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1.
Braz. j. oral sci ; 20: e213736, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1253012

RESUMO

Although Spondias mombin L. extract has an excellent antimicrobial effect against oral microorganisms, it should be clarified how it affects enamel surface properties. Aim: To evaluate the color change, wettability/contact angle, surface roughness and morphology of bovine enamel submitted to the Spondias mombin L. extract. Methods: Thirty bovine teeth were distributed into the following groups: 0.12% chlorhexidine digluconate, 1:32 Spondias mombin L. extract and distilled water. Color change (CC) was evaluated after immerging specimens into the solutions for 14 days. Surface roughness (Ra) was measured using a roughness meter; wettability/contact angles (CA) were determined by the sessile drop method, and scanning electron microscopy images were obtained to characterize the morphology (SMA). The pH of the solutions was evaluated using a pHmeter. The Ra, CA, and CC data were parametric (Kolmogorov-Smirnov; p>0.05). Two-way ANOVA (for Ra and CA) and one-way ANOVA (for CC) with Tukey's posthoc tests at a significance level of 5% were used. SMA was analyzed descriptively. Results: The Spondias mombin L. extract revealed an acidic pH, and when in contact with the bovine teeth, it increased the wettability, but it did not cause statistically significant differences in the Ra. Spondias mombin L. extract caused the highest color change. The SEM images showed differences in the specimens' surface submitted to the extract compared to the other groups. Conclusion: Spondias mombin L. extract provided negative effects on bovine enamel's surface, including a high color change and a more wettable substrate


Assuntos
Animais , Bovinos , Propriedades de Superfície , Anacardiaceae , Esmalte Dentário , Fitoterapia , Antissépticos Bucais
2.
Braz. j. oral sci ; 20: e211670, jan.-dez. 2021. ilus
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1254259

RESUMO

Aim: To evaluate the effect of different surface treatments and adhesive approaches on the microshear bond strength of resin cement to a polymer-infiltrated ceramic network (PICN). Methods: PICN blocks were randomly assigned into 9 groups (n=10): CTRL: no treatment; HF: 5% hydrofluoric acid etching; HF-S: HF + silane; HF-S-A: HF-S + adhesive (Adper Single Bond 2); HF-UA: HF + universal adhesive (Single Bond Universal); SB: sandblasting with 50 µm Al2O3 particles; SB-S: SB + silane; SB-S-A: SB-S + adhesive; SB-UA: SB + universal adhesive. Resin cement microcylinders (Ø = 0.96 mm; height = 1 mm) (RelyX Ultimate) were built upon the PICN surface after roughness and contact angle measurements. Next, microshear bonding tests (µSBS) were performed (0.5 mm/min) after water storage (37ºC, 90 days) and thermocycling (12,000 cycles; 5ºC-55ºC). Failure modes were observed under stereomicroscope. Bond strength data were analyzed by two-way ANOVA/Tukey's test and t-tests. Kruskal-Wallis/Dunn's tests were conducted for roughness and contact angle data (α = 0.05). Results: A rougher surface and lower contact angles were observed for Sandblasting. HF-S (18.54 ± 2.03 MPa), SB-S (19.00 ± 1.66 MPa) and SB-UA (18.07 ± 2.36 MPa) provided the highest bond strength values, followed by the other treated groups. The CTRL group resulted in lower bond strength (7.18 ± 2.34 MPa). Conclusion: Hydrofluoric acid etching followed by silane application and sandblasting followed by silane or universal adhesive are useful clinical steps to enhance bonding to PICN. Adhesive applications after HF etching have no advantages in bonding to PICN


Assuntos
Propriedades de Superfície , Cerâmica , Adesivos Dentinários , Cimentos de Resina , Abrasão Dental por Ar , Ácido Fluorídrico
3.
J Appl Oral Sci ; 29: e20200948, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34495105

