This is the smallest and most common form of dust, sizing up at less than or equal to 5 microns. Currently, there are few reports on the effects of prosthesis grinding powder in vivo.
RAW264.7 macrophages were seeded in a 96-well plate (1104 cells/well) and exposed to 200l of the grinding dust suspension at concentrations of 50, 150, 300, 450, and 600gmll. Chen SJ, Chen F. Learning and summary of lactate dehydrogenase. The amounts of LDH and ROS released were increased with time and concentration, and the differences were statistically significant (P<0.05). The .gov means its official.
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. Takahashi T, et al. Microscopic observation revealed that the dust particles accumulated on the RAW264.7 macrophage surfaces, which caused pseudopod elongation, irregular cell morphology, and ballooning. You might need to clean your shelves and brush off your favorite figures, and second, that visible dust is only a small percentage of all dust. Grinding upon the granite substrate gave a distribution that was relatively bimodal (Fig. However, the total number concentration when grinding upon an aluminum substrate was over 18 times higher. Seldn AI, et al. Note that the hardwood TEM sample did not image well, indicating aerosols composed of volatile organic hydrocarbons. Some discrepancy was observed in the overlap region between the APS and the SMPS/LDMA. contributed to the analysis of the experiments. Fine grinding reduced the particle sizes to a different extent for each dust type. 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. 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. Under low magnification (200), as shown in Fig. The information is extracted from Fig. were responsible for the cell culture and contributed to the writing of the manuscript, X.L. Other substrates, such as wood dusts and metals, can be evaluated and compared with specific exposure criteria. and N.C. contributed to the study design and implementation, W.W. and T.L. reported that the toxicity of hydrogen peroxide (H2O2) was evaluated by detecting the levels of ROS and LDH in RAW264.7 cells21. In vivo Location and dynamic changes of inflammation, fibrosis, and expression levels of related genes in SiO-induced pulmonary fibrosis in rats. The adverse effects of different concentrations of grinding dust (50, 150, 300, 450, and 600gmll) on RAW264.7 macrophages were evaluated, including changes in cell morphology and the production of lactate dehydrogenase (LDH) and reactive oxygen species (ROS). 2019-ZD-0749), Shenyang Major Scientific and Technological Innovation Research and Development Plan (No.
ANTHONY T. ZIMMER, ANDREW D. MAYNARD, Investigation of the Aerosols Produced by a High-speed, Hand-held Grinder Using Various Substrates, The Annals of Occupational Hygiene, Volume 46, Issue 8, September 2002, Pages 663672, https://doi.org/10.1093/annhyg/mef089. 2e).
Two hundred microlitres of 2,7-dichlorofluorescein-diacetate (DCFH-DA) fluorescent probe (10M) was added to each well, and the cells were incubated in 5% CO2 at 37C for 1h. Residual DCFH-DA was then removed by rinsing the cells three times with PBS. Among the three types of denture grinding dust, the percentage of ceramic abrasive grains with a diameter of<5m was the highest (21.05%); therefore, porcelain powder may cause more lung damage than is caused by other dust types. 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). 2g shows the measured aerosol size distribution for grinding of oak hardwood. The cytotoxicity induced in RAW264.7 macrophages by the exposure to different concentrations (50, 150, 300, 450, and 600gmLl) of dust suspensions in DMEM containing 10% inactivated FBS was observed by light and fluorescence microscopy. solid circles for the SMPS/NDMA configuration, hollow circles for the SMPS/LDMA configuration and solid triangles for the APS). At 24h and 48h, culture supernatants were sampled from each well and analysed for LDH level using a lactate dehydrogenase kit. 2d. Once again, it was not possible to distinguish a source and generation mechanism for the particles by morphology alone. 2b). 2f.
