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International Journal of Molecular... Mar 2024In this study, binary amorphous solid dispersions (ASDs, fisetin-Eudragit) and ternary amorphous solid inclusions (ASIs, fisetin-Eudragit-HP-β-cyclodextrin) of fisetin...
In this study, binary amorphous solid dispersions (ASDs, fisetin-Eudragit) and ternary amorphous solid inclusions (ASIs, fisetin-Eudragit-HP-β-cyclodextrin) of fisetin (FIS) were prepared by the mechanochemical method without solvent. The amorphous nature of FIS in ASDs and ASIs was confirmed using XRPD (X-ray powder diffraction). DSC (Differential scanning calorimetry) confirmed full miscibility of multicomponent delivery systems. FT-IR (Fourier-transform infrared analysis) confirmed interactions that stabilize FIS's amorphous state and identified the functional groups involved. The study culminated in evaluating the impact of amorphization on water solubility and conducting in vitro antioxidant assays: 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-ABTS, 2,2-diphenyl-1-picrylhydrazyl-DPPH, Cupric Reducing Antioxidant Capacity-CUPRAC, and Ferric Reducing Antioxidant Power-FRAP and in vitro neuroprotective assays: inhibition of acetylcholinesterase-AChE and butyrylcholinesterase-BChE. In addition, molecular docking allowed for the determination of possible bonds and interactions between FIS and the mentioned above enzymes. The best preparation turned out to be ASI_30_EPO (ASD fisetin-Eudragit containing 30% FIS in combination with HP-β-cyclodextrin), which showed an improvement in apparent solubility (126.5 ± 0.1 µg∙mL) and antioxidant properties (ABTS: IC = 10.25 µg∙mL, DPPH: IC = 27.69 µg∙mL, CUPRAC: IC = 9.52 µg∙mL, FRAP: IC = 8.56 µg∙mL) and neuroprotective properties (inhibition AChE: 39.91%, and BChE: 42.62%).
Topics: Humans; Acetylcholinesterase; Antioxidants; Butyrylcholinesterase; Molecular Docking Simulation; Solubility; Spectroscopy, Fourier Transform Infrared; Adenoma; beta-Cyclodextrins; Polymethacrylic Acids; Sulfonic Acids; Flavonols; Benzothiazoles
PubMed: 38612460
DOI: 10.3390/ijms25073648 -
Clinical and Experimental Dental... Apr 2024To investigate the effect of common beverages on four currently used provisional restoration materials: Protemp®4, Integrity®, polymethyl methacrylate (PMMA) block,...
OBJECTIVE
To investigate the effect of common beverages on four currently used provisional restoration materials: Protemp®4, Integrity®, polymethyl methacrylate (PMMA) block, and acrylic resin. Flowable resin composite is included as a control group.
MATERIALS AND METHODS
Each material was formed into disks of 10-mm diameter and 4-mm thickness (N = 40) by loading the material into acrylic molds. The exposed surface in the mold was covered using a glass slide to prevent an oxygen inhibition layer, and polymerization then proceeded. The solidified disks were placed in distilled water for 24 h. These samples (n = 8) were then immersed for 14 days in one of four different beverages: water, orange juice, cola, and coffee. Changes in color dimension, hardness, and roughness were observed and then analyzed using two-way repeated analysis of variance.
RESULTS
The provisional materials had more obvious changes in all three color dimensions than the flowable resin composite. Integrity showed the biggest changes, followed by acrylic resin and PMMA block, whereas Protemp had the smallest changes. The hardness of all the materials significantly decreased after immersion in any of the beverages for 14 days. There were no changes in surface roughness when the materials were immersed in distilled water. The surface roughness of the PMMA block significantly decreased in orange juice whereas that of Integrity and acrylic resin significantly increased in cola.
CONCLUSION
Different kinds of provisional materials had different degrees of staining due to their composition. Moisture had a significant influence on the hardness of materials, and the acidity of cola significantly roughened the surface of the provisional materials.
Topics: Polymethyl Methacrylate; Beverages; Acrylic Resins; Coffee; Water
PubMed: 38597122
DOI: 10.1002/cre2.842 -
The Journal of Prosthetic Dentistry Jun 2024Additive (AM) and subtractive (SM) manufacturing have become popular for fabricating occlusal devices with materials of different chemical compositions. However,...
