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Biological Trace Element Research Sep 2020Nanotechnology is a vital part of health care system, including the dentistry. This branch of technology has been incorporated into various fields of dentistry ranging... (Review)
Review
Nanotechnology is a vital part of health care system, including the dentistry. This branch of technology has been incorporated into various fields of dentistry ranging from diagnosis to prevention and treatment. The latter involves application of numerous biomaterials that help in restoration of esthetic and functional dentition. Over the past decade, these materials were modified through the incorporation of metal nanoparticles (NP) like silver (Ag), gold (Au), titanium (Ti), zinc (Zn), copper (Cu), and zirconia (Zr). They enhanced antimicrobial, mechanical, and regenerative properties of these materials. However, lately, the toxicological implications of these nanometal particles have been realized. They were associated with cytotoxicity, genotoxicity altered inflammatory processes, and reticuloendothelial system toxicity. As dental biomaterials containing metal NPs remain functional in oral cavity over prolonged periods, it is important to know their toxicological effects in humans. With this background, the present systematic review is aimed to gain an insight into the plausible applications and toxic implications of nano-metal particles as related to dentistry.
Topics: Dentistry; Gold; Humans; Metal Nanoparticles; Nanotechnology; Silver
PubMed: 31782063
DOI: 10.1007/s12011-019-01986-y -
Brazilian Oral Research Jul 2017The aim of this systematic review was to compare the clinical performance and failure modes of teeth restored with intra-radicular retainers. A search was performed on... (Review)
Review
The aim of this systematic review was to compare the clinical performance and failure modes of teeth restored with intra-radicular retainers. A search was performed on PubMed/Medline, Central and ClinicalTrials databases for randomized clinical trials comparing clinical behavior and failures of at least two types of retainers. From 341 detected papers, 16 were selected for full-text analysis, of which 9 met the eligibility criteria. A manual search added 2 more studies, totalizing 11 studies that were included in this review. Evaluated retainers were fiber (prefabricated and customized) and metal (prefabricated and cast) posts, and follow-up ranged from 6 months to 10 years. Most studies showed good clinical behavior for evaluated intra-radicular retainers. Reported survival rates varied from 71 to 100% for fiber posts and 50 to 97.1% for metal posts. Studies found no difference in the survival among different metal posts and most studies found no difference between fiber and metal posts. Two studies also showed that remaining dentine height, number of walls and ferrule increased the longevity of the restored teeth. Failures of fiber posts were mainly due to post loss of retention, while metal post failures were mostly related to root fracture, post fracture and crown and/or post loss of retention. In conclusion, metal and fiber posts present similar clinical behavior at short to medium term follow-up. Remaining dental structure and ferrule increase the survival of restored pulpless teeth. Studies with longer follow-up are needed.
Topics: Bias; Dental Restoration Failure; Dental Restoration, Permanent; Glass; Gold; Humans; Post and Core Technique; Randomized Controlled Trials as Topic; Titanium; Tooth, Nonvital; Treatment Outcome
PubMed: 28678974
DOI: 10.1590/1807-3107BOR-2017.vol31.0064 -
Quintessence International (Berlin,... 2012To systematically review the allergic reactions associated with metal alloys in porcelain-fused-to-metal (PFM) fixed prosthetic devices. (Review)
Review
OBJECTIVE
To systematically review the allergic reactions associated with metal alloys in porcelain-fused-to-metal (PFM) fixed prosthetic devices.
METHOD AND MATERIALS
After reviewing the titles and abstracts of the articles as well as removing duplicates, 22 articles were considered relevant. PubMed, Web of Science, ScienceDirect, and Google Scholar from 1970 to 2012 were evaluated, and randomized studies, review articles, case reports, cross-sectional surveys, and abstracts were included. Conference papers and posters were excluded.
