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Objectives: This study aimed to analyse loss of enamel worn against composite, leucite glass ceramic or enamel antagonists under non-erosive and alternating or simultanuous erosive-attritive conditions., Materials and Methods: Flat human enamel specimens were loaded (1 Hz, 300 g loading weight, each subgroup n = 12) with antagonists made from a hybrid-composite (Z250, 3 M Espe), a nano-composite (Filtek Supreme XTE, 3 M Espe), leucite glass ceramic (IPS Empress CAD LT, Ivoclar Vivadent) or enamel. Specimens were either submitted to mechanical loading in mineral solution (60 s) or to loading under alternating or simultaneous erosive conditions. For alternating erosion-attrition, specimens were eroded by citric acid (pH 2.6, 60 s) and then loaded with the respective antagonist for 60s. For simultaneous erosion-attrition, specimens were loaded with the respective antagonist while being immersed in citric acid (pH 2.6, 60 s). After each cycle, specimens were stored in water for 1 h. After 18 cycles, enamel loss was calculated profilometrically and statistically analysed by two-way ANOVA and Tukey's post-hoc tests (p < 0.05)., Results: Enamel loss (μm, mean ± standard deviation) was significantly highest for simultaneous erosion-attrition (ceramic 9.4 ± 1.1, hybrid-composite 8.3 ± 0.7, nano-composite 7.8 ± 1.2, enamel 7.4 ± 0.8) followed by alternating erosion-attrition (ceramic 3.5 ± 0.5, hybrid-composite 2.1 ± 0.8, nano-composite 1.0 ± 0.2, enamel 2.5 ± 0.7) and attrition in mineral solution (ceramic 0.5 ± 0.3, hybrid composite 0.3 ± 0.1, nano composite 0.1 ± 0.2, enamel 0.1 ± 0.1). Ceramic antagonists resulted in significantly higher loss than the remaining antagonistic materials when alternating or simultaneous erosion-attrition was performed., Conclusion: Erosive conditions had a massive impact on enamel worn against different antagonistic materials, with simultaneous erosive-attritive conditions being more detrimental than alternating erosive-attritive conditions., Clinical Relevance: Enamel wear by antagonistic restorative materials is significantly influenced by erosive conditions.

The efficacy of nanosilicate clay platelets (NSCP), exfoliated silicates from natural montmorillonites, as a feed additive for ameliorating fumonisin B1 (FB1) toxicosis was evaluated. Toxicological mechanisms by NSCP were examined through proteomic and biochemical analyses. Dietary supplementation with NSCP at a low level of 40 mg/kg of feed improved growth performances in chickens with respect to FB1 toxicosis. Other issues of ameliorated symptoms including serum and/or hepatic aspartate aminotransferase activity, oxidative stress indicators, and sphinganine/sphingosine ratio, a hallmark of FB1 toxicosis, were considered. Chickens with NSCP inclusion alone at 1000 mg/kg of feed exhibited no changes in hepatic histology, oxidative status, and serum parameters and even had a higher feed intake. Proteomic analysis with liver tissues identified 45 distinct proteins differentially affected by FB1 and/or NSCP, in which proteins involved in thiol metabolism and redox regulation, glycolysis, carcinogenesis, and detoxification by glutathione S-transferase were promoted by FB1, whereas NSCP caused differential changes of protein abundances related to methionine/cysteine and choline/glycine interconversion for glutathione synthesis, redox regulation by peroxiredoxin, toxin/metabolite delivery by albumin, glycolysis, tricarboxylic acid cycle, adenosine triphosphate (ATP) synthesis, and chaperon escort for endoplasmic reticulum stress relief. Functional analyses confirmed the enhancement of hepatic metabolic processes for ATP and NAD(P)H production to meet the need for detoxification, antioxidative defense, and toxin/metabolite clearance by FB1 or NSCP ingestion. On the basis of the amelioration of FB1 toxicosis, global profile of hepatic protein expressions, and validated toxicological mechanisms, NSCP were concluded as a safe and effective agent for FB1 detoxification.

Idiopathic pleuroparenchymal fibroelastosis (IPPFE) is a recently described rare condition, characterized by pleural and subpleural parenchymal fibrosis, predominantly in the upper lobes. The clinical course of this disease is progressive and prognosis is poor, with little information regarding the etiology of IIPPFE. This report describes an IPPFE patient with convincing evidence of inhalational dust and suggests that dust exposure should be considered as a new causative factor of IPPFE.

Nanoclays have potential applications in biomedicine raising the need to evaluate their toxicity in in vitro models as a first approach to its biocompatibility. In this study, in vitro toxicity of clinoptilolite and sepiolite nanoclays (NC) was analyzed in highly phagocytic cultures of amoebas and human and mice macrophages. While amebic viability was significantly affected only by sepiolite NC at concentrations higher than 0.1 mg/mL, the effect on macrophage cultures was dependent on the origin of the cells. Macrophages derived from human peripheral blood monocytes were less affected in viability (25% decrease at 48 h), followed by the RAW 264.7 cell line (40%), and finally, macrophages derived from mice bone marrow monocytes (98%). Moreover, the cell line and mice macrophages die mainly by necrosis, whereas human macrophages exhibit increased apoptosis. Cytokine expression analysis in media of sepiolite NC treated cultures showed a proinflammatory profile (INFγ, IL-1α, IL-8, and IL-6), in contrast with clinoptilolite NC that induced lees cytokines with concomitant production of IL-10. The results show that sepiolite NC is more toxic to amoebas and macrophages than clinoptilolite NC, mostly in a time and dose-dependent manner. However, the effect of sepiolite NC was comparable with talc powder suggesting that both NC have low cytotoxicity in vitro.

