The Impact of Wireless Emergency Alerts on a Floating Population in Seoul, South Korea: Panel Data Analysis.

BACKGROUND: Wireless emergency alerts (WEAs), which deliver disaster information directly to individuals' mobile phones, have been widely used to provide information related to COVID-19 and to encourage compliance with social distancing guidelines during the COVID-19 pandemic. The floating population refers to the number of people temporarily staying in a specific area, and this demographic data can be a useful indicator to understand the level of social distancing people are complying with during the COVID-19 pandemic. OBJECTIVE: This study aimed to empirically analyze the impact of WEAs on the floating population where WEAs were transmitted in the early stages of the COVID-19 pandemic. As most WEA messages focus on compliance with the government's social distancing guidelines, one of the goals of transmitting WEAs during the COVID-19 pandemic is to control the floating population at an appropriate level. METHODS: We investigated the empirical impact of WEAs on the floating population across 25 districts in Seoul by estimating a panel regression model at the district-hour level with a series of fixed effects. The main independent variables were the number of instant WEAs, the daily cumulative number of WEAs, the total cumulative number of WEAs, and information extracted from WEAs by natural language processing at the district-hour level. The data set provided a highly informative empirical setting as WEAs were sent by different local governments with various identifiable district-hour-level data. RESULTS: The estimates of the impact of WEAs on the floating population were significantly negative (-0.013, P=.02 to -0.014, P=.01) across all specifications, implying that an additional WEA issuance reduced the floating population by 1.3% (=100(1-e-0.013)) to 1.4% (=100(1-e-0.014)). Although the coefficients of DCN (the daily cumulative number of WEAs) were also negative (-0.0034, P=.34 to -0.0052, P=.15) across all models, they were not significant. The impact of WEAs on the floating population doubled (-0.025, P=.02 to -0.033, P=.005) when the first 82 days of observations were used as subsamples to reduce the possibility of people blocking WEAs. CONCLUSIONS: Our results suggest that issuing WEAs and distributing information related to COVID-19 to a specific district was associated with a decrease in the floating population of that district. Furthermore, among the various types of information in the WEAs, location information was the only significant type of information that was related to a decrease in the floating population. This study makes important contributions. First, this study measured the impact of WEAs in a highly informative empirical setting. Second, this study adds to the existing literature on the mechanisms by which WEAs can affect public response. Lastly, this study has important implications for making optimal WEAs and suggests that location information should be included.

Effect of general health checks on the treatment of chronic diseases: accounting for self-selection in the retrospective cohort study using Korea National Health Insurance data.

OBJECTIVE: This study examines the effect of general health checks on the detection and treatment of diabetes and hypertension with controlling for the self-selection problem of undergoing general health checks. DESIGN: Retrospective observational cohort study. SETTING: Sample Research Database offered by Korean National Health Insurance Service, between 2002 and 2013. PARTICIPANTS: Two datasets, focusing on diabetes and hypertensions one by one, are constructed. The number of participants for the datasets is 133 329 (diabetes) and 101 738 (hypertension), respectively. METHODS: A bivariate probit model with selection was adopted to investigate the impact of general health checks on the diagnosis of critical chronic diseases. The dependent variable was an indicator variable denoting whether a participant has been treated for diabetes (or hypertension) or not for the first time during the sample period. An indicator variable that indicates whether that participant is eligible for free general health checks or not in the focal year (year of the first treatment or last year in the sample) was used as instrument variables to control for the self-selection problem of undergoing general health checks. RESULTS: We found that there exists substantial self-selection between undergoing general health checks and diagnosis for chronic diseases. The correlations between the unobserved factors influencing the decisions to obtain general health checks and those determining the detection of chronic diseases are highly significant and positive (ie, 0.188 (p<0.001) in diabetes and 0.220 (p<0.001) in hypertension). We confirmed that these positive, significant correlations generate upward bias in the estimated effect of general health checks on the detection and treatment of diabetes (0.312 (p<0.001) when self-selection ignored but 0.099 (p<0.001) when self-selection considered) and hypertension (0.293 (p<0.001) when self-selection ignored but insignificant when self-selection considered). The effect of general health checks and people's self-selection behaviour may differ by socio-economic characteristics of individuals. The general health check is effective in detecting chronic diseases among low-income individuals rather than high-income individuals, implying that general health checks are contributing to helping medically underprivileged low-income people detect and treat their chronic diseases. High-income individuals showed stronger self-selection behaviour than low-income individuals and this may overstate the effect of general health checks if the self-selection is overlooked, particularly among high-income individuals. CONCLUSION: Self-selection due to unobserved factors between undergoing general health checks and diagnosis of chronic diseases are substantial. After accounting for this, the effect of general health checks on the detection and treatment of diabetes and hypertension is insignificant or marginal. The increases in the treatments of the two diseases following general health checks are 1% and insignificant in diabetes and hypertension, respectively.

