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1.
Nanomedicine (Lond) ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38722243

RESUMO

Aim: To investigate whether medical devices coated with a synthesized nanocomposite of poly(methylmethacrylate-co-dimethyl acrylamide) (PMMDMA) and silver nanoparticles (AgNPs) could improve their antibiofilm and antimicrobial activities. We also investigated the nanocomposite's safety. Materials & methods: The nanocomposite was synthesized and characterized using analytical techniques. Medical devices coated with the nanocomposite were evaluated for bacterial adhesion and hemolytic activity in vitro. Results: The nanocomposite formation was demonstrated with the incorporation of AgNPs into the polymer matrix. The nanocomposite proved to be nonhemolytic and significantly inhibited bacterial biofilm formation. Conclusion: The PMMDMA-AgNPs nanocomposite was more effective in preventing biofilm formation than PMMDMA alone and is a promising strategy for coating medical devices and reducing mortality due to hospital-acquired infections.

2.
Biomedicines ; 11(7)2023 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-37509604

RESUMO

The goal of the current study was to determine the mechanical proprieties of polymethylmethacrylate (PMMA) and the improved compound, the graphene-based PMMA, with Zn and Ag and to compare the results. Scanning electron microscopy analysis of the samples before and after the mechanical test was conducted. The compression behavior, flexural properties, tensile strength, and shape of the samples were all investigated and compared between the variants of PMMA. Commercially available polymethylmethacrylate was used (Orthocryl®-Dentaurum, Ispringen, Germany) with the salt and pepper technique according to the manufacturer's instructions to produce 20 samples for each mechanical trial with standard cylinders (4 mm diameter × 8 mm length) for compression, parallelepipedal prisms for flexing (2 mm × 2 mm × 25 mm) and flat samples for traction. There was no statistical difference in the mechanical proprieties of the samples evaluated, although there were values that could suggest significance. The graphene-based PMMA demonstrated good mechanical proprieties, like the commercially available PMMA, and appears promising for future clinical use based on its multiple advantages.

3.
Small ; 19(39): e2301572, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37236175

RESUMO

Solid-state lithium-ion batteries (SLIBs) are the promising development direction for future power sources because of their high energy density and reliable safety. To optimize the ionic conductivity at room temperature (RT) and charge/discharge performance to obtain reusable polymer electrolytes (PEs), polyvinylidene fluoride (PVDF), and poly(vinylidene fluoride-hexafluoro propylene) (P(VDF-HFP)) copolymer combined with polymerized methyl methacrylate (MMA) monomers are used as substrates to prepare PE (LiTFSI/OMMT/PVDF/P(VDF-HFP)/PMMA [LOPPM]). LOPPM has interconnected lithium-ion 3D network channels. The organic-modified montmorillonite (OMMT) is rich in the Lewis acid centers, which promoted lithium salt dissociation. LOPPM PE possessed high ionic conductivity of 1.1 × 10-3 S cm-1 and a lithium-ion transference number of 0.54. The capacity retention of the battery remained 100% after 100 cycles at RT and 0.5 C. The initial capacity of one with the second-recycled LOPPM PE is 123.9 mAh g-1 . This work offered a feasible pathway for developing high-performance and reusable LIBs.

4.
J Yeungnam Med Sci ; 40(Suppl): S1-S8, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37098682

RESUMO

BACKGROUND: Residual monomer tests using high-performance liquid chromatography and cytotoxicity tests were performed to analyze the effect on the oral mucosa of a self-curing resin for provisional crown production. METHODS: A cytotoxicity test was performed to confirm whether leaked residual monomers directly affected oral mucosal cells. The cytotoxicity of the liquid and solid resin polymers was measured using a water-soluble tetrazolium (WST) test and microplate reader. RESULTS: In the WST assay using a microplate reader, 73.4% of the cells survived at a concentration of 0.2% liquid resin polymer. The cytotoxicity of the liquid resin polymer was low at ≤0.2%. For the solid resins, when 100% of the eluate was used from each specimen, the average cell viability was 91.3% for the solid resin polymer and 100% for the hand-mixed self-curing resin, which is higher than the cell viability standard of 70%. The cytotoxicity of the solid resin polymer was low. CONCLUSION: Because the polymerization process of the self-curing resin may have harmful effects on the oral mucosa during the second and third stages, the solid resin should be manufactured indirectly using a dental model.