2017YFC1104703), National Natural Science Foundation of China (Nos. Rao J, et al. In particular, the changed in nuclear location was more pronounced in the cells exposed to the porcelain dust. The chamber was HEPA filtered to remove aerosols within the chamber and the ventilation system was turned off. In presenting number statistics for the coarse mode, the data obtained by the APS were fitted using the right-hand side of this mode. Isolevuglandins as a gauge of lipid peroxidation in human tumors. Composite of the ultrafine mode experimental results for the Dremel tool and various grinding substrates. Estimation of the human extrathoracic deposition fraction of inhaled particles using a polyurethane foam collection substrate in an IOM sampler. Arnoldussen et al. (1993) have shown particle mobility diameter to agree well with equivalent-sphere projected area diameter for fractal-like particles <1 m. A number of aerosol instruments were used to evaluate the aerosol behavior and the resultant particle size distribution during a grinding operation.
The size of the particle has various effects on the organisms exposed to them. Note that the shut-off valve closed when generating and sampling grinding aerosols. 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). While still bimodal, the lower mode occurs at a much higher diameter than for previous substrates (Table 1). At 6h, the number of viable exposed cells was reduced, but the change was not significant (P>0.05). 19-112-4-027), Shenyang Young and Middle-aged Technological Innovation Talent Plan (No. formId: "e7fc0871-5cca-47e3-95b8-26eb8d9c3013", reported that animals were subjected to mixed dust types generated from grinding dental prostheses (PMMA, Vitallium and porcelain dust, etc. National Institute for Occupational Safety and Health, Division of Applied Research and Technology, 4676 Columbia Parkway, Cincinnati, OH 45226, USA.
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). Occupational health, Inflammasome, Inflammasome, Inflammasome, Occupational health. Assessing the in vitro toxicity of the lunar dust environment using respiratory cells exposed to Al(2)O(3) or SiO(2) fine dust particles. official website and that any information you provide is encrypted 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. Musculoskeletal Symptoms in Professional Musicians: Do Self-employed and Employer-employed Musicians Differ? Previous animal experiments showed that the relatively smaller particle sizes of porcelain and Vitallium dust particles may be more toxic than larger particles15. The negative control cells showed a regular circular shape, but the surface of the cells exposed to prosthesis grinding dust was changed. Removable partial denture with molar uprighting spring: an innovative hybrid appliance. The high density particles produced from the steel substrate ( 7.9 kg/m3), together with uncertainty over their morphology, are probably responsible for the poor transformation between aerodynamic diameter and equivalent-sphere projected area diameter with the APS data. The substrates selected included both relatively homogeneous and heterogeneous materials and included steel, aluminum, polytetrafluoroethylene (PTFE), hardwood, granite and clay ceramic.
1, PMMA dust (g) contained mainly C and O, Vitallium dust (h) was composed mostly of Cr, Co, and Mo, and porcelain dust (i) consisted principally of Si, Al, and O. Simultaneous aerosol sampling (i.e.
An official website of the United States government. RC200060), Medical Engineering, Ministry of Science and Technology of China, and the 111 Project (No. As can be seen, the SMPS/LDMA tended to sample particle sizes corresponding to aerosols located between the ultrafine and coarse modes. It was proposed that grinding dust induced fibrosis in rat lung tissue14. Using stainless steel and flexible graphite tubing to attenuate charging effects within the sample line, the grinding aerosols were collected from the stainless steel chamber from a position located directly above the grinding operation (height 15 cm).
Grinding of the dust samples was performed using a shatter box.
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. Zhou H, et al. will also be available for a limited time. The viability of the RAW264.7 cells exposed to the three kinds of dust was lower than that of the blank control group cells (Fig. The assumption was therefore made that the data from each SMPS could be interpreted in terms of particle equivalent-sphere projected area diameter. 2ag. After 6h of exposure, numerous cells had extended pseudopods, indicating active removal of particles26. It is generally assumed that aerosols generated during mechanical processes such as grinding are characterized by large particles formed through attrition. 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. An open-label, 4-week, prospective clinical study evaluating the efficacy and safety of a novel targeted skin care line addressing five common skin conditions. 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.
