bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative Assessment of the Risk of Lung Cancer Associated with Occupational Exposure to Refractory Ceramic Fibers
Authors: Moolgavkar Suresh H. , Luebeck E. Georg , Turim Jay , Hanna Linda
Published: May 2006

We present the results of a quantitative assessment of the lung cancer risk associated with occupational exposure to refractory ceramic fibers (RCF). The primary sources of data for our risk assessment were two long‐term oncogenicity studies in male Fischer rats conducted to assess the potentialpathogenic effects associated with prolonged inhalation of RCF. An interesting feature of the data was the availability of the temporal profile of fiber burden in the lungs of experimental animals. Because of this information, we were able to conduct both exposure‐response and dose‐response analyse. Our risk assessment was conducted within the framework of a biologically based model for carcinogenesis, the two‐stage clonal expansion model, which allows for the explicit incorporation of the concepts of initiation and promotion in the analyses. We found that a model positing that RCF was an initiator had the highest likelihood. We proposed an approach based on biological considerations for the extrapolation of risk to humans. This approach requires estimation of human lung burdens for specific exposure scenarios, which we did by using an extension of a model due to Yu. Our approach acknowledges that the risk associated with exposure to RCF depends on exposure to other lung carcinogens. We present estimates of risk in two populations: (1)a population of nonsmokers and (2) an occupational cohort of steelworkers not exposed to coke oven emissions, a mixed population that includes both smokers and nonsmokers.
On Intergenerational Equity and Its Clash with Intragenerational Equity and on the Need for Policies to Guide the Regulation of Disposal of Wastes and Other Activities Posing Very Long‐Term Risks
Authors: Okrent David
Published: May 2006

This article begins with some history of the derivation of 40 CFR Part 191, the U.S. Environmental Protection Agency (EPA) standard that governs the geologic disposal of spent nuclear fuel and high‐level and transuranic radioactive wastes. This is followed by criticisms of the standard that were made by a Sub‐committee of the EPA Science Advisory Board, by the staff of the U.S. Nuclear Regulatory Commission, and by a panel of the National Academies of Science and Engineering. The large disparity in the EPA approaches to regulation of disposal of radioactive wastes and disposal of hazardous, long‐lived, nonradioactive chemical waste is illustrated. An examination of the intertwined matters of intergenerational equity and the discounting of future health effects follows, together with a discussion of the conflict between intergenerational equity and intragenerational equity. Finally, issues related to assumptions in the regulations concerning the future state of society and the biosphere are treated, as is the absence of any national philosophy or guiding policy for how to deal with societal activities that pose very long‐term risks.
Performance Assessment in Support of the 1996 Compliance Certification Application for the Waste Isolation Pilot Plant
Authors: Helton J. C. , Anderson D. R. , Jow H.‐N. , Marietta M. G. , Basabilvazo G.
Published: May 2006

The conceptual and computational structure of a performance assessment (PA) for the Waste Isolation Pilot Plant (WIPP) is described. Important parts of this structure are (1) maintenance of a separation between stochastic (i.e., aleatory) and subjective (i.e., epistemic) uncertainty, with stochastic uncertainty arising from the many possible disruptions that could occur over the 10,000‐year regulatory period that applies to the WIPP, and subjective uncertainty arising from the imprecision with which many of the quantities required in the analysis are known, (2) use of Latin hypercube sampling to incorporate the effects of subjective uncertainty, (3) use of Monte Carlo (i.e., random) sampling to incorporate the effects of stochastic uncertainty, and (4) efficient use of the necessarily limited number of mechanistic calculations that can be performed to support the analysis. The WIPP is under development by the U.S. Department of Energy (DOE) for the geologic (i.e., deep underground) disposal of transuranic (TRU) waste, with the indicated PA supporting a Compliance Certification Application (CCA) by the DOE to the U.S. Environmental Protection Agency (EPA) in October 1996 for the necessary certifications for the WIPP to begin operation. The EPA certified the WIPP for the disposal of TRU waste in May 1998, with the result that the WIPP will be the first operational facility in the United States for the geologic disposal of radioactive waste.
Adaptive Spatial Sampling of Contaminated Soil
Authors: Cox Louis Anthony
Published: May 2006

Suppose that a residential neighborhood may have been contaminated by anearby abandoned hazardous waste site. The suspected contamination consistsof elevated soil concentrations of chemicals that are also found in the absence of site‐related contamination. How should a risk manager decide which residential properties to sample and which ones to clean? This paper introduces an adaptive spatial sampling approach which uses initial observations to guide subsequent search. Unlike some recent model‐based spatial data analysis methods, it does not require any specific statistical model for the spatial distribution of hazards, but instead constructs an increasingly accurate nonparametric approximation to it as sampling proceeds. Possible cost‐effective sampling and cleanup decision rules are described by decision parameters such as the number of randomly selected locations used to initialize the process, the number of highest‐concentration locations searched around, the number of samples taken at each location, a stopping rule, and a remediation action threshold. These decision parameters are optimized by simulating the performance of each decision rule. The simulation is performed using the data collected so far to impute multiple probable values ofunknown soil concentration distributions during each simulation run. This optimized adaptive spatial sampling technique has been applied to real data using error probabilities for wrongly cleaning or wrongly failing to clean each location (compared to the action that would be taken if perfect information were available) as evaluation criteria. It provides a practical approach for quantifying trade‐offs between these different types of errors and expected cost. It also identifies strategies that are undominated with respect to all of these criteria.
Comparison of Six Dose‐Response Models for Use with Food‐Borne Pathogens
Authors: Holcomb David L. , Smith Mary A. , Ware Glenn O. , Hung Yen‐Con , Brackett Robert E. , Doyle Michael P.
Published: May 2006