RESULTS
Although reported, allergic reactions to metallic alloys in the context of PFM devices are not well documented. Allergic reactions to high noble and noble metal alloy cores of palladium and gold and to base metal alloys nickel and cobalt in the context of PFM fixed partial dentures (FPDs) are reported. Each type of metal is associated with a different rate of allergic reactions, which may be attributed to the extent of corrosion of the alloy, population exposure, and the biologic environment. Because few studies document allergic reactions to metals that comprise PFM crowns and partial dentures, further research in this field is necessary to determine the frequency and type of reactions elicited.
CONCLUSION
Though allergic reactions to metal alloys used in dentistry are well documented, only few articles focus on the correlation between FPDs and metal allergies. Thus, this paper surveys case reports of hypersensitivity reactions linked to FPDs and reviews the current literature on allergic reactions to the metallic elements comprising those devices.
Topics: Chromium; Cobalt; Corrosion; Crowns; Dental Alloys; Denture, Partial, Fixed; Gold; Humans; Hypersensitivity; Metal Ceramic Alloys; Nickel; Palladium
PubMed: 23115766
DOI: No ID Found -
PloS One 2013The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds)... (Review)
Review
INTRODUCTION
The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure.
OBJECTIVE
To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA.
METHODS
Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors).
RESULTS
Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty.
DISCUSSION
Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed "time out" for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted MoM-bearing should receive regular and standardized monitoring of metal ion concentrations. Further research is indicated especially with regard to potential systemic reactions due to accumulation of metal products.
Topics: Arthroplasty, Replacement, Hip; Body Fluids; Chromium Alloys; Cobalt; Humans; Metals; Molybdenum; Nickel; Postoperative Complications; Titanium
PubMed: 23950923
DOI: 10.1371/journal.pone.0070359 -
The Journal of Bone and Joint Surgery.... Oct 2011The cost of the implant as part of a total knee arthroplasty accounts for a substantial portion of the costs for the overall procedure: all-polyethylene tibial... (Meta-Analysis)
Meta-Analysis Review
Cemented all-polyethylene and metal-backed polyethylene tibial components used for primary total knee arthroplasty: a systematic review of the literature and meta-analysis of randomized controlled trials involving 1798 primary total knee implants.
BACKGROUND
The cost of the implant as part of a total knee arthroplasty accounts for a substantial portion of the costs for the overall procedure: all-polyethylene tibial components cost considerably less than cemented metal-backed tibial components. We performed a systematic review of the literature to determine whether the clinical results of lower-cost all-polyethylene tibial components were comparable with the results of a more expensive metal-backed tibial component.
METHODS
We searched The Cochrane Library, MEDLINE, EMBASE, EBSCO CINAHL, the bibliographies of identified articles, orthopaedic meeting abstracts, health technology assessment web sites, and important orthopaedic journals. This search was performed for the years 1990 to the present. No language restriction was applied. We restricted our search to Level-I studies involving participants who received either an all-polyethylene or a metal-backed tibial implant. The primary outcome measures were durability, function, and adverse events. Two reviewers independently screened the papers for inclusion, assessed trial quality, and extracted data. Effects estimates were pooled with use of fixed and random-effects models of risk ratios, calculated with 95% confidence intervals. Heterogeneity was assessed with the I2 statistic. Forest plots were also generated.
RESULTS
Data on 1798 primary total knee implants from twelve studies were analyzed. In all studies, the median or mean age of the participants was greater than sixty-seven years, with a majority of the patients being female. There was no difference between patients managed with an all-polyethylene tibial component and those managed with a metal-backed tibial component in terms of adverse events. There was no significant difference between the two groups in terms of the durability of the implants at two, ten, and fifteen years postoperatively, regardless of the year or how durability was defined (revision or radiographic failure). Finally, with use of a variety of validated measures, there was no difference between the two groups in terms of functional status at two, eight, and ten years, regardless of the measure used.
CONCLUSION
A less expensive all-polyethylene component as part of a total knee arthroplasty has results equivalent to those obtained with a cemented metal-backed tibial component. Using a total knee implant with a cemented all-polyethylene tibial component could save the healthcare system substantial money while obtaining equivalent results to more expensive cemented designs and materials.
