Background: This study aimed to investigate the erosive potential of powdered vitamin C on the bovine enamel tooth surface. Methods: The experiment included five groups: Lemona, Vitagran, Korea Eundan, Coca-Cola (positive controls), and artificialsaliva (negative controls). The pH and titratable acidity were measured. Bovine enamel specimens were immersed in the experimental solutions for 15 minutes each day for 7 days. The surface microhardness was measured using the Vickers hardness number before immersion and on the 1st, 3rd, 5th, and 7th days. The surfaces of the bovine enamel specimens were observed by scanning electron microscopy (SEM). Results: The pH of the experimental groups was as follows: Lemona (2.04±0.04) had the lowest pH, followed by Vitagran(2.56±0.01), the positive control group Coca-Cola (2.60±0.03), Korea Eundan (3.14±0.02), and the negative control group artificial saliva (7.06±0.05). Surface microhardness decreased significantly during the immersion period (p＜0.001). The largest surface microhardness reduction value was shown in Lemona (–201.22±20.60), followed by Vitagran (–190.02±14.73), Korea Eundan (–189.27±27.14), Coca-Cola (–99.28±17.21), artificial saliva (–10.99±9.94). According to the SEM findings, the experimental and positive control groups exhibited rough surfaces with micropores, whereas the negative control group exhibited smooth surfaces before specimen immersion. Conclusion Consuming powdered vitamin C at a low pH may degrade the enamel surface. To reduce the erosive effect, it isrecommended to rinse the mouth with water and brush the teeth after an hour.

Background: This study aimed to investigate the erosive potential of powdered vitamin C on the bovine enamel tooth surface. Methods: The experiment included five groups: Lemona, Vitagran, Korea Eundan, Coca-Cola (positive controls), and artificialsaliva (negative controls). The pH and titratable acidity were measured. Bovine enamel specimens were immersed in the experimental solutions for 15 minutes each day for 7 days. The surface microhardness was measured using the Vickers hardness number before immersion and on the 1st, 3rd, 5th, and 7th days. The surfaces of the bovine enamel specimens were observed by scanning electron microscopy (SEM). Results: The pH of the experimental groups was as follows: Lemona (2.04±0.04) had the lowest pH, followed by Vitagran(2.56±0.01), the positive control group Coca-Cola (2.60±0.03), Korea Eundan (3.14±0.02), and the negative control group artificial saliva (7.06±0.05). Surface microhardness decreased significantly during the immersion period (p＜0.001). The largest surface microhardness reduction value was shown in Lemona (–201.22±20.60), followed by Vitagran (–190.02±14.73), Korea Eundan (–189.27±27.14), Coca-Cola (–99.28±17.21), artificial saliva (–10.99±9.94). According to the SEM findings, the experimental and positive control groups exhibited rough surfaces with micropores, whereas the negative control group exhibited smooth surfaces before specimen immersion. Conclusion Consuming powdered vitamin C at a low pH may degrade the enamel surface. To reduce the erosive effect, it isrecommended to rinse the mouth with water and brush the teeth after an hour.

Background: This study aimed to investigate the erosive potential of powdered vitamin C on the bovine enamel tooth surface. Methods: The experiment included five groups: Lemona, Vitagran, Korea Eundan, Coca-Cola (positive controls), and artificialsaliva (negative controls). The pH and titratable acidity were measured. Bovine enamel specimens were immersed in the experimental solutions for 15 minutes each day for 7 days. The surface microhardness was measured using the Vickers hardness number before immersion and on the 1st, 3rd, 5th, and 7th days. The surfaces of the bovine enamel specimens were observed by scanning electron microscopy (SEM). Results: The pH of the experimental groups was as follows: Lemona (2.04±0.04) had the lowest pH, followed by Vitagran(2.56±0.01), the positive control group Coca-Cola (2.60±0.03), Korea Eundan (3.14±0.02), and the negative control group artificial saliva (7.06±0.05). Surface microhardness decreased significantly during the immersion period (p＜0.001). The largest surface microhardness reduction value was shown in Lemona (–201.22±20.60), followed by Vitagran (–190.02±14.73), Korea Eundan (–189.27±27.14), Coca-Cola (–99.28±17.21), artificial saliva (–10.99±9.94). According to the SEM findings, the experimental and positive control groups exhibited rough surfaces with micropores, whereas the negative control group exhibited smooth surfaces before specimen immersion. Conclusion Consuming powdered vitamin C at a low pH may degrade the enamel surface. To reduce the erosive effect, it isrecommended to rinse the mouth with water and brush the teeth after an hour.

