Key points to execute internal horizontal mattress suture in tissue augmentation / 口腔疾病防治

@#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.

Aplication of digitally modified fence technique in vertical bone reconstruction / 口腔疾病防治

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.

The application of digital technology in preclinical education for graduate students majoring in oral implantation / 口腔疾病防治

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.

Clinical application of autogenous dentin as a bone graft material / 口腔疾病防治

@#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.

Research progress on extracellular vesicles and bone regeneration / 口腔疾病防治

@#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.

Research progress in the regulation of macrophages in foreign body reaction in bone tissue repair / 口腔疾病防治

@#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.

Progress in the combined application of bone morphogenetic protein-2 and basic fibroblast growth factor in bone tissue engineering / 口腔疾病防治

@#Bone morphogenetic protein-2 (BMP-2) and basic fibroblast growth factor (bFGF) are two important signaling molecules for natural bone repair that are widely applied in the field of bone tissue engineering. BMP-2 accelerates the maturation and mineralization of osteoblasts, and bFGF exhibits significant effects on the promotion of cell division and angiogenesis. The osteogenesis mechanism of BMP-2 differs from that of bFGF, leading to a potentially complementary role between the two proteins. The use of a suitable dose of bFGF in combination with BMP-2 in bone tissue engineering synergistically promotes the formation of new bone and exhibits a better repair effect than either single growth factor. However, the suitable dose range of BMP-2 and bFGF in combination should be further clarified. The mechanism of the synergism and antagonism between BMP-2 and bFGF must be further delineated, and a drug delivery system that better simulates the growth factor release pattern during natural bone repair remains to be designed.

Relationship between T cells and bone regeneration: recent progress and perspectives / 口腔疾病防治

@#Bone is capable of regeneration after injury, but the process of properly restoring form and function is highly complex and prone to failure. The restoration process requires highly ordered and sequential interplay at the injury site between the host immune system and bone tissue. The dynamic process that occurs after bone injury includes the formation of a hematoma, the development of an inflammatory response and callus, and the remodeling of newly formed bone tissue. The inflammatory response at the injury site is essential for the onset of bone regeneration. This inflammatory response is tightly linked with the host immune system, in which various immune cells and molecules are involved. Recently, the relationship between T cells and bone regeneration has become a popular topic; however, currently, there are no summaries of the relationship between T cells and bone regeneration. Thus, this review aimed to elucidate the modulatory functions of T cells in bone regeneration.