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Current Environmental Health Reports Jun 2023Despite increasing awareness of the ubiquity of microplastics (MPs) in our environments, little is known about their risk of developmental toxicity. Even less is known... (Review)
Review
PURPOSE OF REVIEW
Despite increasing awareness of the ubiquity of microplastics (MPs) in our environments, little is known about their risk of developmental toxicity. Even less is known about the environmental distribution and associated toxicity of nanoplastics (NPs). Here, we review the current literature on the capacity for MPs and NPs to be transported across the placental barrier and the potential to exert toxicity on the developing fetus.
RECENT FINDINGS
This review includes 11 research articles covering in vitro, in vivo, and ex vivo models, and observational studies. The current literature confirms the placental translocation of MPs and NPs, depending on physicochemical properties such as size, charge, and chemical modification as well as protein corona formation. Specific transport mechanisms for translocation remain unclear. There is emerging evidence of placental and fetal toxicity due to plastic particles based on animal and in vitro studies. Nine out of eleven studies examined in this review found that plastic particles were capable of placental translocation. In the future, more studies are needed to confirm and quantify the existence of MPs and NPs in human placentas. Additionally, translocation of different plastic particle types and heterogenous mixtures across the placenta, exposure at different periods of gestation, and associations with adverse birth and other developmental outcomes should also be investigated.
Topics: Animals; Pregnancy; Female; Humans; Placenta; Plastics; Microplastics; Water Pollutants, Chemical
PubMed: 36848019
DOI: 10.1007/s40572-023-00391-x -
Frontiers in Public Health 2023Micro/nano-plastics (MNPs) are considered a heterogeneous class of environmental contaminants that cause multiple toxic effects on biological species. As the commonly... (Meta-Analysis)
Meta-Analysis
Micro/nano-plastics (MNPs) are considered a heterogeneous class of environmental contaminants that cause multiple toxic effects on biological species. As the commonly used mammalian models to study the effects of MNPs with regard to their toxic effects, the mouse and rat models are making a great contribution to the disciplines of environmental toxicology and medical health. However, the toxic effects of MNPs have not been systematically summarized. Therefore, a systematic review and a meta-analysis of the toxic effects of MNPs on mouse/rat models were conducted. A total of seven main categories were established in this systematic review, and 24 subcategories were further divided according to the specific physiological significance of the endpoint or the classification of the physiological system, which covered all the selected pieces of literature. A total of 1,762 biological endpoints were found, and 52.78% of them were significantly affected. This fact indicates that there are relative factors, including the size, polymer type, concentration, and exposure time of MNPs and different sexes of mouse/rat models that could significantly affect the biological endpoints. These biological endpoints can be classified into various factors, such as the dose-response relationships between MNP concentration and physiological categories of the nervous system, growth, reproduction, digestive tract histopathology, and inflammatory cytokine level, among others. MNPs negatively affected the blood glucose metabolism, lipid metabolism, and reproductive function in mice. The reproductive function in male mice is more sensitive to the toxic effects of MNPs. These findings also provide insights into and directions for exploring the evidence and mechanisms of the toxic effects of MNPs on human health. It is clear that more research is required on the pathological mechanisms at the molecular level and the long-term effects of tissue accumulation.
Topics: Rats; Mice; Male; Humans; Animals; Plastics; Microplastics; Mammals
PubMed: 37275491
DOI: 10.3389/fpubh.2023.1103289 -
The Science of the Total Environment Dec 2022This systematic review aims to summarize the current knowledge on biological effects of micro- and nanoplastics (MNPs) on human health based on mammalian systems. An...