The aerosol produced solely by the grinding tool and the background corrected measurements for each of the substrates are presented in Fig. This result was subtracted from measured size distributions for each grinding substrate.
sharing sensitive information, make sure youre on a federal 5).
Composite of the coarse mode experimental results for the Dremel tool and various grinding substrates. 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. Jordan JA, et al. 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). Size distribution statistics weighted by particle number for the Dremel tool operating by itself and when grinding upon various substrates. 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). Fig.
After fine milling, only the particle sizes were reduced, but their shapes did not significantly change. cryogenic mill grinding pilot sized union process offers powderbulksolids It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. The Particle binding to cell surface receptors such as scavenger and Toll-like receptors may induce polymerization of the actin cytoskeleton and the formation of pseudopods to envelop the dust particles28. The aerosol number concentrations generated by the Dremel tool on the substrates tested varied greatly (Table 1). A possible cytotoxicity mechanism is the induction of lipid peroxidation and plasma membrane damage as the dust particles penetrate cells. Effect of microporosity on scaffolds for bone tissue engineering. The behavior of this substrate was qualitatively similar to that produced by the grinding tool itself (Fig. X.L., Y.Z.
A number of publications have indicated that for low solubility, chemically inert materials the composition of ultrafine particles is of secondary importance (Oberdorster et al., 1995; Donaldson et al., 1998; Brown et al., 2001). Grinding of the steel substrate led to a distinct difference between the results obtained in the overlap region between the SMPS/LDMA and the APS. Ultrasound changes following controlled mechanical stress in synovial tissue in the hands of healthy individuals. Table Table11 shows detailed information on the particle sizes of the three grinding dust types before and after fine milling. In addition, the percentage of PMMA abrasive dust particles<5m was higher than that of the Vitallium abrasive dust. In this study, the morphologies, particle size distributions, and compositions of the three types of dental prosthesis grinding dust were measured. The dust was sealed in containers with the emery burrs. Acrylic resin pneumoconiosis: report of a case in a dental student. This is a harmful form of dust that can pass into the lungs, bypassing the nose, throat and upper respiratory tract. Furthermore, 42.3% of the finely ground porcelain dust particles were smaller than 10m, which is a higher than the proportions of particles in the same size range for the other types of grinding dust. Pneumoconiosis among cretan dental technicians. It was also evaluated with LDH and ROS assays. Fig.
Exposure to cobalt chromium dust and lung disorders in dental technicians.
LDH activity in RAW264.7 macrophages exposed to different types of dental prosthesis grinding dust for 24h (a) and 48h (b). Mechanical processes such as grinding are classically thought to form micrometer scale aerosols through abrasion and attrition.
Energy dispersive spectroscopy (EDX; Shimadzu, Japan) was used to analyse the elemental compositions of these dust samples. For example, Sato et al.
The cells showed irregular shapes, the number of pseudopods was increased, the pseudopods were elongated to different lengths, and some cells even appeared balloon-like. Choudat D, et al. 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. There are many processes and pieces of equipment that can generate these risk-related particles. PMC legacy view Upadhyay S, et al. The lack of non-organic carbonaceous particles indicated that most of the ultrafine aerosol was associated with incomplete combustion and probably contained a large number of volatile components that evaporated in the TEM. EDX was used to determine the compositions of the three types of dental prosthesis grinding dust particles. This dust is well below visibility which rests around 30 - 40 microns. Macrophage immunoregulatory pathways in tuberculosis. A-1 PMMA, A-2 finely ground PMMA, B-1 Vitallium, B-2 finely ground Vitallium, C-1 porcelain, C-2 finely ground porcelain. The viability of the RAW264.7 cells was inversely proportional to the dust exposure time.