Effect of material and antagonist type on the wear of occlusal devices with different compositions fabricated by using conventional, additive, and subtractive manufacturing.
STATEMENT OF PROBLEM
Additive (AM) and subtractive (SM) manufacturing have become popular for fabricating occlusal devices with materials of different chemical compositions. However, knowledge on the effect of material and antagonist type on the wear characteristics of occlusal devices fabricated by using different methods is limited.
PURPOSE
The purpose of this in vitro study was to evaluate the effect of material and antagonist type on the wear of occlusal devices fabricated by using conventional manufacturing, AM, and SM.
MATERIAL AND METHODS
Two-hundred and forty Ø10×2-mm disk-shaped specimens were fabricated by using heat-polymerized polymethylmethacrylate (control, CM), AM clear device resin fabricated in 3 different orientations (horizontal [AMH], diagonal [AMD], and vertical [AMV]), SM polymethylmethacrylate (SMP), and SM ceramic-reinforced polyetheretherketone (SMB) (n=40). Specimens were then divided into 4 groups based on the antagonists: steatite ceramic (SC); multilayered zirconia (ZR); lithium disilicate (EX); and zirconia-reinforced lithium silicate (ZLS) used for thermomechanical aging (n=10). After aging, the volume loss (mm) and maximum wear depth (μm) were digitally evaluated. Data were analyzed with 2-way analysis of variance and Tukey honestly significant difference tests (α=.05).
RESULTS
The interaction between the device material and the antagonist affected volume loss and maximum depth of wear (P<.001). AMH had volume loss and depth of wear that was either similar to or higher than those of other materials (P≤.044). When SC was used, CM had higher volume loss and depth of wear than AMV, and, when EX was used, AMD had higher volume loss and depth of wear than SMP (P≤.013). SC and ZR led to higher volume loss of CM and AMH than EX and led to the highest depth of wear for these materials, while ZR also led to the highest volume loss and depth of wear of AMD and AMV (P≤.019). EX led to the lowest volume loss and depth of wear of AMV and SMP and to the lowest depth of wear of AMH (P≤.021). Regardless of the antagonist, SMB had the lowest volume loss and depth of wear (P≤.005).
CONCLUSIONS
AMH mostly had higher volume loss and depth of wear, while SMB had the lowest volume loss, and its depth of wear was not affected by the tested antagonists. ZR mostly led to higher volume loss and maximum depth of wear, while EX mostly led to lower volume loss and maximum depth of wear of the tested occlusal device materials.
Topics: Materials Testing; Dental Materials; Polymethyl Methacrylate; Zirconium; Ceramics; Humans; In Vitro Techniques; Occlusal Splints; Dental Restoration Wear; Dental Prosthesis Design; Benzophenones; Dental Porcelain; Polymers; Surface Properties; Polyethylene Glycols; Ketones
PubMed: 38594086
DOI: 10.1016/j.prosdent.2024.03.026 -
International Journal of Biological... May 2024The drug encapsulation efficiency, release rate and time, sustained release, and stimulus-response of carriers are very important for drug delivery. However, these...
The drug encapsulation efficiency, release rate and time, sustained release, and stimulus-response of carriers are very important for drug delivery. However, these always cannot obtained for the carrier with a single component. To improve the comprehensive performance of chitosan-based carriers for 5-Fu delivery, diatomite-incorporated hydroxypropyl cellulose/chitosan (DE/HPC/CS) composite aerogel microspheres were fabricated for the release of 5-fluorouracil (5-Fu), and the release performance was regulated with the content of diatomite, pH value, and external coating material. Firstly, the 5-Fu loaded DE/HPC/CS composite aerogel microspheres and Eudragit L100 coated microspheres were prepared with cross-linking followed by freeze-drying, and characterized by SEM, EDS, FTIR, XRD, DSC, TG, and swelling. The obtained aerogel microspheres have a diameter of about 0.5 mm, the weight percentage of F and Si elements on the surface are 0.55 % and 0.78 % respectively. The glass transition temperature increased from 179 °C to 181 °C and 185 °C with the incorporation of DE and coating of Eudragit, and the equilibrium swelling percentage of DE/HPC/CS (1.5:3:2) carriers are 101.52 %, 45.27 %, 67.32 % at pH 1.2, 5.0, 7.4, respectively. Then, the effect of DE content on the drug loading efficiency of DE/HPC/CS@5-Fu was investigated, with the increase of DE content, the highest encapsulation efficiency was 82.6 %. Finally, the release behavior of DE incorporated and Eudragit L100 Coated microspheres were investigated under different pH values, and evaluated with four kinetic models. The results revealed that the release rate of 5-Fu decreased with the increase of DE content, sustained release with extending time and pH-responsive were observed for the Eudragit-coated aerogel microspheres.