5.
Plants (Basel) ; 12(1)2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36616336

RESUMO

Microplastics are widely spread in aquatic environments. Although they are considered among the most alarming contaminants, toxic effects on organisms are unclear, particularly on freshwater plants. In this study, the duckweed Lemna minuta was grown on different concentrations (50, 100 mg/L) of poly(styrene-co-methyl methacrylate) microplastics (MP) and exposure times (T0, T7, T14, T28 days). The phytotoxic effects of MP were investigated by analyzing several plant morphological and biochemical parameters (frond and root size, plant growth, chlorophyll, and malondialdehyde content). Observations by scanning electron microscope revealed MP adsorption on plant surfaces. Exposition to MP adversely affected plant growth and chlorophyll content with respect to both MP concentrations and exposure times. Conversely, malondialdehyde measurements did not indicate an alteration of oxidative lipid damage in plant tissue. The presence of MP induced root elongation when compared to the control plants. The effects of MP on L. minuta plants were more evident at T28. These results contribute to a better understanding of MP's impact on aquatic plants and highlight that MP contamination manifests with chronic-type effects, which are thus detectable at longer exposure times of 7 days than those traditionally used in phytotoxicology tests on duckweeds.

6.
Ann Anat ; 240: 151879, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34863910

RESUMO

INTRODUCTION: The masseter muscle is considered to be bilayered, consisting of a superficial and a deep part. However, a few historical texts mention the possible existence of a third layer as well, but they are extremely inconsistent as to its position. Here we performed an anatomical study to clarify the presence and morphological characteristics of a distinct third layer of the masseter muscle. MATERIALS AND METHODS: We dissected 12 formaldehyde-fixed human cadaver heads, analysed CTs of 16 fresh cadavers, evaluated MR data from one living subject and examined histological sections using methyl methacrylate embedding of one formaldehyde-preserved head. RESULTS: An anatomically distinct, deep third layer of the masseter muscle was consistently demonstrated, running from the medial surface of the zygomatic process of the temporal bone to the root and posterior margin of the coronoid process. Ours is the first detailed description of this part of the masseter muscle. CONCLUSIONS: To facilitate discussion of this newly described part of the masseter, we recommend the name M. masseter pars coronoidea (coronoid part of the masseter) as a further reference. The arrangement of its muscle fibers suggest it being involved in stabilising the mandible by elevating and retracting the coronoid process.


Assuntos
Mandíbula , Músculo Masseter , Cadáver , Humanos
7.
Methods Mol Biol ; 2412: 233-245, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34918247

RESUMO

Spherical or discoidal lipid polymer nanostructures bearing cationic charges successfully adsorb a variety of oppositely charged antigens (Ag) such as proteins, peptides, nucleic acids, or oligonucleotides. This report provides instructions for the preparation and physical characterization of four different cationic nanostructures able to combine and deliver antigens to the immune system: (1) dioctadecyl dimethylammonium bromide (DODAB) bilayer fragments (DODAB BF); (2) polystyrene sulfate (PSS) nanoparticles (NPs) covered with one cationic dioctadecyl dimethylammonium bromide bilayer (DODAB) named (PSS/DODAB); (3) cationic NPs of biocompatible polymer poly(methyl methacrylate) (PMMA) prepared by emulsion polymerization of the methyl methacrylate (MMA) monomer in the presence of DODAB BF (PMMA/DODAB NPs); (4) antigen NPs (NPs) where the cationic polymer poly(diallyl dimethyl ammonium chloride) (PDDA) directly combined at nontoxic and low dose with the antigen (Ag); when the oppositely charged model antigen is ovalbumin (OVA), NPs are named PDDA/OVA. These nanostructures provide adequate microenvironments for carrying and delivering antigens to the antigen-presenting cells of the immune system.


Assuntos
Nanopartículas , Vacinas , Adjuvantes Imunológicos , Adjuvantes Farmacêuticos , Cátions , Ovalbumina , Polímeros , Polimetil Metacrilato , Compostos de Amônio Quaternário
8.
Asian J Neurosurg ; 16(3): 648-654, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34660389

