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1.
Braz. j. oral sci ; 20: e219342, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1253927

RESUMO

Aim: The aim of this study was to compare the microtensile bond strength (µTBS) and the characteristics of the adhesive interface of Scotchbond Universal - SU ­ etch-and-rise mode (3M ESPE) and Adper Scotchbond Multi-Purpose - MP (3M ESPE) to dentin over time. Methods: Class I cavity preparations were performed in 60 human molars that were randomly divided according to the dentin bonding system (DBS) used (n=30): (1) Acid conditioning + SU and (2) Acid conditioning + MP. For bonding strength (BS) analysis, 30 teeth (n = 15) were sectioned into sticks and submitted to the microtensile test in a universal testing machine after 24 hours and 12 months. The adhesive interface of the others 30 teeth was analyzed in a confocal microscope after 24 hours and 12 months. The data of µTBS were analyzed by two-way repeated measures ANOVA and Tukey's HSD (α = 0.05). Results: SU presented the lowest DBS compared to MP (p=0.000). Time did not influenced DBS for both adhesive systems (p=0.177). Confocal microscopy analysis showed no cracks between both adhesive systems tested. Conclusion: The results indicate that MP - µTBS showed a better performance compared to SU in total-etch mode


Assuntos
Humanos , Adesivos Dentinários , Microscopia Confocal , Dentina , Metacrilatos
2.
Phys Chem Chem Phys ; 23(34): 19011-19021, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34612439

RESUMO

The design of mixed polymeric micelles by a combination of two or more dissimilar polymers is a potential strategy to achieve multiple stimuli-response for anti-cancer drug delivery. However, their drug loading co-micellization behavior and multiple stimuli-responsive drug release mechanism have been poorly understood at the mesoscopic level, especially in the system that involves reduction-response due to the difficulty of simulation on the cleavage of chemical bonds. In this work, the co-micellization behavior, drug distribution regularities and dual pH/reduction-responsive drug release process of mixed micelles formed by disulfide-linked polycaprolactone-b-polyethylene glycol methyl ether methacrylate (PCL-SS-PPEGMA) and poly(ethylene glycol) methyl ether-b-poly(N,N-diethylamino ethyl methacrylate) (PDEA-PPEGMA) were studied by dissipative particle dynamics (DPD) mesoscopic simulations. A dedicated bond-breaking script was employed to accomplish the disulfide bond-breaking simulations. The results showed that PCL55-SS-PPEGMA10 and PDEA34-PPEGMA11 could be well mixed to form superior DOX-loaded micelles with good drug-loading capacity and drug-controlled release performance. To prepare the DOX-loaded micelles with optimized properties, the simulation results suggested the feed ratio of DOX:PCL55-SS-PPEGMA10:PDEA34-PPEGMA11 set to 3:4:4. Compared with the two single stimuli-response, the dual pH/reduction-response process perfectly combined both pH-response and reduction-response together, providing a higher release rate of DOX. Therefore, this study provides theoretical guidance aimed at the property optimization and micellar structure design of the dual pH/reduction-responsive mixed micelles.


Assuntos
Antibióticos Antineoplásicos/química , Doxorrubicina/química , Metacrilatos/química , Simulação de Dinâmica Molecular , Poliésteres/química , Polietilenoglicóis/química , Portadores de Fármacos/química , Concentração de Íons de Hidrogênio , Micelas , Estrutura Molecular , Oxirredução
3.
J Adhes Dent ; 23(5): 469-475, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34549930

RESUMO

PURPOSE: To evaluate the effect of composite cement components and thermocycling on the bond strength of monolithic lithium-disilicate (LS2) glass-ceramic implant-supported restorations bonded to titanium (Ti) abutments. MATERIALS AND METHODS: Eighty LS2 blocks were treated with five types of composite cement and primer, then divided accordingly into groups: M (Multilink hybrid abutment), G (G-CEM LinkAce), GP (G-CEM LinkAce with G-Multi PRIMER), P (Panavia F2.0), and U (RelyX U200). Half of the 16 specimens from each group were subjected to thermocycling (groups T-M, T-G, T-GP, T-P, and T-U). The tensile bond strength (TBS) of all specimens was measured using a pull-off test. The cross section of the LS2 block from which the Ti abutment was removed was examined for mode of failure. Two-way ANOVA and Tukey's HSD test (significance level = 0.05) were used to determine the effect of composite cement composition and thermocycling on TBS. RESULTS: There was no difference in TBS between the five groups before thermocycling (p = 0.16). However, groups M (p < 0.001) and G (p = 0.014) showed significantly lower TBS than the corresponding thermocycled groups. Groups T-GP, T-P, and T-U did not show significant changes in TBS after thermocycling (p > 0.05). All failures occurred at the interface between the composite cement and Ti abutment and not between the cement and the LS2 block. CONCLUSION: Thermocycling can reduce the bond strength between the composite cements and Ti abutment. The composite cements containing 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) or methacrylate phosphate ester monomers stabilize bonding.


