Jihun Kim

Downdrafts are generated indoors because of the water supply and exhaust equipment installed in the clean room of the MLCC factory. In the event of a fire, this downdraft may interfere with the exposure of combustion products, such as heat, smoke, and toxic gases generated from the fire source, to the smoke detector installed on the ceiling. There is a high risk of this adversely affecting people and damaging property, depending on the diffusion of the combustion product. In this study, we analyzed the smoke diffusion patterns according to the operation methods of the supply and exhaust facilities. Modeling was performed using a fire simulation program, and the performance of the water supply and exhaust facilities installed at the analysis site were investigated based on the actual testing, adjusting, and balancing test results to increase the reliability of the modeling results. The analysis indicated that the downdraft from the air-conditioning supply system prevented smoke from the fire source from spreading to the ceiling.

A circulating airflow was generated inside the clean room of an MLCC factory. This airflow affects the movement of combustion products (such as heat, smoke, and toxic gases) when a fire breaks out, and there is a risk of delaying the time required to detect the fire. In this study, testing, adjusting, and balancing were conducted for an actual MLCC plant clean room to analyze the effect of the circulating airflow inside the clean room during fire spread. In addition, the optimal detector location that reduces the time required for smoke detection was determined using a fire simulation program.

Antibiotics are used for the prevention and treatment of infections. This study aimed to investigate the patterns of dental antibiotic prescription in children and adolescents. The Health Insurance Review and Assessment Service provided data on patients who visited medical institutions. It was categorized according to year, sex, age, insurance type, dental institution, and region. Chi-square tests, Fisher’s exact tests, and one-way analyses of variance were performed. Statistical analyses were performed using SAS software (ver. 9.2; SAS Institute, Cary, NC, USA). Amoxicillin and cephalosporins, the most commonly used antibiotics, accounted for approximately 96% of the prescriptions. The younger the child, the more antibiotics were prescribed for trauma, pulpitis, and dental abscesses. However, closer to adolescence, the antibiotics were primarily prescribed to manage impacted teeth and periodontal problems. Antibiotics were prescribed for 3.13 days on average. There were significant differences in the prescription rates according to age, sex, type of insurance, type of medical institution, and region (p < 0.05). This study suggested that antibiotic prescriptions should be closely monitored to ensure appropriate usage of antibiotics.

Background/Aim: The emergence of shared stand‐up electric scooters has led to an increase in their usage and, subsequently, an increase in the incidence of maxillofacial trauma. This study aimed to investigate the trauma pattern associated with the use of stand‐up electric scooters compared with that related to the use of bicycles, which was a popular mode of personal mobility before the emergence of stand‐up electric scooters.Materials and Methods: This study investigated the medical records of patients who visited Wonju Christian Hospital for maxillofacial trauma due to the use of stand‐up electric scooter and bicycles between November 1, 2017 and October 31, 2022. Maxillofacial trauma was analyzed based on medical records, including those in the evaluation results of teeth, maxillofacial bones, and soft tissues.Results: Crown fractures and tooth avulsions were observed more frequently with the use of stand‐up electric scooters than with the use of bicycles. In contrast, crown‐root fractures, tooth subluxation, and extrusive luxation were more commonly observed in bicycle riders. Additionally, the proportion of root fractures was similar between the two groups. However, no vertical root fractures were observed in patients who rode bicycles. The maxillofacial bone fracture rates between the two groups were similar, although the fracture patterns were different.Conclusion: The number of patients using stand‐up electric scooters is increasing, and they are likely to have a worse prognosis compared with those using existing personal mobility devices.

본 연구는 한국 체육 관련 박물관에 관한 연구로 대관령 스키역사관 운영 및 유물 현황, 관리, 유물의 가치 등을 문헌조사 및 현지 조사, 알 아보았고, 구체적 내용은 다음과 같다. 첫째, 체육·스포츠 관련 대회에 서 발생되는 각종 체육 유물과 관련하여 체계적으로 관리할 수 있는 국 가기관이 부재한 상황이다. 둘째, 대관령 스키역사관의 경우 전통 유물 은 체계적으로 전시되어 있으나 체육 유물의 경우 국내, 국외 등 구분이 없이 혼재되어 전시되어 있었다. 셋째, 유물을 관리할 수 있는 전문인력 이 부족하여 훼손, 망실의 위험에 그대로 노출되어 있었다. 넷째, 가치가 있는 유물의 경우에도 보존 처리 및 관리가 소홀하여 시급한 조치가 필 요하다. 마지막으로 2018평창동계올림픽대회 및 동계패럴림픽 기념관과 연계하여 운영하거나 통합하여 운영한다면 현재보다 나은 관리가 가능 할 것이다.