RESUMO

STUDY DESIGN: Prospective. PURPOSE: Over past one and half decade, ready-to-use magnetic resonance imaging (MRI) compatible spinal implants have changed the clinical practice and economics of spinal surgery. These are beyond reach of majority of population of developing countries like India due to financial reasons and also availability in remote areas. There is a growing need for a MRI compatible cost-effective spinal implant of proven quality. The authors used bone cement spacers for the said purpose for various level spine surgeries. OVERVIEW OF LITERATURE: Methylmethacrylate, known as bone cement, was used extensively for spinal surgeries from craniovertebral junction to sacrum for augmentation and replacement of various spinal elements. Its biochemical and biomechanical properties were tested for safe clinical use and was a favored material for spinal surgeons. MATERIALS AND METHODS: The authors made molds for making bone cement spacers for various spine levels with the help of silicone material. RESULTS: Sixteen patients (12 males, 4 females with an average age of 31 years) of various spine level surgeries were done where bone cement spacers were used. It included patients of basilar invagination (n = 9), dorsal Pott's disease (n = 1), lumbar (n = 2), and lumbo-sacral spondylolisthesis (n = 1). Spacers could be used without any difficulties and postoperative day 1- and 3-months follow-up computed tomography scan of the patients revealed no change in the dimensions of the spacer and fusion at 3 months of operated levels. CONCLUSION: The authors feel that bone cement spacers may be an effective and low-cost alternative to the existing costly alternatives.

9.
J Pharm Bioallied Sci ; 13(Suppl 1): S660-S663, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34447175

RESUMO

PURPOSE: The purpose of the study was to assess the effectiveness of erbium:yttrium-aluminum-garnet (Er:YAG) laser surface pretreatment at various pulse durations of exposure on increasing the tensile bonding strength of permanent soft relining material and acrylic resin. MATERIALS AND METHODS: Polymethyl methacrylate resin samples were fabricated and grouped as comparison group (no laser surface pretreatment) and three test groups (received Er:YAG laser surface pretreatment at various pulse durations of 10 s, 20 s, and 30 s) for bonding with the permanent soft relining material, Molloplast B. Following the surface pretreatment, the samples were tested for tensile stress using a universal testing machine. Loads at the point of failure were noted and the tensile bond strength values were obtained. Parametric tests of one-way-ANOVA and Tukey's post hoc tests were done. RESULTS: The highest tensile bonding strength was recorded in Group C, and the control group recorded the lowest bonding strength. CONCLUSION: Er:YAG laser surface pretreatment at 10 Hz, 3 W, and 300 mJ for 30 s improved the bonding strength of the permanent soft relining material to heat-processed acrylic resin material.

10.
Polymers (Basel) ; 13(12)2021 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-34207932

RESUMO

Poly(methyl methacrylate) (PMMA) is a lightweight insulating polymer that possesses good mechanical stability. On the other hand, polyaniline (PANi) is one of the most favorable conducting materials to be used, as it is easily synthesized, cost-effective, and has good conductivity. However, most organic solvents have restricted potential applications due to poor mechanical properties and dispersibility. Compared to PANi, PMMA has more outstanding physical and chemical properties, such as good dimensional stability and better molecular interactions between the monomers. To date, many research studies have focused on incorporating PANi into PMMA. In this review, the properties and suitability of PANi as a conducting material are briefly reviewed. The major parts of this paper reviewed different approaches to incorporating PANi into PMMA, as well as evaluating the modifications to improve its conductivity. Finally, the polymerization condition to prepare PMMA/PANi copolymer to improve its conductivity is also discussed.

11.
Polymers (Basel) ; 13(11)2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-34073877

RESUMO

We report the synthesis and comprehensive characterization of polymethylmethacrylate (PMMA)/polyvinylalcohol (PVA) polymeric blend doped with different concentrations of Copper oxide (CuO) nanoparticles (NPs). The PMMA-PVA/CuO nanocomposite hybrid thin films containing wt.% = 0%, 2%, 4%, 8%, and 16% of CuO NPs are deposited on glass substrates via dip-coating technique. Key optical parameters are measured, analyzed, and interpreted. Tauc, Urbach, Spitzer-Fan, and Drude models are employed to calculate the optical bandgap energy (Eg) and the optoelectronic parameters of PMMA-PVA/CuO nanocomposites. The refractive index and Eg of undoped PMMA-PVA are found to be (1.5-1.85) and 4.101 eV, respectively. Incorporation of specific concentrations of CuO NPs into PMMA-PVA blend leads to a considerable decrease in Eg and to an increase of the refractive index. Moreover, Fourier Transform Infrared Spectroscopy (FTIR) transmittance spectra are measured and analyzed for undoped and doped polymeric thin films to pinpoint the major vibrational modes in the spectral range (500 and 4000 cm-1) as well as to elucidate the nature of chemical network bonding. Thermogravimetric analysis (TGA) is conducted under appropriate conditions to ensure the thermal stability of thin films. Doped polymeric thin films are found to be thermally stable below 105 °C. Therefore, controlled tuning of optoelectronic and thermal properties of doped polymeric thin films by introducing an appropriate concentration of inorganic fillers leads to a smart design of scaled multifunctional devices.