Assuntos
Colagem Dentária , Titânio , Cerâmica , Porcelana Dentária , Análise do Estresse Dentário , Lítio , Teste de Materiais , Metacrilatos , Cimentos de Resina , Propriedades de Superfície , Zircônio
4.
Mater Sci Eng C Mater Biol Appl ; 129: 112367, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34579886

RESUMO

We developed a hemocompatible, bio-inspired, multivalent, polymeric-chelating assembly based on the poly(2-methacryloyloxyethyl phosphorylcholine)-b-poly(serinyl acrylate) (PMPC-b-PserA) zwitterionic diblock copolymer. Functional PMPC-b-PserA was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization to catch and encapsulate free copper ions (Cu2+) in a solution. PMPC with an identical polar group to phospholipids exhibits high hydrophilicity and fouling resistance against non-specific adsorption, and inertness to the metal ions. On the other hand, PserA with pendant groups of amino acids possesses a strong capability to react with Cu2+ by coordination interaction. Therefore, when PMPC-b-PserA was brought into contact with Cu2+, a hydrophobic core with multiple coordination "bridges" between polymers and Cu2+ was formed, leading to self-assembly of core-shell polymer-metal nanoparticles. As a result, free Cu2+ ions can be removed from the solution to prevent damage to cells and tissues. The synthesis and chemical structure of PMPC-b-PserA were characterized, and the formation of self-assembled polymer-Cu2+ nanoparticles and colloidal stability were analyzed. More importantly, the detoxification of PMPC-b-PserA in presence of Cu2+ with fibroblast cells was demonstrated by increased cell viability >80%. In addition, the hemolysis, which occurred due to disruption of RBC membranes by free Cu2+, was effectively suppressed by adding PMPC-b-PserA. The bio-inspired and biocompatible chelating agent of PMPC-b-PserA provides a new treatment approach to encapsulate and detoxify heavy metals in complex media for chelation therapy.


Assuntos
Cobre , Hemólise , Quelantes/farmacologia , Humanos , Metacrilatos , Micelas , Fosforilcolina/farmacologia , Polímeros , Ácidos Polimetacrílicos
5.
Mater Sci Eng C Mater Biol Appl ; 129: 112393, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34579912

RESUMO

Peripheral nerve injury can cause various degrees of damage to the morphological structure and physiological function of the peripheral nerve. At present, compared with "gold standard" autologous nerve transplantation, tissue engineering has certain potential for regeneration and growth; however, achieving oriented guidance is still a challenge. In this study, we used 3D bioprinting to construct a nerve scaffold of RSC96 cells wrapped in sodium alginate/gelatin methacrylate (GelMA)/bacterial nanocellulose (BNC) hydrogel. The 5% sodium alginate+5% GelMA+0.3% BNC group had the thinnest lines among all groups after printing, indicating that the inherent shape of the scaffold could be maintained after adding BNC. Physical and chemical property testing (Fourier transform infrared, rheometer, conductivity, and compression modulus) showed that the 5% alginate+5% GelMA+0.3% BNC group had better mechanical and rheological properties. Live/dead cell staining showed that no mass cell death was observed on days 1, 3, 5, and 7 after printing. In the 5% alginate+5% GelMA group, the cells grew and formed linear connections in the scaffold. This phenomenon was more obvious in the 5% alginate+5% GelMA+0.3% BNC group. In the 5% alginate+5% GelMA+0.3% BNC group, S-100ß immunofluorescence staining and cytoskeleton staining showed oriented growth. Polymerase chain reaction (PCR) array results showed that mRNA levels of related neurofactors ASCL1, POU3F3, NEUROG1, DLL1, NOTCH1 and ERBB2 in the 5%GelMA+0.3%BNC group were higher than those of other groups. Four weeks after implantation in nude mice, RSC96 cells grew and proliferated well, blood vessels grew, and S-100ß immunofluorescence was positive. These results indicate that a 3D-bioprinted sodium alginate/GelMA/BNC composite scaffold can improve cell-oriented growth, adhesion and the expression of related factors. This 3D-bioprinted composite scaffold has good biocompatibility and is expected to become a new type of scaffold material in the field of neural tissue engineering.


Assuntos
Bioimpressão , Gelatina , Alginatos , Animais , Bactérias , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Hidrogéis/farmacologia , Metacrilatos , Camundongos , Camundongos Nus , Proteínas do Tecido Nervoso , Impressão Tridimensional , Engenharia Tecidual , Tecidos Suporte
6.
Phys Rev Lett ; 127(10): 108001, 2021 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-34533362

RESUMO

Limited-valency colloidal particles can self-assemble into polymeric structures analogous to molecules. While their structural equilibrium properties have attracted wide attention, insight into their dynamics has proven challenging. Here, we investigate the polymerization dynamics of semiflexible polymers in 2D by direct observation of assembling divalent particles, bonded by critical Casimir forces. The reversible critical Casimir force creates living polymerization conditions with tunable chain dissociation, association, and bending rigidity. We find that unlike dilute polymers that show exponential size distributions in excellent agreement with Flory theory, concentrated samples exhibit arrest of rotational and translational diffusion due to a continuous isotropic-to-nematic transition in 2D, slowing down the growth kinetics. These effects are circumvented by the addition of higher-valency particles, cross linking the polymers into networks. Our results connecting polymer flexibility, polymer interactions, and the peculiar isotropic-nematic transition in 2D offer insight into the polymerization processes of synthetic two-dimensional polymers and biopolymers at membranes and interfaces.