Food‐related illness in the United States is estimated to affect over six million people per year and cost the economy several billion dollars. These illnesses and costs could be reduced if minimum infectious doses were established and used as the basis of regulations and monitoring. However, standard methodologies for dose‐response assessment are not yet formulated for microbial risk assessment. The objective of this study was to compare dose response models for food‐borne pathogens and determine which models were most appropriate for a range of pathogens. The statistical models proposed in the literature and chosen for comparison purposes were log‐normal,(19) log‐logistic,(17) exponential,(7,9,17)ß‐Poisson(7,9,18) and Welbull‐Gamma.(3) These were fit to four data sets also taken from published literature, Shigella fiexneri,(9,12,13)Shigella dysenteriae,(9,11)Campylobacter jejuni,(15,16) and Salmonella typhosa,(7,14) usingthe method of maximum likelihood. The Weibull‐gamma, the only model with three parameters, was also the only model capable of fitting all the data sets examined using the maximum likelihood estimation for comparisons. Infectious doses were also calculated using each model. Within any given data set, the infectious dose estimated to affect one percent of the population ranged from one order of magnitude to as much as nine orders of magnitude, illustrating the differences in extrapolation of the dose response models. More data are needed to compare models and examine extrapolation from high to low doses for food‐borne pathogens.
Monte Carlo Sensitivity Analysis of Unknown Parameters in Hazardous Materials Transportation Risk Assessment
Authors: Pet‐Armacost Julia J. , Sepulveda Jose , Sakude Milton
Published: May 2006

The US Department of Transportation was interested in the risks associated with transporting Hydrazine in tanks with and without relief devices. Hydrazine is both highly toxic and flammable, as well as corrosive. Consequently, there was a conflict as to whether a relief device should be used or not. Data were not available on the impact of relief devices on release probabilities or the impact of Hydrazine on the likelihood of fires and explosions. In this paper, a Monte Carlo sensitivity analysis of the unknown parameters was used to assess the risks associated with highway transport of Hydrazine. To help determine whether or not relief devices should be used, fault trees and event trees were used to model the sequences of events that could lead to adverse consequences during transport of Hydrazine. The event probabilities in the event trees were derived as functions of the parameters whose effects were not known. The impacts of these parameters on the riskof toxic exposures, fires, and explosions were analyzed through a Monte Carlo sensitivity analysis and analyzed statistically through an analysis of variance. The analysis allowed the determination of which of the unknown parameters had a significant impact on the risks. It also provided the necessary support to a critical transportation decision even though the values of several key parameters were not known.
Health Risk Assessment of a Modern Municipal Waste Incinerator
Authors: Boudet Cline , Zmirou Denis , Laffond Mauricette , Balducci Franck , Benoit‐Guyod Jean‐Louis
Published: May 2006

During the modernization of the municipal waste incinerator (MWI, maximum capacity of 180,000 tons per year) of Metropolitan Grenoble (405,000 inhabitants), in France, a risk assessment was conducted, based on four tracerpollutants: two volatile organic compounds (benzene and 1,1,1 trichloroethane) and two heavy metals (nickel and cadmium, measured in particles). A Gaussian plume dispersion model, applied to maximum emissions measured at the MWI stacks, was used to estimate the distribution of these pollutants in the atmosphere throughout the metropolitan area. A random sample telephone survey (570 subjects) gathered data on time‐activity patterns, according to demographic characteristics of the population. Life‐long exposure was assessed as a time‐weighted average of ambient air concentrations. Inhalation alone was considered because, in the Grenoble urban setting, other routes of exposure are not likely. A Monte Carlo simulation was used to describe probability distributions of exposures and risks. The median of the life‐long personal exposures distribution to MWI benzene was 3.2 · 10−5μg/m3 (20th and 80th percentiles = 1.5 · 10−5 and 6.5 · 10−5μg/m3), yielding a 2.6 · 10−10 carcinogenic risk (1.2 · 10−10 ‐ 5.4 · 10−10). For nickel, the corresponding life‐time exposure and cancer risk were 1.8 ·10−4μg/m3 (0.9 ·10−4 ‐ 3.6 ·10−4μg/m3) and 8.6 · 10−8 (4.3 · 10−8 ‐ 17.3 ·10−8); for cadmium they were respectively 8.3 ·10−6μg/m3 (4.0 ·10−6 ‐ 17.6 ·10−6) and 1.5 · (7.2 · 10−9 ‐ 3.1. · 10−8). Inhalation exposure to cadmium emitted by the MWI represented less than 1% of the WHO Air Quality Guideline (5 ng/m3), while there was a margin of exposure of more than 109 between the NOAEL (150 ppm) and exposure estimates to trichloroethane. Neither dioxins nor mercury, a volatile metal, were measured. This could lessen the attributable life‐long risks estimated. The minute (VOCs and cadmium) to moderate (nickel) exposure and risk estimates are in accord with other studies on modern MWIs meeting recent emission regulations, however.
Dose Response Models For Infectious Gastroenteritis
Authors: Teunis Peter F. M. , Nagelkerke Nico J. D. , Haas Charles N.
Published: May 2006