Congenitally missing teeth are one of the most prevalent dental anomalies in the oral cavity. In this study, the prevalence, distribution, and symmetry of congenitally missing permanent teeth among 1,865 patients aged 7 to 15 years who visited the Pediatric Dentistry Department of Wonju Severance Christian Hospital from March 2011 to May 2021 and took panoramic radiographs were investigated and analyzed. Most of the patients had one or two congenitally missing teeth, mainly in the second premolars and lateral incisors. Congenitally missing teeth occurred more in the mandible than in the maxilla, and there was no significant difference in prevalence between the left and right sides. Congenitally missing teeth tend to occur symmetrically on the left and right sides and in the maxilla and mandible, depending on the tooth. Early oral examination and radiological examination are required to prevent complications due to congenitally missing teeth, and appropriate interdisciplinary treatment is required.

Supernumerary teeth develop from excessive proliferation and development of the dental lamina. Supernumerary teeth can cause several problems, including ectopic eruption, delayed eruption, root resorption of adjacent teeth, and diastema. Supernumerary teeth in infancy are rare and have rarely been reported. Case of a 2-day-old infant with 3 supernumerary teeth is presented here and the patient was followed up for 21 months. The erupted supernumerary tooth in the primary dentition was extracted under moderate sedation at the age of 14 months. Microcomputed tomography analysis of the extracted tooth confirmed microscopic root malformation. After extraction, the midline diastema was reduced and oral hygiene improved. Early diagnosis and prompt treatment can prevent complications of supernumerary teeth.

The study was conducted to analyze the impacts of COVID-19 on the number of dental trauma patients. Based on the data provided by the Health Insurance Review and Assessment Service’s Healthcare Bigdata Hub, dental trauma which occurred from 2010 to 2020 was analyzed. Since the outbreak of COVID-19, the incidence of dental trauma per 100,000 decreased compared to the average Incidence between 2017 to 2019. By age, it decreased by 5.4% (p = 0.017) for 0 - 4 years old, 30.3% (p < 0.001) for 5 - 9 years old, 39.5% (p < 0.001) for 10 - 14 years old, 14.5% (p = 0.002) for 15 - 19 years old, 1.3% for 20 - 29 years old, 0.2% for 40 - 49 years old, 2.7% for 50 - 59 years old, 1.2% for 60 years old or older, but it increased by 2.5% for 30 - 39 years old. Compared monthly, before and after the outbreak of COVID-19 confirmed patients, the number of dental trauma patients dropped sharply. After the outbreak of COVID-19, the incidence of dental trauma decreased significantly for under 20 years old, but the decrease was not significant for 20 years old or older.

This study was conducted to investigate changes in dental visits in children and adolescents due to COVID-19. Based on the data provided by the Korea Health Insurance Review and Assessment Service, the number of dental visits among children and adolescents from January 2019 to August 2020, and the rate change according to Korean disease classification in 2019 and 2020 were analyzed by month and region. From January to August 2020, compared to the same period in 2019, the total number of visits to dental clinics and dental hospitals among children and adolescents decreased by 642,202 times (16.3%) in the 0 - 9 years old group, and 313,488 times (9.2%) in the 10 - 19 years old group. During the same period, the decreases due to Z29 (Need for other prophylactic measures) decreased by 118,219 times (34%) in the 0 - 9 years old group and 83,944 times (31%) in the 10 - 19 years old group, showing the greatest change. It is analyzed that overall dental service of children and adolescents has decreased due to COVID-19, and this may lead to deterioration of oral health of children and adolescents in the future, and this study can be used as a reference in case of an infectious disease such as COVID-19 in the future.