Poly 2-hydroxyethyl Methacrylate Research Articles

Validation of a human saliva model for the determination of leachable monomers and other chemicals from dental materials

This study aimed to prove the validity of a mixture of chemicals, including salts, small organic molecules, mucin, and α-amylase, as saliva surrogate (“artificial saliva”) for assessing leakage of methacrylate monomers and other constituents from dental materials. To achieve this, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of 2-hydroxyethyl methacrylate (HEMA), triethylene glycol dimethacrylate (TEGDMA), diurethane dimethacrylate (UDMA), bisphenol A glycerolate dimethacrylate (BisGMA), diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), bisphenol A (BPA), and five homologues of ethoxylated bisphenol A dimethacrylate (BisEMA EO2–6) in unstimulated and artificial saliva, and compared their concentrations in the two saliva media following either spiking with a mixture of the compounds or incubation of test specimens of printed biomaterials. Test specimens were immersed in unstimulated/artificial saliva, incubated at 37 °C for 24 h, and saliva aliquots were extracted with methanol and subsequently analyzed by LC-MS/MS. The method was validated with regard to matrix effects, linearity, selectivity, lower limits of quantification (LLOQ), precision, bias and combined measurement uncertainty (u′). The performance characteristics of the method were comparable for unstimulated and artificial saliva samples. The combined u’ for individual chemicals at a concentration of 10 × LLOQ were within the range of 5.3–14 % for unstimulated saliva and 6.9–16 % for artificial saliva, except for the BisEMA homologues. Combined u’ for the latter were 27–74 % in unstimulated saliva, and 27–79 % in artificial saliva. There was no detectable release of BPA from the test specimens, and the TPO concentrations were mainly below the LLOQ. TEGDMA and UDMA were detected in the highest quantities, and at comparable concentrations in the unstimulated and artificial saliva. For all BisEMA homologues, the release was higher in unstimulated saliva than in artificial saliva. The study showed that the artificial saliva model can be a suitable replacement for native saliva, but might underestimate leakage of more lipophilic methacrylates.

In Situ Real-Time Atomic Force Microscopy Observations of Chain Mobility at Polymer/Water Interfaces of Poly(methyl methacrylate), Poly(2-hydroxyethyl methacrylate), and Poly(2-methoxyethyl methacrylate) Films in Water.

Polymer materials are widely used in water or in contact with an aqueous environment. However, evaluating the chain mobility, a crucial parameter, at a polymer-water interface is challenging. In this study, we, for the first time, observed poly(methyl methacrylate) (PMMA), poly(2-hydroxyethyl methacrylate) (PHEMA), and poly(2-methoxyethyl methacrylate) (PMEMA) film surfaces in water via in situ real-time atomic force microscopy (AFM) in tapping mode and quantified the chain mobility. The average displacement between adjacent images (nm/8.75 min) was evaluated using particle image velocimetry. The displacement of PMMA, which has a high bulk glass-transition temperature (Tg) (108 °C) and exhibits limited water absorption, was low both in air (0.54 nm/8.75 min) and water (0.86), while PHEMA, which has a high bulk Tg (99 °C) and exhibits high water absorption, exhibited low mobility in air (0.40) but two orders of magnitude higher mobility in water (60). PMEMA, which has a low bulk Tg (14 °C) and exhibits limited water absorption, already started to move in air (4.5), and its mobility moderately increased in water (20). These behaviors were reasonable, considering the bulk Tg and water absorption characteristics of the polymers. Further, the chain mobility in water was compared with that of dried samples at high temperatures in air. The mobility of PMMA, PHEMA, and PMEMA in water corresponded to that of the dried samples observed in air below the surface Tg (97 °C) for PMMA, at ∼125 °C for PHEMA, and at ∼35 °C for PMEMA. In situ real-time AFM analysis of polymer materials in water is an effective method for evaluating the chain mobility at the polymer/water interface.