RESUMO

BACKGROUND: Appropriated denture hygiene is a predictive factor for longevity of rehabilitation treatment and maintenance of the oral mucosal health. Although, disinfectant solutions are commonly used as denture cleansers, the impact of these solutions on acrylic resin-based dentures remain unclear. OBJECTIVE: To evaluate, in vitro, the antibiofilm activity of complete denture hygiene solutions and their effects on physical and mechanical properties of acrylic resin. METHODOLOGY: For antibiofilm activity measurement acrylic resin specimens were contaminated with Candida albicans, Candida glabrata and Streptococcus mutans. After biofilm growth, the specimens were assigned to the hygiene solutions: Distilled water (Control); 0.2% Sodium hypochlorite (SH); Efferdent Power Clean Crystals (EPC) and 6.25% Ricinus communis (RC). The viability of microorganisms was evaluated by agar plate counts. In parallel, physical, and mechanical properties of the acrylic resin were evaluated after simulating a 5-year period of daily immersion in the previously mentioned solutions. The changes in surface roughness, color, microhardness, flexural strength, impact strength, sorption and solubility were evaluated. Data were compared by ANOVA followed by the Tukey test or Kruskal-Wallis followed by the Dunn test depending on the distribution (α=0.05). RESULTS: Regarding antibiofilm action, SH eliminated all microorganisms while EPC and RC exhibited moderate action against S. mutans (p=0.001) and C. glabrata (p<0.001), respectively. Relative to effects on the physical and mechanical properties of the acrylic resin, RC led to higher values of color change (p=0.030), hardness (p<0.001), surface roughness (p=0.006) and flexural strength (p<0.001). Moreover, RC induced the highest values of changes in solubility (p<0.001). EPC promoted greater changes in surface morphology, whereas immersion in SH retained the initial appearance of the acrylic resin surface. All hygiene solutions reduced the impact strength (p<0.05). CONCLUSION: SH presented the most effective antibiofilm activity. In addition, changes on properties were observed after immersion in RC, which were considered within acceptable limits.


Assuntos
Resinas Acrílicas , Higienizadores de Dentadura , Biofilmes , Bases de Dentadura , Higienizadores de Dentadura/farmacologia , Prótese Total , Higiene , Teste de Materiais , Propriedades de Superfície
4.
Mater Sci Eng C Mater Biol Appl ; 128: 112289, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474840

RESUMO

Successful osseointegration, i.e. the fully functional connection of patient's bone and artificial implant depends on the response of the cells to the direct contact with the surface of the implant. The surface properties of the implant which trigger cell responses leading to its integration into the surrounding bone can be tailored by surface modifications or coating with thin layers. One potential material for such applications is ultrananocrystalline diamond (UNCD). It combines the exceptional mechanical properties of diamond with good biocompatibility and possibility of coating as thin uniform films on different substrates of biological interest. In the current work we firstly deposited UNCD films on titanium-coated substrates and applied oxygen or ammonia plasma to modify their surface properties. The as-grown and modified UNCD exhibited relatively smooth surfaces with topography dominated by rounded features. The modifications induced oxygen- or amino-terminated surfaces with increased hydrophilicity. In addition, the UNCD coatings exhibited very low coefficient of friction when diamond was used as a counterpart. As-grown and modified UNCD samples were applied to study the responses of human osteoblast MG63 cells triggered by surfaces with various terminations assessed by proteomic analysis. The results revealed that the coating of Ti with UNCD as well as the plasma modifications resulting in O- or NH2-terminated UNCD induced upregulation of proteins specific for cytoskeleton, cell membrane, and extracellular matrix (ECM) involved in the cell-ECM-surface interactions. Proteins from each of these groups, namely, vimentin, cadherin and fibronectin were further studied immunocytochemically and the results confirmed their increased abundance leading to improved cell-to-surface adhesion and cell-to-cell interactions. These findings demonstrate the potential of implant coating with UNCD and its surface modifications for better osseointegration and bone formation.


Assuntos
Proteoma , Titânio , Diamante , Humanos , Osteoblastos , Proteômica , Propriedades de Superfície
5.
Mater Sci Eng C Mater Biol Appl ; 128: 112297, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474848