This systematic review aims to summarize the current knowledge on biological effects of micro- and nanoplastics (MNPs) on human health based on mammalian systems. An extensive search of the literature led to a total of 133 primary research articles on the health relevance of MNPs. Our findings revealed that although the study of MNP cytotoxicity and inflammatory response represents a major research theme, most studies (105 articles) focused on the effects of polystyrene MNPs due to their wide availability as a well characterised research material that can be manufactured with a large range of particle sizes, fluorescence labelling as well as various surface modifications. Among the 133 studies covered in this review, 117 articles reported adverse health effects after being exposed to MNPs. Mammalian in vitro studies identified multiple biological effects including cytotoxicity, oxidative stress, inflammatory response, genotoxicity, embryotoxicity, hepatotoxicity, neurotoxicity, renal toxicity and even carcinogenicity, while rodent in vivo models confirmed the bioaccumulation of MNPs in the liver, spleen, kidney, brain, lung and gut, presenting adverse effects at different levels including reproductive toxic effects and trans-generational toxicity. In contrast, the remaining 16 studies indicated an insignificant impact of MNPs on humans. A few studies attempted to investigate the mechanisms or factors driving the toxicity of MNPs and identified several determining factors including size, concentration, shape, surface charge, attached pollutants and weathering process, which, however, were not benchmarked or considered by most studies. This review demonstrates that there are still many inconsistencies in the evaluation of the potential health effects of MNPs due to the lack of comparability between studies. Current limitations hindering the attainment of reproducible conclusions as well as recommendations for future research directions are also presented.
Topics: Animals; Humans; Environmental Pollutants; Mammals; Microplastics; Particle Size; Plastics; Polystyrenes
PubMed: 35987230
DOI: 10.1016/j.scitotenv.2022.158111 -
Environmental Pollution (Barking, Essex... Jan 2021Microplastics receive significant societal and scientific attention due to increasing concerns about their impact on the environment and human health. Marine mammals are...
Microplastics receive significant societal and scientific attention due to increasing concerns about their impact on the environment and human health. Marine mammals are considered indicators for marine ecosystem health and many species are of conservation concern due to a multitude of anthropogenic stressors. Marine mammals may be vulnerable to microplastic exposure from the environment, via direct ingestion from sea water, and indirect uptake from their prey. Here we present the first systematic review of literature on microplastics and marine mammals, composing of 30 studies in total. The majority of studies examined the gastrointestinal tracts of beached, bycaught or hunted cetaceans and pinnipeds, and found that microplastics were present in all but one study, and the abundance varied between 0 and 88 particles per animal. Additionally, microplastics in pinniped scats (faeces) were detected in eight out of ten studies, with incidences ranging from 0% of animals to 100%. Our review highlights considerable methodological and reporting deficiencies and differences among papers, making comparisons and extrapolation across studies difficult. We suggest best practices to avoid these issues in future studies. In addition to empirical studies that quantified microplastics in animals and scat, ten studies out of 30 (all focussing on cetaceans) tried to estimate the risk of exposure using two main approaches; i) overlaying microplastic in the environment (water or prey) with cetacean habitat or ii) proposing biological or chemical biomarkers of exposure. We discuss advice and best practices on research into the exposure and impact of microplastics in marine mammals. This work on marine ecosystem health indicator species will provide valuable and comparable information in the future.
Topics: Animals; Caniformia; Ecosystem; Environmental Monitoring; Humans; Microplastics; Plastics; Water Pollutants, Chemical
PubMed: 33288297
DOI: 10.1016/j.envpol.2020.116142 -
BMC Oral Health Aug 2023Large cavity designs and access cavities impair endodontically treated tooth fracture resistance. As the tooth's strength is known to reduce significantly after the root...
BACKGROUND
Large cavity designs and access cavities impair endodontically treated tooth fracture resistance. As the tooth's strength is known to reduce significantly after the root canal treatment, occlusal loading as a result of functions such as chewing, biting and certain parafunctional tendencies makes the endodontically treated tooth vulnerable to fracture. Hence, after endodontic treatment, it is vital to give adequate and appropriate restorative material to avoid tooth fractures. Accordingly, the choice of such restorative material should be dictated by the property of fracture resistance.
OBJECTIVE
The goal of this study was to conduct a systematic review and critical analysis of available data from in vitro studies examining the fracture resistance of endodontically treated posterior teeth restored with fiber-reinforced composites.
