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Cells Oct 2022This systematic review aimed to analyze the development and functionality of microfluidic concentration gradient generators (CGGs) for toxicological evaluation of... (Review)
Review
This systematic review aimed to analyze the development and functionality of microfluidic concentration gradient generators (CGGs) for toxicological evaluation of different biological organisms. We searched articles using the keywords: concentration gradient generator, toxicity, and microfluidic device. Only 33 of the 352 articles found were included and examined regarding the fabrication of the microdevices, the characteristics of the CGG, the biological model, and the desired results. The main fabrication method was soft lithography, using polydimethylsiloxane (PDMS) material (91%) and SU-8 as the mold (58.3%). New technologies were applied to minimize shear and bubble problems, reduce costs, and accelerate prototyping. The Christmas tree CGG design and its variations were the most reported in the studies, as well as the convective method of generation (61%). Biological models included bacteria and nematodes for antibiotic screening, microalgae for pollutant toxicity, tumor and normal cells for, primarily, chemotherapy screening, and Zebrafish embryos for drug and metal developmental toxicity. The toxic effects of each concentration generated were evaluated mostly with imaging and microscopy techniques. This study showed an advantage of CGGs over other techniques and their applicability for several biological models. Even with soft lithography, PDMS, and Christmas tree being more popular in their respective categories, current studies aim to apply new technologies and intricate architectures to improve testing effectiveness and reduce common microfluidics problems, allowing for high applicability of toxicity tests in different medical and environmental models.
Topics: Animals; Anti-Bacterial Agents; Dimethylpolysiloxanes; Environmental Pollutants; Lab-On-A-Chip Devices; Zebrafish
PubMed: 36231063
DOI: 10.3390/cells11193101 -
Operative Dentistry Jan 2021The literature reviewed suggests that airborne particle abrasion has no negative effects on the bond strength of resin-based materials to dentin and that a positive... (Meta-Analysis)
Meta-Analysis
CLINICAL RELEVANCE
The literature reviewed suggests that airborne particle abrasion has no negative effects on the bond strength of resin-based materials to dentin and that a positive influence on dentin bond strength was only achieved in specific air-abrasion conditions.
SUMMARY
In this systematic review the authors investigated how airborne-particle abrasion (APA) using aluminum oxide affects the bond strength of resin-based materials to dentin. The search was performed in three databases. In vitro studies (Type of study) comparing the bond strength of resin-based materials (Outcome) to air-abraded (Intervention) compared with non-air-abraded (Comparison) human dentin (Population) were included (the PICOT elements are given parenthetically). From 5437 unique articles, 65 were read in full, 33 were included in the qualitative synthesis, and 32 were included in the meta-analysis. Methodologic quality and risk of bias were assessed. Comparisons were performed between air-abraded and control dentin groups by adopting a random-effects model (α=0.05). Additional analyses were carried out for the different parameters used in APA: type of surface treatment in the control group, particle size, air pressure, and APA duration. The bond strength to air-abraded dentin was favored only when the control surface was treated with a hand excavator. For particle size, APA was favored when the particle size was >30 μm and the controls were no treatment or hand excavator or when the particle size was ≤30 μm and the control was bur. In addition, the results favored air-abraded groups only when the pressure was > 5 bar and bur was used in the control group. No significant differences were observed for duration of APA. No comparison on bond strength considering the presence of aging conditions was possible in the included studies due to the low number of studies that aged the specimens. In conclusion, APA had no negative effects on the bond strength of resin-based materials to dentin and was able to improve the dentin bond strength only when the particle size was > 30 μm and air pressure was > 5 bar. PROSPERO registration protocol: CRD42018096128.
Topics: Aged; Aluminum Oxide; Composite Resins; Dental Bonding; Dentin; Humans; Materials Testing; Resin Cements; Shear Strength; Surface Properties
PubMed: 32926155
DOI: 10.2341/19-216-L -
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 -
AAPS PharmSciTech May 2022Aqueous colloidal dispersions of water-insoluble polymers (APDs) avoid hassles associated with the use of organic solvents and offer processing advantages related to... (Review)
Review
Aqueous colloidal dispersions of water-insoluble polymers (APDs) avoid hassles associated with the use of organic solvents and offer processing advantages related to their low viscosity and short processing times. Therefore, they became the main vehicle for pharmaceutical coating of tablets and multiparticulates, a process commonly employed using pan and fluidized-bed machinery. Another interesting although less common processing approach is co-spray drying APDs with drugs in aqueous systems. It enables the manufacture of capsule- and matrix-type microspheres with controllable size and improved processing characteristics in a single step. These microspheres can be further formulated into different dosage forms. This systematic review is based on published research articles and aims to highlight the applicability and opportunities of co-spray drying drugs with APDs in drug delivery.
Topics: Drug Compounding; Excipients; Polymers; Solubility; Spray Drying; Tablets; Water
PubMed: 35538248
DOI: 10.1208/s12249-022-02293-x -
Journal of the World Federation of... Dec 2021The study evaluated and compared the force decay of orthodontic elastomeric chains/modules in both in vivo and in vitro settings. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The study evaluated and compared the force decay of orthodontic elastomeric chains/modules in both in vivo and in vitro settings.