Background: Exercise capacity is associated with lung function decline in chronicobstructive pulmonary disease (COPD) patients, but a discrepancy between exercisecapacity and airflow limitation exists. This study aimed to explore factors contributingto this discrepancy in COPD patients. Methods: Data for this prospective study were obtained from the Korean COPD SubgroupStudy. The exercise capacity and airflow limitation were assessed using the6-minute walk distance (6-MWD; m) and forced expiratory volume in 1 second (FEV1).Participants were divided into four groups: FEV1 >50%+6-MWD >350, FEV1 >50%+6-MWD ≤350, FEV1 ≤50%+6-MWD >350, and FEV1 ≤50%+6-MWD ≤350 and their clinicalcharacteristics were compared. Results: A total of 883 patients (male:female, 822:61; mean age, 68.3±7.97 years) wereenrolled. Among 591 patients with FEV1 >50%, 242 were in the 6-MWD ≤350 group, andamong 292 patients with FEV1 ≤50%, 185 were in the 6-MWD >350 group. The multipleregression analyses revealed that male sex (odds ratio [OR], 8.779; 95% confidence interval[CI], 1.539 to 50.087; p=0.014), current smoking status (OR, 0.355; 95% CI, 0.178to 0.709; p=0.003), and hemoglobin levels (OR, 1.332; 95% CI, 1.077 to 1.648; p=0.008)were significantly associated with discrepancies in exercise capacity and airflow limitationin patients with FEV1 >50%. Meanwhile, in patients with FEV1 ≤50%, diffusioncapacity of carbon monoxide (OR, 0.945; 95% CI, 0.912 to 0.979; p=0.002) was significantlyassociated with discrepancies between exercise capacity and airflow limitation. Conclusion The exercise capacity of COPD patients may be influenced by factors otherthan airflow limitation, so these aspects should be considered when assessing andtreating patients.

We aimed to investigate the impact of the coronavirus disease 2019 (COVID-19) pandemic on admissions of patients with acute myocardial infarction, stroke, and severe trauma, and their excess mortality in emergency departments (EDs) in South Korea using registry data from the National Emergency Department Information System (NEDIS) for patients attending EDs of regional and local emergency medical centers. During the outbreak period of 2020, there were 350,698 ED visits, which was lower than the total in 2019 (392,627 visits).Multiple logistic regression revealed that, compared with 2019, there was significantly higher ED mortality rate during the COVID-19 outbreak in 2020 (adjusted odds ratio, 1.10;95% confidence interval, 1.07–1.13). This finding implies that during the early outbreak period, people might have avoided seeking medical care even for acute and life-threatening conditions, or transfer times at the scene to the hospital arrival were delayed, or treatment for the patients in EDs were delayed.

Purpose: The purpose of this study was to examine the psychological distress related to quality of life (QoL) of patients with colorectal cancer receiving 5-fluorouracil (5-FU) chemotherapy at home with disposable Elastomeric infusion pumps. Methods: In this study, 179 colorectal outpatients were recruited between September 2019 and January 2021. National Cancer Center Psychological Symptom Inventory scores, general self-efficacy, and the EORTC QLQ-C30 scores were measured. Data were analyzed using Independent t-test, One-way ANOVA with Bonferroni post hoc analysis, and hierarchical multiple linear regression with the SPSS/WIN 26.0 programs. Results: The overall prevalence of psychological distress was 52.0% in colorectal patients. In multiple regression, psychological distress (β=-.20, p=.005), appetite loss (β=-.20, p=.001), chemotherapy cycles (β= .19, p=.002), fatigue (β=-.16, p=.035), physical functioning (β=-.16, p=.024), and emotional functioning (β=-.15, p=.025) were significant factors of QoL, and the final model explained 45.0% of the total variance of QoL. Conclusion Supporting patients toward decreased psychological distress and increased physical and emotional functioning, especially in the first or second cycle of chemotherapy, could be used to improve their QoL. To consider the thresholds for clinical importance, it is necessary to increase the interpretation of psychological distress in clinical practice and further research.