Design of new zwitterionic microparticles with intrinsic antibacterial activity

AbstractThe crosslinked porous microparticles based on glycidyl methacrylate, N‐vinylimidazole, and triethylene glycol dimethacrylate (molar ratio between monomers 40:30:30) obtained in the presence of three porogenic agents (toluene, n‐butyl acetate, and toluene:n‐butyl acetate mixture, 1:1, v/v) are used as precursors in the polymer analogous reactions with some betainizing agents (sodium monochloroacetate, acrylic acid, methacrylic acid and 1,3–propane sultone) in order to introduce the carboxybetaine/sulfobetaine groups to the tertiary nitrogen atom from the imidazole ring. ATR–FTIR spectroscopy is used to highlight the presence of carboxybetaine/sulfobetaine groups on the structure of the microparticles, but also to calculate the degree of betainization (55.91%–90.2%) The zwitterionic microparticles are characterized by scanning electron and atomic force microscopies, equilibrium swelling ratio as a function of pH values, swelling kinetics, ion exchange capacities and particle size distribution. Also, the parameters of porous structure (pore diameter, pore volume, porosity, and specific surface area) are determined by mercury porosimetry. The antibacterial properties of Gram‐positive (Enterococcus faecalis and Staphylococcus aureus) and Gram‐negative (Escherichia coli and Klebsiella pneumoniae) bacteria are evaluated. It is found that the zwitterionic structures containing a shorter length alkyl chain between ionic groups exhibit excellent antibacterial activity of about 80%–92%.

Preparation of poly(methyl methacrylate)-zinc oxide hybrid nanoparticles via miniemulsion polymerization

The encapsulation of zinc oxide (ZnO) nanoparticles with poly(methyl methacrylate) in the presence of triethylene glycol dimethacrylate (TEGDMA) as a crosslinking agent was synthesized by the miniemulsion polymerization technique. The ZnO as a catalyze was varied from 1 wt% - 7 wt%. Several techniques were used to analyze the PMMA/TEGDMA/ZnO hybrid. The morphology and particle size distribution of the PMMA hybrid was observed using a field emission scanning electron microscope (FE-SEM). The diameter of the PMMA/TEGDMA/ZnO hybrid was in the range of 57 nm to 115 nm. The morphology of the PMMA/ZnO hybrids was sphere-shaped with a narrow particle size distribution and no agglomeration of the hybrids occurred. The encapsulation and crystalline structure of the PMMA ZnO hybrid were determined using a high-resolution transmission electron microscope (HR-TEM). The HR-TEM image demonstrated that the ZnO was encapsulated in the PMMA hybrid. In addition, the high magnification of the TEM image demonstrated the lattice spacing of ZnO and the diffraction mode image presented the crystalline structure of ZnO. Therefore, the photocatalytic properties of the PMMA/ZnO hybrid were examined via the degradation of methylene blue (MB) solution under dark and UV-A irradiation. It was found that the photocatalytic activities of the PMMA/ZnO hybrid increased when the ZnO content increased up to 7 wt%. The maximum MB degradation for PMMA/TEGDMA/ZnO 7 wt% and PMMA/ZnO 7 wt% were 80.1 % and 77.6 %, respectively. Thus, the photocatalytic efficiency of the PMMA/ZnO increased in the presence of TEGDMA as a crosslinking agent.

Well‐defined poly(methyl methacrylate) hybrid titanium dioxide via miniemulsion polymerization: Design and evaluation of methylene blue dye degradation and antibacterial

