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The Journal of Prosthetic Dentistry Sep 2023Denture adhesives improve the mastication of complete denture wearers. However, the impact of denture adhesives with different presentations on mastication remains... (Meta-Analysis)
Meta-Analysis Review
STATEMENT OF PROBLEM
Denture adhesives improve the mastication of complete denture wearers. However, the impact of denture adhesives with different presentations on mastication remains unclear.
PURPOSE
The purpose of this systematic review was to answer the focused question, "Do different presentations of denture adhesives affect the masticatory function of complete denture wearers?".
MATERIAL AND METHODS
This review was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Six databases and the non-peer-reviewed literature were searched up to July 2021. Only clinical studies (randomized clinical trials and nonrandomized clinical trials) comparing the use of different denture adhesive presentations (cream, powder, or strips) were included, without language or follow-up restrictions. The risk of bias was assessed by using the Cochrane tools (RoB 2.0 and ROBINS-I). Masticatory performance, by using single and multiple sieves, masticatory performance with color-changing chewing gum (mixing ability), swallowing threshold (particle size and number of cycles), jaw kinematics, and occlusal force were considered. Meta-analyses were conducted to evaluate masticatory performance (single sieve) and occlusal force outcomes (α=.05), and the certainty of the evidence was determined with the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) evaluations.
RESULTS
Nine studies (6 randomized and 3 nonrandomized clinical trials) were included. The risk of bias was considered moderate. Meta-analyses showed no differences between cream and powder denture adhesives for masticatory performance (standard mean difference=0.02; 95% CI=-0.46 to 0.50, P=.93) or between cream and strip denture adhesives for occlusal force (mean difference=14.35; 95% CI=-11.14 to 39.84, P=.27). Similarly, in qualitative analysis, cream and powder denture adhesives' performances were similar regarding masticatory performance with color-changing chewing gum (mixing ability), occlusal force, swallowing threshold (particle size and number of cycles), and jaw kinematics (P>.05). However, for resorbed ridges, cream denture adhesive resulted in a higher masticatory performance than strip (P<.05). When comparing powder to strip denture adhesives, the occlusal force was higher in the powder group (P<.05). The certainty of evidence was very low for all evaluated outcomes.
CONCLUSIONS
Different presentations of denture adhesives seem to improve the masticatory function of complete denture wearers in a similar way. However, the qualitative analysis showed that, in patients with a resorbed ridge, a cream denture adhesive may be better than strips to improve mastication, although the certainty of evidence was very low.
Topics: Humans; Powders; Chewing Gum; Denture, Complete; Bite Force; Mastication; Adhesives
PubMed: 34772484
DOI: 10.1016/j.prosdent.2021.09.026 -
Environmental Research Feb 2017Particulate matter (PM) as an environmental pollutant is suspected to be associated with autism spectrum disorders. The aim of the present study was to review the... (Meta-Analysis)
Meta-Analysis Review
Particulate matter (PM) as an environmental pollutant is suspected to be associated with autism spectrum disorders. The aim of the present study was to review the epidemiological literature currently available on the relation between PM exposure and diagnosis of ASD. The PubMed database was searched from November 2015 up to January 2016 by one of the authors. We included observational studies (cohort and case-control studies) published in English carried out in children within the last 10 years, measuring PM exposure and health outcomes related to ASD. 13 studies met the inclusion criteria. Four of the studies found no association between PM exposure and ASD. The other 8 studies show positive associations restricted to specific exposure windows which however do not reach statistical significance at times. To conclude, the evidence from the studies allows us to conclude that there is an association between PM exposure and ASD whose strength varies according to the particle size studied with the association with PM and diesel PM being stronger. Given the potential importance for public health, cohort studies with proper adjustment for confounding variables and identification of critical windows of exposure are urgently needed to further improve knowledge about potential causal links between PM exposure and the development of ASD.
Topics: Autism Spectrum Disorder; Female; Humans; Particulate Matter; Pregnancy; Prenatal Exposure Delayed Effects; Vehicle Emissions
PubMed: 27984759
DOI: 10.1016/j.envres.2016.11.022 -
The Science of the Total Environment Feb 2010Most recently, renewed interest has arisen in manufactured silver nanomaterials because of their unusually enhanced physicochemical properties and biological activities... (Review)
Review
An evidence-based environmental perspective of manufactured silver nanoparticle in syntheses and applications: a systematic review and critical appraisal of peer-reviewed scientific papers.