Background: Multiple studies have investigated the relationship between asbestos-related pleural plaques (PPs) and lung function, with disparate and inconsistent results. Most use chest radiographs to identify PPs and simple spirometry to measure lung function. High-resolution CT (HRCT) scanning improves the accuracy of PP identification. Complete pulmonary function tests (PFTs), including spirometry, lung volumes, and diffusing capacity of the lung for carbon monoxide, provide a more definitive assessment of lung function. The goal of this study was to determine, using HRCT scanning and complete PFTs, the effect of PPs on lung function in Libby vermiculite miners., Methods: The results of HRCT scanning and complete PFTs performed between January 2000 and August 2012 were obtained from the medical records of 166 Libby vermiculite miners. Multivariate regression analyses with Tukey multivariate adjustment were used to assess statistical associations between the presence of PPs and lung function. Adjustments were made for age, BMI, smoking history, duration of employment, and years since last occupational asbestos exposure., Results: Nearly 90% of miners (n = 149) had evidence of PPs on HRCT scan. No significant differences in spirometry results, lung volumes, or diffusing capacity of the lung for carbon monoxide were found between miners with PPs alone and miners with normal HRCT scans. Miners with both interstitial fibrosis and the presence of PPs had a significantly decreased total lung capacity in comparison with miners with normal HRCT scans (P = .02). Age, cumulative smoking history, and BMI were significant covariates that contributed to abnormal lung function., Conclusions: Asbestos-related PPs alone have no significant effect on lung function in Libby vermiculite miners.

Aim: To evaluate the effect of muscovite in preventing small bowel injury induced by nonsteroidal anti-inflammatory drugs (NSAIDs)., Methods: We recruited and screened thirty-two healthy volunteers who were randomly allocated equally into two groups: an NSAID control group, who received 75 mg slow-release diclofenac, twice daily for 14 d; and an NSAID-muscovite group, who received 3 g of muscovite in addition to the 75 mg of slow-release diclofenac, twice daily for 14 d. For gastroprotection, both groups were administered 20 mg/d of the proton pump inhibitor omeprazole. All eligible subjects underwent video capsule endoscopy (CE) prior to and 14 d after treatment., Results: Thirty subjects (NSAID-muscovite group, n =16; NSAID control group, n =14) finally completed the whole trail. At the baseline CE examination, no statistically significant differences between the two groups have been observed. However, after 14 d of drug treatment, a significant difference was observed in the percentage of subjects with mucosal breaks when comparing the NSAID-muscovite group with the NSAID control group. While 71.4% (10/14) of subjects in the NSAID control group had at least one mucosal break, co-administration of muscovite in the NSAID-muscovite group reduced the rate to 31.3% (5/16) (P = 0.028). Moreover, higher number of mucosal breaks was found in the NSAID control group vs that in the NSAID-muscovite group (P < 0.05)., Conclusion: Muscovite co-therapy reduced the incidence of small intestinal injury after 14 d of diclofenac administration.

This study focused on test the null hypothesis that there is no difference between the degree of conversion and biocompatibility of different resin reinforced glass ionomer cements (RRGICs). Forty-eight male Wistar rats were used, distributed into four groups (n = 12), as follows: Group C (Control, polyethylene), Group FOB (Fuji Ortho Band), Group UBL (Ultra band Lok), and Group MCG (Multicure Glass), in subcutaneous tissue. The events of edema, necrosis, granulation tissue, multinuclear giant cells, young fibroblasts, and collagen formation were analyzed at 7, 15, and 30 days. The degree of conversion was evaluated by the Fourier method. Biocompatibility and degree of conversion were assessed using the Kruskal-Wallis and Dunn tests, and ANOVA and Tukey's test, respectively (P < 0.05). It was observed that, there was significant difference between Groups FOB and UBL for the presence of young fibroblasts at 15 days (P = 0.034) and between the Control and MCG Groups for the presence of multinucleated giant cells at 30 days (P = 0.009). Monomer conversion increased progressively until day 30, with significant difference between Group FOB and Groups UBL and MCG (P = 0.013) at 15 days. The null hypothesis was partially accepted, Fuji Ortho Band showed a less monomer conversion and a smaller number of young fibroblasts in the time of 15 days., (Copyright © 2014 Wiley Periodicals, Inc.)

Natural halloysite clay nanotubes with 50 nm outer- and 15 nm inner- diameters are described as miniature vehicles for sustained release of drugs and proteins. The release time may be adjusted from 10 to 200 h with the tube surface polymeric coating. An explanation of sustained release through locking electrical potential at the nanotube ends is suggested. These biocompatible ceramic tubes may be also used for architectural construction of nanoshells on microbes through alternation with polycations to enhance the intrinsic properties of biological cells. Halloysite nanotubes (pristine or drug-loaded) are well mixable with polar and low-polar polymers allowing for functional biocomposites with enhanced mechanical strength, adhesivity and slow release of drugs or other chemical agents. Halloysite is nontoxic abundantly available from natural deposit material which does not require exfoliation or other complicated energy consuming processing., (© 2013 Elsevier B.V. All rights reserved.)

