The toxicity of the porcelain dust was greater than that of the Vitallium dust or PMMA dust, and the cytotoxicity increased with increasing dust exposure time and concentration. Andreyev AY, et al. When comparing the instrument response in the overlap region between the SMPS/LDMA and the APS, a distinct difference was noted between the measured results. As in the case of steel, it is likely that uncertainty over the density of the wood-related aerosol and the particle morphology were responsible for a poor transformation between particle aerodynamic diameter and equivalent-sphere projected area diameter. Note that (i) the solid line for each experimental condition represents a log-normal fit of the experimental data, (ii) the error bars represent the standard error associated with three randomized replicate samples and (iii) the experimental data for all substrates have been background corrected for the Dremel tool aerosols. Research advances in silicon pulmonary fibrosis. Transmission electron microscope samples of the various grinding substrates were also collected. Fig. In this case, it was not possible to obtain meaningful information from the samples using EDX. 3ae. shield face grinding chipping impact fsc weldclass 5. 2a) appears to be slightly bimodal. Vitallium (h), porcelain (i). Larger, nanometer scale particles (60.4 nm < dp < 777 nm) were characterized using a SMPS configured with a long DMA (DMA model 3934 and a condensation particle counter model 3022A; TSI Inc.). Even in cases for which the particles are not clearly observed in the nucleus, in the presence of large vesicles, the shape of the nucleus appears abnormal and compressed27. The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative It showed evidence of charring at the grinding interface, supporting the hypothesis that frictional heating during grinding can lead to the formation of ultrafine particles. Wen et al. What was once ignored is now known to be harmful to those in direct contact with excessive amounts dust particles. 2e). formId: "e7fc0871-5cca-47e3-95b8-26eb8d9c3013", Amphiregulin may be a new biomarker of classically activated macrophages. Enriquez LS, et al. Although it was not possible to positively identify these particles, they probably arose from grinding of PTFE because no comparable particles were seen in any of the other samples. Under low magnification (200), as shown in Fig. Received 2019 Dec 19; Accepted 2020 Aug 17. A2, B2, and C2 were finely ground by an agate mortar for 2h, and their morphologies, sizes, chemical compositions, and cytotoxicity were examined. using a rheostat (model 3PN751; Matheson Scientific) and a tachometer. They are readily available and their use raises fewer ethical issues than using human macrophages. The https:// ensures that you are connecting to the Author to whom correspondence should be addressed. 3) showed that after the three types of prosthesis materials were ground, the grinding dust remained in contact with the RAW264.7 macrophages. In many cases the measured size distributions exhibited multi-modal behavior. 81970980 and 31771042), Fok Ying Tung Education Foundation (No. Note that the hardwood TEM sample did not image well, indicating aerosols composed of volatile organic hydrocarbons. The assumption was therefore made that the data from each SMPS could be interpreted in terms of particle equivalent-sphere projected area diameter. To ensure that the aerosols measured representative products of grinding, background aerosol measurements were also taken with the grinding tool freely spinning within the chamber at 20000 r.p.m. Arnoldussen et al. Given the unlikely probability that aerosols were created from the grinding wheel, this measurement represented the aerosols produced primarily by the grinding tool motor. Dental technician's pneumoconiosis: mineralogical analysis of two cases. Sampling was started at this point, based upon CPC measurements suggesting that the aerosol within the chamber was well mixed and that the particle number concentration did not vary appreciably over the necessary time scales. Particles 510m in diameter are deposited in the large and middle airways. 3e). To characterize the particle size distribution, the aerosol-laden air from the chamber was split and directed to three aerosol instruments operated in parallel. Relationship of incisive papilla to maxillary incisors and canines: original research. McCawley et al. })}); ideal for capturing the similarly sized dust particles, How An Outdoor Cooling Mist System Can Create Safer Events, DustBoss Offers Dynamic Dust Control Solution with DB-60 Surge, Odor Control Misting Systems for Soil Remediation, Innovative Dust Suppression Methods for the Scrap Recycling Industry, Dust Suppression Helps Demolition Expert Protect Workers and Surrounding Community from Hazardous Emissions. Removable partial denture with molar uprighting spring: an innovative hybrid appliance. Critical role of MARCO in crystalline silica-induced pulmonary inflammation. Careers. This grinding procedure and the verification that the particles size distribution shifted is a stepping stone for our future research on exposure of these particles to human lung cells. In the absence of a substrate, there was also evidence that the grinding tool led to the formation of ultrafine particles, albeit at a much lower concentration. To quantitatively present the particle size statistics for the combined aerosol instruments, a log-normal particle size distribution was assumed and fitted to the ultrafine and coarse modes in the experimental data (Fig. Pneumoconiosis among cretan dental technicians. Furthermore, the APS data were corrected for sampling train losses between the chamber and the instrument inlet and losses within the APS nozzle (Kinney and Pui, 1995). An overview of peroxidation reactions using liposomes as model systems and analytical methods as monitoring tools. Grinding of the dust samples was performed using a shatter box. method of generation) (ACGIH, 1990; OSHA, 1997). Finally, Fig. In this study, the morphologies, particle size distributions, and compositions of the three types of dental prosthesis grinding dust were measured.
