Estimated economic costs of dental implants among older South Korean adults, 2015-2018.

OBJECTIVE: Dental implants are a considerable financial burden for elderly people and their caregivers. This study aimed to calculate the estimated economic costs of dental implants on the Korean older population. MATERIALS AND METHODS: The economic costs of dental implants for adults aged 75 years and older were estimated from a societal perspective, considering both direct and indirect expenditures. We used data from the Korean National Health Insurance Service for the period 2015-2018 to estimate the medical costs. Noninsured medical costs were estimated from research on medical expenses by the National Health Insurance Review and Assessment Service. Indirect costs related to transportation fees and time loss were obtained. The Cochran Armitage trend test was performed to examine the trend of the economic burden of dental implants. RESULTS: The estimated economic costs showed from 2015 to 2018 (total costs: $26.54-55.66 million, total costs after discount: $17.11-39.56 million). Direct costs, including insured and noninsured medical costs, represented from $25.81 to $47.03 million. Indirect costs, including transportation and time costs, ranged from $0.73 to $1.63 million. The impact of the total dental implant costs was 0.0018%-0.0034% of the Korean annual gross domestic product and 1.03%-1.59% of the annual total costs of dental care benefits. CONCLUSIONS: The estimated economic burden of dental implants significantly increased from 2015 to 2018 in older South Korean adults. These results will provide a foundation and guidance for further health economic studies on the burden of dental implants in the elderly population.

Disparity in access for people with disabilities to outpatient dental care services: a retrospective cohort study.

BACKGROUND: People with disabilities face difficulties in oral health management and gaining access to dental care. The availability of a regular source of dental care (RSDC) is an important factor that influences the access to health services and care management. The purpose of this study was to determine the effect of the availability of RSDC on the number of annual dental visits and dental expenses per visit among people with disabilities. METHODS: Data of 7,896,251 patients with dental problems in South Korea were analyzed using the 2002-2018 National Health Insurance claims data. A generalized estimating equation was applied to analyze the repeated-measurement data, and the interaction effect between RSDC and the disability severity was evaluated. RESULTS: The number of annual dental visits was higher among people with (2.62) than among those without (2.23) disabilities. Despite their increased dental needs, both annual dental visits and dental expenses per visit were low among older individuals (p < 0.001). The proportion and frequency of annual dental visits was lower among women than among men with disabilities. RSDC had differential effects on the severity of disability. Compared to people without disabilities, RSDC increased the number of annual dental visits (p = 0.067) and the dental expenses per visit (p < 0.05) among those with severe disabilities, but the effect on the number of annual dental visits was not significant among those with mild disabilities (p = 0.698). CONCLUSIONS: Our results suggest a need for a special dental care system for people with disabilities, to ensure an RSDC, particularly for women and for older people with disabilities.

The effects of orthodontic treatment on personal dental expenditures in South Korea: a follow-up study using Korean health panel survey.

BACKGROUND: This study aimed to investigate the effects of orthodontic treatment on cumulative out-of-pocket (OOP) expenditures for up to 8 years and the factors contributing to changes in individual OOP dental expenses. METHODS: The data of adults aged ≥19 years, 218 with experience of orthodontic treatment (OT group) and 654 without experience of orthodontic treatment (non-OT group) were extracted from the Korea Health Panel Survey between 2009 and 2017 using the propensity score matching method. The total personal OOP expenditure for dental care incurred after orthodontic treatment in the OT group and that incurred in the matched non-OT group were calculated. Since dependent variables, cumulative dental expenditures, were continuous with excess zeros, Tweedie compound Poisson linear models were used to explore the influence of orthodontic treatment experience and demographic and socioeconomic factors, including private insurance, on per capita OOP dental expenditures. RESULTS: The OT group had socioeconomic characteristics distinct from those of general dental patients. The Box-Cox transformed per capita OOP expenditures for dental care in the OT group were lower than those in the non-OT group (P < 0.05). When all covariates were held constant, the non-OT group spent 1.4-times more on OOP dental expenditures, but this was not statistically significant (P > 0.1). The data from those with higher incomes revealed the opposite trend (P < 0.05), while the other covariates were not statistically significant. CONCLUSIONS: Orthodontic treatment had no positive or negative effect on future oral care use. This finding is similar to the inconsistent results of previous clinical studies on oral health and orthodontic treatment.