Pregnant women in Africa, Asia and Suriname, and some immigrants in Western societies, traditionally consume clay products known by a variety of names such as mabele, calabash chalk, sikor and pimba. Furthermore, clay is used for health purposes in Western societies. Because certain clays can contain high levels of metals and metalloids, the aim of this study was to determine lead, arsenic, mercury and cadmium in clay products for oral use available on the Dutch market. Traditional clays originating from Africa (n = 10) and Suriname (n = 26), and health clays (n = 27) were sampled from 2004 up to and including 2012. Total metal and metalloid contents were measured by ICP-MS and showed maximum levels of lead, arsenic, mercury and cadmium of 99.7, 45.1, 2.2 and 0.75 mg kg⁻¹, respectively. In the absence of maximum limits for these type of clays, the potential exposure was estimated from the determined concentration, the estimated daily use level of the clays, and the estimated bioaccessibility of the different metals and arsenic. The intake estimates were compared with existing health-based guidance values. For lead, the use of 34 of the 36 traditional clays and two of the 27 health clays would result in intake levels exceeding the toxicological limit by up to 20-fold. Use of 15 of the 35 traditional clays and 11 of the 27 health clays would result in intake levels exceeding the toxicological limit for inorganic arsenic by up to 19-fold. Although limited bioaccessibility from the clay may limit the exposure and exceedance of the health-based guidance values, it was concluded that lead and arsenic intakes from some clay products could be of concern also because of their use by pregnant women and the potential developmental toxicity. As a result the use of these products, especially by pregnant women, should be discouraged.

Objectives: To describe asbestos-related mortality among manufacturing workers who expanded and processed Libby vermiculite that contained amphibole fiber., Methods: Standardized mortality ratio was calculated for 465 white male workers 31 years after last Libby vermiculite exposure., Results: Two workers died from mesothelioma, resulting in a significantly increased standardized mortality ratio of 10.5 (95% confidence interval, 1.3 to 38.0). These workers were in the upper 10th percentile of cumulative fiber exposure, that is, 43.80 and 47.23 fiber-years/cm, respectively. One additional worker with cumulative fiber exposure of 5.73 fiber-years/cm developed mesothelioma but is not deceased. There were no other significantly increased standardized mortality ratios., Conclusions: Workers expanding and processing Libby vermiculite in a manufacturing setting demonstrated an increased risk for the development of mesothelioma following exposure to the amphibole fiber contained within this vermiculite ore source.

Purpose: To compare different methods of glycerol-preserved corneas intended for deep anterior lamellar keratoplasty (DALK)., Methods: We analyzed transparency, transmittance, thickness, biomechanics, morphology, and antigenicity of donor corneas preserved by four different glycerol-based methods (n = 6 per group) for 3 months, as follows: tissues in anhydrous glycerol without aluminosilicate molecular sieves at room temperature (GRT); tissues in anhydrous glycerol with aluminosilicate molecular sieves at room temperature (SRT); tissues in anhydrous glycerol without aluminosilicate molecular sieves at -78°C (G78); and tissues in anhydrous glycerol without aluminosilicate molecular sieves at -20°C (G20)., Results: Slit lamp images and transmittance curves obtained by spectrophotometer show that the G78 cornea was the most transparent tissue. Stress-strain behavior indicated that corneas in the G78 group were the most pliable, and SRT corneas were the stiffest. Electron microscopy analysis indicated that corneal cytoarchitecture and keratocyte integrity was destroyed in all glycerol-preserved corneas. Disorganized stromal collagen fibers were evident in groups stored at RT. Especially in SRT corneas, parallelism was lost, fibrils were extremely tortuous and discontinuous, and widespread fibril degeneration could be found. Antigenicity of tissue, assessed via immunohistochemistry for CD45-positive cells, HLA-ABC and HLA-DR, was lowered after glycerol preservation relative to fresh cornea tissues, and immunoreactivity was located mainly on corneal epithelium and limbus rather than stroma., Conclusions: Anhydrous glycerol preservation without molecular sieves in a -78°C freezer was the best method to obtain DALK-eligible tissues that were both transparent and pliable.

Purpose of Review: The vermiculite ore formerly mined in Libby, Montana, contains asbestiform amphibole fibers of winchite, richterite, and tremolite asbestos. Because of the public health impact of widespread occupational and nonoccupational exposure to amphiboles in Libby vermiculite, numerous related studies have been published in recent years. Here we review current research related to this issue., Recent Findings: Excess morbidity and mortality classically associated with asbestos exposure have been well documented among persons exposed to Libby vermiculite. Excess morbidity and mortality have likewise been documented among persons with only nonoccupational exposure. A strong exposure-response relationship exists for many malignant and nonmalignant outcomes and the most common outcome, pleural plaques, may occur at low lifetime cumulative exposures., Summary: The public health situation related to Libby, Montana, has led to huge investments in public health actions and research. The resulting studies have added much to the body of knowledge concerning health effects of exposures to Libby amphibole fibers specifically and asbestos exposure in general.

Objective: Beryllium mine and ore extraction mill workers have low rates of beryllium sensitization and chronic beryllium disease relative to the level of beryllium exposure. The objective was to relate these rates to the solubility and composition of the mine and mill materials., Method: Medical surveillance and exposure data were summarized. Dissolution of BeO, ore materials and beryllium hydroxide, Be(OH)(2) was measured in synthetic lung fluid., Result: The ore materials were more soluble than BeO at pH 7.2 and similar at pH 4.5. Be(OH)(2) was more soluble than BeO at both pH. Aluminum dissolved along with beryllium from ore materials., Conclusion: Higher solubility of beryllium ore materials and Be(OH)(2) at pH 7.2 might shorten particle longevity in the lung. The aluminum content of the ore materials might inhibit the cellular immune response to beryllium.

Ingestion of prion-contaminated materials is postulated to be a primary route of prion disease transmission. Binding of prions to soil (micro)particles dramatically enhances peroral disease transmission relative to unbound prions, and it was hypothesized that micrometer-sized particles present in other consumed materials may affect prion disease transmission via the oral route of exposure. Small, insoluble particles are present in many substances, including soil, human foods, pharmaceuticals, and animal feeds. It is known that meat and bone meal (MBM), a feed additive believed responsible for the spread of bovine spongiform encephalopathy (BSE), contains particles smaller than 20 μm and that the pathogenic prion protein binds to MBM. The potentiation of disease transmission via the oral route by exposure to MBM or three micrometer-sized mineral feed additives was determined. Data showed that when the disease agent was bound to any of the tested materials, the penetrance of disease was increased compared to unbound prions. Our data suggest that in feed or other prion-contaminated substances consumed by animals or, potentially, humans, the addition of MBM or the presence of microparticles could heighten risks of prion disease acquisition.

