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The biomechanical effects of dental tissue according to various dental crown materials were investigated using finite element analysis. Bone, prepared tooth, root canal, and periodontal ligament were modeled based on computed tomography. Depending on the characteristics of the crown material, it was classified into zirconia, hybrid ceramic, gold alloy, and acrylic resin. A loading force of 200 N was applied in the vertical direction to the occlusal surface of the crown, and analysis was performed under the condition that all interfaces were tied. The results demonstrate that the highest von Mises stress was shown in the prepared tooth of the acrylic resin model, which is a temporary prosthesis, and the pulpal pressure was also the highest. Additionally, among the final prosthesis, the highest stress was shown in the hybrid ceramic model prepared teeth. The properties of restoration materials can be a factor influencing the tooth structure. Thus, in order to make a correct decision when selecting a material for restorative treatment, it is necessary to understand, analyze, and evaluate the properties of these restoration materials.

Periodontitis is an inflammatory disease caused by microorganisms that induce the destruction of periodontal tissue. Inflamed and damaged tissue produces various inflammatory cytokines, which activate osteoclasts and induce alveolar bone loss and, eventually, tooth loss. Sirt6 expression suppresses inflammation and bone resorption; however, its role in periodontitis remains unclear. We hypothesized that Sirt6 has a protective role in periodontitis. To understand the role of Sirt6 in periodontitis, we compared periodontitis with ligature placement around the maxillary left second molar in 8-week-old control (C57BL/6J) male mice to Sirt6-overexpressing Tg (Sirt6Tg) mice, and we observed the resulting phenotypes using micro-CT. MDL801, a Sirt6 activator, was used as a therapy for periodontitis through oral gavage. Pro-inflammatory cytokines and increased osteoclast numbers were observed in alveolar bone tissue under periodontitis surgery. In the same condition, interestingly, protein levels from Sirt6 were the most downregulated among sirtuins in alveolar bone tissue. Based on micro-CT and CEJ-ABC distance, Sirt6Tg was observed to resist bone loss against ligature-induced periodontitis. Furthermore, the number of osteoclasts was significantly reduced in Sirt6Tg-ligated mice compared with control-ligated mice, although systemic inflammatory cytokines did not change. Consistent with this observation, we confirmed that bone loss was significantly reduced when MDL801, a Sirt6 activator, was included in the ligation mouse model. Our findings demonstrate that Sirt6 activation prevents bone loss against ligature-induced periodontitis. Thus, a Sirt6 activator may provide a new therapeutic approach for periodontitis.

Dental composite resins are widely used in dental restorations. However, their clinical application is limited by the occurrence of secondary caries. As strontium-modified phosphate-based glass is known to have long-term antibacterial properties, in this study, we incorporated a strontium-modified phosphate-based glass microfiller at 3, 6, and 9 wt.% concentrations into a commercially available composite resin and investigated the mechanical properties (flexural strength, elastic modulus, and microhardness), ion release characteristics, and color of the resultant resins. In addition, we examined the antibacterial effects of the composite resins against Streptococcus mutans (S. mutans). The mechanical properties of the Sr-modified phosphate-based glass groups differed only slightly from those of the control group (p > 0.05). However, the optical density at 600 nm of S. mutans incubated on the experimental group was significantly lower compared to that observed with the control (p

Cancer associated fibroblasts (CAFs) are a mesenchymal cell type found in most solid tumors modulating cancer metastasis by building up and remodeling the extracellular matrix (ECM) structure. We aimed to evaluate the correlation between RhoA and YAP expression in the stroma cells obtained from prostate and ovarian cancer tissues.We analyzed two microarray datasets obtained from NCBI Gene Expression Omnibus(GEO). The sample type of two datasets was RNA, which is displaying the transcriptome profiling. The tumor stroma of patients with invasive prostate cancer and high-grade serous ovarian cancer were obtained from datasets Independent t-test was used to analyze the differentially expressed YAP between normal stroma and cancer stroma. In addition, Pearson's correlation was run to analyze the correlation between YAP and RhoA expressions.In comparison with normal stroma tissues, YAP1 was overexpressed in prostate and ovarian cancer stroma tissues (prostate cancer stroma, p0.05; ovarian cancer stroma, p0.001). Furthermore, a positive correlation was detected between YAP and RhoA expressions in stroma of both tumor types. This correlation was positively strong in prostate cancer stroma (R=0.607) and positively weak in ovarian cancer stroma (R=0.248).We found that YAP was overexpressed in prostate and ovarian cancer stroma. Furthermore, the correlation between RhoA and YAP expression suggested that RhoA-YAP signals could physiologically be involved in tumor stroma. Thus, targeting RhoA-YAP may be an intriguing avenue for cancer therapeutics in neoplastic epithelial cells as well as tumor stroma.