Efficacy of Local Minocycline Agents in Treating Peri-Implantitis: An Experimental In Vivo Study in Beagle Dogs.

BACKGROUND: Local delivery agents (LDA) have the advantage of delivering the antibiotics at high concentrations to the targeted sites. However, the constant flow of gingival crevicular fluids and saliva may restrict their efficacy. Therefore, the drug sustainability and pharmacodynamic properties of any proposed LDA should be evaluated. METHODS: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Peri-implantitis were experimentally induced using silk-ligatures. Each implant was randomly allocated to receive one of the following four treatments: (i) MC (Chitosan-alginate (CA) minocycline), (ii) MP (CA-without minocycline), (iii) PG (Polyacrylate-glycerin minocycline), and (iv) Control (mechanical debridement only). Mechanical therapies and LDAs were administered into the gingival sulcus two times at a 4-week interval. Drug sustainability as well as clinical, radiographical, and immunohistochemical (IHC) analyses were conducted to evaluate the efficacies of treatments. RESULTS: Reduced mean probing depth was observed in all of the test groups after the second delivery. A minimal marginal bone level change was observed during the treatment period (MP (-0.06 ± 0.53 mm) to PG (-0.25 ± 0.42 mm)). The distribution of IHC cell marker analysis of all targeted antibodies ranged from 6.34% to 11.33%. All treatment outcomes between the test groups were comparable. A prolonged retention of LDA was observed from CA microspheres (MC and MP) at both administrations (p < 0.017) and prolonged sustainability of bacteriostatic effect was observed from MC compared to PG after the second administration (p < 0.05). CONCLUSIONS: Prolonged retention of CA microspheres was observed and the longer bacteriostatic effect was observed from the MC group. Mechanical debridement with adjunct LDA therapy may impede peri-implantitis progression, however, prolonged drug action did not lead to improved treatment outcome.

Soft Tissue Dimensions Following Tooth Extraction in the Posterior Maxilla: A Randomized Clinical Trial Comparing Alveolar Ridge Preservation to Spontaneous Healing.

BACKGROUND: To assess the soft tissue dimension following tooth extraction and alveolar ridge preservation in the posterior maxilla compared to spontaneous healing. METHODS: Thirty-five patients randomly assigned to alveolar ridge preservation (ARP) and spontaneous healing (SH) after maxillary molar extraction. The crestal, buccal, and palatal gingival thickness at 6 months was measured around virtually placed implant fixtures using superimposed cone-beam computed tomography and intraoral scan taken at 6 months. Buccal mucogingival junction (MGJ) level change over 6 months was estimated using intraoral scans obtained at suture-removal and 6 months. RESULTS: The crestal gingiva was significantly thinner in group ARP (-1.16 mm) compared to group SH (p < 0.05). The buccal and palatal gingiva was significantly thinner at the implant shoulder (IS) level in group ARP (buccal: -0.75 mm; palatal: -0.85 mm) compared to group SH (p < 0.05). The thickness at 2 mm below the IS of both sides and the buccal MGJ level change were similar in both groups (p > 0.05). CONCLUSIONS: ARP in the posterior maxilla resulted in a thinner soft tissue on top of and at the prospective level of the implant shoulder at 6 months. The buccal MGJ level changed minimal for 6 months in both groups.

Locally Applied Slow-Release of Minocycline Microspheres in the Treatment of Peri-Implant Mucositis: An Experimental In Vivo Study.

