recent years,lower survival rates have been observed in reimplanted implants compared to initial implantations,possibly due to patient factors and site-specific conditions of the failed site.Therefore,in addition to considering the timing of implantation,techniques for soft and hard tissue regeneration,and implant selection,it is important to evaluate the timing and reasons for previous failures as well as the removal methods when perform-ing reimplantation.This review aims to summarize the risk factors affecting the survival rate and discuss treatment strategies for impro-ving outcomes of reimplantation.

The purpose of this study is to construct a muscle-specific synthetic promoter library, screen out muscle-specific promoters with high activity, analyze the relationship between element composition and activity of highly active promoters, and provide a theoretical basis for artificial synthesis of promoters. In this study, 19 promoter fragments derived from muscle-specific elements, conserved elements, and viral regulatory sequences were selected and randomLy connected to construct a muscle-specific synthetic promoter library. The luciferase plasmids pCMV-Luc and pSPs-Luc were constructed and transfected into the myoblast cell line C2C12. The activities of the synthesized promoters were evaluated by the luciferase activity assay. Two non-muscle-derived cell lines HeLa and 3T3 were used to verify the muscle specificity of the highly active promoters. The sequences of promoters with high activity, good muscle specificity, and correct sequences were analyzed to explore the relationship between the element composition and activity of promoters. We successfully constructed a muscle-specific promoter library and screened out 321 effective synthetic promoter plasmids. Among them, the activity of SP-301 promoter was 5.63 times that of CMV. The 15 promoters with high activity were muscle-specific. In the promoters with high activity and correct sequences, there was a relationship between their element composition and activity. Muscle-specific elements accounted for a high proportion in the promoters, while they had weak correlations with the promoter activity, being tissue-specific determinants. Viral elements accounted for no less than 20% in highly active promoters, which may be the key elements for the promoter activity. The content of conserved elements was proportional to the promoter activity. This study lays a theoretical foundation for the synthesis of tissue-specific efficient promoters and provides a new idea for the construction and application of in-situ gene delivery systems.
Promoter Regions, Genetic ; Humans ; Animals ; Mice ; Gene Library ; Cell Line ; Transfection ; HeLa Cells ; Luciferases/metabolism* ; Muscle, Skeletal/metabolism* ; Plasmids/genetics* ; Myoblasts/cytology*

Ideal sutures can provide great fixation, wound closure and a stable environment for healing of the surgical site. Tension-free apposition sutures are important for tissue regeneration and could tackle insufficient amounts of soft and hard tissue, especially in missing tooth sites that require implantation. The internal horizontal mattress suture, similar to the conventional horizontal mattress suture, forms a rectangle that can be bisected by the incision with both intrusion and extrusion of the needle on each side. On the basis of the rectangle, the internal horizontal mattress suture emphasizes that the suture should be located below the incision, so the eversion of the wound margin is the highlight of this procedure. The internal horizontal mattress suture could stabilize the graft on the targeting tissue, realize the fixation of the collagen membrane, apically repositioned flap and soft tissue graft, reduce the tension on the incision, and further release the tension of the incision margin. Beyond the primary need for fixation and wound closure, internal horizontal mattress sutures can also achieve stress interruption that reduces the interference of the surrounding muscle and can better master wound tension with the assistance of interrupted sutures. Given the above advantages, horizontal internal mattress sutures have great potential in the application of implant-related regenerative surgery. In this review, according to our experience in clinical practice and the literature, we summarize the advantages of internal horizontal mattress sutures in tissue augmentation. In addition, the sites and sequence to insert the needle and the spatial relationship between the suture and incision are clarified with the rationale of the naming pattern, which is conducive to experience exchange and clinical practice.

Although NPM1 mutations are frequently found in acute myeloid leukemia patients, therapeutic strategies are scarce and unsuitable for those who cannot tolerate intensive chemotherapy. Here we demonstrated that heliangin, a natural sesquiterpene lactone, exerts favorable therapeutic responses in NPM1 mutant acute myeloid leukemia cells, with no apparent toxicity to normal hematogenous cells, by inhibiting their proliferation, inducing apoptosis, causing cell cycle arrest, and promoting differentiation. In-depth studies on its mode of action using quantitative thiol reactivity platform screening and subsequent molecular biology validation showed that the ribosomal protein S2 (RPS2) is the main target of heliangin in treating NPM1 mutant AML. Upon covalent binding to the C222 site of RPS2, the electrophilic moieties of heliangin disrupt pre-rRNA metabolic processes, leading to nucleolar stress, which in turn regulates the ribosomal proteins-MDM2-p53 pathway and stabilizes p53. Clinical data shows that the pre-rRNA metabolic pathway is dysregulated in acute myeloid leukemia patients with the NPM1 mutation, leading to a poor prognosis. We found that RPS2 plays a critical role in regulating this pathway and may be a novel treatment target. Our findings suggest a novel treatment strategy and lead compound for acute myeloid leukemia patients, especially those with NPM1 mutations.