When pathogenic microorganisms enter the human body via ingestion with food or drinking water, they encounter a system of barriers mounted by the host. In order to reach parts of the intestinal tract that are suitable forgrowth and attachment, each of the bamers must be overcome successfully. The present view on infection states that at least one of the ingested pathogens must survive to start colonization. This is the basis for dose responsemodels, used for quantitative risk assessment. In this paper, the usefulness of the Beta Poisson model for multiple barriers is corroborated. Infection is associated with the presence of elevated numbers of reproducing pathogens in the intestinal tract. This does not necessarily imply illness symptoms: when intestinal microorganisms engage in damaging activities, this may lead to illness symptoms. At the same time, these activities probably elicit defensive measures from the host, promoting the removal of pathogens and terminating infection. The duration of the period of colonization reflects the balance between the colonization potential of pathogens and the strength of host defenses. Starting from the assumption that during infection the host has a certain hazard of becoming ill, a simple dose response relation for acute gastroenteritis is developed. With the use of literature data from volunteer experiments, we show that examples can be found for three possible alternatives: an increase in the probability of illness with increasingdose, a decrease with higher doses, and a probability of illness (given infection) independent of the ingested dose. These alternatives may reflect different modes of interaction between pathogens and host.
Stock Options and the Corporate Demand for Insurance
Authors: Han Li‐Ming , MacMinn Richard
Published: May 2006

Abstract

This article shows that a corporate manager compensated in stock options makes corporate decisions to maximize stock option value. Overinvestment is a consequence if risk increases with investment. Facing the choice of hedging corporate risk with forward contracts on a stock market index fund and insuring pure risks the manager will choose the latter. Hedging with forwards reduces weight in both tails of corporate payoff distribution and thus reduces option value. Insuring pure risks reduces the weight in the left tail where the options are out‐of‐the‐money and increases the weight in the right tail where the options are in‐the‐money; the effect is an increase in the option value. Insurance reduces the overinvestment problem but no level of insurance coverage can reduce investment to that which maximizes the shareholder value.
Bonamia perspora n. sp. (Haplosporidia), a Parasite of the Oyster Ostreola equestris, is the First Bonamia Species Known to Produce Spores
Authors: CARNEGIE RYAN B. , BURRESON EUGENE M. , MIKE HINE P. , STOKES NANCY A. , AUDEMARD CORINNE , BISHOP MELANIE J. , PETERSON CHARLES H.
Published: May 2006

ABSTRACT. Examination of the oyster Ostreola equestris as a potential reservoir host for a species of Bonamia discovered in Crassostrea ariakensis in North Carolina (NC), USA, revealed a second novel Bonamia sp. Histopathology, electron microscopy, and molecular phylogenetic analysis support the designation of a new parasite species, Bonamia perspora n. sp., which is the first Bonamia species shown to produce a typical haplosporidian spore with an orifice and hinged operculum. Spores were confirmed to be from B. perspora by fluorescent in situ hybridization. Bonamia perspora was found at Morehead City and Wilmington, NC, with an overall prevalence of 1.4% (31/2,144). Uninucleate, plasmodial, and sporogonic stages occurred almost exclusively in connective tissues; uninucleate stages (2–6 μm) were rarely observed in hemocytes. Spores were 4.3–6.4 μm in length. Ultrastructurally, uninucleate, diplokaryotic, and plasmodial stages resembled those of other spore‐forming haplosporidians, but few haplosporosomes were present, and plasmodia were small. Spore ornamentation consisted of spore wall‐derived, thin, flat ribbons that emerged haphazardly around the spore, and which terminated in what appeared to be four‐pronged caps. Number of ribbons per spore ranged from 15 to 30, and their length ranged from 1.0 to 3.4 μm. Parsimony analysis identified B. perspora as a sister species to Bonamia ostreae.
Stylonychia lemnae Strains from a North American Site Differ in a Single Nucleotide within the Small Subunit rDNA from Eurasian Strains
Authors: SCHMIDT STEPHANIE L. , AMMERMANN DIETER , SCHLEGEL MARTIN , BERNHARD DETLEF
Published: May 2006

ABSTRACT. Stylonychia lemnae (Ciliophora, Spirotrichea), a member of the Stylonychia mytilus complex, shows a global distribution, occurring in many temperate fresh waters. As there are few descriptions of biogeographical patterns of ubiquitously occurring ciliated protozoans, we report a distinct sequence difference within the small subunit ribosomal DNA gene, which occurs only in the clones of S. lemnae isolated from the surroundings of Ithaca (USA) in comparison with clones of the same species from different regions in Europe, Asia, and South Africa.
Comparative Cytological Study of Four Species in the Genera Holomastigotes and Uteronympha n. comb. (Holomastigotidae, Parabasalia), Symbiotic Flagellates of Termites
Authors: BRUGEROLLE GUY
Published: May 2006