Topics: Chitosan; Microspheres; Cellulose; Delayed-Action Preparations; Fluorouracil; Drug Liberation; Diatomaceous Earth; Polymethacrylic Acids; Drug Carriers; Hydrogen-Ion Concentration; Gels
PubMed: 38588843
DOI: 10.1016/j.ijbiomac.2024.131447 -
Ultrasound in Medicine & Biology Jul 2024We have studied the use of polymethyl methacrylate (PMMA) as an alternative biopsy marker that is readily detectable with ultrasound Doppler twinkling in cases of in... (Comparative Study)
Comparative Study
Long-Term Ultrasound Twinkling Detectability and Safety of a Polymethyl Methacrylate Soft Tissue Marker Compared to Conventional Breast Biopsy Markers-A Preclinical Study in a Porcine Model.
OBJECTIVE
We have studied the use of polymethyl methacrylate (PMMA) as an alternative biopsy marker that is readily detectable with ultrasound Doppler twinkling in cases of in vitro, ex vivo, or limited duration in vivo settings. This study investigates the long-term safety and ultrasound Doppler twinkling detectability of a PMMA breast biopsy marker following local perturbations and different dwell times in a 6-mo animal experiment.
METHODS
This study, which was approved by our Institutional Animal Care and Use Committee, involved three pigs and utilized various markers, including PMMA (Zimmer Biomet), 3D-printed, and Tumark Q markers. Markers were implanted at different times for each pig. Mesh material or ethanol was used to induce a local inflammatory reaction near certain markers. A semiquantitative twinkling score assessed twinkling for actionable localization during monthly ultrasounds. At the primary endpoint, ultrasound-guided localization of lymph nodes with detectable markers was performed. Following surgical resection of the localized nodes, histomorphometric analysis was conducted to evaluate for tissue ingrowth and the formation of a tissue rind around the markers.
RESULTS
No adverse events occurred. Twinkling scores of all markers for all three pigs decreased gradually over time. The Q marker exhibited the highest mean twinkling score followed by the PMMA marker, PMMA with mesh, and Q with ethanol. The 3D-printed marker with mesh and PMMA with ethanol had the lowest scores. All wire-localized lymph nodes were successfully resected. Despite varying percentages of tissue rind around the markers and a significant reduction in overall twinkling (p < 0.001) over time, mean PMMA twinkling scores remained clinically actionable at 6 and 5 mo using a General Electric C1-6 probe and 9L-probe, respectively.
CONCLUSIONS
In this porcine model, the PMMA marker demonstrates an acceptable safety profile. Clinically actionable twinkling aids PMMA marker detection even after 6 mo of dwell time in porcine lymph nodes. The Q marker maintained the greatest twinkling over time compared to all the other markers studied.
Topics: Animals; Polymethyl Methacrylate; Swine; Female; Breast; Ultrasonography, Mammary; Models, Animal; Biopsy
PubMed: 38575416
DOI: 10.1016/j.ultrasmedbio.2024.03.008 -
ANZ Journal of Surgery Apr 2024Surgical glove perforation has been linked to a double-fold increased risk of surgical site infection. Infection in the context of arthroplasty can have devastating...
INTRODUCTION
Surgical glove perforation has been linked to a double-fold increased risk of surgical site infection. Infection in the context of arthroplasty can have devastating consequences. In orthopaedics, use of polymethyl methacrylate (PMMA) bone cement is commonplace, and the impact on glove strength and perforation risk is not fully understood. This study aimed to examine the resistance to perforation and thickness of gloves following PMMA exposure, in accordance with the International Organization for Standardization (ISO) standard for glove integrity.
METHODS
Pairs of gloves were separated and randomly sorted into exposure and control groups. Twenty pairs of latex and 40 pairs of polyisoprene gloves were used. Exposure group glove cuffs were in contact with cement from a single surface of the glove for 13 min as cement cured. Force to perforation and glove thickness were tested in accordance with ISO guidelines.