RESUMO

INTRODUCTION: Peri-implantitis is a bacterially induced inflammatory disease which affects the hard and soft tissues around a dental implant. Microbial biofilm formation is an important causative factor in peri-implantitis. The aim of this study is to develop an effective multifunctional surface coating for antimicrobial property and to counteract oral biofilm-associated infections via a single polydopamine copper coating (PDAM@Cu) on titanium implant surface to regulate endogenous nitric oxide (NO) generation. METHODS: PDAM@Cu coatings were made with different concentrations of CuCl2 on titanium surfaces with a simple dip coating technique. Coatings were characterised to evaluate Cu concentrations as well as NO release rates from the coatings. Further, salivary biofilms were made on the coatings using Brain Heart Infusion (BHI) media in an anaerobic chamber. Biofilms were prepared with three different mixtures, one of which was saliva only, the second had an addition of sheep's blood, and the third was prepared with NO donors S-nitrosoglutathione (GSNO) and L-glutathione (GSH) in the mixture of saliva and blood to evaluate the effects of endogenously produced NO on biofilms. The effectiveness of coated surfaces on biofilms were assessed using four different methods, namely, crystal violet assay, scanning electron microscopy imaging, 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) metabolic assay, and live/dead staining. RESULTS: NO release rates could be controlled with different Cu concentration in PDAM@Cu coatings. NO generated from the PDAM@Cu coatings effectively induced dispersal of biofilms shown by the reduction in biofilm biomass as well as reduced biofilm attachment in samples prepared with blood and NO donors. Cu ions released from the PDAM@Cu coatings resulted in killing of the dispersed bacteria, which was evidenced by the live/dead cell staining and reduced metabolic activity noted from the XTT assay. In contrast, samples prepared with saliva showed no significant reduction in biofilms, indicating the important effect of endogenously generated NO on biofilm dispersal. CONCLUSION: In conclusion, PDAM@Cu coatings with NO generating surfaces have a dual anti-biofilm function, with a synergistic effect on biofilm dispersal from regulated NO generation and bactericidal effects from Cu ions from the coatings.


Assuntos
Cobre , Óxido Nítrico , Animais , Biofilmes , Materiais Revestidos Biocompatíveis/farmacologia , Cobre/farmacologia , Homicídio , Indóis , Polímeros , Ovinos , Propriedades de Superfície , Titânio/farmacologia
6.
Mater Sci Eng C Mater Biol Appl ; 128: 112315, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474866

RESUMO

Implant surface plays a crucial role in improving osseointegration and long-term implant life. When the implant comes in contact with the bone tissue, the bone marrow mesenchymal cells interact with the implant surface and the surface properties such as morphology, wettability, mechanical properties and chemistry influences cell migration, proliferation and differentiation. Different surface modification strategies such as ceramic coatings, surface dealloying, and surface topography modifications for improving osteointegration have been investigated. However, studies have not yet established which of the surface property is more influential. In this study, titanium surfaces were treated hydrothermally with sodium hydroxide and sulfuric acid separately. This treatment led to the development of two unique surface topography at nanoscale. These modified surfaces were characterized for surface morphology, wettability, chemistry, and crystallinity. Cytotoxicity, cell adhesion, proliferation, morphology, and differentiation of adipose derived stem cells on modified surfaces was investigated. The results indicate that wettability does influence initial cell adhesion. However, the surface morphology can play major role in cell spreading, proliferation and differentiation. The results indicate that titanium surfaces treated hydrothermally with sodium hydroxide led to a nanoporous architecture that promoted appropriate cell interaction with the surface promoting osteoblastic lineage.


Assuntos
Osteogênese , Titânio , Adesão Celular , Diferenciação Celular , Proliferação de Células , Osseointegração , Osteoblastos , Células-Tronco , Propriedades de Superfície , Titânio/farmacologia
7.
Mater Sci Eng C Mater Biol Appl ; 128: 112322, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474873

RESUMO

Many studies were conducted to change the surface morphology and chemical composition of Ti implants for the improvement of antibacterial ability and osseointegration between medical Ti and surrounding bone tissue. In this study, we successfully prepared a novel dual-function coating on pure Ti surface, i.e. Cu and Mg-co-doped TiO2 nanotube (TN) coating, by combining anodisation and hydrothermal treatment (HT), which could act as a delivery platform for the sustained release of Cu and Mg ions. Results showed that the amounts of Cu and Mg were about 5.43 wt%-6.55 wt% and 0.69 wt%-0.73 wt%, respectively. In addition, the surface morphology of Cu and Mg-co-doped TN (CuMTN) coatings transformed into nanoneedles after HT for 1 h. Compared with TN, CuMTN had no change in roughness and remarkable improved hydrophilicity. Antibacterial tests revealed that CuMTN had an antibacterial rate of more than 93% against Escherichia coli and Staphylococcus aureus, thereby showing excellent antibacterial properties. In addition, CuMTN could induce the formation of apatite well after being immersed in simulated body fluid, showing good biological activity. Preosteoblasts (MC3T3-E1) cultured on CuMTN-coated Ti demonstrated better proliferation and osteogenic differentiation than pristine and as-anodised specimens. To the best of our best knowledge, this study had successfully attempted to combine anodisation and HT, introduce Cu/Mg elements and functionalise Ti-based implant surfaces with enhanced hydrophilicity, osteogenesis and antimicrobial properties that can meet clinical needs for the first time.