Assuntos
Coloides/química , Modelos Químicos , Cinética , Metacrilatos/química , Compostos de Organossilício/química , Polimerização , Poliestirenos/química
8.
Int J Pharm ; 608: 121075, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34481889

RESUMO

PEGylation is the standard approach for prolonging the plasma exposure of protein therapeutics but has limitations. We explored whether polymers prepared by Reversible Addition-Fragmentation chain-Transfer (RAFT) may provide better alternatives to polyethylene glycol (PEG). Four RAFT polymers were synthesised with varying compositions, molar mass (Mn), and structures, including a homopolymer of N-(2-hydroxypropyl)methacrylamide, (pHPMA) and statistical copolymers of HPMA with poly(ethylene glycol methyl ether acrylate) p(HPMA-co-PEGA); HPMA and N-acryloylmorpholine, p(HPMA-co-NAM); and HPMA and N-isopropylacrylamide, p(HPMA-co-NIPAM). The intravenous pharmacokinetics of the polymers were then evaluated in rats. The in vitro activity and in vivo pharmacokinetics of p(HPMA-co-NIPAM)-conjugated trastuzumab Fab' and full length mAb were then evaluated. p(HPMA-co-NIPAM) prolonged plasma exposure more avidly compared to the other p(HPMA) polymers or PEG, irrespective of molecular weight. When conjugated to trastuzumab-Fab', p(HPMA-co-NIPAM) prolonged plasma exposure of the Fab' similar to PEG-Fab'. The generation of anti-PEG IgM in rats 7 days after intravenous and subcutaneous dosing of p(HPMA-co-NIPAM) conjugated trastuzumab mAb was also examined and was shown to exhibit lower immunogenicity than the PEGylated construct. These data suggest that p(HPMA-co-NIPAM) has potential as a promising copolymer for use as an alternative conjugation strategy to PEG, to prolong the plasma exposure of therapeutic proteins.


Assuntos
Polietilenoglicóis , Polímeros , Animais , Metacrilatos , Ratos , Trastuzumab
9.
ACS Appl Mater Interfaces ; 13(33): 38947-38958, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34433245

RESUMO

Although dressing blood-contacting devices with robust and synergistic antibacterial and antithrombus properties has been explored for several decades, it still remains a great challenge. In order to endow materials with remarkable antibacterial and antithrombus abilities, a stable and antifouling hydrogel coating was developed via surface-initiated polymerization of sulfobetaine methacrylate and acrylic acid on a polymeric substrate followed by embedding of antimicrobial peptides (AMPs), including WR (sequence: WRWRWR-NH2) or Bac2A (sequence: RLARIVVIRVAR-NH2) AMPs. The chemical composition of the AMP-embedded hydrogel coating was determined through XPS, zeta potential, and SEM-EDS measurements. The AMP-embedded antifouling hydrogel coating showed not only good hemocompatibility but also excellent bactericidal and antiadhesion properties against Gram-positive and Gram-negative bacteria. Moreover, the hydrogel coating could protect the AMPs with long-term bioactivity and cover the positive charge of the dotted distributed AMPs, which in turn well retained the hemocompatibility and antifouling capacity of the bulk hydrogels. Furthermore, the microbiological results of animal experiments also verified the anti-infection performance in vivo. Histological and immunological data further indicated that the hydrogel coating had an excellent anti-inflammatory function. Therefore, the present study might provide a promising approach to prevent bacterial infections and thrombosis in clinical applications of blood-contacting devices and related implants.


Assuntos
Antibacterianos/química , Materiais Revestidos Biocompatíveis/química , Fibrinolíticos/química , Hidrogéis/química , Proteínas Citotóxicas Formadoras de Poros/química , Resinas Acrílicas/química , Antibacterianos/farmacologia , Bandagens , Sangue/metabolismo , Sobrevivência Celular , Materiais Revestidos Biocompatíveis/metabolismo , Eritrócitos , Fibrinolíticos/farmacologia , Hemólise , Humanos , Hidrogéis/metabolismo , Metacrilatos/química , Adesividade Plaquetária/efeitos dos fármacos , Polimerização , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Propriedades de Superfície
10.
ACS Appl Mater Interfaces ; 13(33): 38979-38989, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34433249

RESUMO

Chronic infections caused by Pseudomonas aeruginosa pose severe threats to human health. Traditional antibiotic therapy has lost its total supremacy in this battle. Here, nanoplatforms activated by the clinical microenvironment are developed to treat P. aeruginosa infection on the basis of dynamic borate ester bonds. In this design, the nanoplatforms expose targeted groups for bacterial capture after activation by an acidic infection microenvironment, resulting in directional transport delivery of the payload to bacteria. Subsequently, the production of hyperpyrexia and reactive oxygen species enhances antibacterial efficacy without systemic toxicity. Such a formulation with a diameter less than 200 nm can eliminate biofilm up to 75%, downregulate the level of cytokines, and finally promote lung repair. Collectively, the biomimetic design with phototherapy killing capability has the potential to be an alternative strategy against chronic infections caused by P. aeruginosa.