The information is extracted from Fig. In vitro action of quartz on alveolar macrophage lipid peroxides. Grinding represents a typical mechanical operation found in many workplaces. 1. Various particles produce similar results. Dust particles are broken down into three groups based on size and ability. Through TEM analysis, researchers found that dust particles can enter human bronchial epithelial cells. The surface morphologies of the grinding dust were examined by SEM before and after fine milling. 2017YFC1104703), National Natural Science Foundation of China (Nos. When calcium carbonate, silica dust, etc., are applied to cells, reactive oxygen species (ROS) and lactate dehydrogenase (LDH) are commonly measured as indicators of cytotoxicity. Copyright 2022 British Occupational Hygiene Society. The effect of these dust particles at different concentrations on RAW264.7 cells was evaluated. The particle size distribution produced by the Dremel tool alone (Fig. High-speed grinding has been used as the basis for testing the hypothesis that ultrafine particles do not form a substantial component of mechanically generated aerosols. When viewing all of the substrates together for particle diameters corresponding to the ultrafine mode, it can be seen that, with the exception of wood, the size distributions generated by grinding were qualitatively similar to that produced using the grinding tool alone (Fig. The results showed that the three types of grinding dust had entirely different morphologies. The .gov means its official. cryogenic mill grinding pilot sized union process offers powderbulksolids The next dot represents the smallest dust particle that can be seen with the naked eye under ideal lighting conditions such as a beam of sunlight shining through a window. Examining the electron micrographs from each substrate gave little indication of whether particles in the ultrafine mode were primarily associated with the substrate or the carbon brush motor within the grinding tool. This is the smallest and most common form of dust, sizing up at less than or equal to 5 microns. about navigating our updated article layout. When compared with the aerosols produced solely by the grinding tool, the total number concentration for this substrate was over one order of magnitude higher, although qualitatively similar to that produced using only the Dremel tool (Fig. Although these data raise some ambiguity over the source of the ultrafine particles, they also raise the question of whether the process leading to mechanical aerosol generation should be considered a source of particles in its own right. However, the total number concentration when grinding upon an aluminum substrate was over 18 times higher. Upadhyay S, et al. The yellow arrow indicates the pseudopod extension, and the red arrow indicates the balloon change. Effect of microporosity on scaffolds for bone tissue engineering. (, Oxford University Press is a department of the University of Oxford. Currently, there are few reports on the effects of prosthesis grinding powder in vivo. Fig. In addition, the multiple comparison analysis based on LSD showed that the effect of the porcelain dust group was higher than the PMMA group and the Vitallium group, and the difference was statistically significant (P<0.05). were responsible for the cell culture and contributed to the writing of the manuscript, X.L. 2ag.