AbstractA poly(methyl methacrylate)/TiO2 (PMMA/TiO2) hybrid was synthesized in the presence of triethylene glycol dimethacrylate as a crosslinking agent. Different types of TiO2 rutile, anatase, and P25 were employed in this study, and the morphology, crystalline structure, particle size, thermal properties, photocatalytic activity, and antibacterial activity were investigated. The results show that the particle size of the PMMA/TiO2 hybrids was in the range of 73.3 nm to 210.0 nm. The morphology of the PMMA/TiO2 hybrid was spherical with a narrow particle size distribution. The thermal properties of the PMMA/TiO2 hybrid were analyzed using differential scanning calorimetry. The glass transition temperature of the PMMA/TiO2 was higher than that of pristine PMMA. The photocatalytic properties were investigated by monitoring the color changes of methylene blue (MB). It was found that the MB degradation for the PMMA hybrid anatase TiO2 (PMMA/aTiO2) reached 80%, which was similar to that for the PMMA hybrid P25TiO2 at 83% in 60 min. The minimum inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of the PMMA/TiO2 hybrids were estimated. The MIC of PMMA hybrid anatase TiO2 was 9.65 mg mL−1 (P. aeruginosa) and 19.33 mg mL−1 (S. aureus) which can inhibit the bacteria. The MBC results of the PMMA/aTiO2 were 19.33 mg mL−1 for both P. aeruginosa and S. aureus.Highlights TiO2 nanoparticle encapsulation with poly(methyl methacrylate) via mini‐emulsion polymerization. Encapsulated particles exhibit excellent photocatalytic properties. Triethylene glycol dimethacrylate (TEGDMA) crosslinking ensures stability, enhances photocatalytic property. The influence of TEGDMA on the hybrid was discussed.

Argyrodite-Li6PS5Cl/Polymer-based Highly Conductive Composite Electrolyte for All-Solid-State Batteries.

Solid-state batteries (SSBs) that incorporate the argyrodite-Li6PS5Cl (LPSCl) electrolyte hold potential as substitutes for conventional lithium-ion batteries (LIBs). However, the mismatched interface between the LPSCl electrolyte and electrodes leads to increased interfacial resistance and the rapid growth of lithium (Li) dendrites. These factors significantly impede the feasibility of their widespread industrial application. In this study, we developed a composite electrolyte of the LPSCl/polymer to enhance the contact between the electrolyte and electrodes and suppress dendrite formation at the grain boundary of the LPSCl ceramic. The monomer, triethylene glycol dimethacrylate (TEGDMA), is utilized for in situ polymerization through thermal curing to create the argyrodite LPSCl/polymer composite electrolyte. Additionally, the ball-milling technique was employed to modify the morphology and particle size of the LPSCl ceramic. The ball-milled LPSCl/polymer composite electrolyte demonstrates slightly higher ionic conductivity (ca. 2.21 × 10-4 S/cm) compared to the as-received LPSCl/polymer composite electrolyte (ca. 1.65 × 10-4 S/cm) at 25 °C. Furthermore, both composite electrolytes exhibit excellent compatibility with Li-metal and display cycling stability for up to 1000 h (375 cycles), whereas the as-received LPSCl and ball-milled LPSCl electrolytes maintain stability for up to 600 h (225 cycles) at a current density of 0.4 mA/cm2. The SSB with the ball-milled LPSCl/polymer composite electrolyte delivers high specific discharge capacity (138 mA h/g), Coulombic efficiency (99.97%), and better capacity retention at 0.1C, utilizing the battery configuration of coated NMC811//electrolyte//Li-Indium (In) at 25 °C.

Reduced graphene oxide incorporated triple network hydrogels for enhancing solar desalination performance

Solar-driven hydrogel evaporator has attracted great attention in desalination recently. However, it remains a challenge to develop high performance hydrogel evaporators with outstanding mechanical property, high evaporation efficiency and excellent durability. In this study, 2-hydroxyethyl methacrylate (HEMA), sodium alginate (SA) and graphene oxide (GO) were employed for fabricating triple network hydrogels, which were used for solar desalination. The hydrogels were composed of poly(2-hydroxyethyl methacrylate) (PHEMA), SA and reduced graphene oxide (rGO) networks. The rGO network could well wrap on PHEMA and SA networks, forming an interpenetrated structure with good mechanical property. After being reduced of GO, the PHEMA/SA/rGO hydrogels showed excellent solar absorption and evaporation performance due to better photothermal effect of rGO than that of GO. Due to outstanding light absorption characteristic, the as-prepared hydrogels showed maximal energy efficiency of 95.59 % under one sun illumination. The hydrogel evaporator also exhibited excellent reusability for effective desalination. This stable performance may be attributed to its enough water molecules embedded in the crosslinked network, which prevented salt supersaturation. The outdoor solar desalination experiment suggested that concentration of four typical ions (Na+, Mg2+, K+, Ca2+) in purified water fully met drinking water standards. This work may provide a new idea for design and creation of hydrogel evaporator with high mechanical strength and solar energy conversion efficiency for solar steam generation.