Objective: To propose a digitally modified and guided bone regeneration technique supported by a nonabsorbable titanium plate and explore its effect on vertical bone regeneration. Methods: A total of 8 patients with severe vertical bone defects in the edentulous area who wanted to be treated with implants were included in this study. A digitally modified and guided bone regeneration technique supported by a nonabsorbable titanium plate (fence technique) was used for bone augmentation. The patient's jaw, dentition, and soft tissue data were obtained for prosthetically guided implantation and bone regeneration. After virtual bone augmentation, a model of the jaw was obtained through 3D printing technology, and the titanium plate was bent accordingly. The virtual design was transformed through the template (including the base template and the attachment of a periosteal screw and bone block), so the actual osteogenesis space consistent with the design could be realized in the operation. Guided bone regeneration was performed according to the improved procedure and technical process. After 6 ~ 8 months of bone augmentation, cone beam CT was taken to evaluate the effect of bone augmentation. The implant was implanted according to the initial implant design, and bone tissue was obtained for HE and Masson staining. Results: After 6 ~ 8 months of bone augmentation, the vertical linear bone increment reached (5.44 ± 1.73) mm. The implant was implanted according to the initial implant design, and the bone tissue was obtained for histological examination to show the formation of new bone. Conclusion Digital improved fence technique can simplify the preoperative and surgical procedures, and obtain good vertical bone augmentation results. In short, it is a kind of vertical bone augmentation technique worth popularizing and applying.

Autogenous dentin is a promising biological material that can be used as a substitute for autologous bone. It has been used in postextraction site preservation, maxillary sinus floor elevation, and alveolar ridge augmentation. The clinical application methods of autologous dentin have showed great diversity without uniform standard. The present article reviewed the clinical application of autogenous dentin to provide new ideas for its future development. The literature review results show that dentin materials require several preparations before transplantation, among which the demineralization is a common chemical processing method. Demineralization can enhance the osteoconductive and osteoinductive properties of dentin, but the complex and time-consuming operation process has limited its application to a certain extent. Partial demineralization may be a more appropriate choice. During transplantation, the morphology of dentin depends on the condition of the bone defect and the surgical method. Granular materials with different diameters are convenient for filling irregular defects. Block materials are conducive to maintaining the space of the reconstruction site. Hollow frame materials are slightly more complicated to process but can combine the advantages of granular and block grafts. In addition to being used alone, dentin can also be transplanted in combination with multiple biological materials. Platelet-rich plasma combined with dentin materials has shown ideal results in clinical studies. Plaster of paris and calcium phosphate ceramics have also been combined with dentin materials in animal experiments. But since they have not been applied in humans, their clinical effects require further research.

Objective: To discuss the application of digital technology in the education of implant dentistry. Methods: According to the teaching method that combines case-, problem- and team-based learning, a course on implant theory was carried out in a class of 20 students. Then, all the students in this class were divided into two groups to receive two clinical operation training courses. The first was the training of a free-hand implant, and the second was an implant operation under a digital template. The courses introduced digital technology into preclinical education and simulated implant training. After the two courses, students were organized to analyze the accuracy of the implant, the operation time and the experiences of these two courses. Through the comparison of students′ operations of free-hand and template implants, students could analyze their own faults and propose a method of improvement. The students scored the two classes. Results : Through the two classes, all the students completed the implant operation under the guidance of a template and free-hand method and found their own problems and solutions. The combination of theory and practice deepened the students′ understanding of the teaching content. Finally, the classes were graded comprehensively by students, showing that the students′ satisfaction with the digital template class was higher than that with the free-hand class (P < 0.05). Conclusion The addition of a digital implant technology class significantly improved students′ comprehensive assessment, improved the teaching effect and was more acceptable to students in terms of gaining additional professional skills.

The foreign body reaction refers to a chronic inflammatory reaction and a wound-healing reaction that mainly involve macrophages and foreign body giant cells, which occur after a biological material is implanted into the body. Since macrophages in the foreign body reaction are recruited to the surface of the material after implantation of the material, subsequent secretion of a series of inflammatory factors and fusion into foreign body giant cells may lead to the degradation of the biological materials and environmental stress cracking. Moreover, the prolongation of macrophage polarization and the influence of related receptors may also lead to the phenomenon of fiber encapsulation, resulting in poor prognosis. Some scholars are committed to reducing the response of foreign bodies from the perspective of macrophages and foreign body giant cells, specifically by regulating the secretion of related inflammatory factors, reducing the subtypes of M1 macrophages, promoting their polarization to M2 macrophages, and regulating the fusion of macrophages and selective expression of macrophage-associated receptors to regulate fibrosis. The new immunological view holds that macrophages have the potential to repair bone tissue via angioplasts and osteogenesis in foreign body reactions. Therefore, the gold standard that has long been considered in regenerative medicine, which is that an inert material does not cause a foreign body reaction, is expected to be gradually replaced by tissue engineering that regulates tissue activity and function.

Extracellular vesicles (EVs) are lipid bilayers secreted by a variety of cells that contain nucleic acids, proteins, etc. They can be used as a carrier for cell-to-cell communication. In related research on bone regeneration, mechanisms for transmitting regeneration signals to target cells to achieve the desired goal of osteogenesis have become one of the most important and unsolved topics. Therefore, this review aims to explore the role of mesenchymal stem cells and EVs derived from osteoblasts in bone regeneration in four processes, immunity, angiogenesis, osteogenesis and mineralization, and to provide new ideas for basic and clinical research.