Lucky for us there are ways toreduce the risk of dust harming those near it. and transmitted securely. These mobile machines have a large range of coverage and allow for protection anywhere on the jobsite. 1). dust particle weight Fig. Dust particles are often thought of as the large, visible dust bits in the air you can see floating around without a care in a warm sunbeam, or the collected dust resting on the shelves of various knick knacks you've accumulated over the past years. Radi S, et al. Statistical analysis was performed with SPSS 17.0 (IBM Corp., Armonk, NY, USA). First things first. These systems spray water that captures fugitive dust hanging in the air and drops it to the ground. Use, Smithsonian 19-112-4-027), Shenyang Young and Middle-aged Technological Innovation Talent Plan (No. The Vitallium group (c, d) consisted of particles arranged in a sheet with irregular edge morphology. In presenting number statistics for the coarse mode, the data obtained by the APS were fitted using the right-hand side of this mode. Grinding was accomplished using a Multipro (model 395; Dremel, Racine, WI), a variable speed tool with rotational speeds that can be varied from 5000 to 30000 r.p.m. Researchers found that RAW macrophage cells effectively internalized both 0.1- and 0.5-m-diameter dust particles. Astrophysical Observatory. 2. hbspt.forms.create({ When the particle number concentration was reduced to a value of 50 particles/cm3, the air cleaner was turned off to prevent flow through the chamber. Barrett TE, et al. Results show a significant increase in fine particles (diameter < 10m) post grinding. Dental prostheses are made and tested, a variety of dust particles are emitted from the grinding performed to correct defects14. Pascoe CD, Jha A, Basu S, Mahood T, Lee A, Hinshaw S, et al. Meng C, et al. After fine milling, only the particle sizes were reduced, but their shapes did not significantly change. SMPS/NDMA, SMPS/LDMA and APS) was started 60 s after the grinding burst. Some substrates have no specific exposure criteria and are evaluated as a particulate not otherwise regulated with exposure limits ranging from 5 to 15 mg/m3 for respirable and total exposure, respectively (OSHA, 1997). APS aerosol size distributions were therefore transformed to particle number concentration versus equivalent-sphere projected area diameter assuming spherical particles with the same density as the bulk substrate material. Fluorescent staining of RAW264.7 cells exposed to 300gmLl dust from grinding different types of dental prosthesis materials: negative control (a,b), PMMA (c,d), Vitallium (e,f), and porcelain (g,h). Variation in particle number concentration [dN/d log(dp)] as a function of equivalent-sphere projected surface area diameter for (a) the Dremel tool without a grinding substrate, (b) a granite substrate, (c) a clay ceramic substrate, (d) a steel substrate, (e) an aluminum substrate, (f) a PTFE substrate and (g) a hardwood substrate using the SMPS/NDMA (solid circles), SMPS/LDMA (hollow circles) and APS (solid triangles). When comparing the particle size distributions for the various substrates, it appears that the coarse modes varied markedly (Fig. Particle statistics represent average values for three replicate sample runs and the reported statistics for each substrate have been background corrected. Grinding was accomplished such that the cylindrical wheel was placed normal to the substrate with a constant applied force of 3.96 N. A wide variety of grinding substrates were selected for evaluation to represent the broad spectrum of materials available. Suppressive oligodeoxynucleotides inhibit silica induced pulmonary inflammation. However, when applied to nanometer sized particles EDX is limited by long sample collection times and the sensitivity of the sample to beam damage and contamination. The most effective method of protecting on-site workers and the surrounding community is with dust control systems. Complete culture medium (DMEM supplemented with 10% inactivated serum) was used as a negative control. Acrylic resin pneumoconiosis: report of a case in a dental student. Measures of LDH activity can reflect changes in membrane permeability and damage of RAW264.7 cells19. During dust storms, we are exposed to a high concentration of dust particles. However, apart from these studies there is little in the literature to indicate the likely contribution of mechanical processes to ultrafine aerosols in the workplace. Three types of dental prosthesis grinding dust particles, PMMA dust, Vitallium dust, and dentin porcelain dust, were all toxic to RAW264.7 cells. Large particles (diameter < 10m) can be trapped by the nose and mouth, while smaller particles (diameter < 2.5m, also known as PM2.5) may permeate deep into lungs. Zhang ZY, et al. ), and then, the histopathology of their lung tissue was examined. After 24h, the culture medium was discarded, and a 300g/ml suspension of each of the three kinds of dust particles was added to a volume of 200l in each well for the exposure test. The large amount of ROS can produce cell lipid peroxidation, which damages normal cells and tissues18. 141039), Liaoning Province, colleges and universities basic research projects (No. The extent of the toxicity and pathogenicity of exposure to PMMA dust, Vitallium dust, and dentin porcelain dust differs. Grinding on wood resulted in an ultrafine aerosol with a markedly larger median diameter and substantially higher number concentration. With increasing dust exposure time, the cell survival rate decreased. Consequently, little attention has been given to the generated particle concentration much below 1 m. Isolevuglandins as a gauge of lipid peroxidation in human tumors. 4a,c,e,g, no abrasive grinding dust was found to induce apoptosis of the RAW264.7 cells. 2b). Additionally, it appears that the count median particle diameters varied markedly from substrate to substrate, with no discernable pattern. The aerosol number concentrations generated by the Dremel tool on the substrates tested varied greatly (Table 1). Protective effect of polysaccharides from Sargassum horneri against oxidative stress in RAW264.7 cells. 