METHODS
A protocol in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was formulated and registered with the International Prospective Register of Systematic Reviews. A total of 53 articles (44 in vitro and 9 in vivo studies) found via search of the electronic databases of Cochrane and the National Library of Medicine (MEDLINE; PubMed), and manual search of the gray literature from institutional library resources, were selected. Data extraction, quality analysis, risk of bias assessment, and meta-analysis of the level of force decay of elastomeric chains/modules were conducted per standard protocol, and suitable statistical analyses were applied.
RESULTS
The mean force decay in the in vivo setting was 41.9% at 24 hours, 42.6% after 1 week, 46.8% after 2 weeks, and 55.0% after 3 weeks. Similarly, the force decay in the in vitro studies was 38.9% at 24 hours, 42.1% after 1 week, 44.6% after 2 weeks, and 51.1% after 3 weeks. However, at the 95% confidence interval, the force decay rates of in vivo and in vitro studies overlap, with a statistically insignificant difference in force decay observed in the in vivo and in vitro settings.
CONCLUSIONS
This systematic review and meta-analysis observed more force decay in the in vivo studies versus the in vitro studies (although this difference was statistically insignificant), with the maximum force decay occurring during the initial days, with a reduction to approximately 50% within 3 weeks. Hence, change of the elastomeric chains/module, at intervals of 3 weeks, is advised. (PROSPERO registration no. CRD42020209535).
Topics: Elasticity; Elastomers; Mechanical Phenomena; Orthodontic Appliances; United States
PubMed: 34364839
DOI: 10.1016/j.ejwf.2021.07.003 -
Environmental Pollution (Barking, Essex... Nov 2022The soil environment serves as an assembling area for microplastics, and is an important secondary source of microplastics in other environmental media. Recently, soil... (Meta-Analysis)
Meta-Analysis Review
The soil environment serves as an assembling area for microplastics, and is an important secondary source of microplastics in other environmental media. Recently, soil microplastics have been extensively studied; however, high variability is observed among the research results owing to different soil properties, and the complexity of soil microplastic composition. The present study amassed the findings of 2886 experimental groups, across 38 studies from 2016 to 2022, and used meta-analysis to quantitatively analyze the differences in the effects of microplastic exposure on soil physicochemical properties and biota. The results showed that among the existing soil microplastic research, agricultural soils maintained a higher environmental exposure distribution than other environments. Microplastic fibers and fragments were the predominant shapes, indicating that the extensive use of agricultural films are the primary influencing factor of soil microplastic pollution at present. The results of the meta-analysis found that microplastic exposure had a significant negative effect on soil bulk density (lnRR = -0.04) and aggregate stability (lnRR = -0.085), indicating that microplastics may damage the integrity of soil structure or damage the soil surface. The significant changes in plant root biomass and soil phosphatase further signified the potential impact of microplastics on soil nutrient and geochemical element cycling. We further constructed species sensitivity distribution curves, revealing that invertebrates had a higher species sensitivity to microplastics, as they can pass through the gut wall of soil nematodes, causing oxidative stress and affecting gene expression. In general, soil is an interconnected complex, and microplastic exposure can directly or indirectly interact with environmental chemical processes in the soil environment, potentially harming the soil ecosystem; however, current research remains insufficient with respect to breadth and depth in terms of the comprehensive "source-sink" mechanism of soil microplastics, the hazard of exposure, and the overall toxic effects.
Topics: Biota; Ecosystem; Environmental Monitoring; Microplastics; Phosphoric Monoester Hydrolases; Plastics; Soil; Soil Pollutants
PubMed: 36126769
DOI: 10.1016/j.envpol.2022.120183 -
The Spine Journal : Official Journal of... Dec 2014The spine contains intervertebral discs and the interspinous and longitudinal ligaments. These structures are elastomeric or viscoelastic in their mechanical properties... (Review)
Review
BACKGROUND CONTEXT
The spine contains intervertebral discs and the interspinous and longitudinal ligaments. These structures are elastomeric or viscoelastic in their mechanical properties and serve to allow and control the movement of the bony elements of the spine. The use of metallic or hard polymeric devices to replace the intervertebral discs and the creation of fusion masses to replace discs and/or vertebral bodies changes the load transfer characteristics of the spine and the range of motion of segments of the spine.
PURPOSE
The purpose of the study was to survey the literature, regulatory information available on the Web, and industry-reported device development found on the Web to ascertain the usage and outcomes of the use of polyurethane polymers in the design and clinical use of devices for spine surgery.
STUDY DESIGN/SETTING
A systematic review of the available information from all sources concerning the subject materials' usage in spinal devices was conducted.
METHODS
A search of the peer-reviewed literature combining spinal surgery with polyurethane or specific types and trade names of medical polyurethanes was performed. Additionally, information available on the Food and Drug Administration Web site and for corporate Web sites was reviewed in an attempt to identify pertinent information.
RESULTS
The review captured devices that are in testing or have entered clinical practice that use elastomeric polyurethane polymers as disc replacements, dynamic stabilization of spinal movement, or motion limitation to relieve nerve root compression and pain and as complete a listing as possible of such devices that have been designed or tested but appear to no longer be pursued. This review summarizes the available information about the uses to which polyurethanes have been tested or are being used in spinal surgery.