Topics: Arthroplasty, Replacement, Knee; Cost-Benefit Analysis; Female; Humans; Knee Prosthesis; Male; Metals; Polyethylenes; Prosthesis Design; Prosthesis Failure; Tibia; Treatment Outcome
PubMed: 22005864
DOI: 10.2106/JBJS.J.01303 -
Current Environmental Health Reports Dec 2022In epidemiologic studies, biomarkers are the best possible choice to assess individual exposure to toxic metals since they integrate all exposure sources. However,... (Review)
Review
Validity of Geolocation and Distance to Exposure Sources from Geographical Information Systems for Environmental Monitoring of Toxic Metal Exposures Based on Correlation with Biological Samples: a Systematic Review.
PURPOSE OF REVIEW
In epidemiologic studies, biomarkers are the best possible choice to assess individual exposure to toxic metals since they integrate all exposure sources. However, measuring biomarkers is not always feasible, given potential budgetary and time constraints or limited availability of samples. Alternatively, approximations to individual metal exposure obtained from geographic information systems (GIS) have become popular to evaluate diverse metal-related health outcomes. Our objective was to conduct a systematic review of epidemiological studies that evaluated the validity of GIS-based geolocation and distance to pollutant sources as an approximation of individual metal exposure based on correlation with biological samples.
RECENT FINDINGS
We considered 11 toxic metals: lead (Pb), cadmium (Cd), antimony (Sb), aluminum (Al), arsenic (As), chromium (Cr), nickel (Ni), mercury (Hg), tungsten (W), uranium (U), and vanadium (V). The final review included 12 manuscripts which included seven metals (Pb, Cd, Al, As, Cr, Hg, and Ni). Many studies used geolocation of the individuals to compare exposed (industrial, urban, agricultural, or landfill sources) and unexposed areas and not so many studies used distance to a source. For all metals, except lead, there was more animal than human biosampling to conduct biological validation. We observed a trend towards higher levels of Cd, Cr, Hg, and Pb in biosamples collected closer to exposure sources, supporting that GIS-based proxies for these metals might approximate individual exposure. However, given the low number and heterogeneity of the retrieved studies, the accumulated evidence is, overall, not sufficient. Given the practical benefits and potential of modern GIS technologies, which allow environmental monitoring at a reasonable cost, additional validation studies that include human biosampling are needed to support the use of GIS-based individual exposure measures in epidemiologic studies.
Topics: Humans; Geographic Information Systems; Cadmium; Environmental Monitoring
PubMed: 36447111
DOI: 10.1007/s40572-022-00383-3 -
Journal of Toxicology and Environmental... 2015Some forms of chromium (Cr) and nickel (Ni) are toxic, especially with chronic elevated exposure, and certain forms such as hexavalent chromium or nickel carbonyl were... (Review)
Review
Some forms of chromium (Cr) and nickel (Ni) are toxic, especially with chronic elevated exposure, and certain forms such as hexavalent chromium or nickel carbonyl were labeled as carcinogens. Since both metals are naturally occurring, and used in industrial processes, individuals may be exposed through ingestion of contaminated food or water, inhalation, or dermal contact. This study focused on the impact of toxic forms of Cr and Ni during pregnancy and outcomes in newborn and young children. A systematic literature review following "The Navigation Guide" was applied, and 16 reports that satisfied the inclusion criteria were scored. Six papers studied birth weight, prematurity, or gestational age: one found an association between Ni and small for gestational age, while another linked Ni with low birth weight; however, four reported no marked associations. Of six studies that examined birth defects, three found no significant associations; one noted an association between Ni and neural tube defects; one showed an association between Ni and structural birth defects; and one reported a weak effect for Cr exposure and musculoskeletal defects. In the remaining four studies, weak associations were found for hexavalent Cr and neuroblastoma, Ni and autism spectrum disorder, Cr and Ni and DNA damage, and Cr and lymphocyte damage. Among the studies that were rated as good for execution and reliability, there was weak evidence of an association between Ni and autism spectrum disorder and small for gestational age, but no significant association between Cr and a child outcome.