12.
J Prosthodont ; 30(8): 656-664, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34036676

RESUMO

PURPOSE: This systematic review and meta-analysis of in vitro studies compared the prepolymerized acrylic resin used for CAD/CAM complete denture manufacturing versus the heat-polymerized acrylic resin for conventional complete dentures in terms of surface roughness, wettability, hardness and flexural strength. MATERIALS AND METHODS: An electronic search was performed in the PubMed, Embase, LILACS and Web of Science databases, without language or date restrictions. Gray literature and manual search tools were also used. The systematic review was carried out by two researchers independently, following the inclusion criteria: in vitro studies testing the CAD/CAM acrylic resin with a control group of heat-polymerized acrylic resin which compared at least one of the four material properties above. The meta-analysis was performed separately for each property, using a random effect model. RESULTS: Of the 914 studies found by means of search strategies, 698 were selected for the systematic review. After applying the eligibility criteria, only 17 articles were selected for the qualitative analysis in the systematic review; among these, 14 were included in the quantitative meta-analysis. The CAD/CAM prepolymerized acrylic resin in blocks had similar properties when compared to heat-polymerized acrylic resin in almost all outcome measures, with the exception of a statistically significant reduction in surface roughness. CONCLUSIONS: Based on the findings of this systematic review and meta-analysis, equally satisfactory results can be expected from dental prosthesis manufactured by the CAD/CAM system when compared to conventional ones, with the additional potential of reducing the pigmentation and attached microorganisms due to the reduced surface roughness of the prepolymerized resin.


Assuntos
Resinas Acrílicas , Desenho Assistido por Computador , Prótese Total , Teste de Materiais , Polimerização , Propriedades de Superfície
13.
BMC Musculoskelet Disord ; 22(1): 358, 2021 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-33863329

RESUMO

BACKGROUND: There is little evidence on techniques for management of peri-prosthetic infection (PJI) in the context of severe proximal femoral bone loss. Custom-made articulating spacers (CUMARS) utilising cemented femoral stems as spacers was described providing better bone support and longer survival compared to conventional articulating spacers. We retrospectively report our experience managing PJI by adaptation of this technique using long cemented femoral stems where bone loss precludes use of standard stems. METHODS: Patients undergoing 1st stage revision for infected primary and revision THA using a cemented long stem (> 205 mm) and standard all-polyethylene acetabulum between 2011 and 2018 were identified. After excluding other causes of revision (fractures or aseptic loosening), Twenty-one patients remained out of total 721 revisions. Medical records were assessed for demographics, initial microbiological and operative treatment, complications, eradication of infection and subsequent operations. 2nd stage revision was undertaken in the presence of pain or subsidence. RESULTS: Twenty-one patients underwent 1st stage revision with a cemented long femoral stem. Mean follow up was 3.9 years (range 1.7-7.2). Infection was eradicated in 15 (71.4%) patients. Two patients (9.5%) required repeat 1st stage and subsequently cleared their infection. Three patients (14.3%) had chronic infection and are on long term suppressive antibiotics. One patient (4.8%) was lost to follow up before 2 years. Complications occurred in seven patients (33%) during or after 1st stage revision. Where infection was cleared, 2nd stage revision was undertaken in 12 patients (76.5%) at average of 9 months post 1st stage. Five (23.8%) CUMARS constructs remained in-situ at an average of 3.8 years post-op (range 2.6-5.1). CONCLUSIONS: Our technique can be used in the most taxing of reconstructive scenarios allowing mobility, local antibiotic delivery, maintenance of leg length and preserves bone and soft tissue, factors not afforded by alternative spacer options.


Assuntos
Artrite Infecciosa , Artroplastia de Quadril , Prótese de Quadril , Infecções Relacionadas à Prótese , Artroplastia de Quadril/efeitos adversos , Cimentos Ósseos/efeitos adversos , Prótese de Quadril/efeitos adversos , Humanos , Desenho de Prótese , Falha de Prótese , Infecções Relacionadas à Prótese/diagnóstico por imagem , Infecções Relacionadas à Prótese/cirurgia , Reoperação , Estudos Retrospectivos , Resultado do Tratamento
14.
Polymers (Basel) ; 12(12)2020 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-33287277