METHODOLOGY
The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRIS-MA) Statement was used to guide the reporting of this systematic review A comprehensive literature search was performed using MEDLINE (via PubMed), Scopus, ScienceDirect, Google Scholar, and LILACS. A manual search of the reference lists of the articles was also performed. The databases provided a total of 796 studies from the electronic systematic search. The databases provided a total of 796 studies from the electronic systematic search. Two reviewers scrutinized the papers for eligibility based on inclusion/exclusion criteria and extracted data. The studies were assessed for their potential risk of bias. Based on modified JBI & CRIS (checklist for reporting in vitro studies) guidelines, along with the methodology and treatment objective, we have formulated 13 parameters specifically to assess the risk of bias. A total of 18 studies met the inclusion criteria and were included for qualitative analysis. Considering the high heterogeneity of the studies included, a meta-analysis could not be performed.
RESULTS
The majority of the included studies had a moderate or high risk of bias. When compared to traditional hybrid composites, fiber-reinforced composites showed increased fracture resistance of endodontically treated teeth in the majority of investigations. On the other hand, limited evidence was found for the bulk fill composites. Moreover, moderate evidence was found for the fracture resistance of inlays and fiber posts with fiber-reinforced composites for core build-up in endodontically treated teeth. No evidence could be found comparing the fracture resistance of endo crowns and fiber-reinforced composites in endodontically treated teeth.
CONCLUSION
According to the research, using fiber-reinforced composites instead of conventional hybrid composites improves the fracture resistance of endodontically treated teeth. However, there was a high risk of bias in the research considered. No judgments could be reached about the superiority of one material over another based-on comparisons between other core restorations.
Topics: Humans; Tooth, Nonvital; Dental Materials; Crowns; Tooth Fractures; Composite Resins; Dental Stress Analysis
PubMed: 37574536
DOI: 10.1186/s12903-023-03217-2 -
Clinical Oral Investigations Sep 2023The aim of this systematic review and meta-analysis is to assess the comparative clinical success and survival of intracoronal indirect restorations using gold, lithium... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
The aim of this systematic review and meta-analysis is to assess the comparative clinical success and survival of intracoronal indirect restorations using gold, lithium disilicate, leucite, and indirect composite materials.
MATERIAL AND METHODS
This systematic review and meta-analysis were conducted following the Cochrane Handbook for Systematic Reviews of Interventions and PRISMA guidelines. The protocol for this study was registered in PROSPERO (registration number: CRD42021233185). A comprehensive literature search was conducted across various databases and sources, including PubMed/Medline, Embase, Cochrane Library, Web of Science, ClinicalTrials.gov, and gray literature. A total of 7826 articles were screened on title and abstract. Articles were not excluded based on the vitality of teeth, the language of the study, or the observation period. The risk difference was utilized for the analyses, and a random-effects model was applied. All analyses were conducted with a 95% confidence interval (95% CI). The calculated risk differences were derived from the combined data on restoration survival and failures obtained from each individual article. The presence of heterogeneity was assessed using the I statistic, and if present, the heterogeneity of the data in the articles was evaluated using the non-parametric chi-squared statistic (p < 0.05).
RESULTS
A total of 12 eligible studies were selected, which included 946 restorations evaluated over a minimum observation period of 1 year and a maximum observation period of 7 years. Results of the meta-analysis indicated that intracoronal indirect resin composite restorations have an 18% higher rate of failure when compared to intracoronal gold restorations over 5-7 years of clinical service (risk difference = - 0.18 [95% CI: - 0.27, - 0.09]; p = .0002; I = 0%). The meta-analysis examining the disparity in survival rates between intracoronal gold and leucite restorations could not be carried out due to methodological differences in the studies.
CONCLUSIONS
According to the currently available evidence, medium-quality data indicates that lithium disilicate and indirect composite materials demonstrate comparable survival rates in short-term follow-up. Furthermore, intracoronal gold restorations showed significantly higher survival rates, making them a preferred option over intracoronal indirect resin-composite restorations. Besides that, the analysis revealed no statistically significant difference in survival rates between leucite and indirect composite restorations. The short observation period, limited number of eligible articles, and low sample size of the included studies were significant limitations.