HEPA-filtered, particle-free air was pulled upward through a stainless steel chamber (0.914 m long, 0.813 m wide, 1.19 m tall) using a commercially available, industrial air cleaner (model 73-800G; ACE Corp., St Louis, MO) (Fig. Larger, primarily micrometer scale particles (523 nm < dp < 20.5 m) were characterized using an aerodynamic particle sizer (APS) (model 3320; TSI Inc.). Lung granulomatosis in a dental technician. with an unused sintered aluminum oxide grinding wheel. solid circles for the SMPS/NDMA configuration, hollow circles for the SMPS/LDMA configuration and solid triangles for the APS). 3b). Implementing dust control equipment significantly reduces the risk of dust-related illnesses. While it is conceivable that the mass-weighted distribution of such aerosols may be dominated by super-micrometer particles, it is by no means clear that the same will apply for particle number- and surface area-weighted distributions. The results of LDH and ROS fluorescence intensity detection are shown in Figs. The chamber was HEPA filtered to remove aerosols within the chamber and the ventilation system was turned off. Grinding of clay ceramic led to a distinct bimodal particle size distribution (Fig. As can be seen, the SMPS/LDMA tended to sample particle sizes corresponding to aerosols located between the ultrafine and coarse modes. Accessibility PMC legacy view Before Cell viability was tested by the MTT method.
window.hsFormsOnReady = window.hsFormsOnReady || []; Thus it is likely that the observed mismatch is attributable to instrument response and conversion errors between particle diameters. The effects of dust on macrophages via the classical (type 1 helper T cell factor involvement) and selective activation (type 2 helper T cell factor involvement) pathways31. Particles engulfed by macrophages are transported in vesicles. Microscopic observation revealed that the dust particles accumulated on the RAW264.7 macrophage surfaces, which caused pseudopod elongation, irregular cell morphology, and ballooning. 3d) and many more nanometer size particles. Note that the shut-off valve closed when generating and sampling grinding aerosols. The aerosol produced when grinding on a steel substrate is shown in Fig. Brancaleone, P. et al. When it comes to industrial facilities, many of their processes can create dust -- much of which is tiny, respirable dust. Aerosols from the grinder were produced in a controlled environment, using a variety of grinding substrates, and the grinding aerosol was characterized over a particle size range from 4.22 nm to 20.5 m. Thorette C, et al. Scanning electron microscopy (SEM; SSX-550y, Shimadzu, Japan) was used to observe the morphology of the dental prosthesis grinding dust. Search for other works by this author on: Elevated COVID-19 Case Rates of Government Employees, District of Columbia, 20202022, Evaluation of Face Shields, Goggles, and Safety Glasses as a Virus Transmission Control Measure to Protect the Wearer Against Cough Droplets, Understanding the Impacts of the COVID-19 Pandemic on Small Businesses and Workers Using Quantitative and Qualitative Methods, Development of Harmonized COVID-19 Occupational Questionnaires. The cells were stained by fluorescent dye by adding 1ml of 95 v/v % alcohol to each well and, 30min later, followed by the addition of 0.1mgmll acridine orange and incubation for 15min in the dark at room temperature. For full access to this pdf, sign in to an existing account, or purchase an annual subscription. After exposure for 6, 12, 24, and 48h, 10l of MTT reagent (Sigma-Aldrich) was added to each well and incubated for 4h. Then, the supernatants were removed, 200l of DMSO was added, and the 96-well plate was shaken on a horizontal shaker for 10min. All three types of fine dental prosthesis grinding dust led to ROS increases in the macrophages in a time-dependent manner. A wide variety of grinding substrates were selected for evaluation to represent the broad spectrum of materials available. About Annals of Work Exposures and Health, About the British Occupational Hygiene Society, Receive exclusive offers and updates from Oxford Academic, Comparison of Nanoparticle Filtration Performance of NIOSH-approved and CE-Marked Particulate Filtering Facepiece Respirators, A New Approach to Sampling for Particle Size and Chemical Species Fingerprinting of Workplace Aerosols, Assessment of Particle Size Distributions of Health-relevant Aerosol Exposures of Primary Lead Smelter Workers. Fig. Rajaram MVS, et al. 2c). Fine grinding reduced the particle sizes to a different extent for each dust type. Respiratory diseases, including pulmonary fibrosis, silicosis, and allergic pneumonia, can be caused by long-term exposure to dental prosthesis grinding dust. A phase-displaced microscope was used to observe the morphological changes of the RAW264.7 cells after 24h and 48h of exposure at a concentration of 300gml1. A similar aerosol