Assuntos
Antibacterianos/química , Verde de Indocianina/química , Nanocápsulas/química , Fármacos Fotossensibilizantes/química , Polímeros/química , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/radioterapia , Células A549 , Animais , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Composição de Medicamentos , Liberação Controlada de Fármacos , Sinergismo Farmacológico , Humanos , Verde de Indocianina/farmacologia , Raios Infravermelhos , Masculino , Metacrilatos/química , Camundongos Endogâmicos BALB C , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Polietilenoglicóis/química , Pseudomonas aeruginosa/efeitos dos fármacos
11.
Int J Mol Sci ; 22(15)2021 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-34361005

RESUMO

Although the development of gene delivery systems based on non-viral vectors is advancing, it remains a challenge to deliver plasmid DNA into human blood cells. The current "gold standard", namely linear polyethyleneimine (l-PEI 25 kDa), in particular, is unable to produce transgene expression levels >5% in primary human B lymphocytes. Here, it is demonstrated that a well-defined 24-armed poly(2-dimethylamino) ethyl methacrylate (PDMAEMA, 755 kDa) nano-star is able to reproducibly elicit high transgene expression (40%) at sufficient residual viability (69%) in primary human B cells derived from tonsillar tissue. Moreover, our results indicate that the length of the mitogenic stimulation prior to transfection is an important parameter that must be established during the development of the transfection protocol. In our hands, four days of stimulation with rhCD40L post-thawing led to the best transfection results in terms of TE and cell survival. Most importantly, our data argue for an impact of the B cell subsets on the transfection outcomes, underlining that the complexity and heterogeneity of a given B cell population pre- and post-transfection is a critical parameter to consider in the multiparametric approach required for the implementation of the transfection protocol.


Assuntos
Linfócitos B/metabolismo , Técnicas de Transferência de Genes , Vetores Genéticos/genética , Linfócitos B/citologia , Células Cultivadas , Humanos , Metacrilatos/química , Nylons/química , Transgenes
12.
Int J Mol Sci ; 22(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34445545

RESUMO

Six novel urethane-dimethacrylate analogues (QAUDMAs) were synthesized and characterized. They consisted of the 2,4,4,-trimethylhexamethylene diisocyanate (TMDI) core and two methacrylate-terminated wings containing quaternary ammonium groups substituted with alkyl chains of 8, 10, 12, 14, 16, or 18 carbon atoms. QAUDMAs, due to the presence of quaternary ammonium groups, may have possible antibacterial effects. Since they showed satisfactory physicochemical properties, they will be subjected to further research towards the development of dental composites with a capacity to reduce secondary caries. The synthesis of QAUDMAs included three stages: (i) transesterification of methyl methacrylate (MMA) with N-methyldiethanolamine (MDEA), (ii) N-alkylation of the tertiary amino group with alkyl bromide, and (iii) addition of TMDI to the intermediate achieved in the second stage. The formation of QAUDMAs was confirmed by 1H and 13C NMR. They were characterized for density (dm), viscosity (η), refractive index (RI), glass transition temperature (Tg), polymerization shrinkage (S), and degree of conversion (DC). QAUDMAs were yellow, viscous resins (the η values ranged from 1.28 × 103 to 1.39 × 104 Pa·s, at 50 °C). Their RI ranged from 1.50 to 1.52, Tg from -31 to -15 °C, DC from 53 to 78%, and S from 1.24 to 2.99%, which is appropriate for dental applications.


Assuntos
Compostos de Amônio/química , Resinas Compostas/síntese química , Metacrilatos/química , Poliuretanos/química , Teste de Materiais , Projetos Piloto , Polimerização , Propriedades de Superfície , Viscosidade
13.
Langmuir ; 37(33): 9982-9995, 2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34378943

RESUMO

Cationic amphiphilic polymers have been a platform to create new antimicrobial materials that act by disrupting bacterial cell membranes. While activity characterization and chemical optimization have been done in numerous studies, there remains a gap in our knowledge on the antimicrobial mechanisms of the polymers, which is needed to connect their chemical structures and biological activities. To that end, we used a single giant unilamellar vesicle (GUV) method to identify the membrane-disrupting mechanism of methacrylate random copolymers. The copolymers consist of random sequences of aminoethyl methacrylate and methyl (MMA) or butyl (BMA) methacrylate, with low molecular weights of 1600-2100 g·mol-1. GUVs consisting of an 8:2 mixture of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol), sodium salt (POPG) and those with only 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were prepared to mimic the bacterial (Escherichia coli) or mammalian membranes, respectively. The disruption of bacteria and mammalian cell membrane-mimetic lipid bilayers in GUVs reflected the antimicrobial and hemolytic activities of the copolymers, suggesting that the copolymers act by disrupting cell membranes. The copolymer with BMA formed pores in the lipid bilayer, while that with MMA caused GUVs to burst. Therefore, we propose that the mechanism is inherent to the chemical identity or properties of hydrophobic groups. The copolymer with MMA showed characteristic sigmoid curves of the time course of GUV burst. We propose a new kinetic model with a positive feedback loop in the insertion of the polymer chains in the lipid bilayer. The novel finding of alkyl-dependent membrane-disrupting mechanisms will provide a new insight into the role of hydrophobic groups in the optimization strategy for antimicrobial activity and selectivity.