Effects of tooth loss on functional impairment in elderly: A secondary data analysis of elderly cohort in the South Korea.

INTRODUCTION: This study aimed to assess the association of tooth loss with physical and cognitive impairments in the elderly aged over 65 years. METHODS: The Elderly Cohort database (2008-2013) of National Health Insurance Services in South Korea was used; 1485 individuals who underwent physical impairment evaluation and 1410 individuals who underwent cognitive impairment evaluation were analysed. The dependent variables were the standardized physical and cognitive function score. The generalized estimating equation method was used for repeated measures. The total number of teeth lost during the study period, sex, age, Charlson comorbidity index, income, medical aid, long-term care facility residence, living alone, and long-term care beneficiary was used as covariates. RESULTS: Differences between the baseline and endpoint standardized function scores of the participants with impaired physical function and impaired cognitive function were 13.6 and 20.1, respectively. The magnitude of functional impairment due to tooth loss was greater for cognitive function than for physical function. The number of teeth lost was associated with approximately 1.4- and 1.7-point decrease in physical and cognitive functions, respectively (both p < 0.001). CONCLUSIONS: These findings suggest that the oral health status is essential for maintaining physical and cognitive functions and that oral health services can be effective in delaying functional impairment among the elderly residing in coordinated long-term care facilities.

Access to antenatal healthcare and the prevalence of oral clefts: a spatial analysis.

Congenital anomalies are caused by a variety of risk factors, including individual and environmental ones. This study estimated the prevalence of oral clefts and examined their area-level risk indicators using data from The National Congenital Anomaly Survey in South Korea. Disease mapping and ecological regression were used to assess the geographical variation and potential risk indicators for oral clefts, such as living in a rural area, material deprivation, and limited access to antenatal healthcare. In South Korea, 1.15 (95% CI, 1.08-1.23) children out of every 1,000 births were born with oral clefts during 2005 and 2006. The most common oral cleft type was cleft palate, followed by cleft lip, then cleft lip and palate. Disease mapping showed that the proportion of areas with a higher risk than the national average was relatively higher for oral clefts than for all congenital abnormalities among rural and healthcare underserved areas. The relative risk of oral cleft prevalence was higher in rural areas and healthcare underserved areas than in urban areas and areas with better access to healthcare. The findings suggest that access to antenatal healthcare as well as area-level risk indicators should be considered a priority when developing measures to decrease the occurrence of oral clefts.

Implant survival and patient satisfaction in completely edentulous patients with immediate placement of implants: a retrospective study.

BACKGROUND: This study evaluated full-arch rehabilitation of patients with immediately placed implants in terms of the cumulative implant survival rate, risk factors for implant failure, and patient satisfaction. METHODS: Time-to-event data of 52 completely edentulous jaws (370 implants) were collected using retrospective clinical chart review for the time period from 2008 to 2014. A conventional two stage approach for surgery was adopted to immediately placed implants in the maxilla, and immediate placement and immediate loading protocols for the mandible were followed. The study calculated the 7-year cumulative survival rates (CSR), and a Bayesian hierarchical Cox proportional hazard model was used to measure the effect of covariates. Patient satisfaction on chewing ability, esthetic appearance, and overall satisfaction was also measured with a face-to-face interview survey. RESULTS: Of the total 370 implants, 194 were immediate placement. Two delayed loading maxillary implants failed within the first year, and another one failed in the second year of loading. Two failures were recorded in the first year and one in seven years for the immediate loading mandibular implants. The 1-, 5-, and 7-year CSR of the 370 implants were 0.989 (0.979, 1.000), 0.986 (0.975, 0.998), and 0.978 (0.957, 0.999), respectively. Only the length of the implant affected implant failure (p < 0.05); other patient characteristics, systemic diseases, implant diameter, immediate loading, and immediate placement, did not have an effect on implant failure rates. Patients reported a high degree of satisfaction regardless of their age group or length of the observation period. CONCLUSIONS: Immediately placed implant had CSR as high as delayed placed implants, and 7-year CSRs of immediate loading were not significantly different from delayed loading. The procedure also had a high degree of chewing ability, esthetic appearance, and overall satisfaction. The study results suggested that the clinical procedures applied in this study to completely edentulous patients were acceptable rehabilitation procedures.