Liu YM, et al. Grinding typically occurs on a wide variety of substrates. For a better understanding of the source of the ultrafine mode arising from grinding on these substrates, the use of alternative sample collection methods or analytical methods such as electron energy loss spectroscopy (EELS) should be considered for future research (Brydson, 2000; Maynard, 2000). Commonly used prosthetic materials include PMMA, Vitallium, and porcelain, and the dust created from grinding them may pose various health hazards to oral care workers, such as pulmonary fibrosis, silicosis, allergic pneumonia, lung granuloma, asthma, and lung cancer58. Twenty-four hours after low-concentration dust was applied to RAW264.7 cells, the ROS content level decreased slightly compared with that of the negative control group, which may have been the result of differences in the degree of immune repair regulation caused by the dust-induced damage to the cells36. Arnoldussen YJ, et al. Sato T, et al. LDH activity was observed, in descending order, for the porcelain dust group, Vitallium group and PMMA group. 4a,c,e,g, no abrasive grinding dust was found to induce apoptosis of the RAW264.7 cells. Hard metal pneumoconiosis: a case of giant-cell interstitial pneumonitis in a machinist. Brancaleone, P. et al. Particles 510m in diameter are deposited in the large and middle airways. All these events can trigger an inflammatory response30. This type also possesses the ability to enter the human system, but unlike the other two forms, it can be visible to the human eye. Fig. Wen et al.
RAW264.7 macrophages were selected in logarithmic phase, adjusted to 1106 cells/ml and inoculated in 96-well plates, with 200l of the cell suspension added to each well, and cultured in a 37C in an incubator with 5% CO2. Grinding upon a surface such as ceramic or granite produced an aerosol with appreciable number concentrations and a distinct mode, while grinding upon surfaces such as aluminum produced low particle number concentrations and an indistinct mode. and K.Z. Research advances in silicon pulmonary fibrosis. Zhang ZQ, et al. The rotational speed of the grinding wheel was determined using a tachometer (Dynapar model HT50; Danaher Controls, Gurnee, IL). 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. 2018225078), Liaoning Provincial Natural Science Foundation Guidance Project (No. 3ae. Also, micrographs from the steel substrate showed the existence of nanometer size primary particles within large open agglomerates. Li XM, et al.
Thorette C, et al. Cokic SM, et al. Scanning electron microscopy images of dental prosthesis grinding dust: PMMA (a), finely ground PMMA (b), Vitallium (c), finely ground Vitallium (d), porcelain (e), finely ground porcelain (f), and their composition: PMMA (g). 2a). region: "", dust particle weight First things first. The importance of reporting house dust mite endotoxin abundance: impact on the lung transcriptome. P values less than 0.05 were stated as statistically significant. There was no significant difference between the PMMA group and the Vitallium group, and the porcelain group was significantly different from both other groups (P<0.05). The aerosol that resulted from grinding a PTFE substrate is shown in Fig. The grinding wheel was placed on the substrate and the grinding speed was adjusted to 20000 r.p.m. Vitallium (h), porcelain (i). The pro-inflammatory cytokines, salivary cortisol and alpha-amylase are associated with generalized anxiety disorder (GAD) in patients with asthma. Most of dust is very tiny, so tiny that it's not even visible to the human eye. Kartaloglu Z, et al. ), and then, the histopathology of their lung tissue was examined.
The authors declare no competing interests. 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. Ten grams of each dust type was weighed. Statistical analysis was performed with SPSS 17.0 (IBM Corp., Armonk, NY, USA). The measurements obtained using each aerosol instrument are represented by different symbols (i.e. 2c). Therefore, clinicians who regularly work with these materials should wear the appropriate personal protection equipment to minimize exposure and reduce the health risks caused by these particulates. Dust particles are broken down into three groups based on size and ability. The authors acknowledge financial support from the National Key Research and Development Program of China (No. target: "#hbspt-form-1659158004000-5174664924", Both instruments showed decreased detection efficiency for particles in the region of 500 nm and it is likely that this was the source of the observed mismatch. 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. To characterize the particle size distribution over particle sizes ranging from 4.2 nm to 20.5 m, the aerosol-laden air collected from an enclosed chamber was split and directed to three aerosol instruments operated in parallel. Current investigations into magnetic nanoparticles for biomedical applications. During dust storms, we are exposed to a high concentration of dust particles.