Assuntos
Anti-Infecciosos , Fosfatidilcolinas , Animais , Bicamadas Lipídicas , Metacrilatos , Polímeros
14.
Zhonghua Shao Shang Za Zhi ; 37(8): 770-780, 2021 Aug 20.
Artigo em Chinês | MEDLINE | ID: mdl-34404159

RESUMO

Objective: To investigate the biological activity of biomimetic dermal papilla spheres (DPSs) prepared by three-dimensionally cultured dermal papilla cells (DPCs) of mice based on the biomimetic microenvironment of gelatin methacrylate (GelMA) and hanging drop method and its hair-inducing function in nude mice. Methods: Experimental research methods were adopted. DPCs from the vibrissa of male C57BL/6J mice aged 5 to 6 weeks and keratinocytes (KCs) from the skin of 1 d old C57BL/6J mice were obtained by enzymatic digestion method. A stable expression of DPCs markers such as nerve cell adhesion molecules, alkaline phosphatase (ALP), ß-catenin, and α-smooth muscle actin were identified by immunofluorescence method in the third passage of the former cells, while the latter primary cells stably expressed keratin 15, a marker of KCs. The 8th passage of DPCs were re-suspended with GelMA and inoculated on the bottom surface of the Transwell plate insert, and then the GelMA drops were photocrosslinked and cultured upside down later. The DPCs aggregation in GelMA drops after in cultures of 0 (immediately) and 3 day (s) was observed under an optical microscope (the DPCs aggregates were the biomimetic DPSs). The cell viability of 3 day biomimetic DPSs culture was detected by live/dead staining kit. The primary DPCs and the 8th passage of DPCs derived from traditionally two-dimensional cultures, and the biomimetic DPSs prepared by the above-mentioned method were set as primary DPCs group, the 8th passage of DPCs group, and biomimetic DPSs group, respectively. Transcriptome sequencing was performed using the high-throughput sequencing technology platform, with 3 samples in each group analyzed after three days in culture. The principal component analysis, Pearson similarity analysis, and screening of differentially expressed genes were performed using OmicShare Tools based on the transcriptome data. Cluster analysis of expression patterns of differentially expressed genes was performed using time series trend analysis software. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses of differentially expressed genes with specific expression patterns were performed using the OmicShare Tools. The cells were grouped as before, and the sex determining region Y-Box 8 (SOX8), matrix metallopeptidase 9 (MMP-9), collagen type ΧΧⅥ alpha 1 chain (COL26A1), and wingless-type MMTV integration site family member 6 (Wnt6) were screened out from the differentially expressed genes according to the random number table, which were determined by real-time fluorescent quantitative reverse transcription polymerase chain reaction (RT-PCR) to verify the consistency between mRNA expression of differentially expressed genes and sequencing results (n=9); the mRNA expressions of DPCs biological function markers fibroblast growth factor 7 (FGF7), Wnt10a, lymphoid enhancement factor 1 (LEF1), ALP, ß-catenin, versican, and SOX2 were determined by real-time fluorescent quantitative RT-PCR (n=9). Three male BALB/c nude mice aged 5-6 weeks were divided into primary DPCs group, the 8th passage of DPCs group, and biomimetic DPSs group. The primary DPCs, the 8th passage of DPCs, and the biomimetic DPSs were mixed with primary KCs at a ratio of 2∶1 in cell number and then injected subcutaneously into mice of corresponding groups, with 6 injection regions for each mouse. Two weeks after the injection, the full-thickness skin of the injection region was taken, the regenerated hair was counted, and the regenerated hair follicle was observed after hematoxylin-eosin staining. Data were statistically analyzed with one-way analysis of variance, Tukey test, and Bonferroni correction. Results: After 3 days of culture, DPCs aggregated into biomimetic DPSs in GelMA hanging drops from the dispersed state on culture day 0, and the cells in the biomimetic DPSs had good cell activity. After 3 days of culture, principal component analysis showed that compared with that of the 8th passage of DPCs group, the degree of variation among samples within primary DPCs group and biomimetic DPSs group was relatively low, and the degree of variation was the lowest between samples of biomimetic DPSs group and primary DPCs group; the variation of gene profile data of more than 90% of DPCs samples in 3 groups could be explained by the first and second principal components. Pearson similarity analysis showed that samples within each group had good repeatability. The similarity was 0.84-0.95 between samples of primary DPCs group and biomimetic DPSs group, and was 0.72-0.87 between samples of primary DPCs group and the 8th passage of DPCs group. The differentially expressed genes among the three groups were analyzed and 642 differentially expressed genes with group intersection were screened out. Clusters of expression patterns showed that two gene expression patterns had a significant trend (P<0.05), the first pattern showed that gene expression of the 8th passage of DPCs group was significantly lower than that of primary DPCs group or biomimetic DPSs group, and the second pattern showed that gene expression of the 8th passage of DPCs group was significantly higher than that of primary DPCs group or biomimetic DPSs group, including a total of 411 differentially expressed genes. KEGG enrichment analysis showed that the 411 differentially expressed genes were significantly enriched in Wnt signaling pathway and phosphatidylinositol 3 kinase/protein kinase B pathway (P<0.05), while GO enrichment analysis showed that GO terms such as extracellular matrix, classical Wnt signaling pathway, and cell differentiation were significantly enriched (P<0.05). The mRNA expressions of genes SOX8, MMP-9, COL26A1 and Wnt6 of cells in the 8th passage of DPCs group were significantly decreased compared with those in primary DPCs group and biomimetic DPSs group (q=15.950, 8.854, 11.890, 11.050, 9.851, 5.884, 7.418, 4.870, P<0.01), consistent with the sequencing data. Compared with those in primary DPCs group and biomimetic DPSs group, the mRNA expressions of biological function markers FGF7, Wnt10a, LEF1, ALP, ß-catenin, versican, and SOX2 of cells in the 8th passage of DPCs group were significantly decreased (q=11.470, 9.795, 4.165, 9.242, 10.970, 10.570, 8.005, 7.472, 4.976, 3.651, 4.784, 5.236, 6.825, 5.214, P<0.05 or P<0.01). Two weeks after injection, nude mice in the 8th passage of DPCs group failed to regenerate hair, while the numbers of hair regenerated in nude mice in biomimetic DPSs group and primary DPCs group were close (q=1.852, P>0.05) and both were significantly higher than the number in the 8th passage of DPCs group (q=18.980, 17.130, P<0.01). In the 8th passage of DPCs group, only necrotic foci were found in the injection region of the skin of nude mice, while regenerated hair follicles were observed in the injection region of the skin of nude mice in both biomimetic DPSs group and primary DPCs group, and melanosis was observed in the cross section of hair follicles. Conclusions: Based on GelMA biomimetic microenvironment and hanging drop method, the biomimetic DPSs culturing model prepared by three dimensional culture of DPCs of mice can restore the hair-inducing ability of high passage of DPCs in nude mice to a certain extent, and its biological characteristics are more similar to those of the primary DPCs, which can restore the characteristics of DPCs after amplification.