Inequality in unmet dental care needs among South Korean adults.

BACKGROUND: The current public health research agenda was to identify the means to reduce oral health inequalities internationally. The objectives of this study were to provide evidence of inequality in unmet dental needs and to find influencing factors attributable to those among South Korean adults. METHODS: Pooled cross-sectional data from the fourth Korean National Health and Nutrition Examination Survey (2007-2009) on 17,141 Korean adults were used. Demographic factors (sex, age, and marital status), socioeconomic factors (education level, employment status, and income level), need factors (normative dental needs and self-perceived oral health status), and oral health-related factors (the number of decayed teeth, the presence of periodontitis, and the number of missing teeth) were included. Multiple logistic regression analysis was performed. RESULTS: Of South Korean adults, 43.9% had perceived unmet dental needs, with the most common reason being financial difficulties. The disparities in unmet dental care needs were strongly associated with income level, normative treatment needs, and self-perceived oral health status. The low-income group, people with normative dental treatment needs, and those with perceived poor oral health status were more likely to have unmet dental needs. There was considerable inequality in unmet dental care needs due to economic reasons according to such socioeconomic factors as income and education level. CONCLUSIONS: Public health policies with the expansion of dental insurance coverage are needed to reduce inequalities in unmet dental care needs and improve the accessibility of dental care services to vulnerable groups who are experiencing unmet dental care needs due to socioeconomic factors despite having normative and self-perceived needs for dental treatment.

Determinants of gastric cancer screening attendance in Korea: a multi-level analysis.

BACKGROUND: We aimed to assess individual and area-level determinants of gastric cancer screening participation. METHOD: Data on gastric cancer screening and individual-level characteristics were obtained from the 2007-2009 Fourth Korea National Health and Nutrition Examination Survey. The area-level variables were collected from the 2005 National Population Census, 2008 Korea Medical Association, and 2010 National Health Insurance Corporation. The data were analyzed using multilevel logistic regression models. RESULTS: The estimated participation rate in gastric cancer screening adhered to the Korea National Cancer Screening Program guidelines was 44.0% among 10,658 individuals aged over 40 years who were included in the analysis. Among the individual-level variables, the highest income quartile, a college or higher education level, living with spouse, having a private health insurance, limited general activity, previous history of gastric or duodenal ulcer, and not currently smoking were associated with a higher participation rate in gastric cancer screening. Urbanization showed a significant negative association with gastric cancer screening attendance among the area-level factors (odds ratio (OR) = 0.73; 95% confidence interval (CI) = 0.57-0.93 for the most urbanized quartile vs. least urbanized quartile). CONCLUSION: There are differences in gastric cancer screening attendance according to both individual and regional area characteristics.

Association of periodontal disease treatment with mortality in patients with dementia: a population-based retrospective cohort study (2002-2018).

Dementia is one of the leading causes of death worldwide. In this study, we analyzed the association of periodontal treatment with the risk of death in patients with dementia. The analyzed data were obtained by linking the National Health Insurance Corporation claims data between 2002 and 2018 to the Statistics Korea death registry. In total, 1,131,406 patients with dementia aged ≥ 65 years had undergone dental treatment during the study period. Time-dependent Cox proportional hazards model was performed. The mortality rate was approximately 10% among the patients with dementia. The 17-years cumulative survival rates for patients who received periodontal treatment and their untreated counterparts were 83.5% and 71.5%, respectively. The crude hazard ratio of the periodontal group was approximately twice as high as that of the non-periodontal group (1.99; P < 0.001). Furthermore, in the regression model that was adjusted for socio-demographic variables and systematic chronic diseases, the risk of death in the non-periodontal group was approximately 1.83 times higher than that of the periodontal group (P < 0.00). These findings suggest that preventive periodontal treatment may decrease mortality risk in older people with dementia.

Trend in the Incidence of Severe Partial Edentulism among Adults Using the Korean National Health Insurance Service Claim Data, 2014-2018.