RESULTS
Latex gloves were found to have a significantly increased force to perforation following PMMA exposure (10.26 Newtons (N) vs. 9.81 N, P = 0.048). Both polyisoprene under- and over-gloves were shown to have no significant change in strength to perforation post exposure (9.69 N vs. 9.83 N, P = 0.561, and 10.26 N vs. 10.65 N, P = 0.168, respectively). All groups were over the ISO standard minimum strength of 5 N.
CONCLUSIONS
Exposure of latex and polyisoprene surgical gloves to PMMA bone cement does not appear to increase glove perforation risk and rather may improve natural rubber latex glove strength. This study supports the use of latex and polyisoprene surgical gloves in procedures that involve the handling of PMMA bone cement.
Topics: Humans; Gloves, Surgical; Polymethyl Methacrylate; Bone Cements; Latex; Orthopedics
PubMed: 38572937
DOI: 10.1111/ans.18927 -
Environmental Science and Pollution... Apr 2024Inappropriate disposal of plastic wastes and their durability in nature cause uncontrolled accumulation of plastic in land/marine ecosystems, also causing destructive...
Inappropriate disposal of plastic wastes and their durability in nature cause uncontrolled accumulation of plastic in land/marine ecosystems, also causing destructive effects by bioaccumulating along the food chain. Microplastics may cause chronic inflammation in relation to their permanent structures, especially through oxidative stress and cytotoxic cellular damage, which could increase the risk of cancer development. The accumulation of microplastics in the liver is a major concern, and therefore, the identification of the mechanisms of their hepatotoxic effects is of great importance. Polymethyl methacrylate (PMMA) is a widely used thermoplastic. It has been determined that PMMA disrupts lipid metabolism in the liver in various aquatic organisms and causes reproductive and developmental toxicity. PMMA-induced hepatotoxic effects in humans have not yet been clarified. In our study, the toxic effects of PMMA (in the range of 3-10 μm) on the human liver were investigated using the HepG2/THP-1 macrophage co-culture model, which is a sensitive immune-mediated liver injury model. Cellular uptake of micro-sized PMMA in the cells was done by transmission electron microscopy. Determination of its effects on cell viability and inflammatory response, oxidative stress, along with gene and protein expression levels that play a role in the mechanism pathways underlying the effects were investigated. The results concluded that inflammation, oxidative stress, and disruptions in lipid metabolism should be the focus of attention as important underlying causes of PMMA-induced hepatotoxicity. Our study, which points out the potential adverse effects of microplastics on human health, supports the literature information on the subject.
Topics: Humans; Polymethyl Methacrylate; Microplastics; Hep G2 Cells; Oxidative Stress; Coculture Techniques; Liver
PubMed: 38564126
DOI: 10.1007/s11356-024-33086-3 -
[Comparison of polymethyl methacrylate skull implant fixation by three types of titanium fasteners].Zhurnal Voprosy Neirokhirurgii Imeni N.... 2024To evaluate mechanical strength of three methods of polymethyl methacrylate skull implant fixation in two experimental models.
OBJECTIVE
To evaluate mechanical strength of three methods of polymethyl methacrylate skull implant fixation in two experimental models.
MATERIAL AND METHODS
The first experiment was performed on a plastic model that was as close as possible to bone in structural characteristics. The second experiment was performed on a biological specimen (a ram's head). We assessed the quality of implant fixation to bone window edges by craniofixes, ties and microscrews and lateral intercortical screws.
RESULTS
Craniofixes are feasible for small flat flaps, but not advisable for wide highly curved implants. They are also the most expensive method of fixation. Implant fixation by ties and microscrews is a universal method comparable in price to craniofix. Lateral intercortical fixation is effective both for small flat implants and wide implants with large curvature. However, this method is not always applicable.
CONCLUSION
Combined fixation by lateral intercortical screws and ties allows for the most effective fixation while reducing the overall price of consumables.
Topics: Male; Animals; Sheep; Polymethyl Methacrylate; Titanium; Skull; Prostheses and Implants; Craniotomy
PubMed: 38549407
DOI: 10.17116/neiro20248802123 -
Journal of the Mechanical Behavior of... Jun 2024The influence of various aging protocols, representing and accelerating influences present in the dental context, on possible changes in the microstructure and...
OBJECTIVE
The influence of various aging protocols, representing and accelerating influences present in the dental context, on possible changes in the microstructure and mechanical properties of thermoplastics was investigated. In order to minimize the complexity of the systems, first pure polymers and then later the equivalent dental polymeric materials were analyzed.