ABSTRACT. Cytological features observed using light, immunofluorescence, and electron microscopy of the type species Holomastigotes elongatum were compared with Holomastigotes lanceolata and to Holomastigotes flexuosum n. sp. The comparison was extended to Spirotrichonymphella pudibunda and to Uteronympha africana n. gen. n. sp., in order to present the common features of the Holomastigotidae (Spirotrichonymphida). All these species have anterior basal bodies bearing microfibrillar or striated rootlets that are reduced or absent posterior to the nucleus. An axostylar trunk is present in Holomastigotes elongatum and Holomastigotes lanceolata, whereas the axostylar microtubules do not extend posterior to the nucleus in Holomastigotes flexuosum, Spirotrichonymphella, and Uteronympha. Uteronympha africana has specific features, such as a transverse plaque inside the columella from which arise microtubules capping the nucleus, and as in Spirotrichonympha the striated lamina is present all along the flagellar lines. Uteronympha africana has ability to endocytose wood particles in addition to the osmotrophic feeding that occurs in all the Holomastigotidae.
Ocular complications in a child with acute graft‐versus‐host disease following cord blood stem cell transplantation: therapeutic challenges
Authors: Uchino Miki , Ogawa Yoko , Kawai Masataka , Shimada Hiroyuki , Kameyama Kaori , Okamoto Shinichiro , Dogru Murat , Tsubota Kazuo
Published: May 2006

We present the first child case of pseudomembranous conjunctivitis accompanied by an extensive corneal ulcer with acute graft‐versus‐host disease (GVHD) after cord blood stem cell transplantation (CBSCT). The histopathology of the pseudomembrane and the ocular changes following its excision were investigated specifically. One week after the excision of pseudomembrane, the extensive corneal epithelial defects had totally disappeared. Pseudomembrane excision may be an effective method of treatment in corneal epithelial defects observed after GVHD.
Early diagnosis of exfoliation syndrome in the offspring of affected patients
Authors: Oliveira Cristiano , Schlötzer‐Schrehardt Ursula , Vieira Geraldo , Liebmann Jeffrey , Ritch Robert
Published: May 2006

Purpose:  To determine whether conjunctival biopsy in the offspring of patients with exfoliation syndrome (XFS) can provide early diagnosis of the disease.

Methods:  Patients with XFS with or without glaucoma were invited to ask their sons and daughters over the age of 40 years to participate in the study. After a complete eye examination, those without clinically evident XFS underwent conjunctival biopsy. The specimens were examined by transmission electron microscopy.

Results:  A total of 17 sons and daughters (seven men, 10 women) of 17 patients were enrolled. Their mean age was 50.3 ± 8 years. Twelve specimens were negative and five presented precursor material evidence of typical exfoliation material.

Conclusion:  Evidence of early deposition of exfoliation material can be found in the conjunctiva of the middle‐aged offspring of patients with XFS, substantiating the existence of a hereditary predisposition to this disease.
Dental status, diet and cardiovascular risk factors in middle‐aged people in northern Sweden
Authors: Johansson Ingegerd , Tidehag Per , Lundberg Vivan , Hallmans Göran
Published: May 2006

Abstract The aim of the present study was to compare the dietary intake and the levels of traditional cardiovascular (CVD) risk factors in edentulous middle‐aged individuals and individuals of the same age and sex who still had natural teeth. The study was performed within the framework of the MONICA‐project. Population registers were used to sample randomly 1287 men and 1330 women aged 25–64 yr. Data were collected from a mailed questionnaire, blood analyses, registrations of blood pressure and anthropometric measures. The estimated daily energy intake did not differ between the two groups, but edentulous men and women ate more sweet snacks compared to those who still had teeth. Edentulous men also ate less fruits, vegetables and fibre and edentulous women ate more fat than dentates. Edentulous men and women were more obese and had lower serum HDL‐cholesterol concentrations than those with remaining teeth. Edentulous women also had significantly higher concentrations of total cholesterol and triglycerides in serum than dentate women. Edentulous men and women were more often regular smokers, but not snuff users, than dentates of the same age and sex. Thus, the presence of two or more cardiovascular risk factors was more common in edentulous individuals than in those who still had natural teeth. In summary, these results support the hypothesis that edentulous middle‐aged individuals have a more unfavourable risk factor profile for CVD. Counselling on balanced dietary habits and non‐smoking given by dental personnel to orally diseased patients – recommendations given to improve resistance to dental caries or periodontitis – might therefore improve general health and possibly also improve risk factors for CVD.
Perceived, desired, and normatively determined orthodontic treatment needs in male US Army recruits
Authors: Searcy Victoria L. , Chisick Michael C.
Published: May 2006