Background Phosphate-based glass (PBG) is an attractive bioactive material for promoting the cellular regenerative response. PBG consists of glass network which contains phosphate as the main component and can be substituted into various therapeutic ions. Strontium (Sr) can stimulate osteogenic activity and inhibit the pro-inflammatory response. However, there are limited studies on the characterization and biological performance Sr-substituted PBG (PSr). In this study, PSr was characterized and its of immuno-osteogenic response potential was investigated for substituting Ca with Sr. Considering a priority for cellular activity, we compared the optimized PSr against the benchmark 45S5 bioactive glass (BG) for its effect on cellular bioactive response and regenerative hard tissue. Methods PSr groups were fabricated by a melt-quenching method; subsequently, they were characterized and their biological performance was investigated for the preference of PSr. Considering the clinically used BG as the benchmark, PSr was evaluated based on the cytotoxicity assay, osteogenic activity, pro-inflammatory response, and implantation of calvaria bone defect. Results PSr groups exhibited a glass structure and phosphate network similar to that of PBG. However, the results of ion release analysis showed that PSr6 was stable in accordance with Ca/P, Ca/Sr, and P/Sr ratios. Based on these results, the cellular response of PSr6 was the highest, which increased for the early osteogenic marker and inhibited the inflammatory response. Compared to the clinically used BG as the benchmark, PSr6 promoted osteogenic activity and suppressed inflammatory response. The results of in vivo study indicated that the new bone formation in the PSr6 was similar to that in benchmark BG. However, the limitation of this study was the four weeks of implantation. However, the results of our study suggest that PSr6 is promising for enhancing the immuno-osteogenic response and regenerating hard tissue with the optimized glass structure having Ca/Sr ratio of 2:1. Conclusions The developed PSr6 demonstrated stable physical properties, favorable cytocompatibility, and immune-osteogenic response. Compared with benchmark BG, PSr6 exhibited enhanced immuno-osteogenic response and regeneration of new bone and connective tissues. Therefore, PSr6 is a potential bone grafting material for regenerative hard tissue.

Poly (methyl methacrylate) (PMMA) is a commonly used denture material with poor antimicrobial effects. This study investigated the antimicrobial effects of PMMA-containing silver-phosphate glass. We fabricated a novel material comprising PMMA-containing silver-phosphate glass. Then, microhardness, flexural strength, and gloss unit were analyzed. Antimicrobial activity against Streptococcus mutans and Candida albicans was investigated. Colony-forming units were counted, and antimicrobial rates were measured. Biocompatibility tests were performed using a colorimetric MTT assay for evaluating cell metabolic activity. The microhardness, flexural strength, and gloss unit of the experimental groups (with silver-phosphate glass) were not significantly different from those of the control group (no silver-phosphate glass) (P > 0.05), which showed clinically valid values. With increasing proportions of silver-phosphate glass, the antimicrobial activity against the two microorganisms increased (P < 0.05). Furthermore, S. mutans showed more than 50% antimicrobial activity in 4%, 6%, and 8% experimental groups, C. albicans showed more than 50% antimicrobial activity in 6% and 8% groups, and a statistically significant difference in antimicrobial activity was observed compared to the control (P < 0.05). The cell viability of the experimental groups was not significantly different from that of the control group (P > 0.05). Both control and experimental groups showed approximately 100% cell viability. These results suggest that silver-phosphate glass is a promising antimicrobial material in dentistry.