CLINICAL SIGNIFICANCE
Bearing in mind the limitations of the reviewed literature, this systematic review and meta-analysis help clinicians make evidence-based decisions on how to restore biomechanically compromised posterior teeth.
Topics: Dental Porcelain; Aluminum Silicates; Composite Resins; Gold
PubMed: 37597003
DOI: 10.1007/s00784-023-05050-x -
Environmental Pollution (Barking, Essex... Dec 2022The dispersion of microplastics (MPs) in coastal and marine environments and their potential harmful effects on organisms and ecosystems makes MPs pollution an emerging... (Review)
Review
The dispersion of microplastics (MPs) in coastal and marine environments and their potential harmful effects on organisms and ecosystems makes MPs pollution an emerging problem that has gained increasing attention from the scientific community. Despite the recent increase in the number of studies on MPs presence in different marine environments, investigations in Latin America and the Caribbean (LAC) are still relatively limited. This review presents the spatial distribution (where) and the methods applied (how) in assessing MPs contamination on LAC sandy beaches, identifying the challenges to be faced in advancing the understanding of this emerging contaminant. Most of the 39 papers reviewed were published between 2020 and 2021 (51%) and conducted on Brazilian beaches (43%). The LAC investigations apply spot sampling (69%) on shoreline stretches between 10 and 1000 km (59%). These works used inconsistent sampling methods, incomparable techniques for MPs extraction from sediments, and different measurement units to report their data. The MPs presence on LAC beaches is not negligible, as it varies significantly in its distribution and concentration (0-2457 MP/dw kg and 0-5458 MP/m). Its highest accumulation is on ocean island beaches; however, there are still large stretches of coastline (Cuba, Venezuela, Argentina) with no data on MPs presence and a small number of studies exploring these contaminants' temporal variability. The lack of standardization in the studies' methodologies, particularly their measurement units, hinders their quantitative comparison and our ability to establish baseline values regarding MPs abundance on LAC beaches. In this sense, future works should direct efforts towards the spatial and temporal expansion of their sampling, as well as protocol standardization to facilitate result comparability on MPs on LAC sandy beaches.
Topics: Microplastics; Plastics; Ecosystem; Latin America; Environmental Monitoring; Water Pollutants, Chemical; Caribbean Region; Geologic Sediments
PubMed: 36152712
DOI: 10.1016/j.envpol.2022.120231 -
Sexual Medicine Reviews Oct 2022Vaginal stenosis is a distressing side effect of radiation therapy that can impair quality of life. Dilator therapy is an option for patients undergoing pelvic... (Review)
Review
INTRODUCTION
Vaginal stenosis is a distressing side effect of radiation therapy that can impair quality of life. Dilator therapy is an option for patients undergoing pelvic radiotherapy to mitigate vaginal stenosis. Currently, the dilators given to patients by most hospitals are made of plastic, compared to silicone dilators which are available on the market for purchase.
OBJECTIVES
We conducted a systematic literature review to find information to guide clinical recommendations to pelvic radiotherapy patients on potential differences regarding the use of plastic vs silicone dilators with regard to efficacy, cost, and patient preferences.
METHODS
A systematic literature review was conducted in Embase, MEDLINE, and PubMed using Emtree terms. To be included in the review, papers needed to: focus on female patients undergoing radiation therapy, assess a vaginal dilator, measure any dilator intervention outcome, and specifically compare plastic vs silicone dilators for any measured outcome (either qualitative or quantitative).
RESULTS
The initial search yielded 195 articles. Two area experts, with a third expert for arbitration, read each article and found that none met all review inclusion criteria. No studies were found that compared silicone to plastic dilators with regard to efficacy in treating vaginal stenosis due to radiation therapy, no studies were found that compared cost or cost-effectiveness of the 2 dilator types, and no studies were found comparing patient preferences or experiences (eg, comfort, adherence, ease of use) between the 2 dilator types.