PURPOSE: Missing teeth is one of the most important indicators of oral health behavior and the result of dental caries, periodontal disease, and injuries. This study examined a trend in the incidence of severe partial edentulism (SPE) using the Korean National Health Insurance Service (KNHIS) data. MATERIALS AND METHODS: Data of adults aged ≥20 years were obtained from the KNHIS for the 2014-2018 period. SPE was defined in dental information within a population with a treatment history of dental scaling as having 1 to 8 natural teeth. Crude incidence rates (CIRs) and age-standardized incidence rates (AIRs) with 95% confidence interval were calculated per 100000 persons. The Cochran Armitage trend (CAT) test and average annual percentage change were used to analyze SPE trends. RESULTS: The CIRs among Korean adults were from 346.29 to 391.11 in 2014-2016 and from 391.11 to 354.09 in 2016-2018. The AIRs trend statistically increased by 4.31% from 346.29 to 376.80 and decreased by 4.72% from 376.80 to 342.10. The AIRs in men increased by 4.00% and decreased by 3.01%. The AIRs in women decreased by 2.18% and increased by 2.11% (CAT; p<0.01). The AIRs by region and income also showed trends of increase and decrease. CONCLUSION: The study showed that the incidence trend of SPE increased and decreased from 2014 to 2018. This result would be able to aid in the planning of public oral health, and may also serve as fundamental data for verifying the impact of the public oral health policies implemented.

Travel Time for Dental Care Services Based on Patient Preference in South Korea.

This study analyzed patient preferences using travel time from residence to dental institution when selecting dental care services. We used data from the Korean Health Panel from 2008 to 2017 and analyzed each dental service episode. Since the distribution of travel time was skewed to the left, median travel time was analyzed. The association of travel time with services was analyzed via the population-averaged generalized estimating equation (GEE) with the Poisson family. The median of the average travel time per episode was longer for non-National Health Insurance (NHI)-covered services and shorter for NHI-covered services. The first quintile of low-income subjects traveled the longest for all services and utilized dental care the most. In the GEE analysis, travel time was approximately three times longer for implant treatment and gold inlay/resin fillings and >2 times longer for orthodontic care than for NHI-covered services. Patients residing in rural counties traveled for longer than residents of large cities. Income was statistically significant; however, the coefficient was close to zero. Travel time was related to the type of service and reflected patient preference. This was more prominent for expensive non-NHI-covered services than for NHI-covered services. The findings suggest patients' subjective preferences for dental clinic selection are expressed as rational deliberation considering each individual's situation.

Incidence of edentulism among older adults using the Korean National Health Insurance Service database, 2013-2018.

OBJECTIVES: Population aging is rapidly accelerating worldwide. Oral diseases related to aging are also on the rise. This study examined trends in the incidence of edentulism among the older Korean population using data from the Korean National Health Insurance Service (KNHIS). METHODS: Data on older adults, aged ≥75 years of age, were obtained from the KNHIS for the period 2013-2018. Edentulism was defined as a treatment history of complete dentures in the KNHIS database. The exclusion criteria consisted of both disease codes and treatment codes related to conservative dental treatment, including periodontal and extraction treatment afterward. Crude incidence rates (CIRs) and age-standardized incidence rates (AIRs) with 95% confidence intervals were calculated and reported per 100,000 person-years by the direct method. Trends were tested by Cochrane Armitage models. RESULTS: Statistically significant increasing trends in both CIRs and AIRs were found among the older Korean population registered in the KNHIS (CIRs, 707.92 to 895.92; AIRs, 705.11 to 889.68; p<0.01). The incidence tended to increase in both genders (p<0.01). Both CIRs and AIRs in specific regions also showed slight but significant annual increases except for Jeju Island (p<0.01 or <0.05). The incidence showed increasing trends (p<0.01) in all income quintiles apart from the highest quintile. The edentulism incidence was highest in the lowest income group (the first quintile). CONCLUSIONS: Our data showed that the incidence of edentulism among the elderly showed an increasing trend from 2013 to 2018. This result provides a basis for future epidemiological studies on the incidence of edentulism in the older Korean population.

Dental Expenditure by Household Income in Korea over the Period 2008-2017: A Review of the National Dental Insurance Reform.