RESUMO

In this study, we report on the use of poly(cyclohexylmethacrylate) (PCHMA) as an alternative to the commonly used poly(methylmethacrylate) (PMMA) for the design of efficient luminescent solar concentrators (LSCs). PCHMA was selected due to its less polar nature with respect to PMMA, a characteristic that was reported to be beneficial in promoting the fluorophore dispersibility in the matrix, thus maximizing the efficiency of LSCs also at high doping. In this sense, LSC thin films based on PCHMA and containing different contents of Lumogen F Red 305 (LR, 0.2-1.8 wt%) demonstrated optical efficiencies (ηopt) comprising between 9.5% and 10.0%, i.e., about 0.5-1% higher than those collected from the LR/PMMA systems. The higher LR/polymer interactions occurred using the PCHMA matrix maximized the solar harvesting characteristics of the fluorophore and limited the influence of the adverse dissipative phenomena on the fluorophore quantum efficiency. These effects were also reflected by varying the LSC film thickness and reaching maximum ηopt of about 11.5% in the case of PCHMA films of about 30 µm.

15.
Cureus ; 12(7): e9452, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32864273

RESUMO

The presentation of acute mastoiditis has become erratic over the last decades secondary to the wide use of broad-spectrum antibiotics. While establishing this diagnosis requires a high degree of suspicion, imaging is necessary because of the concurrence of intracranial complications. Therefore, the diagnostic hypothesis of acute mastoiditis must prompt the evaluation for the presence of intracranial complications, such as intracranial epidural abscess (ICEA) formation. Hereby, we present a case of a 33-year-old woman presented to the ED of our institution with symptoms consistent with acute mastoiditis. She had a history of a methyl-methacrylate (MMA) cranioplasty performed 10 years before presentation for debulking of an epidermoid cyst. She was found to have the formation of an ICEA. Development of infection in patients with MMA cranioplasty is seen most commonly within one year of the implantation with the late presentation being a rare occurrence. Treatment in these cases is comprised of antibiotic therapy, but most importantly of the removal of the infected foreign material to prevent further complications from the infection.

16.
Lupus ; 29(10): 1292-1296, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32605524

RESUMO

BACKGROUND: Autoimmune/inflammatory syndrome induced by adjuvants has been associated with different substances used for cosmetic purposes; for example, silicone, methylmethacrylate, autoimmune disorders and cancer. DISCUSSION: A 40-year-old man with a prior history of methylmethacrylate injection in the buttocks for aesthetic purposes 8 years ago, presented with deep venous thrombosis in the left leg 6 months ago, accompanied with inflammation, hardening, changes in colour, ulceration in the buttocks, arthritis, myalgias and fever. Weak and moderate lupus anticoagulant and low levels of anticardiolipin antibodies were present. Thoracoabdominal tomography showed hepatosplenomegaly and a pulmonary nodule, the biopsy of which showed chronic granulomatous inflammation. After a month, a new chest tomography showed multiple nodular pulmonary lesions. The new pulmonary biopsy showed a diffuse large B-cell non-Hodgkin's lymphoma which was treated with cyclophosphamide, doxorubicin, vincristine, prednisone, and rituximab for four cycles, with good response of the autoimmune/inflammatory syndrome, but partial response of the diffuse large B-cell non-Hodgkin's lymphoma. CONCLUSION: We describe the first case of seronegative antiphospholipid syndrome and lymphoma associated with methylmethacrylate in a patient with autoimmune/inflammatory syndrome.


Assuntos
Doenças Autoimunes/induzido quimicamente , Preenchedores Dérmicos/efeitos adversos , Metilmetacrilato/efeitos adversos , Adulto , Síndrome Antifosfolipídica/complicações , Doenças Autoimunes/diagnóstico por imagem , Humanos , Linfoma Difuso de Grandes Células B/complicações , Linfoma Difuso de Grandes Células B/diagnóstico por imagem , Linfoma Difuso de Grandes Células B/patologia , Masculino , Síndrome
17.
J Prosthodont ; 29(5): 422-428, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32233047