Assuntos
Gelatina , Metacrilatos , Animais , Biomimética , Células Cultivadas , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Nus
15.
Dent Mater ; 37(10): 1486-1497, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34376295

RESUMO

OBJECTIVE: This study evaluated the cytotoxic and estrogenic effects of dust and eluates released into simulated wastewater after grinding of dental resin-based materials. METHODS: Four materials were used: ceram.x® universal, Filtek™ Supreme XTE, Lava™ Ultimate and Core-X™ flow. From each composite material, samples (5 × 2 mm, n = 50) were prepared according to the manufacturers' instructions. Lava™ Ultimate was used as blocks. All samples were ground to dust with a diamond bur (106 µm) and suspended in distilled water at 60 mg/mL. After storage for 72 h, the suspensions were separated into a soluble (eluate) and a particulate (dust) fraction. Eluates and dusts were evaluated for inhibition of Vibrio fischeri bioluminescence and cytotoxicity on human A549 lung cells (WST-1-Assay). The estrogenic activity was assessed by YES-Assay using Saccharomyces cerevisiae. Additionally, dental monomers (BisGMA, BisEMA, UDMA, TEGDMA, HEMA) and Bisphenol A were investigated. RESULTS: All eluates showed inhibition of V. fischeri bioluminescence at concentrations above 1.1 mg/mL (p < 0.05). The activity of the eluates of ceram.x® universal and Filtek™ Supreme XTE was significantly higher than Lava™ Ultimate and Core-X™ flow (p < 0.05). In the WST-1-Assay, all materials induced cytotoxic effects at concentrations of 0.1 mg/mL (p < 0.05), while no significant differences were detected among them. The tested materials revealed no estrogenic activity. All dental monomers and Bisphenol A showed concentration dependent cytotoxic effects (p < 0.05), whereas only Bisphenol A induced an estrogenic effect (p < 0.01). SIGNIFICANCE: Dust and eluates of resin-based dental materials released into wastewater exert bactericidal and cytotoxic effects in vitro. However, they reveal no estrogenic effect.


Assuntos
Resinas Compostas , Águas Residuárias , Resinas Compostas/toxicidade , Materiais Dentários , Humanos , Teste de Materiais , Metacrilatos
16.
Dent Mater ; 37(10): 1569-1575, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34407920

RESUMO

OBJECTIVE: The use of resin cements in clinical practice entails photopolymerization through prosthetic devices, which precludes light penetration. The objective of this study was to modify experimental resin cements (ERCs) with diphenyliodonium hexafluorophosphate (DPI) in an attempt to improve chemical and mechanical properties of materials cured with reduced irradiance and final radiant exposure. METHODS: A co-monomer base containing a 1:1 mass ratio of 2.2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane (bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA) was prepared, with 1mol% of camphorquinone and 2mol% of ethyl 4-(dimethylamino)benzoate as initiator system. The resin was divided into 4 fractions according to the DPI concentrations (0, 0.5, 1 and 2mol%). The challenging polymerization condition was simulated performing the light activation (12, 23 and 46s) through a ceramic block (3mm thick). The irradiance was assessed with a calibrated spectrometer (1320mW/cm2), resulting in three levels of radiant exposure (0.58, 1.1 and 2.2J/cm2). The polymerization kinetics was evaluated in real-time using a spectrometer (Near-IR). Water sorption and solubility was analyzed and the cohesive strength of resins obtained through the microtensile test. Polymerization stress was assessed by Bioman method. RESULTS: Resins containing DPI had higher degree of conversion and rate of polymerization than the control (without DPI). The use of DPI reduced water sorption and solubility, and led to higher cohesive strength compared to resins without the iodonium salt. However, the stress of polymerization was higher for experimental resins with DPI. SIGNIFICANCE: Even under remarkably reduced irradiance, cements containing a ternary initiating system with an iodonium salt can present an optimal degree of conversion and chemical/mechanical properties.