Since 2009, the National Health Insurance in Korea (NHI) has been implementing a series of policies to expand the scope of dental benefits. This study reviewed the changes in co-payments and dental use patterns before (2008 to 2012) and after (2013 to 2017) the NHI's dental health insurance reform. The study used Korea Health Panel data of 7681 households (16,493 household members) from a 10-year period (2008-2017). Dental expenditures and equivalent income using square root of household size were analyzed. Dental services were categorized into 13 types and a concentration index and 95% confidence interval using the delta method was calculated to identify income-related inequalities by a dental service. Dental expenditures and the number of dental services used increased significantly, while the proportion of out-of-pocket spending by the elderly decreased. The expenditure ratio for implant services to total dental expenditures increased substantially in all age groups, but the ratio of expenditures for dentures and fixed bridges decreased relatively. The concentration index of implant services was basically in favor of the rich, but there was no longer a significant bias favoring the better-off after the reforms. The dental health insurance reform in Korea appears to contribute not only to lowering the ratio of out-of-pocket to total dental expenses per episode in the elderly but also to improving the inequality of dental expenses.

Differences in income-related inequality and horizontal inequity in ambulatory care use between rural and non-rural areas: using the 1998-2001 U.S. National Health Interview Survey data.

BACKGROUND: To better understand income-related inequalities in health care use, it is imperative to identify sources of inequalities and assess the extent to which health care use is still related to income after differences in need across the income distribution are accounted for. Little is known regarding rural-urban differences in income-related inequalities and subgroup variation in horizontal inequities in health care use. This study decomposes income-related inequalities in ambulatory care use into contributions of need and non-need factors and compares horizontal inequities of subgroups in rural and non-rural areas. METHODS: This analysis used non-elderly adult samples from the 1998 to 2001 U.S. National Health Interview Survey data. The area of residence was categorized as rural for non-Metropolitan Statistical Area (MSA) and non-rural for MSA. Concentration indices of ambulatory care use were used to gauge income-related inequalities and decomposed into contributing factors. Horizontal inequities were measured using two methods and the results were compared. RESULTS: Ambulatory care use was disproportionately concentrated in the poor before need adjustment. However, the results of decomposition and horizontal inequity analyses indicate that the pro-poor concentration of health care use was due to greater health care need in low-income groups. Adjusting for need, ambulatory care use was distributed favoring the better-off, to a larger degree in non-rural areas. Health-related variables were the major contributors to income-related inequalities. Non-need factors, including socioeconomic factors, health insurance, and usual source of care, also contributed to income-related inequalities. There were variation in determinants' contributions to income-related inequalities between rural and non-rural populations and subgroup differences in horizontal inequities. Horizontal inequities were greater within non-whites, high school graduates, individuals with private health insurance, and those without a usual source of care with some geographic variation. CONCLUSIONS: Our analysis shows that seemingly pro-poor income-related inequalities in ambulatory care use were largely due to greater health care need among low-income groups. The results demonstrate different contributions of determinants to income-related inequalities and variation in horizontal inequities by subgroup and locale. The findings of this study should help identify targets for policy intervention for each rural and non-rural area.

Effects of socioeconomic factors and human activities on children's PM(10) exposure in inner-city households in Korea.

PURPOSE: In this study, we investigated how socioeconomic factors contributed to airborne PM(10) concentrations in living rooms and children's bedrooms in 50 homes in Korea from July to September 2008. METHODS: PM(10) was measured with the personal environmental monitor, and both a questionnaire and time activity diary were used to acquire data on socioeconomic factors and various human activities (i.e., cooking, cleaning, and smoking). Analysis of variance and general linear model were used to identify the effects of socioeconomic and behavioral factors on PM(10) concentrations. RESULTS: Mean PM(10) concentrations in living rooms and children's rooms were 45.3 ± 33.3 µg/m(3) and 45.9 ± 21.0 µg/m(3), respectively, whereas outdoor PM(10) concentrations were 50.0 ± 19.8 µg/m(3). Significant relationships were found between concentrations in children's rooms and living rooms, and also between indoor and outdoor concentrations. PM(10) concentrations in children's rooms varied significantly by region, parental education, floor of residence, and average monthly household expenses. Concentrations in living rooms varied significantly by the number of children. This implies that lower socioeconomic status can contribute to higher indoor PM(10) concentrations. Indoor PM(10) concentrations in households with cleaning, cooking, and smoking were higher than in homes without these activities. General linear model showed that the effects of socioeconomic factors on PM(10) concentrations were significant in the following order: region (the increment in estimate ß = 24.16), parental education (ß = -18.84), type of housing (ß = -16.97; p < 0.01), and number of children (ß = 19.12; p < 0.05). CONCLUSIONS: We found that indoor PM(10) concentrations were affected by socioeconomic factors rather than human behavioral activities. In determining the environmental policy for indoor air quality, it is important to consider various socioeconomic factors of subjects.