RESUMO

PURPOSE: To evaluate and compare the surface properties (roughness and hardness) of poly(methylmethacrylate) denture base material modified with zirconium dioxide (ZNPs), silicon dioxide (SNPs), and diamond (DNPs) nanoparticles. MATERIALS AND METHODS: Two hundred sixty heat-polymerized acrylic resin disks (15 × 2 mm) were prepared. ZNPs, SNPs, and DNPs were added in concentrations of 0%, 0.5%, 1.0%, 2.5%, and 5.0% by weight of acrylic powder. This yielded a total of 13 groups for each test according to filler type and concentration (n = 10/group). The control group was made of pure acrylic. A mechanical polisher was used to standardize specimens' surfaces before testing. A profilometer and Vickers hardness indenter were used to test the surface roughness and hardness, respectively. ANOVA and Tukey post hoc tests were used for data analysis (α = 0.05). RESULTS: In comparison to control, results showed a nonsignificant increase in surface roughness (Ra ) of acrylic material after the addition of 0.5% nanoparticles (ZNPs p = 0.168, SNPs p = 0.166, and DNPs p = 0.177), while a significant increase was seen with all other concentrations (p ˂ 0.05). Ra values of ZNP and DNP groups were significantly higher than those of the SNPs group (p < 0.001). The addition of any of the fillers to acrylic denture base materials significantly increased the hardness (p ˂ 0.05), with ZNPs and DNPs having values lower than those of the SNPs group (p < 0.001). CONCLUSIONS: Although nanofiller addition increased the hardness of denture base material, Ra was adversely affected when the concentration exceeded 0.5%. Therefore, 0.5% is suggested to be the most appropriate ratio to improve hardness with acceptable Ra .


Assuntos
Nanopartículas , Polimetil Metacrilato , Bases de Dentadura , Dureza , Teste de Materiais , Propriedades de Superfície
18.
Artigo em Inglês | MEDLINE | ID: mdl-32266236

RESUMO

Industrial biotechnology can lead to new routes and potentially to more sustainable production of numerous chemicals. We review the potential of biobased routes from sugars to the large volume commodity, methacrylic acid, involving fermentation based bioprocesses. We cover the key progress over the past decade on direct and indirect fermentation based routes to methacrylic acid including both academic as well as patent literature. Finally, we take a critical look at the potential of biobased routes to methacrylic acid in comparison with both incumbent as well as newer greener petrochemical based processes.

19.
J Funct Biomater ; 11(1)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32053986

RESUMO

The insufficient radiopacity of dental adhesives applied under composite restorations makes the radiographic diagnosis of recurrent caries challenging. Consequently, the misdiagnosis may lead to unnecessary replacement of restorations. The aims of this study were to formulate experimental dental adhesives containing cerium dioxide (CeO2) and investigate the effects of different loadings of CeO2 on their radiopacity and degree of conversion for the first time. CeO2 was characterized by X-ray diffraction analysis, Fourier transforms infrared spectroscopy, and laser diffraction for particle size analysis. Experimental dental adhesives were formulated with CeO2 as the inorganic filler with loadings ranging from 0.36 to 5.76 vol.%. The unfilled adhesive was used as a control. The studied adhesives were evaluated for dispersion of CeO2 in the polymerized samples, degree of conversion, and radiopacity. CeO2 presented a monoclinic crystalline phase, peaks related to Ce-O bonding, and an average particle size of around 16 µm. CeO2 was dispersed in the adhesive, and the addition of these particles increased the adhesives' radiopacity (p < 0.05). There was a significant decrease in the degree of conversion with CeO2 loadings higher than 1.44 vol.%. However, all materials showed a similar degree of conversion in comparison to commercially available adhesives. CeO2 particles were investigated for the first time as a promising compound to improve the radiopacity of the dental adhesives.

20.
Carbohydr Polym ; 230: 115608, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31887870

RESUMO

The treatment of vulvovaginal candidiasis (VVC) is based on oral and vaginal formulations which show limited effectiveness. In this study, amphotericin B-loaded Eudragit RL100 nanoparticles coated with hyaluronic acid (AMP EUD nanoparticles/HA) were developed to overcome the drawbacks of the conventional formulations. AMP EUD nanoparticles/HA were synthesized by nanoprecipitation, formulated by statistical experimental design, and characterized. AMP release from EUD nanoparticles/HA and its antifungal activity in a murine model of VVC were evaluated. Nanoparticles showed 147.6 ±â€¯16.7 nm of diameter, 0.301 ±â€¯0.09 of polydispersity index, - 29.9 ±â€¯3.76 mV of zeta potential, and 87.27 % of encapsulation efficiency. They released about 81 % of AMP in 96 h; and provided the elimination of 100 % of the vaginal fungal burden in 24 h. It was suggested that the AMP EUD nanoparticles/HA penetrated into the vaginal epithelium via CD44 receptors. These AMP EUD nanoparticles/HA represent a non-conventional vaginal formulation to improve the treatment of VVC.

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