Abstract This study assessed perceived, desired, and normative need for orthodontic care in a systematic random sample of 576 male enlisted Army recruits at one Army post in fall 1990. Perceived and desired need were collected using a pretested questionnaire. Normative need was assessed on all participants by one dentist using the Treatment Priority Index. Results show 16.3% of enlisted male Army recruits have severe or handicapping malocclusions. yet only one‐third desire corrective treatment. Preference for orthodontic care is strongly influenced by the recruit's education level. We recommend that military health policymakers consider expanding access to adult orthodontic care for active duty military personnel to keep pace with its widening acceptance by the general public and to keep the military health benefits package competitive with those of civilian employers.
Influence of exposure to various fluoride technologies on the prevalence of dental fluorosis
Authors: Clark D. Christopher , Hann H. Jack , Williamson Malcolm F. , Berkowitz Jonathan
Published: May 2006

Abstract An increase in the prevalence of dental fluorosis among children in North America is well documented. Published reports of the relationship between the occurrence of dental fluorosis and early exposure to various fluorides and the use of different types of infant feeding practices have begun to provide insights into possible causes for this increase. This study was designed to investigate this issue for children living in a non‐fluoridated and a fluoridated community in British Columbia, Canada. Parents or guardians completed a questionnaire which detailed exposure to different types of fluorides and infant feeding practices during the first 6 yr of life. Completed questionnaires were returned and examinations were performed on 1131 children. 60% of children had dental fluorosis, and only 8% presented with scores of 2 or greater. Logistic regression analyses showed that the use of infant formula and parental educational attainment were significantly associated with the occurrence of dental fluorosis in the range of scores from 2 to 6. Despite these statistically significant findings, these variables actually had little additional predictive value beyond a chance occurrence in determining which children would have dental fluorosis.
Use of dental services by the middle‐aged and the elderly in Hong Kong
Authors: Schwarz Eli , Lo Edward C. M.
Published: May 2006

Abstract The objectives of this analysis were to describe the dental service use pattern of the 35–44‐ and 65–74‐yr‐old age groups and to determine to what extent this pattern could be explained by selected sociodemographic and attitudinal variables. The study populations comprised 398 35–44‐yr‐old and 559 65–74‐yr‐old Hong Kong Chinese. Use of dental services was determined on the basis of the respondents' own perception of the regularity of their dental visits and by the time since the last denial visit. The younger groups was categorized into regular users, irregular users, and nonusers, and the older group was categorized into three groups according to last dental visit (within 2 yr, 2–5‐yr, 5 yr or more). A modification of the Andersen and Newman model for individual determinants of health care use was used as the framework for a logistic regression analysis. Predisposing variables were sex, education, occupation, altitudes, knowledge, preventive orientation, and dental anxiety; enabling variables were Family Possession Index, income, family support and access to a dental programme; need variables were perceived conditions of teeth, denial problems, denial pain, need for treatment, normative need for treatment, and denture wearing. In general, use of denial services was low. For the 35–44‐yr‐olds, the best regression model (sensitivity: 62%, specificity: 95%, overall correct classification: 88%) indicated that there was an increased probability of having a regular dental care pattern if respondents were prevention oriented, had access to a dental benefit programme, had not experienced pain, had a higher income, perceived their teeth as fair or poor, and perceived a need of treatment. For the 65–74‐yr‐olds, three variables remained in the final model (sensitivity: 51%, specificity: 68%, overall correct classification: 61%). Respondents who had not seen a dentist within the last 2 yr were more likely to have had pain and to know less about dental caries. As the number of teeth in need of treatment increased by 1, respondents were 1.09 times more likely not to have seen a dentist within 2 yr.
Periodontal conditions among the middle‐aged and the elderly in Hong Kong
Authors: Holmgren Christopher J. , Corbet Esmonde F. , Lim L. P.
Published: May 2006

Abstract The aim of this study was to describe the periodontal conditions in 372 35–44‐yr‐old and 537 noninstitutionalized 65–74‐yr‐old Hong Kong Chinese who were examined clinically for loss of attachment, recession, probing depth, calculus, and bleeding after probing. Community Periodontal Index (CPI) data and treatment need indications were compiled from index teeth or their substitutes. The prevalence of loss of attachment varied considerably in both cohorts according to the definition of the threshold (≥6, ≥9, and ≥12 mm, respectively). The mean numbers of teeth with loss of attachment at the ≥6‐mm threshold and at higher thresholds were small. In both age cohorts, about one‐fifth of subjects had probing depths ≥6‐mm, while al the ≥9‐mm threshold only 2–3% were so affected. Although recession was an important component of loss of attachment in the younger cohort, in the older cohort the prevalence and extent of recession were greater than for probing depths at thresholds ≥4 mm. All subjects had one or more teeth with calculus, bleeding, or both, most teeth being so affected. Eighty‐four of the 537 65–74‐yr‐old subjects were excluded either because of edentulousness or because extractions indicated for the remaining teeth would have rendered the subjects edentulous. The distribution of subjects according to their highest CPI score was remarkably similar for the two cohorts. No subjects in either age group were assessed as “healthy” (CPI code 0) or had “bleeding only” (code 1) as their highest score. While most subjects scored CPI code 2 or 3 us their highest score, only 17% of the younger and 15% of the older cohort scored Community Periodontal Index of Treatment Needs (CPITN) code 4. Differences in the mean number of sextants affected by CPI codes between the two cohorts were mainly due to a greater number of excluded sextants in the older cohort. CPI findings for 35–44‐yr‐olds differed little from those reported in 1984.
Utilization of dental services in refugees in Sweden 1975–1985
Authors: Zimmerman M. , Bornstein R. , Martinsson T.
Published: May 2006