We reanalyzed the Libby vermiculite miners' cohort assembled by Sullivan to estimate potency factors for lung cancer, mesothelioma, nonmalignant respiratory disease (NMRD), and all-cause mortality associated with exposure to Libby fibers. Our principal statistical tool for analyses of lung cancer, NMRD, and total mortality in the cohort was the time-dependent proportional hazards model. For mesothelioma, we used an extension of the Peto formula. For a cumulative exposure to Libby fiber of 100 f/mL-yr, our estimates of relative risk (RR) are as follows: lung cancer, RR = 1.12, 95% confidence interval (CI) =[1.06, 1.17]; NMRD, RR = 1.14, 95% CI =[1.09, 1.18]; total mortality, RR = 1.06, 95% CI =[1.04, 1.08]. These estimates were virtually identical when analyses were restricted to the subcohort of workers who were employed for at least one year. For mesothelioma, our estimate of potency is K(M) = 0.5 x 10(-8), 95% CI =[0.3 x 10(-8), 0.8 x 10(-8)]. Finally, we estimated the mortality ratios standardized against the U.S. population for lung cancer, NMRD, and total mortality and obtained estimates that were in good agreement with those reported by Sullivan. The estimated potency factors form the basis for a quantitative risk assessment at Libby.

Aim: To evaluate the abrasivity of different toothpastes both quantitatively and qualitatively with a profilometer technique and to correlate these findings to the radioactive dentin abrasivity (RDA) value., Materials and Methods: Acrylic plates were exposed to brushing in a brushing machine with 11 different toothpastes. The results were evaluated using a profilometer. A surface roughness value (Ra-value), that is, a qualitative measurement, and also a volume value, that is, a quantitative measurement, were calculated from the profilometer results. These values were then correlated to each other and to the RDA-value. A comparison between RDA, Ra and volume measurements was performed using linear fitting procedure., Results: The results showed that the correlation between RDA and Ra measurements was low (R(2) = 0.04) and also that the correlation between RDA and volume measurements was low (R(2) = 0.00002). Correlation between Ra and abraded volume was high (R(2) = 0.87)., Conclusions: It is important to consider not only the RDA-value when evaluating toothpaste abrasivity. From the profilometer results both a quantitative (volume) and qualitative (roughness) measurement of the abrasivity of a toothpaste can be obtained.

Objective: To test the null hypothesis that there is no significant difference between the microleakage of adhesive interferences at the occlusal and gingival margins of both ceramic and metallic brackets bonded with light-cured resin-modified glass ionomer and a conventional adhesive., Materials and Methods: Sixty freshly extracted human maxillary premolar teeth were randomly divided into four groups of 15 teeth each. Metal and ceramic brackets were bonded to groups 1 and 2 with resin-modified glass ionomer adhesive (RMGIA). Metal and ceramic brackets were bonded to group 3 and group 4 with a conventional adhesive (CA) system. A dye-penetration method was used for microleakage evaluation. Microleakage from the occlusal and gingival margins was determined by a stereomicroscope for the enamel-adhesive and bracket-adhesive interfaces. Statistical analysis was performed using the Kruskal-Wallis test and the Mann-Whitney U-test with a Bonferroni correction., Results: The gingival side of all groups exhibited higher microleakage scores compared with the occlusal side for both adhesive interfaces. All bracket and adhesive combinations displayed statistically significant differences in microleakage between the enamel-adhesive and adhesive-bracket interfaces at the occlusal and gingival sides of the brackets (P < .001). When the adhesive systems were compared, the RMGIA showed more microleakage than the CA between the different interfaces., Conclusions: The hypothesis is rejected. RMGIA results in more microleakage between enamel-adhesive interfaces.

Rationale: From 1921 to 1990, vermiculite ore from Libby, Montana, was shipped worldwide for commercial and residential use. A 1980 study of a manufacturing facility using Libby vermiculite was the first to demonstrate a small but significant prevalence of pleural chest radiographic changes associated with amphibole fibers contained in the ore., Objectives: This follow-up study of the original cohort evaluated the extent of radiographic changes and cumulative fiber exposure (CFE) 25 years after cessation of exposure., Methods: From the original cohort of 513 workers, 431 (84%) were living and available for participation and exposure reconstruction. Of these, 280 (65%) completed both chest radiographs and interviews. Primary outcomes were pleural and/or interstitial changes., Measurements and Main Results: Pleural and interstitial changes were demonstrated in 80 (28.7%) and 8 (2.9%) participants, respectively. Of those participants with low lifetime CFE of less than 2.21 fiber/cc-years, 42 (20%) had pleural changes. A significant (P < 0.001) exposure-response relationship of pleural changes with CFE was demonstrated, ranging from 7.1 to 54.3% from the lowest to highest exposure quartile. Removal of individuals with commercial asbestos exposure did not alter this trend., Conclusions: This study indicates that exposure within an industrial process to Libby vermiculite ore is associated with pleural thickening at low lifetime CFE levels. The propensity of the Libby amphibole fibers to dramatically increase the prevalence of pleural changes 25 years after cessation of exposure at low CFE levels is a concern in view of the wide national distribution of this ore for commercial and residential use.