BACKGROUND
Most recently, renewed interest has arisen in manufactured silver nanomaterials because of their unusually enhanced physicochemical properties and biological activities compared to the bulk parent materials. A wide range of applications has emerged in consumer products ranging from disinfecting medical devices and home appliances to water treatment. Because the hypothesized mechanisms that govern the fate and transport of bulk materials may not directly apply to materials at the nanoscale, there are great concerns in the regulatory and research communities about potential environmental impacts associated with the use of silver nanoparticles. In particular, the unlimited combinations of properties emerging from the syntheses and applications of silver nanoparticles are presenting an urgent need to document the predominant salt precursors, reducing agents and stabilizing agents utilized in the synthesis processes of silver nanoparticles to guide the massive efforts required for environmental risk assessment and management.
OBJECTIVES
The primary objective of this study is to present an evidence-based environmental perspective of silver nanoparticle properties in syntheses and applications. The following specific aims are designed to achieve the study objective: Aim 1--to document the salt precursors and agents utilized in synthesizing silver nanoparticles; Aim 2--to determine the characteristics of silver nanoparticles currently in use in the scientific literature when integrated in polymer matrices to form nanocomposites and combined with other metal nanoparticles to form bimetallic nanoparticles; Aim 3--to provide a summary of the morphology of silver nanoparticles; and (4) Aim 4--to provide an environmental perspective of the evidence presented in Aims 1 to 3.
METHODS
A comprehensive electronic search of scientific databases was conducted in support of the study objectives. Specific inclusion criteria were applied to gather the most pertinent research articles. Data and information extraction relied on the type of synthesis methods, that is, synthesized silver nanoparticles in general and specific applications, nanocomposites, and bimetallic techniques. The following items were gathered for: type of silver salt, solvent, reducing agent, stabilizing agent, size, and type of application/nanocomposite/bimetallic, and template (for nanocomposites). The description of evidence was presented in tabular format. The critical appraisal was analyzed in graphical format and discussed.
RESULTS
An analysis of the scientific literature suggests that most synthesis processes produce spherical silver nanoparticles with less than 20nm diameter. Silver nanoparticles are often synthesized via reduction of AgNO(3), dissolution in water, and utilization of reductants also acting as capping or stabilizing agents for the control of particle size to ensure a relatively stable suspension. Two of the most commonly used reductants and stabilizing agents are NaBH(4) and citrate which yield particles with a negative surface charge over the environmental pH range (3-10). The environmental perspectives of these parameters are discussed.
CONCLUDING REMARKS
It is expected that the antibacterial property of bulk silver is carried over and perhaps enhanced, to silver nanoparticles. Therefore, when one examines the environmental issues associated with the manufacture and use of silver nanoparticle-based products, the antibacterial effects should always be taken into account particularly at the different stages of the product lifecycle. Currently, there are two arguments in the scientific literature about the mechanisms of antimicrobial properties of silver nanoparticles as they relate to colloidal silver particles and inonic silver. Methodologies of risk assessment and control have to account for both arguments.
Topics: Environmental Pollution; Metal Nanoparticles; Nanotechnology; Particle Size; Risk Assessment; Silver
PubMed: 19945151
DOI: 10.1016/j.scitotenv.2009.11.003 -
Food Research International (Ottawa,... Jun 2020Anthocyanins, a kind of phenolic compounds are present in plant kingdom. They exhibit biological activities such as anti-inflammatory and anti-cancer properties as well... (Meta-Analysis)
Meta-Analysis
Anthocyanins, a kind of phenolic compounds are present in plant kingdom. They exhibit biological activities such as anti-inflammatory and anti-cancer properties as well as imparting colors to various plants. The objective of this review is to provide a systematic evaluation of the evidence and a meta-analysis of published researches on the nano/microencapsulation of anthocyanins. A comprehensive literature search was conducted for articles published in 2016 to 2019 on PubMed, Web of Sciences and Scopus databases. Overall 45 eligible articles (51 cases; some authors studied 2 or more encapsulation methods) with appropriate data were included in the statistical analysis. In the current work, based on the technique and equipment applied for the formulation of micro/nanoencapsulation systems, the anthocyanin-loaded nano/microcarriers were classified into five main classes: (a) spray dried particles (spray-drying); (b) freeze-dried particles (freeze-drying); (c) lipid-based particles (emulsification and liposomal encapsulation); (d) electrospun fibers and electrosprayed particles (electrohydrodynamic encapsulation); and (e) nano/micro-gels (gelation). Based on the results from the meta-analysis, the studied technique for encapsulation of anthocyanins can be ordered as: spray-drying (33.33%), freeze-drying (27.08%), gelation (20.83%), lipid-based particles (14.58%) and electrohydrodynamic processes (4.17%). In addition, carbohydrates such as maltodextrin (19.56%) and gums (15.22%) have been the most frequently used biopolymers for encapsulation of anthocyanins in the selected studies.