Abstract Prior to 1940 the population of Sweden was one of the most homogeneous in Europe, with only 0.5% foreign born. Fifty years later, in 1990, the proportion of immigrants was around 15%. In order to describe and analyze consumption of dental care in different refugee groups in Sweden, data registered by the Department of Immigration and the National Social Insurance Board, on a random sample of 2489 refugees arriving in Sweden 1975–85, were merged. Information on nationality, date of arrival in Sweden, date of granting of permanent resident status and statistics on consumption of dental care were retrieved. During the period studied a total of 50 521 refugees arrived in Sweden. The average interval between arrival in Sweden and the first dental visit was 4.5 yr (95% < 1: 4.2–4.7). The total treatment time during the first course of treatment was 165.5 min (95% < 1: 148.7–182.3). Consumption of dental care did not decrease with an increased number of treatments. Only 38% of the refugees had visited a dentist at all in Sweden. With increasing number of years in Sweden the number of courses of dental treatment increased, but 41% of the refugees who had visited the dentist in Sweden had done so only once. This study shows a low utilization of dental services among refugees in Sweden in general. Refugees with dental visits in Sweden, in particular, had a high dental consumption.
How is oral health education conducted in Finnish health centers'
Authors: Laiho Marja , Honkala Eino , Kaunas Lasse
Published: May 2006

Abstract The oral health education (OHE) given in Finnish health centers is mostly implemented by dental assistants and hygienists. However, there is no exact information concerning the distribution of OHE work and the working methods among individual health educators. The aims of this study were to assess 1) the time used for OHE by the dental professionals who bear most of the responsibility for OHE in health centers, and to evaluate 2) the collaboration between OH‐educators and the parents of schoolchildren, school personnel and the other health care personnel and 3) the sources of the OHE knowledge and skills of these OH‐educators and their methods according to their work load. The data for this study were collected from 323 OH‐educators. About one fourth (28%) of the OH‐educators used 40% or more of their working time for group OHE and one third (33%) used 40% or more of their time for individual OHE. These workers were considered to be full‐time OH‐educators. The mean age of the OH‐educators was 36 yr. The mean length of the OHE career was 8 yr. The most common OHE methods were a usual type of school lesson or a lesson in which the audience was questioned. Slides, models, transparencies and leaflets were the most general visual aids used.
Oral health in adolescents from a small French town
Authors: Weissenbach Michel , Chau Nearkasèn , Benamghar Lahoucine , Lion Christine , Schwartz Françoise , Vadot Jean
Published: May 2006

Abstract In France, caries are more prevalent in rural areas than in large cities. This study analyzed the relationship between number of oral health indices and some known risk factors (toothbrushing, sugar consumption, saliva components) and sociodemographic factors in adolescents from a small town. The sample included 112 children aged 12–14 in the north‐east of France. School marks was found to be better linked with dental caries indices than the socio‐occupational category of parents: gingival index (GI), DMFS, DMFT and caries severity (CS) significantly increased with decreasing school marks; oral plaque was related to socio‐occupational of parents. The analysis using the regression method showed that the variance explained by the various factors studied was modest (between 23 and 30%) for GI, initial caries sites (IS), DS, DMFS, DMFT and CS. and was small for plaque (5%) and calculus (3%). This would be due in part to the wide dispersion of these indices. The sex had a non‐significant regression coefficient for all oral health indices investigated. For GI, only mutans streptococci (MS) and plaque had a significant regression coefficient. Calculus was explained by any factor considered. Only MS had a significant part in plaque. IS was explained by MS, tooth‐brushing and age. For DS, only toothbrushing, MS and sweet drinks during meals had a significant part. DMFS and DMFT were explained only by MS and age. CS was explained by MS, age, salivary buffer pH, salivary flow rate, and tooth‐brushing.
Energy intake, dental caries and periodontal disease in 11‐year‐old black children in two regions of Southern Africa: KwaZulu and Namibia
Authors: Mackeown Jennifer M. , Cleaton‐Jones Peter E. , Hargreaves J. Anthony
Published: May 2006

Abstract The study examined energy intake in relation to dental caries and periodontal disease in 11‐yr‐old rural and urban black children in low fluoride areas of KwaZulu and Namibia (0.15 ppm F) and one higher fluoride area of Namibia (1.56 ppm F). Twenty‐four hour dietary recalls were conducted by trained interviewers and daily energy intake estimated using the MRC dietary analysis programme. DMFS was recorded according to WHO criteria; periodontal disease was measured using CPITN and SAS was used for statistical analysis. The prevalence of dental caries and periodontal disease (using CPITN), were compared within three energy groupings; ≤850 kcal/day; > 850, < 1400 kcal/day and ≥1400 kcal/day. The rural low fluoride Namibian children had the lowest mean energy intake (616 kcal/day), which also was the grouping with highest healthy periodontal prevalence (65%). The urban groups had higher energy intakes than the rural communities. Statistically significant effects on caries prevalence were seen for country and fluoride grouping; for periodontal disease, significant effects were noted for country, fluoride group and environment. Energy intake had no statistically significant effect, so this is not a risk marker for the disease.
Relationship between gap width and recurrent dental caries beneath occlusal margins of amalgam restorations
Authors: Hodges Dain J. , Mangum Frank I. , Ward Marilyn T.
Published: May 2006