We present the first case of foreign body granuloma in the cervical (submandibular) region as a result of migration of noninjected aluminium silicate particles from the oral mucosa. This migration can be explained by macrophage phagocytosis and transport through the local lymphatic network and surgical disruption of fascial layers. The appearance of foreign body granulomas in distant sites may appear several weeks after the local event in a specific disposition according with the migration route. This entity must be born in mind in differential diagnosis of multiple nodules, pigmentation, or persistent swelling in the cervical-orofacial region.

An unusual case of pleuroparenchymal lung disease caused by the inhalation of vermiculite dust, presumably containing asbestos fibers is described. The uniqueness of the case lies in the very indirect nature of exposure -- the wife of a factory owner, rather than a worker exposed to asbestos, whose factory manufactured vermiculite. The present case illustrates the importance of taking careful occupational histories of all household members when presented with a patient whose chest radiograph exhibits features consistent with asbestos exposure.

Background: Vermiculite from the mine near Libby, Montana, is contaminated with tremolite asbestos and other amphibole fibers (winchite and richterite). Asbestos-contaminated Libby vermiculite was used in loose-fill attic insulation that remains in millions of homes in the United States, Canada, and other countries., Objective: This report describes asbestos-related occupational respiratory disease mortality among workers who mined, milled, and processed the Libby vermiculite., Methods: This historical cohort mortality study uses life table analysis methods to compare the age-adjusted mortality experience through 2001 of 1,672 Libby workers to that of white men in the U.S. population., Results: Libby workers were significantly more likely to die from asbestosis [standardized mortality ratio (SMR) = 165.8; 95% confidence interval (CI), 103.9-251.1], lung cancer (SMR = 1.7; 95% CI, 1.4-2.1), cancer of the pleura (SMR = 23.3; 95% CI, 6.3-59.5), and mesothelioma. Mortality from asbestosis and lung cancer increased with increasing duration and cumulative exposure to airborne tremolite asbestos and other amphibole fibers., Conclusions: The observed dose-related increases in asbestosis and lung cancer mortality highlight the need for better understanding and control of exposures that may occur when homeowners or construction workers (including plumbers, cable installers, electricians, telephone repair personnel, and insulators) disturb loose-fill attic insulation made with asbestos-contaminated vermiculite from Libby, Montana.

Statement of Problem: Ceramic restorations have been known to cause wear of opposing enamel., Purpose: The purpose of this study was to evaluate enamel wear caused by 3 ceramic substrates in the glazed and polished conditions., Material and Methods: Sixty ceramic discs (10 x 2 mm)-20 each of Finesse, All-Ceram, and IPS-Empress-were prepared and glazed. Each group of 20 was divided into 2 groups of 10. The surfaces of one group were ground and polished using a porcelain polishing kit (Dialite). The remaining 10 were left as glazed. Ten specimens of a type III gold alloy were cast into rectangular shapes of 10 x 12 x 2 mm and polished. Seventy human cusps were prepared from sound, caries-free, extracted teeth and abraded against the substrates in a wear machine for a total of 10,000 cycles. The cusp height loss was traced before and after the wear test using a profile projector. Mean surface roughness (R(a)) values for the substrates were also recorded with a profilometer before testing. Differences in R(a) were evaluated using 1- and 2-way ANOVA and the Scheffe post hoc test (alpha = .05)., Results: One-way ANOVA indicated that enamel height loss was significantly different by material (P < .001) and surface condition (glazed and polished or glazed; P < .05). Gold, polished Finesse, and polished All-Ceram were the least abrasive, whereas glazed IPS-Empress was the most abrasive. There was no significant interaction effect between substrate type and surface condition. Significant differences were found when R(a) of the substrate condition was compared with enamel wear (P < .01)., Conclusions: Gold, polished Finesse, and polished All-Ceram caused the least enamel wear, whereas IPS-Empress caused the most wear. Cast gold was significantly different than glazed IPS-Empress (P < .05), whereas other groups overlapped. There was significant correlation between R(a) and enamel wear (P < .01).

Objective: To explore the potential association between asbestos exposure and risk of autoimmune disease, we conducted a case-control study among a cohort of 7,307 current and former residents of Libby, Montana, a community with historical occupational and environmental exposure to asbestos-contaminated vermiculite., Methods: Cases were defined as those who reported having one of three systemic autoimmune diseases (SAIDs): systemic lupus erythematosus, scleroderma, or rheumatoid arthritis (RA). Controls were randomly selected at a 3:1 ratio from among the remaining 6,813 screening participants using frequency-matched age and sex groupings., Results: The odds ratios (ORs) and 95% confidence intervals (CIs) for SAIDs among those >or=65 years of age who had worked for the vermiculite mining company were 2.14 (95% CI, 0.90-5.10) for all SAIDs and 3.23 (95% CI, 1.31-7.96) for RA. In this age group, exposure to asbestos while in the military was also an independent risk factor, resulting in a tripling in risk. Other measures of occupational exposure to vermiculite indicated 54% and 65% increased risk for SAIDs and RA, respectively. Those who had reported frequent contact with vermiculite through various exposure pathways also demonstrated elevated risk for SAIDs and RA. We found increasing risk estimates for SAIDs with increasing numbers of reported vermiculite exposure pathways (p<0.001)., Conclusion: These preliminary findings support the hypothesis that asbestos exposure is associated with autoimmune disease. Refined measurements of asbestos exposure and SAID status among this cohort will help to further clarify the relationship between these variables.