Topics: Anthocyanins; Biological Availability; Color; Databases, Factual; Drug Compounding; Freeze Drying; Nanotechnology; Particle Size; Phenols; Polysaccharides
PubMed: 32331692
DOI: 10.1016/j.foodres.2020.109077 -
Environment International Dec 2017The link between PM exposure and adverse health outcomes is well documented from studies across the world. However, the reported effect estimates vary across studies,... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The link between PM exposure and adverse health outcomes is well documented from studies across the world. However, the reported effect estimates vary across studies, locations and constituents. We aimed to conduct a meta-analysis on associations between short-term exposure to PM constituents and mortality using city-specific estimates, and explore factors that may explain some of the observed heterogeneity.
METHODS
We systematically reviewed epidemiological studies on particle constituents and mortality using PubMed and Web of Science databases up to July 2015.We included studies that examined the association between short-term exposure to PM constituents and all-cause, cardiovascular, and respiratory mortality, in the general adult population. Each study was summarized based on pre-specified study key parameters (e.g., location, time period, population, diagnostic classification standard), and we evaluated the risk of bias using the Office of Health Assessment and Translation (OHAT) Method for each included study. We extracted city-specific mortality risk estimates for each constituent and cause of mortality. For multi-city studies, we requested the city-specific risk estimates from the authors unless reported in the article. We performed random effects meta-analyses using city-specific estimates, and examined whether the effects vary across regions and city characteristics (PM concentration levels, air temperature, elevation, vegetation, size of elderly population, population density, and baseline mortality).
RESULTS
We found a 0.89% (95% CI: 0.68, 1.10%) increase in all-cause, a 0.80% (95% CI: 0.41, 1.20%) increase in cardiovascular, and a 1.10% (95% CI: 0.59, 1.62%) increase in respiratory mortality per 10μg/m increase in PM. Accounting for the downward bias induced by studies of single days, the all-cause mortality estimate increased to 1.01% (95% CI: 0.81, 1.20%). We found significant associations between mortality and several PM constituents. The most consistent and stronger associations were observed for elemental carbon (EC) and potassium (K). For most of the constituents, we observed high variability of effect estimates across cities.
CONCLUSIONS
Our meta-analysis suggests that (a) combustion elements such as EC and K have a stronger association with mortality, (b) single lag studies underestimate effects, and (c) estimates of PM and constituents differ across regions. Accounting for PM mass in constituent's health models may lead to more stable and comparable effect estimates across different studies.
SYSTEMATIC REVIEW REGISTRATION
PROSPERO: CRD42017055765.
Topics: Air Pollutants; Air Pollution; Cities; Databases, Factual; Humans; Mortality; Particulate Matter; Regression Analysis
PubMed: 28988023
DOI: 10.1016/j.envint.2017.09.010 -
Chemical Research in Toxicology Sep 2022Although most studies that explore the cytotoxicity of titanium dioxide nanoparticles (nano-TiO) have focused on cell viability and oxidative stress, the cell cycle, a... (Meta-Analysis)
Meta-Analysis Review
Although most studies that explore the cytotoxicity of titanium dioxide nanoparticles (nano-TiO) have focused on cell viability and oxidative stress, the cell cycle, a basic process of cell life, can also be affected. However, the results on the effects of nano-TiO on mammalian cell cycle are still inconsistent. A systematic review and meta-analysis were therefore performed in this research based on the effects of nano-TiO on the mammalian cell cycle to explore whether nano-TiO can induce cell cycle arrest. Meanwhile, the impact of physicochemical properties of nano-TiO on the cell cycle was investigated, and the response of normal cells and cancer cells was compared. A total of 33 articles met the eligibility criteria after screening. We used Review Manager 5.4 and Stata 15.1 for analysis. The results showed an increased percentage of cells in the sub-G1 phase and an upregulation of the p53 gene after being exposed to nano-TiO. Nevertheless, nano-TiO had no effect on cell percentage in other phases of the cell cycle. Furthermore, subgroup analysis revealed that the cell percentage in both the sub-G1 phase of normal cells and S phase of cancer cells were significantly increased under anatase-form nano-TiO treatment. Moreover, nano-TiO with a particle size <25 nm or exposure duration of nano-TiO more than 24 h induced an increased percentage of normal cells in the sub-G1 phase. In addition, the cell cycle of cancer cells was arrested in the S phase no matter if the exposure duration of nano-TiO was more than 24 h or the exposure concentration was over 50 μg/mL. In conclusion, this study demonstrated that nano-TiO disrupted the cell cycle . The cell cycle arrest induced by nano-TiO varies with cell status and physicochemical properties of nano-TiO.