CONCLUSIONS
The use of polyurethanes in medicine has expanded as modifications to the stability of the polymers in the physiological environment have been improved. The potential for the use of elastomeric materials to more closely match the mechanical properties of the structures being replaced and to maintain motion between spinal segments appears to hold promise. The published results from the use of the devices that are discussed show early success with these applications of elastomeric materials.
Topics: Humans; Polyurethanes; Spine; Total Disc Replacement
PubMed: 25151132
DOI: 10.1016/j.spinee.2014.08.012 -
Clinical and Experimental Dental... Dec 2023The aim of this study was to review the selection criteria of resin cements for different types of partial coverage restorations (PCRs) and investigate if the type of... (Review)
Review
OBJECTIVE
The aim of this study was to review the selection criteria of resin cements for different types of partial coverage restorations (PCRs) and investigate if the type of restorations or restorative materials affect the type of selected resin cement.
MATERIALS AND METHODS
An electronic search (1991-2023) was performed in PubMed, Medline, Scopus, and Google Scholar databases by combinations of related keywords.
RESULTS
A total of 68 articles were included to review the selection criteria based on the advantages, disadvantages, indications, and performance of resin cements for different types of PCRs.
CONCLUSIONS
The survival and success of PCRs are largely affected by appropriate cement selection. Self-curing and dual-curing resin cements have been recommended for the cementation of metallic PCRs. The PCRs fabricated from thin, translucent, and low-strength ceramics could be adhesively bonded by light-cure conventional resin cements. Self-etching and self-adhesive cements, especially dual-cure types, are not generally indicated for laminate veneers.
Topics: Resin Cements; Ceramics; Dental Cements; Cementation
PubMed: 37427500
DOI: 10.1002/cre2.761 -
Evidence-based Dentistry Sep 2022Design Systematic review. Case selection This systematic review had a focused and structured research question in term of PICO (Population, Intervention, Comparison and... (Review)
Review
Design Systematic review. Case selection This systematic review had a focused and structured research question in term of PICO (Population, Intervention, Comparison and Outcomes). Patients included within the study were those with undergoing primary root canal treatment on a permanent tooth. The intervention was obturation with gutta percha and a resin-based sealer in comparison to obturation with gutta percha and another sealer type. The primary outcome being measured was post-operative pain incidence and/or intensity. An additional, secondary outcome, aimed to assess analgesic intake following treatment.Data analysis Data analysis was carried out by two independent reviewers using a specifically designed template which gave a concise summary of the study included within the review. The form allowed the following details to be recorded: whether a single operator completed treatment; pulpal status; irrigants used; sealer placement technique and type; obturation technique and quality; evaluation time; and outcome measures. An assessment was carried out of each study to ascertain the risk of bias which was categorised as low risk, having some areas of concerns or high risk.Six studies were included within the quantitative analysis which involved analysis of post-operative pain experiences at specified intervals. Qualitative data analysis was completed using a digital software package which allowed comparable results to be combined.Results The results from this systematic review demonstrated no significant difference in post-operative pain incidence between endodontic treatment using resin or non-resin sealers. While seven of the studies had high risk of overall bias, four were deemed low risk, and the majority of studies confirmed that there was no significant difference in the intensity of pain between the two groups. This review also confirmed that analgesic intake is not increased in patients where resin-based sealers are used when compared to non-resin sealers.Conclusion There is no significant difference in post-operative pain when resin-based root canal sealers are used when compared to other root canal sealers. For both resin and non-resin sealers, analgesics use, pain incidence post-operatively and intensity of pain reduce after 24 hours.
Topics: Epoxy Resins; Gutta-Percha; Humans; Pain, Postoperative; Root Canal Filling Materials; Root Canal Obturation
PubMed: 36151287
DOI: 10.1038/s41432-022-0804-3 -
International Journal of Biological... Dec 2022Lignin is a major phenolic polymer from the plant biomass. Due to its abundant functional groups (carboxyl and hydroxyl groups), lignin could act as an antioxidant,... (Review)
Review
Lignin is a major phenolic polymer from the plant biomass. Due to its abundant functional groups (carboxyl and hydroxyl groups), lignin could act as an antioxidant, antimicrobial as well as an immune modulator. These remarkable biological properties render lignin a highly potential bioactive candidate in the biomedical applications including tissue engineering. Although several effective applications of lignin-based composites have been reported in tissues repairing and organ regeneration, a systematic review to summarize the recent utilization of lignin-based composites in different tissue engineering fields is still lacking. Hence, the aim of this review is to delineate the biological functions of lignin and to highlight the latest applications of lignin-based composites in different tissue engineering fields, such as bone regeneration, organ regeneration and wound dressing. This review will serve as an illuminating resource to direct and promote the biomedical applications of lignin and lignin-based composites.
Topics: Tissue Engineering; Lignin; Bone Regeneration; Polymers; Biomass
PubMed: 36191783
DOI: 10.1016/j.ijbiomac.2022.09.267