OBJECTIVES: To estimate the prevalence of edentulism according to the socio-demographic variables of Korean adults between 2007 and 2018 and to analyze the trends. METHODS: This study was conducted using raw data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2007 to 2018. Edentulism was defined as the absence of upper and lower teeth or the retained root of the missing teeth. To obtain the prevalence of edentulism, complex sample frequency analysis and regression analysis were performed according to the socio-demographic variables to represent the national population. The Korean population structure in 2005 was exploited as a standard population to calculate age-standardized edentulism. RESULTS: The prevalence of edentulism in 2016-2018 was 9.7% in the Korean elderly, and the change of age-standardized edentulism steadily declined over time from 2007, 12.8%. In particular, it decreased by approximately 20% in the period between 2016 and 2018 compared to that in 2007 for those in their 80s. The trend of the prevalence according to gender decreased significantly in women. According to the level of education, the greatest decrease was seen in the group with the lowest education, although the prevalence itself was higher than that seen in those who were more educated. CONCLUSIONS The prevalence of edentulism among the older Korean population has decreased over time. However, the concern is on those with lower education and men as these groups are still at higher risk for edentulism.

OBJECTIVES: To estimate the prevalence of edentulism according to the socio-demographic variables of Korean adults between 2007 and 2018 and to analyze the trends. METHODS: This study was conducted using raw data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2007 to 2018. Edentulism was defined as the absence of upper and lower teeth or the retained root of the missing teeth. To obtain the prevalence of edentulism, complex sample frequency analysis and regression analysis were performed according to the socio-demographic variables to represent the national population. The Korean population structure in 2005 was exploited as a standard population to calculate age-standardized edentulism. RESULTS: The prevalence of edentulism in 2016-2018 was 9.7% in the Korean elderly, and the change of age-standardized edentulism steadily declined over time from 2007, 12.8%. In particular, it decreased by approximately 20% in the period between 2016 and 2018 compared to that in 2007 for those in their 80s. The trend of the prevalence according to gender decreased significantly in women. According to the level of education, the greatest decrease was seen in the group with the lowest education, although the prevalence itself was higher than that seen in those who were more educated. CONCLUSIONS The prevalence of edentulism among the older Korean population has decreased over time. However, the concern is on those with lower education and men as these groups are still at higher risk for edentulism.

The aim of this study was to investigate the usefulness of a clinical screening test [the Korean Infant and Child Developmental Test (KICDT)] compared to language specific tests: the sequenced language scale for infant (SELSI) and the Preschool Receptive-Expressive language Scale (PRES) in children with delayed language development. A retrospective chart review was conducted on 615 children who visited the Department of Pediatrics at Chonbuk National University Hospital from January 2013 to December 2016. All patients were evaluated with KICDT as a clinical screening test and SELSI or PRES as a language specific test. Language Developmental Quotients (LDQs) from the KICDT were compared with the Receptive Language Quotient (RLQ) and expressive language quotient (ELQ) from the SELSI or PRES. The sensitivity, specificity and predictive values of LDQ of KICDT were calculated by comparing with SELSI/PRES. Language DQs from the KICDT were significantly correlated with the RLQ (r=0.706), ELQ (r=0.768), and total language quotient (TLQ) (r=0.766) from the SELSI/PRES (p<0.05). In cross tabulation, the patients belonging to the retardation groups in both KICDT and SELSI/PRES were 417 (67.8%). Otherwise, patients belonging to the normal group in KICDT but not in SELSI/PRES were 151 (24.6%). Sensitivity and specificity of LDQ of KICDT relative to SELSI/PRES were 72.3% and 92.2% respectively (p<0.05). Our data suggests that clinical screening tests alone, not cumbersome language specific tests, can determine language developmental delays in children.