Assuntos
Metacrilatos , Cimentos de Resina , Bis-Fenol A-Glicidil Metacrilato , Resinas Compostas , Teste de Materiais , Polimerização
17.
Dent Mater ; 37(10): 1601-1614, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34454738

RESUMO

OBJECTIVE: To develop a model for quantitative comparison of elutable substances by direct elution from resin-bonded composite (RBC) test specimens versus indirect elutability of substances from RBC-restored teeth. Furthermore, it was to be investigated whether the different composites of the Tetric® RBC product family release different types and amounts of substances. METHODS: Four different composite materials from the Tetric® product family were studied. For each material subgroup ten human third molar teeth were prepared with standard Class-I occlusal cavities. These 'tooth group' specimens were provided with a three-step adhesive system (incorporating TEGDMA) and the respective composite restoration. Same sized control specimens, of each RBC restorative material, were prepared ('direct RBC' groups). All specimens were placed in individual elution chambers such that the elution media (ethanol/water, 3:1) only came into contact with either the tooth root or ¾ height of the 'direct RBC' materials. They were incubated at 37 °C for up to 7 d. Samples of the eluant were taken after 1, 2, 4 and 7 d and were analysed by high-temperature gas chromatography/mass spectrometry. RESULTS: Bisphenol A ethoxylate dimethacrylate (bisEMA), bisphenol A glycidyldimethacrylate (bisGMA), tetraethylene glycol dimethacrylate (TEEGDMA), decan-1,10-diol dimethacrylate (DDDMA) were mostly found in the eluates of the 'direct RBC' groups in statistically significantly greater amounts than in the eluates of the 'tooth groups'. Such quantitative differences were also the case with eluates containing bisphenol A (BPA), dicyclohexyl phthalate (DCHP) and drometrizole, which are common in the environment. In contrast to the behavior found with all the other monomers, up to 3 orders of magnitude more triethylene glycol dimethacrylate (TEGDMA) was found in the 'tooth groups' compared to the 'direct RBC' groups, evidently released by the adhesive system. SIGNIFICANCE: The release of most of the substances was clearly delayed in the 'tooth groups' indicative of their chronic, rather than acute, elution to the oral environment. A barrier function of the residual dentin layer and the adhesion layer can be inferred. The different release patterns of substances from the various composites of the RBC product family is a manifestation of their different and indication-specific compositions. Consideration of an overall restorative care (RBC plus adhesive) system, when assessing the total amount of released substances, is emphasized.


Assuntos
Resinas Compostas , Metacrilatos , Materiais Dentários , Humanos , Teste de Materiais , Polietilenoglicóis , Ácidos Polimetacrílicos
18.
Dent Mater ; 37(10): 1463-1485, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34456050

RESUMO

OBJECTIVE: The purpose of this systematic review and meta-analysis was to analyze the literature on the bond strength of self-etching (SE) adhesives containing 10-MDP or other acidic functional monomers, comparing the bonding performance of both compositions. METHODS: This study is registered in PROSPERO (CRD42020175715) and it followed the PRISMA Statement. The literature search was performed in PubMed, Web of Science, SciELO, Scopus, LILACS, IBECS, and BBO from the starting coverage date through 30 June 2021. Study eligibility criteria consisted of in vitro studies that evaluated the bond strength (microtensile, microshear, tensile or shear testing) to sound dentin/enamel of a minimum of two distinct SE systems, with at least one material containing 10-MDP and one other being comprised of a distinct acidic composition. Statistical analyses were carried out with RevMan 5.3.5 and using random-effects models with the significance level at p < 0.05. Also, Bayesian network meta-analysis (NMA) was conducted using MetaInsight V3 tool. RESULTS: From 740 relevant studies evaluated in full-text analysis, 210 were incorporated to the systematic review and 206 in meta-analysis. The majority of studies was classified as having medium risk of bias (56.7%), followed by low (35.2%) and high (8.1%) risk of bias. Data from a total of 64 adhesive systems were collected, which favored the 10-MDP-based group at both dentin (overall effect: 6.98; 95% CI: 5.61, 8.36; p < 0.00001) and enamel (overall effect: 2.79; 95% CI: 1.62, 3.96; p < 0.00001) substrates. Microtensile testing was more frequently used (73.4%) in the included studies. Adhesives based on 10-MDP showed greater bonding performance than adhesives comprised of monomers such as PENTA, 6-MHP, 4-META, 4-MET, pyrophosphate esters, mixed composition or monomers derived from sulfonic acid (p ≤ 0.01); whereas similar bond strength values were verified between 10-MDP-based materials and those containing PEM-F, acrylamide phosphates, 4-AET, MAC-10, or monomers derived from polyacrylic and phosphonic acids (p ≥ 0.05). Adhesives based on GPDM were the only ones that resulted in greater bonding potential than the 10-MDP-based group (p = 0.03). Dental bonds in dentin were favored with the application of 2-step 10-MDP-based adhesives; whereas in enamel the dental bonds were favored for both 2-steps versions of adhesives, regardless of the presence of 10-MDP. Indirect evidence from NMA revealed that 1-step 10-MDP-free and universal 10-MDP-free adhesives seemed to perform worst in dentin and enamel, respectively. SIGNIFICANCE: Adhesives containing 10-MDP showed higher bonding performance than materials formulated with other acidic ingredients, although this result relied on the type of mechanical testing, type of the substrate, acidic composition of the adhesive, and the application category of the SE system. This review summarized the effects of the foregoing factors on the adhesion to dental substrates.