Abstract This study examines the relationship between gap width and the presence of recurrent dental caries subjacent to occlusal margins of amalgam restorations. The study population consisted of 35 adult patients of the university's dental clinic who were having occlusal amalgam restorations removed solely because of defective margins. In this group, an impression was made recording the width of a clinically detected gap between the amalgam restoration and the adjacent enamel cavosurface. Of this study population, 20 teeth with recurrent caries were identified from 18 subjects after restoration removal. Upon removal of the restoration, the presence and location of recurrent dental caries associated with a margin was noted. The mean gap widths of recurrent carious sites and non‐carious sites were compared in the same tooth. A difference of 187 μm was found between the mean gap width of the recurrent caries sites and the non‐carious sites, with the recurrent caries gaps being wider. A paired t‐test based on the differences was calculated (P < 0.0001). The results suggest that there is a direct association between gap width and recurrent caries in occlusal margins of amalgam restorations.
Relationship between dental caries and risk factors for atherosclerosis in Swedish adolescents'
Authors: Larsson Bengt , Johansson Ingegerd , Hallmans Göran , Ericson Thorild
Published: May 2006

Abstract In an earlier study on a selected group of adolescents with high caries prevalence we found dietary habits that resembled those considered to promote the development of atherosclerosis. In the present study we have compared DMF‐score with factors traditionally associated with the risk for development cardiovascular diseases (CVD), All 15‐yr‐olds living in an urban community in Northern Sweden 1987–1989 were included. Medical variables related lo the risk of developing CVD were evaluated in groups of adolescents with various levels of manifest caries expressed as decayed and filled surfaces (DPS). The proportion of individuals with no medical risk factor at an unfavorable level was significantly higher in a caries free than in a high‐caries (DFS9) group. Adolescents with two or more medical factors reaching unfavorable levels had a significantly higher caries score than the group with no factor at unfavorable level. A significant positive correlation was found for the whole group between DFS‐score and relative body weight (body mass index) in an univariate correlation test as well as multiple linear regression analysis. The hypothesis that high caries score can be an indicator for unfavorable levels of traditional risk factors for CVD is not contradicted by the results in the present study but supported by the observed covariation with BMI. We therefore suggest that dietary counseling to adolescents with a high caries score in combination with a moderate obesity can be of advantage in reducing the caries risk as well as the risk for development of CVD at higher ages.
Radiographic study of approximal restorative treatment in children and adolescents in two Swedish communities differing in caries prevalence
Authors: Lith Agneta , Pettersson Lars G. , Gröndahl Hans‐Göran
Published: May 2006

Abstract In two groups of patients, differing in caries prevalence, the restorative treatment of posterior approximal surfaces in permanent teeth was studied in radiographs obtained as part of the dental care provided from age 6 up to and including age 18. The study determined at what age, at which lesion depth and in which surfaces restorative treatment was performed. Furthermore, the conditions of non restored dentin lesions were evaluated over time. Nearly 50% of the restorations were placed in the mesial surface of the first molars. In both groups more than 2/3 of the restorations were placed in surfaces with dentin lesions. In the group with the highest caries prevalence 50% of the lesions in the outer half of the dentin were restored when first detected in contrast to 20% in the groups with the lower prevalence. For the superficial dentin lesions not immediately restored, average time between their detection and restoration, the end of the study or, detection in the inner half of the dentin was practically the same in both groups (19.3 and 20.4 months). The variation in this average time was only to a limited degree explained by the variation in the caries experience of the patients.
Concentrations of blood, serum and urine components in relation to number of amalgam tooth fillings in Swedish women
Authors: Ahlqwist Margareta , Bengtsson Calle , Lapidus Leif , Lindstedt Göran , Lissner Lauren
Published: May 2006

Abstract Altogether 1462 women aged 38, 46, 50, 54 and 60 yr were examined in 1968/69 in a combined medical and denial population study in Gothenburg, Sweden. Number of tooth surfaces restored with amalgam fillings was assessed. The examination was repealed in 1980/81 including a new dental examination. The results from a number of biochemical analyses of blood, serum and urine were analyzed for a possible statistical relationship to number of denial amalgam fillings. As emphasis has been put in the literature on special influence from amalgam on kidney function and on the immunological system, special attention was paid to variables which might reflect these functions in our analyses. When potential con‐founders were taken into consideration, no significant correlations remained which seemed to be of clinical importance. Specifically, amalgam fillings were not found to be associated with impairment of the kidney function or the immunological status.
Comparison of oral health data from self‐administered questionnaire and clinical examination
Authors: Axelsson Gudjón , Helgadóttir Sigrún
Published: May 2006