Topics: Child, Preschool; Chromium; Environmental Pollutants; Female; Humans; Infant; Infant, Newborn; Nickel; Pregnancy; Pregnancy Complications; Prenatal Exposure Delayed Effects
PubMed: 26571332
DOI: 10.1080/15287394.2015.1090939 -
Ecotoxicology and Environmental Safety Jan 2023Risk assessment of heavy metals is critical in controlling and preventing risks of foodborne diseases. Fish can be used as bioindicators for exposure to potential toxic... (Review)
Review
Risk assessment of heavy metals is critical in controlling and preventing risks of foodborne diseases. Fish can be used as bioindicators for exposure to potential toxic elements (PTEs), which can represent potential risks for humans. The long Iranian coastline and three major fishery regions in the country, including the northern (Caspian Sea) and southern (Persian Gulf and Gulf of Oman) seas as well as inland waters and aquacultures (rivers, dams, wetlands and fish farms) have made Iran a large producer of fish. In the first step of the present study, data collection and report of PTEs in fish from the three fishery regions (2010-2022) were carried out. In the second step, health risks were assessed using Monte Carlo simulation in child and adult consumers. The average concentrations of Cd, Hg and Pb for the northern sea, southern sea, and inland waters and aquacultures were 0.273, 0.249, 1.077; 0.430, 0.423, 1.182; and 1.387, 0.232, 1.703 μg/g per dry weight, respectively. Based on the target hazard quotient results, Hg intake of Iranian children from all the three fishery regions was more than 1, which was alarming. In the adult age group, southern sea fish consumers were at risk of Hg adverse health effects. Moreover, Cd included the highest carcinogenic risk of toxic elements in fish from the three fishery regions of Iran. Estimation of THQ, HI, ILCR and EDI revealed that consumption of fish might induce health complexities for the consumers in Iran. Moreover, Iranians from northern and southern regions of the country consumed further seafood due to the availability of high seafood sources in these regions. Hence, various indices must be used for the risk assessment of general human health. Due to the high risks of carcinogenicity/non-carcinogenicity estimated in the risk assessment, consumption of fish by infants and pregnant women must critically be assessed.
Topics: Adult; Animals; Child; Female; Humans; Infant; Pregnancy; Cadmium; Environmental Monitoring; Fishes; Food Contamination; Indian Ocean; Iran; Mercury; Metals, Heavy; Risk Assessment
PubMed: 36508819
DOI: 10.1016/j.ecoenv.2022.114349 -
Clinical Orthopaedics and Related... Dec 2014Metal-on-metal (MoM) total hip arthroplasties (THAs) and the head-neck and neck-body junctions in modular THA are associated with a variety of local and systemic... (Review)
Review
BACKGROUND
Metal-on-metal (MoM) total hip arthroplasties (THAs) and the head-neck and neck-body junctions in modular THA are associated with a variety of local and systemic reactions to their related wear and corrosion products. Although laboratory testing is available, the relationship between laboratory values--including serum metal ion levels--and adverse local tissue reactions (ALTRs) remains controversial and incompletely characterized.
QUESTIONS/PURPOSES
(1) What is the range of serum metal levels associated with ALTR in patients who have MoM THAs or corrosion at the head-neck and neck-body junctions in metal-on-polyethylene (or ceramic-on-polyethylene) THAs? (2) How much wear occurs in patients with MoM total hips? (3) Is there evidence of a dose-response relationship between wear and ALTR?