Socioeconomic and personal behavioral factors affecting children's exposure to VOCs in urban areas in Korea.

Volatile organic compounds (VOCs) are known to cause adverse health effects. We investigated the relationships between children's VOC exposure and socioeconomic and human activity factors with passive personal samplers, questionnaires, and time-activity diaries (TAD). Statistical analyses were conducted using SAS 9.1, and the results were organized using SigmaPlot 8.0 software. Chemicals such as benzene, toluene, 2-butanone, ethylbenzene, xylene, chloroform, n-hexane, heptane, and some kinds of decanes, which are known to adversely affect public health, were identified in measured samples. These were mainly emitted from outdoor sources (e.g., vehicular traffic) or indoor sources (e.g., household activities such as cooking and cleaning) or both. We concluded that region was the most important socioeconomic factor affecting children's VOC exposure, and the significant compounds were n-hexane (p = 0.006), 1,1,1-trichloroethane (p = 0.001), benzene (p = 0.003), toluene (p = 0.002), ethylbenzene (p = 0.020), m-, p-xylene (p = 0.014), dodecane (p = 0.003), and hexadecane (p = 0.001). Parental education, year of home construction and type of housing were also slightly correlated with personal VOC exposure. Only the concentration of o-xylene (p = 0.027) was significantly affected by the parental education, and the concentrations of benzene (p = 0.030) and 2-butanone (p = 0.049) by the type of housing. Also, tridecane (p = 0.049) and n-hexane (p = 0.033) were significantly associated with the year of home construction. When household activities such as cooking were performed indoors, children's VOC concentrations tended to be higher, especially for n-hexane, chloroform, heptane, toluene (p < 0.05), 1,1,1-trichloroethane, benzene, dodecane, and hexadecane (p < 0.01). However, smoking had a significant effect for only dodecane, and cleaning had no impact on any VOC concentrations. Considering both socioeconomic and personal behavioral factors simultaneously, socioeconomic factors such as region had a greater effect on children's VOC exposures than indoor activities. From this study, we can suggest that socioeconomic factors as well as environmental factors should be considered when formulating environmental policy to protect children's health.

Spatial barriers and the bypassing of nearby dental clinics for dental services: a secondary data analysis in Korea.

OBJECTIVE: This study aimed to calculate the distance patients travel to dental clinics, the rate of bypassing nearby dental clinics and the distance covered when bypassing nearby dental clinics, and explored factors associated with patients' spatial access to dental clinics. DESIGN: A secondary data analysis. SETTING: Korea Health Panel. PARTICIPANTS: We included users of dental care services from 2008 to 2011. A total of 2375 patients and 15 978 dental visits were analysed. PRIMARY OUTCOME MEASURES: Korea Health Panel data (2008-2011) were used to geocode patients' and healthcare facilities' addresses. The distance travelled was calculated using road network information. To analyse the panel data, we adopted a generalised estimating equation: geographical measures on the choice of dental care facility were examined based on sex, age, educational level, equivalent income, treatment details and regional classification. RESULTS: The median distance travelled to a dental clinic was 1.8 km, which is farther for rural (8.4 km) than for urban (1.5 km) patients. The bypass rate was 58.9%. Patients bypassing nearby dental clinics travelled 9.6 times farther for dental care (p<0.001). Unlike bypass distance, travel distance was not associated with equivalent income. People with higher education and those with implants/orthodontic treatment were more likely to bypass nearby dental clinics and travelled 1.27 times and 1.17 times farther (p<0.01), respectively. CONCLUSIONS: Given the spatial barrier to available dental resources, factors associated with spatial access were mostly the same between travel and bypass distance except for equivalent income. The findings of this study suggest that spatial distance acts as a utilisation barrier and demands additional opportunity cost. At the same time, patients' preferences for services also increase their willingness to bypass nearby dental clinics and travel greater distances.