Abstract In order to assess the validity of self‐reported oral health data 319 subjects randomly selected from the respondents to an oral health survey were examined clinically. The level of agreement between the two methods of examination was estimated by the kappa statistic. Substantial agreement (k=0.65) was found between the reported and observed number of remaining teeth and the difference between underreporting and reporting was small. The results indicate that valid data for planning purposes and for monitoring changes in such oral health indicators as the proportion of individuals having 28 or more teeth, the proportion of subjects having a minimum of 20 functional teeth, the level of edentulousness and the presence of complete and partial dentures, can be obtained from postal questionnaires.
Identification of areas with high levels of untreated dental caries
Authors: Ellwood R.P. , O'Mullane D.M. , Ellwood R. R
Published: May 2006

Abstract In order to examine the geographical variation of dental health within 10 county districts in North Wales, 3538 children were examined. The associations between three demographic indicators, based on the 1981 OPCS census, and dental health outcomes were assessed for electoral wards within the county districts. The Townsend and Jerman indices were the first two indicators employed and the third was based on a mathematical model representing the variation in the mean number of untreated decayed surfaces per person for the wards. This model was developed using the children examined in the five most westerly county districts. Using the data derived from the five most easterly county districts, the three indicators were assessed. All three showed strong correlations (r0.88) with dental health. These results indicate that measures of dental health based on large administrative units may obscure variation within them. It is concluded that geographical methods of this type may be useful for targeting dental resources at small areas with high levels of need.
The tooth wear index: a flawed epidemiological tool in an ageing population group
Authors: Donachie M. A. , Walls A. W. G.
Published: May 2006

Abstract With a greater number of people living longer and tending to retain many natural teeth, the problems associated with tooth wear are likely to place greater demands upon dental professionals in the future. Several attempts have been made to develop an index to measure tooth wear, for use at both the individual and population level. A review of these indices is undertaken, and difficulties experienced with the tooth wear index (TWI) of Smith & Knight (1984) in a large adult dental health survey is discussed. In the elderly population the scoring criteria of the TWI proved to be difficult to apply without additional qualification, and in cases of extreme wear a five‐point ordinal scale was found to be inadequate to describe the range of wear observed. The concept of “pathological” levels of wear proposed by the TWI are challenged and modification to the index suggested for use among the elderly population.
Accuracy of dental hygienists in diagnosing dental decay
Authors: Öhrn K. , Crossner C.‐G. , Börgesson I. , Taube A.
Published: May 2006

Abstract During recent decades, the duties and care rendered by Swedish dental hygienists have continuously expanded, and since 1991 they are licensed to practice dental hygiene independently. The aim of the present study was to investigate the accuracy of dental hygienists in examining and recording dental caries in comparison with dentists performing identical examinations. The study included two parts: A) Registration of carious lesions from radiographs of 100 extracted teeth, where the correct diagnosis could be verified, and B) clinical examination and registration of carious lesions in 213 patients. No statistically significant differences could be found between the dental hygienists” and their control dentists' accuracy to diagnose and record dental decay, with the exception of the number of initial lesions (white spot lesions) registered clinically, where the dental hygienists recorded more buccal and lingual lesions. Irrespective of the group of examiners (dental hygienists or dentists), however, the inter‐examiner variation was wide. The variation decreased with the size of the lesion and increased with the age of the patient. This study suggests that no patient with a restorative treatment need would have been neglected if the dental hygienists had performed the examination, and, possibly, a more accurate non‐restorative treatment need would have been addressed.
Dental malocclusion in native children of British Columbia, Canada
Authors: Harrison R. L. , Davis D. W.
Published: May 2006

Abstract Since 1972, the Medical Services Branch (MSB). Pacific Region of Health Canada, has conducted quadrennial surveys of the dental health status of Native children in British Columbia (B.C.), Canada. This paper will analyze the findings related to dental malocclusion. Data from the most recent survey in 1988 are compared to data from 1980, and also to similar data from the most recent B. C. Children's Dental Health Survey. Prevalences of abnormal and severe malocclusion are also compared to the original 1972 data. Methods used in the surveys were detailed in a previous paper (1). Significant decreases in the percentage of children with drifting due to premature space loss (P<0.05), as well as a slight decrease in the percentage of children with crowding were observed. A trend towards an increase in Class II molar relationship was demonstrated, but was not consistent for all age groups. In contrast, there was a slight, but consistent, trend towards a decrease in the percentage of children with an anterior openbite. Comparisons between the age groups demonstrated an increased prevalence of abnormal molar relationship, drifting due to space loss, crowding, crossbite, and overjet greater than 4 mm in children older than 7 years. Native children had a significantly greater prevalence of Class III molar relationship, crossbite, crowding, negative overjet. and anterior openbite than other schoolchildren in B.C. (P<0.05). However, percentage of Native children with a severe malocclusion decreased significantly from 1972 lo 1988 for 7, 9, and 11 year old children (P<0.05), but not for 13 and 15‐yr‐olds. Improvement has occurred over time in some aspects of dental malocclusion in these Native Canadian children, but malocclusion continues to be a frequent problem, especially amongst adolescents.