Improved triamcinolone acetonide-eluting contact lenses based on cyclodextrins and high hydrostatic pressure assisted complexation

Contact lenses (CLs) constitute an advantageous platform for the topical release of corticosteroids due to their prolonged contact with the eye. However, the lipophilic nature of corticosteroids hampers CLs' ability to release therapeutic amounts. Two approaches to improve loading and release of triamcinolone acetonide (TA) from poly(2-hydroxyethyl methacrylate)-based hydrogels were investigated: adding 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) to the monomers solution before polymerization (HEMA/i-CD) and an hydrogels' post-treatment with HP-β-CD (HEMA/p-CD). The effect of HP-β-CD and sterilization by high hydrostatic pressure (HHP) on the hydrogel properties (water content, oxygen and ion permeability, roughness, transmittance, and stiffness) was evaluated. The HEMA/i-CD hydrogels had stronger affinity for TA, sustaining its release for one day. HHP sterilization promoted the formation of cyclodextrin-TA complexes within the hydrogels, improving their drug-loading capacity »60 %. Cytotoxicity and irritability tests confirmed the safety of the therapeutic CLs. TA released from the hydrogels permeated through ocular tissues ex vivo and showed anti-inflammatory activity. Finally, a previously validated mathematical model was used to estimate the ability of the TA-loaded CLs to deliver therapeutic drug concentrations to the posterior part of the eye. Overall, HP-β-CD-containing CLs are promising candidates for the topical ocular application of TA as an alternative delivery system to intraocular injections.

Effect of Silicon Carbide Fiber Length on the Flexural Strength and Flexural Modulus of Short Silicon Carbide Fiber-Reinforced Resin.

Silicon carbide fibers have superior flexural properties and chemical stability compared to glass fibers. We investigated the flexural strength and modulus of an experimental, short silicon carbide fiber-reinforced resin. Short silicon carbide fibers with lengths of ~0.5, 1, 2, and 3 mm were prepared and silanized. Urethane dimethacrylate and triethylene glycol dimethacrylate were mixed at a 70:30 wt% ratio and used as the matrix resins. Each length of short silicon carbide fibers and the matrix resin were combined using a mixing machine and then used for specimen preparation. The three-point bending test conditions were in accordance with ISO 4049:2009. The fracture surfaces of the specimens after the three-point bending test were observed using secondary electron images. The data were statistically analyzed with a one-way analysis of variance and Tukey's HSD test (α = 0.05). The flexural strength and modulus of the specimens containing 2 mm or 3 mm silicon carbide fibers were significantly higher than the other specimens. The river pattern was observed more clearly in specimens containing shorter silicon carbide fibers, although this pattern was observed in all specimens.

Block-copolymer-armed star polyampholyte with pH- and temperature-tunable supramolecular nanostructures for enhanced dye adsorption

The present investigation involves the synthesis of a series of block-copolymer-armed polyampholyte star polymers with sensitivity to changes in pH and temperature. The polymers are prepared using poly(2-hydroxyethyl methacrylate) core, while the arms are composed of a block copolymers consisting of acrylic acid and 2-(dimethylamino)ethyl methacrylate. The synthesis process involves a three-stage polymerization procedure utilizing reversible addition fragmentation chain transfer. The synthesized structures undergo characterization, and their self-assembly behavior is examined in relation to the adsorption of methylene blue, methyl orange, and the concurrent adsorption of both dyes. The development of spherical electrostatic complexes with varying diameters are seen as a consequence of pH variation. The present study investigates the impact of various parameters, including time, block location in the arms, pH, molecular weight, self-assembly effects, dye concentration, and temperature, on the process of adsorption. The study elucidates the adsorption phenomenon by examining its kinetics, thermodynamics, and adsorption isotherms. The findings of the study reveal that the greatest percentages of methylene blue adsorption are seen under alkaline pH conditions, whereas the most adsorption of methyl orange occurres under acidic pH conditions. The adsorption process by star-block polymers may be characterized as a spontaneous and endothermic mechanism, including heterojunction and multilayer adsorption. The polymers show promise for water purification applications due to their ability to simultaneously adsorb two dyes and their sensitivity to temperature and pH.