Topics: Animals; Cell Cycle; Mammals; Nanoparticles; Reactive Oxygen Species; Titanium
PubMed: 35998370
DOI: 10.1021/acs.chemrestox.1c00402 -
Chemical Research in Toxicology Sep 2021The unique properties of graphene-based materials (GBMs) placed them among the most exciting nanomaterials of the past decade. Scientists and industry are looking...
The unique properties of graphene-based materials (GBMs) placed them among the most exciting nanomaterials of the past decade. Scientists and industry are looking forward to working with not only efficient but also safe, sustainable GBMs. Designing a safer-by-design GBM implies to acquire the knowledge of which physicochemical characteristics (PCCs) can increase toxicity. In this systematic review, we extracted data from the literature to provide the available information about the structure-activity relationship of GBMs. 93 papers studying a total of 185 GBMs are included. Graphene oxides (GOs) and few-layer graphenes (FLGs) are the most studied GBMs. While reduced graphene oxides were often classified as poorly oxidant and weakly cytotoxic, graphene quantum dots were mostly moderately or highly cytotoxic. FLGs demonstrated relationships between median size and oxidative stress, between lateral size and both cytotoxicity and oxidative stress, and between thickness and cytotoxicity. We also underline relationships between median size, lateral size, and thickness of GOs and oxidative stress. However, it appears difficult to highlight clear structure-activity relationships for most PCCs and biological end points because despite a large amount of available data, the GBMs are often too poorly characterized in terms of PCCs descriptors and the biological end points investigation is not standardized enough. There is an urgent need for a better standardization of the experimental investigation of both PCCs and biological end points to allow research teams to play a part in the collaborative work toward the construction of a safer-by-design GBM through a better understanding of their key toxicity drivers.
Topics: Animals; Cell Line, Tumor; Graphite; Humans; Molecular Structure; Nanostructures; Oxidative Stress; Particle Size; Structure-Activity Relationship; Toxicity Tests
PubMed: 34424669
DOI: 10.1021/acs.chemrestox.1c00243 -
The Science of the Total Environment Mar 2019Recent systematic review and meta-analyses have tried to identify an association between PM exposure and stroke, but few could find a conclusive and comprehensive... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Recent systematic review and meta-analyses have tried to identify an association between PM exposure and stroke, but few could find a conclusive and comprehensive evidence. Moreover, the associations between PM, neurodegenerative diseases and neurodevelopmental disorders have never been reviewed. We aimed to assess the effects of PM exposure on stroke, dementia, Alzheimer's disease, autism spectrum disorder (ASD), Parkinson's disease, and mild cognitive impairment (MCI).
METHODS
We searched PubMed and CNKI databases for articles published until June 2018. Studies were eligible for analysis if they were human studies and provided risk estimates with 95% CI. We screened 1645 articles and identified 80 eligible studies covering 26 countries across all continents except Antarctica. Risks of incidence and mortality were extracted and stratified by types of neurological disorders, PM concentration and duration of PM exposure.
RESULTS
We found significant association between PM exposure and stroke, dementia, Alzheimer's disease, ASD, Parkinson's disease. The risks of ischemic and hemorrhagic stroke were higher than that of stroke in general, and that hemorrhagic stroke had by far the highest mortality. The risk of stroke for heavily polluted countries was significantly higher than that of lightly polluted countries. Short- and long-term PM exposure was associated with increased risks of stroke (short-term odds ratio 1.01 [per 10 μg/m increase in PM concentrations], 95% CI 1.01-1.02; long-term 1.14, 95% CI 1.08-1.21) and mortality (short-term 1.02, 95% CI 1.01-1.04; long-term 1.15, 95% CI 1.07-1.24) of stroke. Long-term PM exposure was associated with increased risks of dementia (1.16, 95% CI 1.07-1.26), Alzheimer's disease (3.26, 95% 0.84-12.74), ASD (1.68, 95% CI 1.20-2.34), and Parkinson's disease (1.34, 95% CI 1.04-1.73).
CONCLUSIONS
There is a strong association between PM exposure and neurological disorders. National governments should exert greater efforts to improve air quality given its health implications.
