In orthodontic treatment, the use of bone replacement material can improve effectiveness of treatment by preventing delayed healing of tooth extraction wounds and bone loss in the extraction wounds. Cells, scaffolds, and growth factors are considered crucial three factors for bone regeneration. In this study, as conditions for bone reconstruction of tooth extraction wound, coral granules were used as a scaffold and autologous fibrinogen glue (AFG) obtained from plasma was used as a growth factor. The extraction wounds experimentally prepared in the mandibles of a beagle dog filled with AFG and coral granules (CG) served as the experimental group and those filled with CG served as the control group. Microfocus X-ray CT images and histopathological samples were observed at 4 and 12 weeks after filling, and plaster casts at the time points immediately after extraction, 4 weeks, and 12 weeks after filling were made to evaluate changes in length of alveolar. At 4 weeks after filling, new bone formation was observed in the control group, while new bone increase was observed in the experimental group. At 12 weeks after filling, the control group showed that new bone and bone marrow formation in the extraction wounds and that CG was barely present.

On the other hand, the experimental group showed that bone reconstruction and bone marrow formation at all layers of the extraction wounds. Therefore, it is suggested that the filling of CG with AFG in extraction wound promotes healing and is effective for bone reconstruction.

In orthodontic treatment, it is common to perform strategic tooth extraction and move teeth towards the extraction sites. Therefore, the rapid completion of the healing process at the extraction site is important for orthodontic treatment. During the initial stages of extraction wound healing, the formation of blood clots and granulation tissue is observed. Concentrated Growth Factors (CGF), produced by excluding blood cell components from blood, contain fibrin and growth factors, which are thought to promote hemostasis and cell proliferation, potentially shortening the wound healing period. In this study, the effect of CGF on the healing process of extraction wounds was observed by comparing an experimental group with CGF implanted into the extraction wounds of beagle dogs and a control group with no implantation. Four weeks after extraction, in the soft tissue at the center of the extraction wounds of the control group, inflammatory cells, capillaries, and thin, irregular collagen fibers were observed. In the experimental group, compared to the control group, there was an increase in new bone volume and a decrease in inflammatory cells. Twelve weeks after extraction, the extraction wounds in the control group were filled with new bone, but their surface was coarse. In the experimental group, the extraction wounds were filled with bone trabeculae, and the surface was covered with thick, dense bone compared to the control group, and the surface was smooth. Furthermore, in the control group, tall osteoblasts and Tartrate-resistant acid phosphatase-positive giant cells were observed on the surface of the new bone within the extraction wounds at 12 weeks after-extraction, but their presence was reduced in the experimental group. These findings suggest that CGF implantation leads to the early completion of extraction wound healing and that implanting CGF into extraction wounds accelerates the healing process. It is expected that this technology will also be used for convenient removal during orthodontic treatment.

Dental desensitizing materials are often applied to wedge defects, potentially allowing the material to come into contact with pulp cells. In this study, we aimed to clarify cell proliferation, calcium dynamics, and expression of integrin α_vβ₃ by culturing cells in a medium containing a calcium carbonate-based dental hypersensitivity treatment agent.

In this experiment, we performed a WST assay and observed fluorescently labeled antibodies using a confocal laser scanning microscope. The number of cells increased in the experimental group compared to the control group on day 1 of incubation. On days 4 and 7 of incubation, material-derived calcium was localized in the cytoplasm of the experimental group, overlapping with the Integrin α_vβ₃ expression sites. It was suggested that calcium derived from the material is taken up into the cytoplasm and promotes cell proliferation in the early stages of culture.

The flowable composite resins have been routinely used in recent clinical dentistry. However, few studies have investigated the biological influence of flowable composite resins commercially available in Japan. In this study, we compared cell viability among 5 products currently available in dental clinical practice. Using mouse-derived Balb/c 3T3 cells, DMEM containing 5% fetal calf serum was adopted as an assay medium. Initially, the flowable resins were dissolved in the assay medium in the presence of dimethyl sulfoxide (DMSO) be-fore photopolymerization, and each solution was diluted multiple times to investigate cell viability.

As a result, all products showed cell death at a dilution ratio of 2. At a dilution ratio of 4 or 8, there was a marked decrease in cell viability. At a dilution ratio of 16, Subsequently, cell viability tests after photopolymerization were performed. Samples were irradiated with an LED-type light irradiator for 5 or 10 seconds, and cell viability was investigated using the three-dimensional culture method with collagen. Cell viability was evaluated using MTT assay. Cell viability in the 10-second irradiation group for all products was higher than in the 5-second irradiation group. Some products showed no significant difference in comparison with the negative control group. There was no relationship between the monomer composition or filler type of any product and cell viability. The results of this study showed that cell viability slightly differed among the 5 clinically available products. There was no product for which cell viability was particularly low.

Tooth surfaces are exposed to saliva, food and drink, and microorganisms in the oral cavity. Adhesions are formed on the tooth surface by saliva-derived components, microorganisms, and microbial products. These deposits can cause tooth discoloration, staining, caries, or periodontal disease. The acquired film is one of the adherents of the teeth and is composed mainly of organic nitrogen compounds found in saliva. While the acquired film protects the tooth structure from drying and demineralization, it can also become a springboard for bacteria to grow if the acquired film remains attached to the tooth surface for a long period of time. In addition to the purpose of preventing dental disease, removal of dental adhesions is important when prosthetic or orthodontic devices are bonded to teeth. Thus, the removal of acquired coatings is important in oral care and clinical practice. Therefore, it is necessary to accumulate research on the formation and removal of artificially acquired coatings on the tooth surface. In this study, we attempted to form an artificial acquired film by using two organic nitrogen compounds and attaching them to the surface of bovine anterior tooth enamel, observing the presence of nitrogen on the enamel that is not removed by rinsing and the changes in its microstructure.

During childhood and adolescence, dentin hypersensitivity with substantial loss of tooth structure such as erosive tooth wear and enamel hypoplasia becomes a clinical challenge. When using dental desensitizing agents for the treatment of dentin hypersensitivity, the biocompatibility of the material with dental pulp cells and its impact on wound healing are crucial. Dental desensitizing agents primarily composed of calcium carbonate exhibit biocompatibility with human deciduous pulp fibroblast-like cells. It is known that human deciduous pulp fibroblast-like cells can enhance cell proliferation ability under appropriate thermal stimulation. In an environment heated to 43°C for 15 minutes, heat shock proteins and after 24 hours, the proliferation of human deciduous pulp fibroblast-like cells is enhanced. In this study, the relationship between biocompatible dental desensitizing agents and thermal stimulation was investigated using human deciduous pulp fibroblast-like cells, revealing that cells cultured with the added material exhibited enhanced cell proliferation under conditions of thermal stimulation.