Revolutionizing contact lens manufacturing: exploring cutting-edge techniques and innovations for enhanced vision and comfort

Abstract This review paper delves into the advancements and innovations revolutionizing contact lens (CL) manufacturing, focusing on techniques and technologies aimed at improving vision quality and wearer comfort. The article begins by tracing the evolution of CL fabrication techniques, paying homage to Leonardo da Vinci’s early contributions. It then discusses traditional methods such as lathe-cutting, spincasting, molded lens fabrication, and the recent advent of 3D printing in CL production. The review further explores advanced CL designs, including spherical, aspheric, toric, and bifocal/multifocal CLs, highlighting their specific applications and benefits. Material innovations in lens manufacturing are examined, with an emphasis on silicone hydrogel CL, hybrid lenses combining different materials, and the development of biocompatible and gas-permeable (GP) materials. Evaluation of optical design efficiency is another crucial aspect covered in this paper, encompassing visual acuity, contrast sensitivity, through-focus curves, reading performance, peripheral refraction, and patient-reported outcomes for quality of vision. Additionally, the role of nanotechnology and surface modifications in enhancing lens properties is explored, along with advances in lens coating and surface treatments, including antimicrobial and UV protection coatings. Nanocomposites of polymethyl methacrylate (PMMA) and TiO2 showed refractive indices between 1.52 and 1.59, while combining TiO2 NPs with poly(2-hydroxyethyl methacrylate) (PHEMA) yielded values ranging from 1.47 to 1.53. PGMA-TiO2 nanocomposites exhibited refractive indices between 1.47 and 1.50. Furthermore, nanocomposites of PVP-PVA-Ag with silver (Ag) NPs achieved higher refractive indices within the range of 1.45 to 1.49. This article concludes by discussing the challenges and future directions in CL manufacturing, focusing on addressing lens discomfort, improving oxygen permeability and moisture retention, and enhancing manufacturing efficiency and scalability. Overall, this review offers valuable insights into the cutting-edge techniques and innovations transforming CL production and paving the way for improved vision correction and wearer satisfaction.

Chemical Modification of Dental Dimethacrylate Copolymer with Tetramethylxylylene Diisocyanate-Based Quaternary Ammonium Urethane-Dimethacrylates-Physicochemical, Mechanical, and Antibacterial Properties.

In this study, two novel quaternary ammonium urethane-dimethacrylates (QAUDMAs) were designed for potential use as comonomers in antibacterial dental composite restorative materials. QAUDMAs were synthesized via the reaction of 1,3-bis(1-isocyanato-1-methylethyl)benzene with 2-(methacryloyloxy)ethyl-2-decylhydroxyethylmethylammonium bromide (QA10+TMXDI) and 2-(methacryloyloxy)ethyl-2-dodecylhydroxyethylmethylammonium bromide (QA12+TMXDI). Their compositions with common dental dimethacrylates comprising QAUDMA 20 wt.%, urethane-dimethacrylate monomer (UDMA) 20 wt.%, bisphenol A glycerolate dimethacrylate (Bis-GMA) 40 wt.%, and triethylene glycol dimethacrylate (TEGDMA) 20 wt.%, were photocured. The achieved copolymers were characterized for their physicochemical and mechanical properties, including their degree of conversion (DC), glass transition temperature (Tg), polymerization shrinkage (S), water contact angle (WCA), flexural modulus (E), flexural strength (FS), hardness (HB), water sorption (WS), and water leachability (WL). The antibacterial activity of the copolymers was characterized by the minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) against Staphylococcus aureus and Escherichia coli. The achieved results were compared to the properties of a typical dental copolymer comprising UDMA 40 wt.%, Bis-GMA 40 wt.%, and TEGDMA 20 wt.%. The introduction of QAUDMAs did not deteriorate physicochemical and mechanical properties. The WS and WL increased; however, they were still satisfactory. The copolymer comprising QA10+TMXDI showed a higher antibacterial effect than that comprising QA12+TMXDI and that of the reference copolymer.