METHODS
PubMed and Embase databases were reviewed for English-language studies assessing serum metal levels in the presence of ALTR and papers describing the results of wear measurements from revised MoM implants and ALTR histopathology were systematically reviewed. Reported linear wear data were separated into groups with ALTR and without ALTR as listed in individual papers and graphed to determine whether a dose-response relationship was present between wear and ALTR. Overall, 15 studies including 338 hips with ALTR with corresponding serum metal levels were identified and analyzed. Twelve studies reported the wear depth or volume of MoM components from patients with a variety of local reactions. Two studies investigated corrosion at the head-neck and neck-body junctions in metal-on-polyethylene THA. There was a high level of variability and study heterogeneity, and so data pooling (meta-analysis) could not be performed.
RESULTS
Average reported metal concentrations were elevated above established normal values in patients with ALTR (cobalt concentrations ranged from 5 to 40 ppb, and chromium levels ranged from 5 to 54 ppb). Whereas several studies demonstrated that patients with ALTR had higher average linear wear of the bearing surfaces, this finding was not made in all studies that we identified in this systematic review. Because of this high degree of variability, no clear dose-response relationship between wear and ALTR could be established.
CONCLUSIONS
Serum metal level analysis and implant retrieval analysis both contribute to the understanding of ALTR. Serum metal levels generally are elevated in the presence of ALTR but should not be used in isolation for clinical decision-making. Many but not all patients with ALTR, including those with pseudotumors, demonstrate high wear, but more data and more systematic descriptions of the histopathology are needed to define the amount of wear that induces adverse reactions.
Topics: Arthroplasty, Replacement, Hip; Biomarkers; Biomechanical Phenomena; Ceramics; Device Removal; Foreign-Body Reaction; Hip Joint; Hip Prosthesis; Humans; Metal-on-Metal Joint Prostheses; Metals; Polyethylene; Predictive Value of Tests; Prosthesis Design; Prosthesis Failure; Reoperation; Risk Factors; Stress, Mechanical; Treatment Outcome
PubMed: 25160942
DOI: 10.1007/s11999-014-3893-2 -
Clinical Orthopaedics and Related... Dec 2012Less than 1% of all primary TKAs are performed with an all-polyethylene tibial component, although recent studies indicate all-polyethylene tibial components are equal... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Less than 1% of all primary TKAs are performed with an all-polyethylene tibial component, although recent studies indicate all-polyethylene tibial components are equal to or better than metal-backed ones.
QUESTIONS/PURPOSES
We asked whether the metal-backed tibial component was clinically superior to the all-polyethylene tibial component in primary TKAs regarding revision rates and clinical functioning, and which modifying variables affected the revision rate.
METHODS
We systematically reviewed the literature for clinical studies comparing all-polyethylene and metal-backed tibial components used in primary TKAs in terms of revision rates, clinical scores, and radiologic parameters including radiostereometric analysis (RSA). Meta-regression techniques were used to explore factors modifying the observed effect. Our search yielded 1557 unique references of which 26 articles were included, comprising more than 12,500 TKAs with 231 revisions for any reason.
RESULTS
Meta-analysis showed no differences between the all-polyethylene and metal-backed components except for higher migration of the metal-backed components. Meta-regression showed strong evidence that the all-polyethylene design has improved with time compared with the metal-backed design.
CONCLUSIONS
The all-polyethylene components were equivalent to metal-backed components regarding revision rates and clinical scores. The all-polyethylene components had better fixation (RSA) than the metal-backed components. The belief that metal-backed components are better than all-polyethylene ones seems to be based on studies from earlier TKAs. This might no longer be true for modern TKAs.
LEVEL OF EVIDENCE
Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
Topics: Aged; Arthroplasty, Replacement, Knee; Biomechanical Phenomena; Female; Foreign-Body Migration; Humans; Knee Joint; Knee Prosthesis; Male; Metals; Middle Aged; Polyethylene; Prosthesis Design; Prosthesis Failure; Recovery of Function; Reoperation; Risk Assessment; Risk Factors; Tibia; Time Factors; Treatment Outcome
PubMed: 22972656
DOI: 10.1007/s11999-012-2582-2