Background: Beidellitic montmorillonite is a purified clay containing a double aluminium and magnesium silicate., Aim: To assess the efficacy and the safety of beidellitic montmorillonite (3 g, t.d. for 8 weeks) in patients with irritable bowel syndrome (IBS)., Methods: A multicentre, double-blind, placebo-controlled, randomized study with parallel groups, was performed in IBS patients selected according to ROME I criteria. Patients were included after a 1-week washout period to confirm that abdominal pain and/or discomfort was rated at least 2 on a 0-4 graded Likert scale. Patients were then randomized and stratified according to their predominant bowel habit profile into three groups. The use of rescue medication was allowed: polyethylene glycol 4000 (10-20 g/day) as a laxative agent in case of stool absence for three consecutive days, phloroglucinol (80 to a maximum of 320 mg/day) as a spasmolytic agent for no more than 8 days. The main end-point was the improvement of abdominal pain and/or discomfort by at least 1 point on the Likert scale., Results: A total of 524 patients constituted the overall intent-to-treat population (ITT), 263 were assessed in the beidellitic montmorillonite group, i.e. 93 diarrhoea-predominant IBS (D-IBS), 83 constipation-predominant IBS (C-IBS), 87 alternating constipation/diarrhoea-IBS (A-IBS); 261 in the placebo group, i.e. 81 D-IBS, 92 C-IBS and 88 A-IBS. Initial analysis in the ITT population demonstrated a higher rate of success with beidellitic montmorillonite (51.7%) when compared with the placebo group (45.2%); however, the difference was not statistically significant. Improvement was significant in C-IBS both in ITT (beidellitic montmorillonite group = 49.4%, placebo group = 31.5%, P < 0.016) and per protocol populations (59.4% vs. 37.8%) (P < 0.01). The time to improvement of abdominal pain and/or discomfort (log Rank test) was also significantly in favour of beidellitic montmorillonite, (P < 0.04). The average number of stools per day was not different from baseline, either in all patients or in C-IBS patients. Spasmolytic and laxative agent intakes were not different between the two groups. Subjective evaluation by patients of treatment efficacy and visual analogue scale test of treatment efficacy by investigators were significantly better in the beidellitic montmorillonite group (P < 0.05). Tolerance of beidellitic montmorillonite was considered optimal without any significant adverse event., Conclusions: Although pain or discomfort was not significantly improved in the entire IBS population treated with beidellitic montmorillonite in comparison with placebo, this study demonstrates that beidellitic montmorillonite is efficient for C-IBS patients (P < 0.016). This effect of beidellitic montmorillonite on pain cannot be explained by changes in bowel habits. The efficacy of this well-tolerated therapy warrants further confirmatory therapeutic trials in C-IBS patients.

Background: There are few reports on the clinical, radiologic, and pathologic features of pure mica pneumoconiosis., Methods: A case of definite pure mica pneumoconiosis in a rubber factory worker is reported with the clinicopathological findings., Results: Chest HRCT demonstrated subpleural and peribronchovascular interstitial thickening. The characteristic histologic features were pulmonary fibrosis accompanied by prominent histiocytic granulomas containing giant cells., Conclusions: Pure mica pneumoconiosis can be identified by specific radiologic and pathologic findings., (Copyright 2004 Wiley-Liss, Inc.)

Study Objectives: The purpose of this study was to describe the clinical, chest radiographic, high-resolution CT, and histopathologic features of clay dye "sendo" dust pneumoconiosis in seven rush mat ("tatami") workers., Patients: Seven patients with a history of occupational exposure to sendo dust and radiographic changes suggestive of pneumoconiosis were retrospectively reviewed., Results: The duration of exposure ranged from 15 to 45 years (median, 30 years). Three patients had cough, and four patients had abnormal pulmonary function test results. Chest radiographs showed nodular opacities < 3 mm in diameter (types p and q) in all patients. The standard International Labor Office profusion score ranged from 0/1 to 1/1 (median, 1/0). High-resolution CT demonstrated small nodular opacities (types p and q) in all seven patients. In four patients, high-resolution CT demonstrated branching centrilobular structures, airway ectasia, airway wall thickening, and emphysematous changes. None of the patients had conglomerate nodules, large opacities, honeycombing, pleural effusion, or lymphadenopathy. Microscopic examination of the specimens obtained by open lung biopsy or transbronchial lung biopsy revealed nodular fibrosis with accumulation of dust-laden macrophages, but no silicotic nodules. Needle-like particles of 1 to 20 microm in length were evident among the dust deposits, and birefringent crystals were identified under polarizing microscopy. Four of seven patients showed intra-alveolar fibroblastic foci similar to Masson bodies, accompanied by dust deposition., Conclusion: Rush mat workers' sendo dust pneumoconiosis is caused by dust containing free silica. The radiographic and high-resolution CT findings consist of small nodular opacities < 3 mm in diameter and bronchial and bronchiolar abnormalities.

Because the risk of dental caries increases with the use of orthodontic appliances and its control cannot depend only on the patient's self-care, this study evaluated the effect of a glass ionomer cement on reducing enamel demineralization around orthodontic brackets. Fourteen orthodontic patients were randomly divided into 2 groups of 7; they received 23 brackets fitted to their premolars, bonded with either Concise (3M Dental Products, St Paul, Minn), a composite resin (control group), or Fuji Ortho LC (GC America, Chicago, Ill), a resin-modified glass ionomer cement (experimental group). The volunteers lived in a city that has fluoridated water, but they did not use fluoridated dentifrices during the study. After 30 days, the teeth were extracted and longitudinally sectioned; in the enamel around the brackets, demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits, and at occlusal and cervical points 100 and 200 microm away from them. In all of these positions, indentations were made at depths from 10 to 90 microm from enamel surface. Analysis of variance showed statistically significant effects for position, material, depth, and their interactions (P<.05). The Tukey test showed that the glass ionomer cement was statistically more efficient than the control, reducing enamel demineralization in all analyses (P<.05). The use of glass ionomer cement for bonding can be encouraged because it decreases the development of caries around orthodontic brackets.