Effect of silanization of poly (urea-formaldehyde) microcapsules on the flexural strength and self-healing efficiency of an experimental self-healing dental resin composite (An in-vitro study)

ObjectivesThis study investigated the impact of using γ-methacryloxypropyl trimethoxy silane (MPS) for surface silanization of poly (urea-formaldehyde) (PUF) microcapsules which enclose a healing liquid of “triethylene glycol dimethacrylate (TEGDMA) and N,N dihydroxyethyl-p-toluidine (DHEPT)” on some mechanical properties of an experimental dental composite as well as its self-healing efficiency. MethodsSynthesis of PUF microcapsules was done via in situ polymerization, followed by silanization with MPS silane. Silanized and non-silanized microcapsules were incorporated into a composite containing 30% polymer matrix and 70% fillers at different weight percentages (0%, 5%, 7.5% and 10%). The composite strength and elastic modulus were evaluated by Flexural testing. Fracture toughness KIc and self-healing efficiency were assessed by utilizing the “single edge notched beam” method. ResultsFlexural strength of all groups containing silanized microcapsules was non-significantly different from control group without microcapsules. However, in contrast to control group, all groups containing non-silanized microcapsules displayed considerably decreased flexural strength. Adding silanized and non-silanized microcapsules didn't show a significant change in the KIc-virgin. The silanized microcapsules' groups achieved a self-healing efficiency of about 49–77% recovery in KIc-virgin compared to 38–69% for their non-silanized counterparts. SignificanceIn order to increase the interfacial adhesion with the polymer matrix, improve the mechanical properties, and increase the efficiency of self-healing of dental resin composite, PUF microcapsules were silanized for the first time in the dental field using MPS silane. This innovative silanized microcapsule-containing self-healing composite may hold promise for repairing the damage caused by restorative cracks and extending their service life.

Monomer release, cell adhesion, and cell viability of indirect restorative materials manufactured with additive, subtractive, and conventional methods.

The aim of this study was to measure residual monomer, cell adhesion, and cell viability of 3-dimensional printable permanent resin (PR), hybrid ceramic block (HCB), and indirect composite (IC) produced with additive, subtractive, and conventional techniques. Five 8 × 8 × 2 mm3 samples of each material were prepared for each experiment. In a 24-h period, monomer release was analyzed with high-performance liquid chromatography, and cell viability and adhesion were evaluated with the water-soluble tetrazolium salt test. Data were analyzed with IBM SPSS Statistics 26.0 statistical software, and results were regarded as significant at α = 0.05. Monomer release (triethylene glycol dimethacrylate, urethane dimethacrylate, and Bisphenol A glycerolate dimethacrylate) was significantly higher in the IC group. Mean cell viability was significantly lower in the HCB group than in the IC group. All monomers in the tested materials were released at rates that were below clinical significance. Cell adhesion rates in the groups were similar. Cytotoxic response was classified as minor in the HCB and PR groups and non-cytotoxic in the IC group.

Physical and mechanical characterizations of experimental pit and fissure sealants based on bioactive glasses.

Fissure sealants commonly exhibit weak mechanical and physical properties, potentially compromising their effectiveness in preventing dental caries. Therefore, this laboratory study aimed to synthesize and characterize experimental pit and fissure sealants in comparison with a commercially available sealant. Three different formulations of experimental pit and fissure sealing materials were synthesized using a blend of bisphenol A-glycidyl methacrylate (Bis-GMA) and triethylene glycol dimethacrylate (TEGDMA) monomers. The resin composition encompassed 70 wt.%, with 30 wt.% fillers comprising 10 wt.% silica in each composition, while 20 wt.% bioactive glasses. Specifically, group G1 employed Biomin F powder, group G2 utilized Biomin C powder, and group G3 incorporated S53P4 powder. The control group (GC) was a commercially available pit and fissure sealant (Seal-Rite). Ten disk-shaped specimens from each study group were fabricated (n = 10/group). The surface roughness, water contact angle, nanohardness (nH), elastic modulus (EM), water solubility and sorption were statistically evaluated using a one-way analysis of variance (p < 0.05). The surface roughness of the G1 & G2 groups and the water contact angle of G1, G2 & G3 groups were significantly lower compared to the control group (p < 0.05). However, nH, EM, water solubility, and sorption were notably higher in the control group compared to the experimental groups, except G1, which exhibited no significant difference from the control group (p > 0.05). The inclusion of micron-sized Biomin F powder in the experimental Bis-GMA/TEGDMA resin formulation demonstrated advantageous effects in reducing surface roughness and forming a lower contact angle without compromising the mechanical attributes.