4). When it comes to industrial facilities, many of their processes can create dust -- much of which is tiny, respirable dust. This information may provide a basis for determining the best personal protection for use by dental clinicians and guide follow-up research. In presenting number statistics for the ultrafine mode, the data obtained by the SMPS/NDMA were used for fitting the left-hand side of this mode as this instrument was optimized to sample aerosols in the particle size range 10100 nm. These cell samples were observed under an inverted phase-contrast microscope. 3b). During a typical experimental sample run, the grinding substrate was attached to a holder. This process damages cells, releases dust particles, initiates re-phagocytosis, and stimulates the proliferation and aggregation of macrophages. Yang CJ, et al. The results showed that the three types of grinding dust had entirely different morphologies. 2). Limited data indicate that it is possible to generate high particle number concentrations from mechanical processes. Respiratory symptoms, lung function, and pneumoconiosis among self employed dental technicians. The big dot represents the cross section of an average human hair or approximately 100 microns in diameter. Transmission electron microscope samples of the various grinding substrates were also collected. The yellow arrow indicates the pseudopod extension, and the red arrow indicates the balloon change. Finally, the cells were gently rinsed with PBS and observed under a fluorescence microscope. Moreover, there was no significant difference between the Vitallium group and the PMMA group. 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. shield face grinding chipping impact fsc weldclass 3c), indicating nucleation followed by growth through coagulation. Amphiregulin may be a new biomarker of classically activated macrophages. 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. RAW264.7 cells are mouse mononuclear macrophage leukaemia cells that play key roles in inflammation, immunity and phagocytosis. The three types of dust particles were allocated to groups A, B, and C, which in turn were divided into two subgroups, namely, A1, A2, B1, B2, C1, and C2. reported that macrophages exposed to silica dust activated classical pathways and therefore generated superoxide anion (O2) and hydroxyl (OH), which caused oxidative damage to the cells34. It also is about 1/12th the width of the average human hair. Respiratory morbidity in a population of French dental technicians. The cells were incubated in 5% CO2 at 37C for 6, 12, 24, and 48h. However, the incubation times were only 24h and 48h for the LDH analysis. World at work: dental laboratory technicians. 5 and and66 The data were subjected to multiple linear regression and showed that the order of influence of the factors on LDH and ROS was the time of exposure to the dust, the dust concentration, and the dust type. The results of LDH and ROS fluorescence intensity detection are shown in Figs. Schematic of the grinding generation and aerosol sampling apparatus. 3a). showed that the release of ROS from astrocytes increased with increasing concentration, but these cells did not produce ROS when exposed to a low concentration level (0.0009g/cm2) for 72 h38.
To prevent cross-contamination, new grinding wheels were used for each substrate tested. 81970980 and 31771042), Fok Ying Tung Education Foundation (No. Yan JB, et al. 2ag, with electron micrographs of representative particles shown in Fig. Transmission electron microscope micrographs of the various grinding substrates including: (a) granite, (b) clay ceramic, (c) steel, (d) aluminum and (e) PTFE.
Grinding on wood resulted in an ultrafine aerosol with a markedly larger median diameter and substantially higher number concentration. 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.
Since the SMPS tends to overestimate particle counts at high diameters when particle counts at lower diameters are significantly higher (an artifact associated with particle residence time within the system), it is conceivable that, in the absence of such an artifact, better agreement between the SMPS and APS would be seen. A1, B1, and C1 were untreated samples. However, in the case of highly toxic particles such as silica, it would be important to differentiate between the aerosols generated by these two sources. Yang et al. Compared with the control group, the difference was statistically significant (P<0.01). Therefore, the occupational protection of the clinician should be increased to reduce the damage of the dust to the doctor. It appears that the ultrafine aerosols were formed by the following processes: (i) from within the grinding motor, (ii) from the combustion of amenable grinding substrates and (iii) from volatilization of amenable grinding materials at the grinding wheel/substrate interface.