Assuntos
Nanotubos , Osteogênese , Antibacterianos/farmacologia , Materiais Revestidos Biocompatíveis/farmacologia , Íons/farmacologia , Propriedades de Superfície , Titânio/farmacologia
8.
Mater Sci Eng C Mater Biol Appl ; 128: 112349, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474898

RESUMO

Concise, low-cost preparation of titanium alloy implants with high cell proliferation and osteogenic differentiation is urgently needed. Nanosecond laser ablation of titanium alloy has the advantages of short processing time, less pollution, and non-contact. In this research, we adopt a nanosecond UV laser to process the closed groove and cross groove titanium alloys with length to width ratio of 1:1, 2.5:1, 4:1, and 6:1. The surface morphology, surface roughness, phase, element distribution, surface chemistry, and wettability were characterized. The effect of the patterned surface's properties on the adhesion, proliferation, and osteogenic differentiation of stem cells was studied. The results show the laser-ablated lattice structure's surface energy can increase rapidly in the natural environment. The cell adhesion of stem cells on a lattice structure with low roughness and high surface energy is optimal. The element concentration at the ablated edges is higher than at the bottom under Marangoni and surface tension. Stem cells preferentially adhere to the ablated edges with high roughness, element concentration, and hardness. Cell differentiation is chiefly affected by patterning structure. On the surface of the boss structure with a length to width ratio of 2.5:1, the proportion of cell length to diameter is about 2.5, and the cell area is greater. The osteogenic differentiation of cells is the highest on the surface.


Assuntos
Ligas , Titânio , Diferenciação Celular , Proliferação de Células , Lasers , Osteoblastos , Osteogênese , Propriedades de Superfície , Titânio/farmacologia
9.
Nanoscale ; 13(33): 14119-14129, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34477693

RESUMO

Nanoparticles (NPs) have been studied for biomedical applications, ranging from prevention, diagnosis and treatment of diseases. However, the lack of the basic understanding of how NPs interact with the biological environment has severely limited their delivery efficiency to the target tissue and clinical translation. Here, we show the effective regulation of the surface properties of NPs, by controlling the surface ligand density, and their effect on serum protein adsorption, cellular uptake and cytotoxicity. The surface properties of NPs are tuned through the controlled replacement of native ligands, which favor protein adsorption, with ligands capable of increasing protein adsorption resistance. The extent and composition of the protein layer adsorbed on NPs are strongly correlated to the degree of ligands replaced on their surface and, while BSA is the most abundant protein detected, ApoE is the one whose amount is most affected by surface properties. On increasing the protein resistance, cellular uptake and cytotoxicity in mouse embryonic fibroblasts of NPs are drastically reduced, but the surface coating has no effect on the process by which NPs mainly induce cell death. Overall, this study reveals that the tuning of the surface properties of NPs allows us to regulate their biological outcomes by controlling their ability to adsorb serum proteins.


Assuntos
Nanopartículas Metálicas , Coroa de Proteína , Animais , Proteínas Sanguíneas , Fibroblastos , Nanopartículas Metálicas/toxicidade , Camundongos , Prata , Propriedades de Superfície
10.
Int J Mol Sci ; 22(16)2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34445511

RESUMO

We use coarse-grained molecular dynamics simulations to study adsorption on ligand-tethered particles. Nanoparticles with attached flexible and stiff ligands are considered. We discuss how the excess adsorption isotherm, the thickness of the polymer corona, and its morphology depend on the number of ligands, their length, the size of the core, and the interaction parameters. We investigate the adsorption-induced structural transitions of polymer coatings. The behavior of systems involving curved and flat "brushes" is compared.