The contamination of feed with micotoxin has been a serious problem in animal nutrition. Many existing methods of decontamination are not satisfying due to the toxicological safety and health quality of the fodder materials. It stimulates the scientists to search for the new methods. The use of sorbents in the form of natural and synthetic aluminosilicates is a promising direction. The efficacy of aluminosilicates towards aflatoxins has been proved. However, their influence on other micotoxins is not that obvious. According to the last investigations, the use of aluminosilicates in nutrition does not cause any side effects and widespread pathological effects are observed only when dosage is incorrect. Regarding the analyses that were published, it can be supposed that the addition of several different aluminosilicates is a sufficient protection against mycotoxicoses.

Background: Vermiculite is a silicate used as an insulating agent, soil additive, and carrier for chemicals and fertilizers. It is currently perceived to have no adverse effects to "end-product" users. An 82-year-old man presented with complaints of progressive dyspnea on exertion., Methods: A clinical evaluation included a chest radiograph, complete pulmonary function testing, CT scan of the thorax, and comprehensive occupational and environmental history., Results: The patient had clinical and radiographic features of advanced pulmonary interstitial fibrosis. The presence of calcified pleural plaques, together with the other clinical and radiographic features, strongly supported a diagnosis of asbestosis. His only significant exposure was to vermiculite used in the workplace for several hours per day from 1970 to 1987., Conclusions: This case represents the first report of an end-product vermiculite-user with probable asbestosis, and together with recent similar findings in a vermiculite expansion plant worker, requires further epidemiologic investigations., (Published 2003 Wiley-Liss, Inc.)

Epidemiological data has demonstrated that environmental and/or occupational exposure to mineral particulates may result in the development of pulmonary fibrosis, bronchogenic carcinoma and malignant mesothelioma many years following exposure. It has been suggested that the genotoxic effects of fibrous particulates, such as asbestos, is due in part to the generation of reactive oxygen species (ROS) from iron associated with the particulates. However, the molecular mechanisms by which mineral particulates induce ROS that results in genotoxic damage remains unclear. The naturally occurring zeolites, erionite and mordenite share several physiochemical properties but they elicit very different biological responses, with erionite, a fibrous particulate, being highly toxic, and mordenite, a nonfibrous particulate, being relatively benign. We are using these natural zeolites as a model system to determine what physicochemical properties of these zeolites are responsible for their biological response(s) and to evaluate the parameters that influence these responses. The purpose of the present study was to determine the mutagenic potential of erionite and mordenite and to determine whether this mutagenic potential was modulated by iron. The results of this study using the Chinese hamster ovary cell line AS52 demonstrated that erionite was more cytotoxic than mordenite. However, the cytotoxicity of both zeolites was increased in the presence of physiological concentrations of ferrous chloride. Ferrous ions (5-20 microM) significantly (p<0.001) increased the cytotoxicity of mordenite, but only at the highest concentration (16 microg/cm(2)) of mordenite tested. Conversely, only the highest concentration (20 microM) of ferrous ion significantly (p<0.001) increased the cytotoxicity of erionite, but this enhanced cytotoxicity occurred over a wider concentration range (6-16 microg/cm(2)) of erionite. Mordenite was not mutagenic at any of the concentrations tested, and the mutagenic potential of mordenite was not enhanced by the addition of ferrous ion. Conversely, erionite was mutagenic in a dose-response manner at concentrations greater than 6 microg/cm(2) and the mutagenic potential of erionite was significantly enhanced by the addition of ferrous ions. These results suggest that while the cytotoxicity of mordenite and erionite may be related to the ability of these fibers to transport iron into a cell, the different coordination state of iron associated with the two fiber surfaces is critical for inducing genotoxic damage.

Environmental and/or occupational exposure to minerals, metals, and fibers can cause lung diseases that may develop years after exposure to the agents. The presence of toxic fibers such as asbestos in the environment plus the continuing development of new mineral or vitreous fibers requires a better understanding of the specific physical and chemical features of fibers/particles responsible for bioactivity. Toward that goal, we have tested aluminosilicate zeolites to establish biological and chemical structure-function correlations. Zeolites have known crystal structure, are subject to experimental manipulation, and can be synthesized and controlled to produce particles of selected size and shape. Naturally occurring zeolites include forms whose biological activity is reported to range from highly pathogenic (erionite) to essentially benign (mordenite). Thus, we used naturally occurring erionite and mordenite as well as an extensively studied synthetic zeolite based on faujasite (zeolite Y). Bioactivity was evaluated using lung macrophages of rat origin (cell line NR8383). Our objective was to quantitatively determine the biological response upon interaction of the test particulates/fibers with lung macrophages and to evaluate the efficacy of surface iron on the zeolites to promote the Fenton reaction. The biological assessment included measurement of the reactive oxygen species by flow cytometry and chemiluminescence techniques upon phagocytosis of the minerals. The chemical assessment included measuring the hydroxyl radicals generated from hydrogen peroxide by iron bound to the zeolite particles and fibers (Fenton reaction). Chromatography as well as absorption spectroscopy were used to quantitate the hydroxyl radicals. We found that upon exposure to the same mass of a specific type of particulate, the oxidative burst increased with decreasing particle size, but remained relatively independent of zeolite composition. On the other hand, the Fenton reaction depended on the type of zeolite, suggesting that the surface structure of the zeolite plays an important role.