MATERIALS AND METHODS
Pure polymers (Poly(methyl methacrylate) - PMMA, Polyoxymethylene homopolymer - POM-H, Polyether ether ketone - PEEK, Nylon 12 - PA12, Polypropylene - PP) were analyzed before as well as after applying different aging protocols relevant to the oral environment (ethanol, thermocycling, alkaline and acidic setting) by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The thermoanalytical parameters used were glass transition temperature (T), melting peak and crystallization peak temperature (T T) and decomposition behavior. In a second step selected commercially available dental products (Telio CAD - PMMA, Zirlux Acetal - POM, Juvora Natural Dental Disc - PEEK) aged by the protocol that previously showed strong effects were examined and additionally tested for changes in their Vickers and Martens hardness by Mann-Whitney-U test.
RESULTS
The combinations of pure polymers and viable aging protocols analyzed within this study were identified via TGA or DSC as PA12 & thermocycling, POM-H & denture cleanser/lactic acid/ethanol, PP & lactic acid. The dental polymeric materials PMMA and POM due to aging in lactic acid showed slight but significantly (p < 0.01) reduced Vickers and partly Martens hardness. PEEK showed the greatest material resistance within this study.
Topics: Animals; Polymethyl Methacrylate; Materials Testing; Hardness; Mustelidae; Polymers; Polyethylene Glycols; Ketones; Ethanol; Lactic Acid; Dental Materials; Surface Properties; Benzophenones
PubMed: 38531182
DOI: 10.1016/j.jmbbm.2024.106501 -
The Journal of Prosthetic Dentistry Jun 2024Denture base materials are highly susceptible to microbial colonization, which can lead to denture stomatitis. In addition, patients who sleep with their dentures have...
STATEMENT OF PROBLEM
Denture base materials are highly susceptible to microbial colonization, which can lead to denture stomatitis. In addition, patients who sleep with their dentures have an increased chance of contracting pneumonia. Commercially available antimicrobial denture base materials to prevent or combat microbial colonization are lacking.
PURPOSE
The purpose of this in vitro study was to determine the effects of K18 quaternary ammonium methacryloxy silane-functionalized filler (K18-Filler) and methyl methacrylate (K18-MMA) on the polymerization of 3D printed denture base material and its esthetic, mechanical, and antimicrobial properties.
MATERIAL AND METHODS
K18-Filler (0%, 10%, 20% w/w) and K18-MMA (0%, 5%, 12.5% w/w) were added to a 3D printable denture base resin (Denture Base Resin, Original Pink; Formlabs Inc) and 3D printed. Specimens were tested by using the Rockwell hardness, near infrared FTIR monomer-to-polymer degree of conversion (DoC), transparency parameter (TP), color shift, and 3-point bend and by counting colony forming units against Streptococcus aureus, Streptococcus sanguinis and Candida albicans tests. Data were analyzed using analysis of variance with the Tukey-Kramer HSD post hoc test.
RESULTS
Control resins had significantly higher Rockwell hardness than most of the K18 groups (P<.05) but had comparable DoC with all K18 groups except one, showing that all groups were well polymerized. Controls had significantly higher TP than most K18 groups, but most K18 groups had ΔE<3.3, so the color shift was not noticeable. However, the 12.5% K18-MMA with 10% and 20% K18-Filler groups, which were also the groups used to test for antimicrobial activity, had ΔE>8. All K18 groups had comparable or greater moduli than the controls, but the controls had significantly higher ultimate transverse strengths than most K18 groups (P<.05). All 12.5% K18-MMA with K18-Filler groups had significant antimicrobial activity against S. aureus, S. sanguinis, and C. albicans.
CONCLUSIONS
12.5% K18-MMA and K18-Filler produced 3D printable denture materials with comparable polymerization properties and significant antimicrobial properties against S. mutans, S. sanguinis, and C. albicans. High K18-MMA and K18-Filler concentrations caused significant color shifts and reductions in ultimate strengths.
Topics: Denture Bases; Methylmethacrylate; Silanes; Quaternary Ammonium Compounds; Printing, Three-Dimensional; Dental Materials; Anti-Infective Agents; Materials Testing; Polymerization; In Vitro Techniques; Humans; Candida albicans
PubMed: 38523046
DOI: 10.1016/j.prosdent.2024.03.013