BACKGROUND: The objective of this is preclinical investigation was to evaluate the differential drug sustainability and pharmacodynamic properties of two local minocycline microsphere carriers: chitosan-coated alginate (CA) and poly(meth)acrylate-glycerin (PG). METHODS: Four dental implants were placed unilaterally in the edentulous mandible of six beagle dogs. Each implant was randomly assigned to receive one of the following four treatments: (i) CA (CA-based minocycline), (ii) placebo (CA substrate without minocycline), (iii) PG (PG-based minocycline) and (iv) control (mechanical debridement only). After inducing peri-implant mucositis, the randomly assigned treatments were administered into the gingival sulcus twice at a 4-week interval using a plastic-tipped syringe. Drug sustainability and pharmacodynamic (clinical, radiographical and cell marker intensity) evaluations were performed after each administration. RESULTS: The CA microspheres remained longer around the healing abutment compared to the PG microspheres at both administrations and a longer bacteriostatic effect was observed from CA (7.0 ± 5.7 days) compared to PG (1.2 ± 2.6 days). The efficacy of the applied therapies based on clinical, radiographical and histological analyses were comparable across all treatment groups. CONCLUSIONS: CA microspheres showed longer carrier and bacteriostatic effect sustainability when compared to PG microspheres, however, longer drug sustainability did not lead to improved treatment outcomes.

Long-term assessment of periodontal disease progression after surgical or non-surgical treatment: a systematic review.

The primary aim of this systematic review was to assess the evidence on periodontal disease progression after treatment in patients receiving supportive periodontal therapy (SPT) and to identify predictors of clinical attachment level (CAL) loss. A protocol was developed to answer the following focused question: In adult patients treated for periodontitis, what is the disease progression in terms of CAL loss after surgical or non-surgical treatment? Randomized controlled clinical trials, prospective cohort studies, and longitudinal observational human studies with a minimum of 5 years of follow-up after surgical or non-surgical treatment that reported CAL and probing depth changes were selected. Seventeen publications reporting data from 14 investigations were included. Data from 964 patients with a follow-up range of 5-15 years was evaluated. When the CAL at the latest follow-up was compared to the CAL after active periodontal therapy, 10 of the included studies reported an overall mean CAL loss of ≤0.5 mm, 3 studies reported a mean CAL loss of 0.5-1 mm, and 4 studies reported a mean CAL loss of >1 mm. Based on 7 publications, the percentage of sites showing a CAL loss of ≥2 mm varied from 3% to 20%, and a high percentage of sites with CAL loss was associated with poor oral hygiene, smoking, and poor compliance with SPT. The outcomes after periodontal therapy remained stable over time. Disease progression occurred in a reduced number of sites and patients, mostly associated with poor oral hygiene, poor compliance with SPT, and smoking.

Prevalence of Alzheimer's dementia and its risk factors in community-dwelling elderly koreans.

OBJECTIVE: We estimated the prevalence of Alzheimer's dementia (AD) and mild cognitive impairment (MCI) and their risk factors in an urban community setting, focusing especially on metabolic syndrome. METHODS: A two-phase investigation based on a door-to-door survey was performed. In Phase I, we administered the Korean version of the Mini-Mental State Examination (MMSE-KC) of the Consortium to Establish a Registry for Alzheimer's disease (CERAD-K). Assessment Packet and the Korean version of the Geriatric Depression Scales (GDS-K) to all 706 participants aged 65 years or older. In Phase II of the study, 175 persons underwent physical and neurological examinations according to the protocol of the CERAD-K clinical assessment battery [CERAD-K (C)] and the neuropsychological assessment battery [CERAD-K (N)]. We also examined the association between cognitive decline and metabolic syndrome. AD and MCI were defined using the DSM-IV-TR criteria and the Clinical Dementia Rating (CDR) scales. RESULTS: The mean age (+/-SD) of the subjects was 74.3+/-16.7 years and the ratio of males to females was 53.2 to 46.8. The prevalence of Alzheimer's dementia was 9.0%, while that of MCI was 32.9%. Old age and lower educational level had significant associations with cognitive decline in the elderly, but gender, years of alcohol intake or smoking, and metabolic syndrome were not associated with AD or MCI. CONCLUSION: In this study, metabolic syndrome was not associated with Alzheimer's AD or MCI. Information regarding an association between Alzheimer's dementia and metabolic syndrome in this study will be helpful in formulating future public health policy and prevention strategies in Korea.