Background Regdanvimab is the only monoclonal antibody available in Korea that targets the receptor-binding domain of SARS-CoV-2. Although the efficacy of regdanvimab against the original and beta variant viruses was demonstrated, it remains uncertain whether it has therapeutic effect on delta variant in the real world. Methods We retrospectively evaluated the characteristics and clinical outcome of patients hospitalized for COVID-19 and treated with regdanvimab in two university-affiliated hospitals between September and December 2021, during the delta variant-predominant period in Korea. Results A total of 374 mild to moderate COVID-19 patients treated with regdanvimab were included in this study. The median age was 65 (interquartile range, IQR 17-92) and 178 (47.6%) patients were male. A total of 322 (86.1%) patients had median 2 (IQR 1-3) risk factors for disease progression. The most common underlying disease was cardiovascular disease (198, 52.9%), followed by diabetes mellitus (95, 25.4%), cancer (40, 10.7%), chronic lung disease (34, 9.1%), immunosuppression (1 7, 4.5%), and chronic kidney disease (12, 3.2%). There were 43 (11.5%) patients with a body mass index ≥ 30. The median time to regdanvimab treatment from symptom onset was 4 (IQR 2-6) days. 226 (60.4%) patients were fully vaccinated, and 109 (29.1%) were not vaccinated at all. 185 (49.5%) patients had pneumonia. Most (342/374, 91.4%) patients improved without any other treatment for COVID-19 and were discharged. Only 32 (8.6%) patients required other therapeutic agents such as remdesivir, corticosteroids or oxygen therapy after regdanvimab administration. The time from regdanvimab infusion to addition of other therapeutic agents was median 5 days (IQR 3-6.5). When comparing the characteristics of 32 patients who needed other treatment with those who improved only with regdanvimab treatment, there was a significant difference in the presence of pneumonia (27/32, 84.4% vs. 158/342, 46.2%, P< 0.001) and there was no significant difference in vaccination status (15/32, 46.9% vs. 211/342 61.7% P=0.101). Conclusion This study shows the potential clinical benefits of regdanvimab in mild to moderate COVID-19 patients in the real world during the delta variant predominant period in Korea. Disclosures All Authors: No reported disclosures.

Background Antibiotic resistance threatens public health worldwide, and inappropriate use of antibiotics is one of the main causes. Antibiotic use for asymptomatic bacteriuria (ABU) has been defined as “antibiotics never events”, and urinary tract infection (UTI) is one of the most common infectious diseases for which antibiotics are prescribed in Korea. To establish an effective antimicrobial stewardship strategy, a qualitative assessment of antibiotic use in actual clinical syndrome is necessary. Methods Cases of positive urine cultures (≥105 CFU/ml), performed in inpatient, outpatient, and emergency departments in April 2021 were screened in 26 hospitals located throughout Korea. Cases were classified into ABU, lower UTI, and upper UTI. The appropriateness of antibiotic use was retrospectively evaluated by infectious disease specialists using quality indicators based on the domestic clinical guideline for ABU and UTI. Figure 1.Study flow diagram Results A total of 2697 cases of ABU or UTI were included. The appropriateness of antibiotic use was assessed in 1157 cases with asymptomatic bacteriuria, 677 and 863 cases with lower and upper UTI (Figure 1). Antibiotics were prescribed in 21.7% (251 of 1157) of ABU without appropriate indication. Of 66 ABU cases with appropriate indication in which prophylactic antibiotics were prescribed, the duration of antibiotics was adequate in only 34.8% (Table 1). For lower UTI, the appropriateness of empirical and definite antibiotics was 77.8% (527 of 677) and 68.0% (353 of 519). In terms of upper UTI, 86.3% (745 of 863) and 78.2% (583 of 746) was appropriate, respectively. The duration of antibiotics was adequate in 65.7% (421 of 641) of lower UTI and 77.9% (592 of 760) in upper UTI (Table 2, 3). Conclusion This nationwide qualitative assessment of antibiotic use in ABU and UTI revealed that a significant proportion of antibiotics were prescribed inappropriately and, furthermore the duration of antibiotics was prolonged unnecessarily. Interventions for appropriate antibiotic use in ABU and UTI at the national level are required. Disclosures All Authors: No reported disclosures.

Data on the longevity of humoral and cell-mediated immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with coronavirus disease 2019 (COVID-19) are limited. We evaluated the detailed kinetics of antibody and T-cell responses at the acute, convalescent, and post-convalescent phases in COVID-19 patients with a wide range of severity. We enrolled patients with COVID-19 prospectively from four hospitals and one community treatment center between February 2020 and January 2021. symptom severity was classified as mild, moderate, or severe/critical. Patient blood samples were collected at 1 week (acute), 1 month (convalescent), and 2 months after symptom onset (post-convalescent). Human SARS-CoV-2 IgG and IgM antibodies were measured using in-house-developed ELISA. The SARS-CoV-2-specific T-cell responses against overlapping peptides of spike proteins and nucleoprotein were measured by interferon-γ enzyme-linked immunospot assays. Twenty-five COVID-19 patients were analyzed (mild, n = 5; moderate, n = 9; severe/critical, n = 11). IgM and IgG antibody responses peaked at 1 month after symptom onset and decreased at 2 months. IgG response levels were significantly greater in the severe/critical group compared with other groups. Interferon-γ-producing T-cell responses increased between 1 week and 1 month after symptom onset, and had a trend toward decreasing at 2 months, but did not show significant differences according to severity. Our data indicate that SARS-CoV-2-specific antibody responses were greater in those with severe symptoms and waned after reaching a peak around 1 month after symptom onset. However, SARS-CoV-2-specific T-cell responses were not significantly different according to symptom severity, and decreased slowly during the post-convalescent phase.