Topics: Air Pollutants; Environmental Exposure; Humans; Incidence; Nervous System Diseases; Particle Size; Particulate Matter
PubMed: 30577116
DOI: 10.1016/j.scitotenv.2018.11.218 -
International Journal of Molecular... Jun 2018In the field of medicine, nanomaterials, especially those derived using the green method, offer promise as anti-cancer agents and drug carriers. However, the biosafety... (Meta-Analysis)
Meta-Analysis Review
In the field of medicine, nanomaterials, especially those derived using the green method, offer promise as anti-cancer agents and drug carriers. However, the biosafety of metallic nanoparticles used as anti-cancer agents remains a concern. The goal of this systematic review was to compare the cytotoxicity of different plant-mediated syntheses of metallic nanoparticles based on their potency, therapeutic index, and cancer cell type susceptibility in the hopes of identifying the most promising anti-cancer agents. A literature search of electronic databases including Science Direct, PubMed, Springer Link, Google Scholar, and ResearchGate, was conducted to obtain research articles. Keywords such as biosynthesis, plant synthesis, plant-mediated, metallic nanoparticle, cytotoxicity, and anticancer were used in the literature search. All types of research materials that met the inclusion criteria were included in the study regardless of whether the results were positive, negative, or null. The therapeutic index was used as a safety measure for the studied compound of interest. Data from 76 selected articles were extracted and synthesised. Seventy-two studies reported that the cytotoxicity of plant-mediated synthesis of metallic nanoparticles was time and/or dose-dependent. Biosynthesised silver nanoparticles demonstrated higher cytotoxicity potency compared to gold nanoparticles synthesised by the same plants (, , and ) irrespective of the cancer cell type tested. This review also identified a correlation between the nanoparticle size and morphology with the potency of cytotoxicity. Cytotoxicity was found to be inversely proportional to nanoparticle size. The plant-mediated syntheses of metallic nanoparticles were predominantly spherical or quasi-spherical, with the median lethal dose of 1⁻20 µg/mL. Nanoparticles with other shapes (triangular, hexagonal, and rods) were less potent. Metallic nanoparticles synthesised by , , , , and were acceptably safe as anti-cancer agents, as they had a therapeutic index of >2.0 when tested on both cancer cells and normal human cells. Most plant-mediated syntheses of metallic nanoparticles were found to be cytotoxic, although some were non-cytotoxic. The results from this study suggest a focus on a selected list of potential anti-cancer agents for further investigations of their pharmacodynamic/toxicodynamic and pharmacokinetic/toxicokinetic actions with the goal of reducing the Global Burden of Diseases and the second leading cause of mortality.
Topics: Animals; Gold; Humans; Metal Nanoparticles; Particle Size; Plants
PubMed: 29891772
DOI: 10.3390/ijms19061725 -
International Journal of Dentistry 2021This study aimed to evaluate the effect of sandblasting on the bond strength of denture base resin to soft liners. (Review)
Review
OBJECTIVES
This study aimed to evaluate the effect of sandblasting on the bond strength of denture base resin to soft liners.
MATERIALS AND METHODS
This report follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, Embase, Cochrane, Scopus, and OpenGrey databases were searched for in vitro studies that compared sandblasting with no treatment in terms of the tensile, shear, and peel bond strength of resilient lining materials (acrylic-based or silicone-based) to polymethyl methacrylate denture base resin. Based on the outcome, the analysis was carried out in three groups of tensile, shear, and peel bond strength. Subgroup analysis was done for the effect of size of particles on sandblasting, blasting pressure, and type of soft liner whenever possible. Heterogeneity was evaluated among the studies, and meta-analysis was performed with random effect models ( < .05).
RESULTS
After screening, 16 articles met the inclusion criteria for meta-analyses. No treatment showed significantly higher tensile ( < 0.001) or peel (=0.04) bond strength, although shear bond strength of sandblasted resin was significantly better (=0.008). Results of subgroup analyses of particle size favored the control group in 50 AlO particle size ( < 0.001). In analyses of blasting pressure, the control group had significantly better tensile bond strength than specimens with blasting pressure ≤1 bar ( < 0.001) while specimens with blasting pressure beyond 1 bar showed significantly more tensile strength than control group (=0.03). In silicon-based liners, groups without any surface treatment had significantly higher tensile bond strength ( < 0.001).
CONCLUSION
According to the in vitro studies, sandblasting would not lead to significant increase in bond strength of soft liner to the denture base resin.
PubMed: 34976062
DOI: 10.1155/2021/5674155