size distribution was measured for the aluminum substrate, although no comparable discrepancy between the SMPS/LDMA and APS was seen (Fig. Respiratory morbidity in a population of French dental technicians. In the overlap regions there was relatively good agreement among the aerosol instruments. This study focused on the classical pathway. The behavior of this substrate was qualitatively similar to that produced by the grinding tool itself (Fig. The dust was sealed in containers with the emery burrs. Composite of the ultrafine mode experimental results for the Dremel tool and various grinding substrates. The macrophage pneumoconiosis model is a currently established model16. However, the experimental results showed that Vitallium abrasive dust caused slightly greater damage to the RAW264.7 cells, but the difference was not statistically significant and may be related to the dust particle structures, element compositions or way of entering the body. RAW264.7 cells are mouse mononuclear macrophage leukaemia cells that play key roles in inflammation, immunity and phagocytosis. A possible cytotoxicity mechanism is the induction of lipid peroxidation and plasma membrane damage as the dust particles penetrate cells. EDX was used to determine the compositions of the three types of dental prosthesis grinding dust particles. The absorbance measurement of the wells without dust suspension were used as the reference points for the absorbance measurement of the exposed cells, as determined by a microplate reader (Bio Tek, Winooski, VT) at 490nm. Particles<5m in diameter can damage alveolar macrophages and cause silicosis, pulmonary fibrosis, and other respiratory diseases25. At 24h, the ROS fluorescence intensity of the three dust samples was slightly lower than that of the negative control group. will also be available for a limited time. There's usually no need to worry about the typical dust in a home, but those working in the industrial sector needdust controland can come into contact with these harmful, micro-sized dust particles on a regular basis. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. Fig. 
Rogak et al. Wen ZS, et al. Moreover, there was no significant difference between the Vitallium group and the PMMA group. The micrograph also revealed evidence of large numbers of nanometer size particles on the substrate, although it is not clear whether these originated from the granite substrate or the grinding tool itself. Ultrasound changes following controlled mechanical stress in synovial tissue in the hands of healthy individuals. After 30 s, grinding was conducted on the substrate for 10 s, ensuring that the aerosol number concentration was sufficiently low to suppress coagulation dynamics (typical number concentrations were <106 particles/cm3). Zhang ZQ, et al. The dust from grinding dental prosthesis made of these three materials was characterized in terms of morphology, particle size, and elemental composition. To ensure that there was little temporal variation over the time scales needed to collect aerosol samples, a CPC was used to characterize the temporal variation of the total number concentration during a grinding sample run. Agreement NNX16AC86A, Is ADS down? The reason for the ROS increase might be related to short-term and low-dose dust exposure initiating defence measures in the body. Arnoldussen YJ, et al. The total sample time for each SMPS measurement was 230 s (up-scan time 200 s, down-scan time 30 s) while the total sample time for each APS measurement was 200 s. Transmission electron microscope (TEM) samples of the aerosol generated from each substrate type were also collected using a point-to-plane electrostatic precipitator (Cheng et al., 1981). At 24h and 48h, the difference between the porcelain dust group and the PMMA group was statistically significant (P<0.05), and the difference between the Vitallium group and the PMMA group at 48h was statistically significant (P<0.05). Yang et al. DustBoss dust control systemsuse a techonlogy know as atomized mist to create 50-200 micron sized water dropletsideal for capturing the similarly sized dust particles. The three types of grinding dust particles showed had wide range of size distributions that significantly differed from each other. sharing sensitive information, make sure youre on a federal 1, the morphology of the PMMA group particles (a, b) was irregular and very different in size.
Part 2: Palateless Dentures. Sleeth DK, et al. These particles can not only find their way to the lungs, but the material dust is made up of can come with its own unique hazards. Small, nanometer scale particles [4.22 nm < dp (particle diameter) < 100 nm] were characterized using a scanning mobility particle sizer (SMPS) configured with a nano differential mobility analyzer (DMA) (electrostatic classifier model 3080 using a DMA model 3085 and a condensation particle counter model 3022A; TSI Inc., St Paul, MN).