Background and Objectives The purpose of this study is to investigate the replacement of external sound processors and to help understand the economic burden experienced from cochlear implant users.Subjects and Method Among the 500 cases of cochlear implant surgery from 1992 to 2019, 336 cases from 311 patients who had used a cochlear implant for more than 1 year were enrolled. The period of cochlear implant use, replacement of the sound processor, the number, method, and reason of replacements were examined.Results One hundred sixty cases (47.62%) replaced the sound processor at least once. There were a total of 213 replacements made in 160 cases. The most common reason for replacing the sound processors was because it could not be repaired (71 replacements, 33.33%), with their period of use being an average of 12 years. The most common replacement method of the sound processors was by purchasing with medical insurance benefits (100 replacements, 46.95%), with the usage period being an average of 11 years and 4 months.Conclusion Cochlear implant users replaced the sound processor for various reasons and the period of using one sound processor was relatively short. About half of all replacement cases were made by applying for medical insurance benefits. Others purchased directly through a sales company and paid a relatively high cost. Therefore, it is necessary to expand the medical insurance for external sound processor of cochlear implants to include exchange times considering the economic burden of cochlear implant users.

Colonization of auto-polymerized acrylic resin by pathogenic Candida albicans is a common problem for denture users. In this study, zinc-modified phosphate-based glass was introduced into an auto-polymerized acrylic resin at concentrations of 3, 5, and 7 wt.%. The mechanical or physical properties (flexural strength, elastic modulus, microhardness, and contact angle), surface morphology of the resultant materials, and the antimicrobial effect on C. albicans were investigated. There were no statistical differences in the mechanical properties between the control and the zinc-modified phosphate-based glass samples (p > 0.05); however, the number of C. albicans colony-forming units was significantly lower in the control group (p C. albicans tended not to adhere to the zinc-modified-phosphate-based glass samples. Thus, the zinc-modified materials retained the advantageous mechanical properties of unaltered acrylic resins, while simultaneously exhibiting a strong antimicrobial effect in vitro.

Regdanvimab is the only monoclonal antibody available in Korea that targets severe acute respiratory syndrome coronavirus 2. We retrospectively evaluated the clinical characteristics of 374 adults hospitalized with coronavirus disease 2019 (COVID-19) who were treated with regdanvimab from September through December 2021. In total, 322 (86.1%) patients exhibited risk factors for disease progression. Most patients (91.4%) improved without additional treatment. No patient died or was transferred to intensive care. This study shows that regdanvimab prevented disease progression in high-risk patients with mild to moderate COVID-19 infections during Delta variant predominance.

The purpose of this study is to provide the general history of fostering dentists in Japan and introducing their new roles. This research was conducted based on the government policy report on dentists and the information published by each educational institution. Based on the collected data, the official websites were used to represent the latest statistics of the institutions. The number of dentists in Japan has increased. The government established the National Examination for Dentists to guarantee the quality of dentists. After the standards for developing questions for the national examination were established in 1985, the contents of the examination have been appropriately improved by revising the standards every four years. This improvement has required dental students to study a variety of subjects for six years at dental school. Since dentists in Japan are required to respond to various demands from the nation; the Model Core Curriculum for Dental Education was developed to teach medical ethics and abilities to ensure that dentists conduct themselves professionally. Recently, the roles of dentists have been changing in Japan. When providing dental services to older patients over the age of 65, dentists and other dental professions focus on maintaining oral functions, such as saliva secretion, bite force, tongue movement, and masticatory/swallowing functions. However, oral function-related services for children are different. In addition to providing essential dental services, dental practitioners also provide special treatment, such as oral muscle training, myofunctional therapy, health guidance, and space retainers to the child patients with developmental insufficiency in oral functions. Dentistry in Japan has undergone numerous changes over the years and has continued to offer high-quality dental health services. Thus, information gained from the Japanese experience may be helpful to dental professions in other developed countries for planning oral health measures.