Assuntos
Colagem Dentária , Adesivos Dentinários , Teorema de Bayes , Cimentos Dentários , Dentina , Teste de Materiais , Metacrilatos , Cimentos de Resina , Resistência à Tração
19.
Dent Mater ; 37(10): 1592-1600, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34456051

RESUMO

OBJECTIVE: The objective is to develop and characterize an ester-free ether-based photo-CuAAC resin with high mechanical performance, low polymerization-induced stress compared with common BisGMA/TEGDMA (70/30) resins, and improved water stability in comparison to previously developed urethane-based photo-CuAAC resins. METHODS: Triphenyl-ethane-centered ether-linked tri-azide monomers were synthesized and co-photopolymerized with ether-linked tri-alkyne monomers under visible light irradiation using a copper(II) pre-catalyst and CQ/EDAB as the initiator. The ether-based CuAAC formulation was investigated for thermo-mechanical properties, polymerization kinetics and shrinkage stress, and flexural properties with respect to a conventional BisGMA/TEGDMA (70/30) dental resin. In addition, both the ether-based CuAAC resin and the urethane-based CuAAC resin were examined for their water stability using the BisGMA/TEGDMA (70/30) resin as a control. RESULTS: The ether-based CuAAC network (AK/AZ-1) exhibited a slightly lower glass-transition temperature compared with the BisGMA/TEGDMA network (108 °C vs 128 °C), but because of its much sharper glass transition, the AK/AZ-1 CuAAC-network maintained storage modulus higher than 1 GPa up to 100 °C. In addition, the ether-based AK/AZ-1 network exhibited reduced shrinkage stress (0.56 MPa vs 1.0 MPa) and much higher flexural toughness (7.6 MJ/m3vs 1.6 MJ/m3) while showing slightly lower flexural modulus and slightly higher flexural strength compared with the BisGMA/TEGDMA network. Moreover, the ether-based AK/AZ-1 CuAAC network displayed comparable water stability in comparison to the BisGMA/TEGDMA network with slightly higher water sorption (46 µg/mm3vs 38 µg/mm3) and much lower water solubility (2.3 µg/mm3vs 4.4 µg/mm3). SIGNIFICANCE: Employing the ether-based hydrophobic CuAAC formulation significantly improved the water stability of the CuAAC network compared with previously developed urethane-based CuAAC networks. Furthermore, compared with the conventionally used BisGMA/TEGDMA formulation, the reduced shrinkage stress, comparable flexural strength/flexural modulus, and the superior flexural toughness of the ether-based CuAAC network make it a promising ester-free alternative to the currently widely-used methacrylate-based dental restoratives.


Assuntos
Alcinos , Azidas , Bis-Fenol A-Glicidil Metacrilato , Catálise , Resinas Compostas , Cobre , Reação de Cicloadição , Ésteres , Teste de Materiais , Metacrilatos , Polietilenoglicóis , Polimerização , Polímeros , Ácidos Polimetacrílicos , Água
20.
Dent Mater ; 37(10): 1542-1552, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34462139

RESUMO

OBJECTIVE: Resin-modified glass ionomer cements (RMGICs) present several advantages (e.g. fluoride release), but their reported cytotoxicity has been associated with hydroxyethyl methacrylate (HEMA) monomer release. Therefore, different monomers were tested for use in RMGICs in order to improve their biocompatibility and reduce monomer release. METHODS: Eight experimental liquid compositions were prepared replacing different percentages of HEMA (conventional monomer used in commercial RMGICs) with hydroxypropyl-methacrylate (HPM) and/or tetrahydrofurfuryl-methacrylate (THFM), which are known to have better biocompatibility. Moreover, two commercial materials (Fuji-Plus and RelyX) and two compositions, based on these (home), were included as controls. Monomer release of all materials (commercial, home and experimental) were tested using high-performance liquid chromatography (HPLC) methods after immersing discs in deionized-water (DW) or ethanol:DW. Cytotoxicity of the materials extracts was tested on normal human oral fibroblast line (NHOF-1) using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. RESULTS: Three experimental materials containing THFM (F3, R3 and R4) showed less or similar monomer release compared to corresponding commercial products. Furthermore, two experimental materials (F3 and F4) showed similar effects on NHOF-1 cells compared to the negative control medium. SIGNIFICANCE: The lower monomer release and higher cell viability of some experimental THFM compositions are encouraging. THFM partially replacing HEMA is potentially a suitable alternative for producing biocompatible RMGICs.


Assuntos
Cimentos de Ionômeros de Vidro , Cimentos de Resina , Cimentos de Ionômeros de Vidro/toxicidade , Humanos , Teste de Materiais , Metacrilatos/toxicidade
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