Residual Monomer Release after the Polymerization of Different-Colored Flowable Compomer.

Compomers are restorative materials commonly used in pediatric dentistry. It is important to investigate the monomer release of materials used especially in pediatric patients. The aim of this study was to evaluate the residual monomer released from different-colored flowable compomers at five polymerization times. Three experimental groups were formed: Group 1: pink flowable compomer (Twinky Star, VOCO, Germany), Group 2: blue flowable compomer (Twinky Star, VOCO), Group 3: white flowable compomer, A2 color of Dyract XP (Dentslpy DeTrey, Konstanz, Germany). For each group, samples were prepared using standard cylindrical Teflon molds (n = 10), and the compomers were cured using a light-emitting diode (LED) source in accordance with the manufacturer's recommendations. During each time period, the number of residual monomers: bisphenol-A glycidyl methacrylate (bis-GMA), urethane dimethacrylate (UDMA), hydroxyethyl methacrylate (HEMA), and triethylene glycol dimethacrylate (TEGDMA) were determined with high-performance liquid chromatography (HPLC). All data were analyzed statistically. In all groups, the amount of residual monomers increased after 1-h release periods (P < 0.05). For 2 weeks, the total residual monomers released were determined at most in Group 3 and at least in Group 1. However, there was no significant difference between the groups in terms of released amounts of monomers (P > 0.05). According to the study, when the total amount of residual monomer released from all groups was compared, no difference was found and it was observed that none of them exceeded the toxic dose. Flowable colored compomers can be used as safely as white compomers in pediatric dentistry.

Block copolymer synthesis in ionic liquid via polymerisation-induced self-assembly: a convenient route to gel electrolytes.

We report for the first time a reversible addition-fragmentation chain transfer polymerisation-induced self-assembly (RAFT-PISA) formulation in ionic liquid (IL) that yields worm gels. A series of poly(2-hydroxyethyl methacrylate)-b-poly(benzyl methacrylate) (PHEMA-b-PBzMA) block copolymer nanoparticles were synthesised via RAFT dispersion polymerisation of benzyl methacrylate in the hydrophilic IL 1-ethyl-3-methyl imidazolium dicyanamide, [EMIM][DCA]. This RAFT-PISA formulation can be controlled to afford spherical, worm-like and vesicular nano-objects, with free-standing gels being obtained over a broad range of PBzMA core-forming degrees of polymerisation (DPs). High monomer conversions (≥96%) were obtained within 2 hours for all PISA syntheses as determined by 1H NMR spectroscopy, and good control over molar mass was confirmed by gel permeation chromatography (GPC). Nanoparticle morphologies were identified using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM), and further detailed characterisation was conducted to monitor rheological, electrochemical and thermal characteristics of the nanoparticle dispersions to assess their potential in future electronic applications. Most importantly, this new PISA formulation in IL facilitates the in situ formation of worm ionogel electrolyte materials at copolymer concentrations >4% w/w via efficient and convenient synthesis routes without the need for organic co-solvents or post-polymerisation processing/purification. Moreover, we demonstrate that the worm ionogels developed in this work exhibit comparable electrochemical properties and thermal stability to that of the IL alone, showcasing their potential as gel electrolytes.

Comparison study of surface-initiated hydrogel coatings with distinct side-chains for improving biocompatibility of polymeric heart valves.