CONCLUSION
The materials used to create dilators have never been rigorously compared in the context of radiotherapy-related vaginal stenosis. Institutions and patients have no data to guide their choice. Significantly more research at the patient and institutional level is needed to explore the potential long-term quality of life and cost benefits of improved adherence with silicone dilator use, and to guide shared decision-making regarding dilator choice. Morgan O, Lopez MD, Martinez AJC, et al. Systematic Review of Comparisons Between Plastic and Silicone Dilators: Revealing a Knowledge Gap. Sex Med Rev 2022;10:513-519.
Topics: Constriction, Pathologic; Female; Humans; Plastics; Quality of Life; Silicones; Vagina
PubMed: 36030181
DOI: 10.1016/j.sxmr.2022.06.008 -
Clinical Oral Investigations Apr 2022This systematic review investigated the hypothesis that preheated resin composites (RCs) used as luting agents improve the mechanical properties, physicochemical... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
This systematic review investigated the hypothesis that preheated resin composites (RCs) used as luting agents improve the mechanical properties, physicochemical performance, and color of indirect ceramic restorations.
MATERIALS AND METHODS
Literature search was performed in three databases (Medline/PubMed, Scopus, and Web of Science) and in the grey literature (OpenGrey, ProQuest, and Catalog of Theses & Dissertations from CAPES). Eligibility criteria included only studies comparing at least one preheated RC used as a luting agent with resin cements.
RESULTS
Data regarding the mechanical properties, physicochemical characteristics, and color were analyzed qualitatively, and the microtensile bond strength and film thickness were also evaluated by meta-analysis. The search strategy identified 3894 papers, and 28 were full-text screened. Seven studies were included in the review, and 5 were included in the meta-analysis. No significant difference was found for microtensile bond strength (P = 0.14). Preheated RCs showed significantly higher film thickness than resin cements (P = 0.001).
CONCLUSION
Overall, the use of preheated RCs as luting agents offers similar to poorer performance than using resin cements for bonding indirect restorations.
CLINICAL RELEVANCE
Despite the claim that preheated RC could be used as a luting agent, further studies should investigate the effect of clinically unacceptable film thickness.
Topics: Composite Resins; Dental Bonding; Dental Cements; Materials Testing; Resin Cements; Surface Properties
PubMed: 35149906
DOI: 10.1007/s00784-022-04406-z -
Dental Materials : Official Publication... Dec 2023To answer the PICO(S) question: Is there a difference in clinical longevity between direct and indirect resin composite restorations placed on permanent posterior teeth? (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
To answer the PICO(S) question: Is there a difference in clinical longevity between direct and indirect resin composite restorations placed on permanent posterior teeth?
DATA
Randomized controlled clinical trials (RCTs) investigating direct and indirect resin composite restorations in posterior permanent teeth were considered.
SOURCES
Several electronic databases were searched, with no language or date restrictions. The revised Cochrane Collaboration's tool for assessing risk of bias (RoB-2) was used to analyze the studies; meta-analyses were run and the certainty of evidence was assessed by the GRADE tool. A subgroup meta-analysis was performed for resin composite restorations placed on posterior worn dentition.
STUDY SELECTION
Twenty-three articles were included in qualitative synthesis, while 8 studies were used for meta-analyses. According to the RoB-2 tool, 5 studies were ranked as "low risk", 7 had "some concerns", while 11 papers were rated as "high risk" of bias. There were no statistically significant differences in short-term (p = 0.27; RR=1.54, 95% CI [0.72, 3.33]), medium-term (p = 0.27; RR=1.87, 95% CI [0.61, 5.72]) and long-term longevity (p = 0.86; RR=0.95, 95% CI [0.57, 1.59]). The choice of restorative technique had no influence on short-term survival of resin composite restorations placed on worn dentition (p = 0.13; RR=0.46, 95% CI [0.17, 1.25]). The certainty of evidence was rated as "very low".
CONCLUSIONS
Direct and indirect resin composite restorations may show similar clinical longevity in posterior region, regardless of the observation period or substrate (wear-affected and non-affected dentition). The very low quality of evidence suggests that more long-term RCTs are needed to confirm our results.
Topics: Dental Restoration, Permanent; Composite Resins; Molar
PubMed: 37827872
DOI: 10.1016/j.dental.2023.10.009