Does the regional deprivation impact the spatial accessibility to dental care services?

The aim of the present study was to assess the regional deprivation and individual factors that influence how far a person will travel to access dental care. Using data from the Korea Health Panel (2008 to 2011), we selected a group of 4,256 subjects and geocoded their homes and dental hospitals/clinics. Using the road network analysis, we calculated the distance traveled by the subjects for dental care. We used the generalized estimating equation (GEE) for repeated data analysis and included an interaction term between regional deprivation and individual income to determine the effects of the two factors on the choice of a dental hospital/clinic. When the regional deprivation index was divided into three quarters (high, middle, and low), urban areas had higher"high" and "low" levels of deprivation, and rural areas had relatively higher middle level of deprivation. GEE regression showed that the level of education, regional deprivation level, and income all affected the distance traveled to dental clinics. The regional deprivation level had a higher association than income with the travel distance. At the same income level, subjects who lived in the least deprived areas were more likely to travel longer distances than subjects living in the most deprived areas. Regarding the distribution of dental hospitals/clinics, incentive based dental polices for either dental providers or patients are needed that will assure the delivery of dental care despite spatial inequality.

Geographical Distribution and Seasonal Indices of Chigger Mites on Small Mammals Collected on the East Coast of the Republic of Korea.

The geographical distributions and relative population densities of scrub typhus vector mites collected from small mammals were determined for 5 locations on the east coast of the Republic of Korea. Collection sites included Goseong, Gangneung, and Hoengseong in Gangwon province and Uljin and Yeongdeok in Gyeongbuk province. A total of 275 small mammals including members of Rodentia (rodents) and Soricomorpha (shrews, such as Crocidura lasiura ) belonging to 4 genera and 4 species were captured in the field from 2012 to 2013. Apodemus agrarius was collected most frequently (220, 80%), followed by C. lasiura (25, 9.1%), Mus musculus (15, 5.5%), and Myodes regulus (15, 5.5%). A total of 23,436 larval chigger mites (Family Trombiculidae) belonging to 3 genera and 8 species (Leptotrombidium pallidum, Leptotrombidium scutellare, Leptotrombidium palpale, Leptotrombidium orientale, Leptotrombidium zetum, Neotrombicula tamiyai, Neotrombicula japonica, and Euschoengastica koreaensis) were collected from the small mammals. The predominant chigger species collected during the spring and fall seasons from A. agrarius were L. pallidum (57.6%), L. palpale (14.5%), and L. scutellare (7.9%). Leptotrombidium scutellare was collected only along the southeastern coast at Yeongdeok, Gyeongbuk province. The geographical distribution of scrub typhus vectors and reservoir hosts are important aspects of understanding the epidemiology of the disease as well as the potential impacts of climate change and health risks.

Diseases having an influence on inhibition of angiogenesis as risk factors of osteonecrosis of the jaw.

OBJECTIVES: The objective of this study was to retrospectively investigate the association of diseases having an influence on inhibition of angiogenesis such as hypertension, diabetes mellitus type II, hypercholesterolemia, and rheumatoid arthritis (RA) with the development of osteonecrosis of the jaws. MATERIALS AND METHODS: The 135 patients were allocated into 4 groups of bisphosphonate-related osteonecrosis of the jaw (BRONJ) group (1A); non-BRONJ group (1B); osteonecrosis of the jaw (ONJ) group (2A); and control group (2B), according to histologic results and use of bisphosphonate. This retrospective study was conducted with patients who were treated in one institute from 2012 to 2013. Fisher's exact test and logistic regression analysis were used to analyze the odds ratios of diseases having an influence on inhibition of angiogenesis for development of ONJ. RESULTS: The effects of diabetes and hypertension were not statistically significant on development of ONJ. When not considering bisphosphonate use, RA exhibited a high odds ratio of 3.23 (P=0.094), while hyperlipidemia showed an odds ratio of 2.10 (P=0.144) for development of ONJ. More than one disease that had an influence on inhibition of angiogenesis showed a statistically significant odds ratio of 2.54 (P=0.012) for development of ONJ. CONCLUSION: Patients without diseases having an influence on inhibition of angiogenesis were at less risk for developing ONJ.