Relationship between community-level variables and number of general dentists.

BACKGROUND: In this study, the authors used observational data from 2014 to evaluate the association between the number of general dentists and several community characteristics. METHODS: The authors collected community-level characteristics from secondary sources for all 947 Iowa incorporated communities to study their relationships with the mean number of general dentists per 1,000 population per square mile (population density), the dependent variable. The authors used zero-inflated negative binomial models to examine the association between the dependent and predictor variables. RESULTS: Only 22.8% of communities had a dentist. Urban, young, well-educated, fluoridated communities with at least 1 elementary school had the highest estimated mean concentration of dentists. Isolated communities with older, less educated adults and lacking fluoridation and an elementary school had the fewest dentists. CONCLUSIONS: Although population is an important determinant for where a dentist practices, other variables such as urbanization, demographic characteristics, fluoridation status, and presence of at least 1 elementary school are also predictors of the number of dentists in a community. PRACTICAL IMPLICATIONS: These findings provide dental students and young practitioners useful information by highlighting community characteristics that are associated with office locations.

Travel burden and dentist bypass among dentally insured children.

OBJECTIVES: Using administrative data from Iowa Medicaid and a large private dental insurer, we compared distance to the nearest primary care dentist for children ages 6-15 in 2012. Additionally, we examined rates of provider bypass in both populations as an indicator of spatial accessibility to dental care. METHODS: We calculated measures of travel burden, including distance to the nearest primary care dentist and distance to current primary care dentist. Distance outcomes and rates of bypass, traveling beyond the nearest dentist for care, were compared by insurance type. RESULTS: We found that Medicaid-enrolled children lived farther from the nearest dentist and farther from their current dentist than privately insured children. However, rates of bypass were higher among the privately insured population. These results were consistent among urban and rural residents; additionally, both rural populations demonstrated greater travel distances than urban dwellers. CONCLUSIONS: Travel burden was greater among Medicaid-enrolled children. Lower rates of bypass, in conjunction with lower rates of dental utilization in this population, may indicate a distance threshold beyond which dental care becomes unattainable.

Uncontrolled combustion of shredded tires in a landfill -Part 2: Population exposure, public health response, and an air quality index for urban fires.

The Iowa City Landfill in eastern Iowa, United States, experienced a fire lasting 18 days in 2012, in which a drainage layer of over 1 million shredded tires burned, generating smoke that impacted the surrounding metropolitan area of 130,000 people. This emergency required air monitoring, risk assessment, dispersion modeling, and public notification. This paper quantifies the impact of the fire on local air quality and proposes a monitoring approach and an Air Quality Index (AQI) for use in future tire fires and other urban fires. Individual fire pollutants are ranked for acute and cancer relative risks using hazard ratios, with the highest acute hazard ratios attributed to SO2, particulate matter, and aldehydes. Using a dispersion model in conjunction with the new AQI, we estimate that smoke concentrations reached unhealthy outdoor levels for sensitive groups out to distances of 3.1 km and 18 km at 24-h and 1-h average times, respectively. Modeled and measured concentrations of PM2.5 from smoke and other compounds such as VOCs and benzo[a]pyrene are presented at a range of distances and averaging times, and the corresponding cancer risks are discussed. Through reflection on the air quality response to the event, consideration of cancer and acute risks, and comparison to other tire fires, we recommend that all landfills with shredded tire liners plan for hazmat fire emergencies. A companion paper presents emission factors and detailed smoke characterization.