Polymeric heart valves (PHVs) present a promising alternative for treating valvular heart diseases with satisfactory hydrodynamics and durability against structural degeneration. However, the cascaded coagulation, inflammatory responses, and calcification in the dynamic blood environment pose significant challenges to the surface design of current PHVs. In this study, we employed a surface-initiated polymerization method to modify polystyrene-block-isobutylene-block-styrene (SIBS) by creating three hydrogel coatings: poly(2-methacryloyloxy ethyl phosphorylcholine) (pMPC), poly(2-acrylamido-2-methylpropanesulfonic acid) (pAMPS), and poly(2-hydroxyethyl methacrylate) (pHEMA). These hydrogel coatings dramatically promoted SIBS's hydrophilicity and blood compatibility at the initial state. Notably, the pMPC and pAMPS coatings maintained a considerable platelet resistance performance after 12 h of sonication and 10 000 cycles of stretching and bending. However, the sonication process induced visible damage to the pHEMA coating and attenuated the anti-coagulation property. Furthermore, the in vivo subcutaneous implantation studies demonstrated that the amphiphilic pMPC coating showed superior anti-inflammatory and anti-calcification properties. Considering the remarkable stability and optimal biocompatibility, the amphiphilic pMPC coating constructed by surface-initiated polymerization holds promising potential for modifying PHVs.

Physicochemical properties of flowable composites using isobornyl methacrylate as diluent monomer.

this study sought to evaluate the effect of isobornyl methacrylate (IBOMA) as a diluent monomer on the physicochemical properties of experimental flowable resin composites. the organic resin matrix of a modal flowable resin composite was formulated with 50 wt.% of bisphenol-A-glycidyl methacrylate (Bis-GMA) and 50 wt.% of a diluent monomer, in which IBOMA was used as a combining or substituent diluent monomer to triethylene glycol dimethacrylate (TEGDMA). The resin matrices were filled with 55 wt.% particles, of which 10 wt.% was 0.05-μm fumed silica, and 45 wt.% was 0.7-μm BaBSiO2 glass. Polymerization shrinkage stress (PSS; n=10), degree of conversion (DC; n=3), maximum rate of polymerization (Rpmax; n=3), film thickness (FT; n=10), sorption (Wsp; n=10), solubility (Wsl; n=10), flexural strength (FS; n=10), flexural modulus (FM; n=10), Knoop microhardness (KH; n=10), and microhardness reduction after chemical softening (HR; n=10) were evaluated. Data were analyzed using one-way ANOVA, followed by Tukey's test (α=0.05; β=0.2). the results showed that the substitution or addition of IBOMA reduced FT (p=0.001), PSS (p=0.013), Rpmax (p=0.001), DC (p=0.001), FM (p=0.006) Wsp (p=0.032), and Wsl (p=0.021). However, when used as a complete substituent, IBOMA demonstrated significantly lower FS (p=0.017) and KH (p=0.008), while TEGDMA demonstrated significantly lower HR (p=0.022). the flowable composite containing IBOMA combined with TEGDMA showed no effect in KH and FS and effectively reduced the PSS, RP, FT, Wsp, and Wsl. However, it showed a reduction in DC, FS, and an increase in HR.

A mini-review on different polymerization protocols for resin-based dental composites

Biocompatibility is one of the major prerequisites for safe clinical application of materials. Dental resin composites may release their components into oral environment, which can lead to adverse reactions. Several studies have identified that many organic components of composites resin, such as bisphenol-A-glycidyl-methacrylate (Bis-GMA), triethylene glycol dimethacrylate (TEGDMA), urethane dimethacrylate (UDMA) and 2-hydroxyethyl methacrylate (HEMA) show a cytotoxic profile. Cytotoxicity is mainly sustained by free monomers released after polymerization process. Direct restorations are polymerized at body temperature by visible light emitting lamps, but the conversion from monomer to polymer after light-curing is never complete. To improve the degree of conversion of resin-based composites, additional curing protocols performed at increased temperatures, such as heat-curing, can be employed. Polymerization reaction plays a key role in the conversion of the free monomers into polymers and resin-based composites with high degree of conversion might show higher biocompatibility. The aim of this mini-review is to report current knowledge about the cytotoxicity of different composite resins, cured in two different ways. Further studies are necessary to better understand the relationship between the cytotoxicity and the degree of polymerization of resin-based composites.