The authors report the case of a 65-year-old accountant whose only asbestos exposure was during a summer job 50 years earlier in a California vermiculite expansion plant. Vermiculite is a silicate material that is useful in building and agriculture as a filler and insulating agent. He developed extensive fibrocalcific pleural plaques and end-stage pulmonary fibrosis, with rapidly progressive respiratory failure. Careful occupational and environmental history revealed no other source of asbestos exposure, and the initial clinical diagnosis was idiopathic pulmonary fibrosis; open lung biopsy shortly before his death confirmed asbestosis. Electron microscopic lung fiber burden analysis revealed over 8,000,000 asbestos fibers per gram dry lung, 68% of which were tremolite asbestos. Additional asbestiform fibers of composition not matching any of the standard asbestos varieties were also present at over 5,000,000 fibers per gram dry lung. Comparison analysis of a sample of Libby, Montana, vermiculite showed a similar mix of asbestiform fibers including tremolite asbestos. This case analysis raises several concerns: risks of vermiculite induced disease among former workers of the more than 200 expansion plants throughout the United States; health effects of brief but very high-intensity exposures to asbestos; and possible health effects in end-users of consumer products containing vermiculite.

Background: Mica exposure is frequent in mines, mills, agriculture, construction, and industry. This is a case report of possible mica pneumoconiosis., Methods: Case report and description of pathology. Histology slides were subjected to spectroscopic examination., Results: Fibrosis in the presence of mica, without evidence of silica was confirmed., Conclusions: This report indicates that mica exposure may result in mica pneumoconiosis., (Copyright 2002 Wiley-Liss, Inc.)

Objectives: Leakage around retrograde fillings is an important cause of endodontic surgery. This in vitro study sought to compare the following: (1) methylene blue dye leakage linked to retrofillings in human and sheep teeth with the degree of dye penetration when intermediate restorative materials and Chemfil were used as retrofillings, (2) the apical microleakage in filled with that in unfilled root canals, and (3) 2 storage techniques, incubator-based and subcutaneous implantation in rats., Study Design: Tested were 198 human and 196 sheep teeth that were retrofilled with intermediate restorative material or Chemfil, then stored in an incubator or subcutaneously in rats for 10, 20, and 30 days before immersion in methylene blue dye for 24 hours. Linear dye penetration was evaluated, and the results were statistically analyzed by means of analysis of variance., Results: Leakage between sheep and human teeth was significantly different (P <.05). Chemfil had significantly less leakage than intermediate restorative material after storage in rat (P <.05) for up to 20 days, but not after 30 days. No differences were found between leakage of unfilled and filled human root canal teeth., Conclusions: The sheep incisor is a poor experimental model of the human tooth, and both aging procedures demonstrate extensive leakage of retrofilling materials after long-term storage.

Ceramic artists can be exposed to many hazards including metals (such as lead), fibrogenic dusts (such as silica), heat, repetitive motion, radiation, and toxic emissions from kilns. The health risks of these exposures have not been well characterized among artists, although limited information is available from commercial potteries. Adverse health effects may be prevented by using less hazardous materials (such as lead-free glazes), improved ventilation, and proper work practices. Special precautions must be in place if children have access to the ceramics studio. The use of glazed ceramic dishes can be a risk for lead toxicity. Food should not be stored in glazed ceramics, and pregnant women should avoid daily use of ceramic mugs for drinking hot beverages.

We report a 52-year-old woman who underwent otoneurosurgery to resect acoustic neurinoma. Bone reconstruction was performed with an aluminium (Al)-containing cement. Six weeks later the patient suffered from loss of consciousness, myoclonic jerks, and persistent grand mal seizures, clinical symptoms that resembled those of lethal dialysis encephalopathy of the 1960s and 1970s. She died 6 months later because of septic complications. Light- and electron-microscopic investigation of the central nervous system (CNS) showed pathognomonic Al-containing intracytoplasmic argyrophilic inclusions in choroid plexus epithelia, neurons, and cortical glia. These changes are characteristics of dialysis-associated encephalopathy (DAE), induced nowadays by long-term ingestion of Al-containing drugs (and with benign clinical courses). Atomic absorption spectrometry showed an increase of mean bulk Al concentration of the cortex and subcortex up to 9.3 microg/g (normal range <2 microg/g); laser microprobe showed the increase of Al in subcellular structures. This unique case again shows the extraordinary neurotoxicity of Al, which was, in our patient, initiated by an amount of about 30 mg Al and apparently caused by direct Al access to the brain parenchyma via a cerebrospinal fluid leakage., (Copyright 2001 by W.B. Saunders Company)

Objectives: The long-term results of the implantation of glass ionomer cement in the human mastoid and middle ear were studied., Study Design: A prospective study of the survival of bone cement in the middle ear., Methods: Ionocem (IONOS, Medizinische Produkte Gmbh & Co., Seefeld/Obb, Germany), a two-compound bone material that forms a stable, water-proof junction with bone, was implanted in 23 middle ears of 23 patients (13 male and 10 female patients). Closure of the dehiscence of the tegmen was performed in 7 cases, obliteration of the mastoid cavity in 10 cases, and ossicular chain reconstruction in 6 cases., Results: The follow-up period was 5.1 years. Complications attributable to operation were not seen, but adverse tissue reaction with severe middle ear infection and abundant otorrhea occurred in six cases after 12 months, requiring repeat operation. In three more cases, a spontaneous extrusion of the bone cement was seen after 4 years. The bone cement was totally extruded in nine cases. The mean survival time was 28 months., Conclusions: The use of Ionocem for obliteration of the mastoid cavity or for the closure of dehiscence of the tegmen has a high risk of extrusion. Therefore, it is not the first-choice material to use for obliteration or tegmen defect closure in the middle ear.

The article covers differential diagnostic features of pulmonary tuberculosis and pneumoconiosis in workers engaged into mullite refractories production. The authors suggest that the disease courses as a new form of lung disorder--mullitosis.