Assuntos
Nanopartículas/química , Polímeros/química , Adsorção , Simulação por Computador , Ligantes , Modelos Moleculares , Simulação de Dinâmica Molecular , Propriedades de Superfície
11.
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
12.
Int J Mol Sci ; 22(16)2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34445213

RESUMO

Titanium surface is an important factor in achieving osseointegration during the early wound healing of dental implants in alveolar bone. The purpose of this study was to evaluate sandblasted-etched surface implants to investigate the osseointegration. In the present study, we used two different types of sandblasted-etched surface implants, an SLA™ surface and a Nanoblast Plus™ surface. Roughness and chemical composition were evaluated by a white light interferometer microscope and X-ray photoelectron spectroscopy, respectively. The SLA™ surface exhibited the higher values (Ra 3.05 µm) of rugosity compared to the Nanoblast Plus™ surface (Ra 1.78 µm). Both types of implants were inserted in the femoral condyles of ten New Zealand white rabbits. After 12 weeks, histological and histomorphometric analysis was performed. All the implants were osseointegrated and no signs of infection were observed. Histomorphometric analysis revealed that the bone-implant contact % (BIC) ratio was similar around the SLA™ implants (63.74 ± 13.61) than around the Nanoblast Plus™ implants (62.83 ± 9.91). Both implant surfaces demonstrated a favorable bone response, confirming the relevance of the sandblasted-etched surface on implant osseointegration.


Assuntos
Fêmur , Implantes Experimentais , Osseointegração , Titânio , Animais , Fêmur/lesões , Fêmur/metabolismo , Fêmur/patologia , Coelhos , Propriedades de Superfície
13.
Int J Mol Sci ; 22(15)2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34360861

RESUMO

In response to the demand for high-performance materials, epoxy thermosetting and its composites are widely used in various industries. However, their poor toughness, resulting from the high crosslinking density of the epoxy network, must be improved to expand their application to the manufacturing of flexible products. In this study, ductile epoxy thermosetting was produced using thiol compounds with functionalities of 2 and 3 as curing agents. The mechanical properties of the epoxy were further enhanced by incorporating fumed silica into it. To increase the filler dispersion, epoxide-terminated polydimethylsiloxane was synthesized and used as a composite component. Thanks to the polysiloxane-silica interaction, the nanosilica was uniformly dispersed in the epoxy composites, and their mechanical properties improved with increasing fumed silica content up to 5 phr (parts per hundred parts of epoxy resin). The toughness and impact strength of the composite containing 5 phr nanosilica were 517 (±13) MJ/m3 and 69.8 (±1.3) KJ/m2, respectively.


Assuntos
Resinas Compostas/síntese química , Resinas Epóxi/síntese química , Dimetilpolisiloxanos/química , Teste de Materiais , Dióxido de Silício/química , Propriedades de Superfície , Resistência à Tração
14.
Langmuir ; 37(32): 9694-9700, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34369779

RESUMO

Water-stable gold nanoparticle vesicles (GNVs) with hollow interiors have attracted attention due to their great potential for biological applications; however, their preparation through the self-assembly approaches has been restricted due to the limited understanding of their critical mechanistic issues. In this paper, we demonstrate that a fluorinated tetra (ethylene glycol) (FTEG)-terminated tetra (ethylene glycol) (EG4), namely, FTEG-EG4, ligand can self-assemble with gold nanoparticles (5 and 10 nm) into GNVs with a hollow structure in THF due to the solvophobic feature of the ligand. Time-dependent studies showed that the GNVs with a closely packed surface derived from the incomplete and irregular GNVs, but not through the fusion of the GNV precursors. After dialysis in water, the assemblies retained vesicular structures in water, even though GNVs aggregated together, which was initiated by the hydrophobic interactions between the FTEG heads of the surface ligands on GNVs. This study provides a new insight into the design of novel small surface ligands to produce water-stable GNVs for biological applications.


Assuntos
Ouro , Nanopartículas Metálicas , Etilenoglicol , Ligantes , Propriedades de Superfície , Água
15.
J Contemp Dent Pract ; 22(6): 630-636, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34393119

RESUMO

AIM AND OBJECTIVE: To chemically characterize restorative composite resin polymerized with 20 wt.% and 40 wt.% dipentaerythritol penta-/hexaacrylate (DPEPHA) comonomer. Furthermore, this study aimed to evaluate the conversion degree (DC) and glass transition temperature (Tg) of the newly formed copolymer. MATERIALS AND METHODS: The trial groups were photo-polymerized with DPEPHA comonomer, whereas the control group was photo-polymerized only with the propriety resin monomers. Infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies were used for establishing copolymerization. The characteristics and composition (mass %) of the surface were explained by field-emission scanning electron microscopy (FESEM) and energy-dispersive X-ray (EDX) spectroscopy, respectively. The DC and Tg of the resultant copolymers were evaluated through FTIR and differential scanning calorimetry, respectively. Appropriate statistical tests with corresponding post hoc tests were employed to compare the medians and means of DC and Tg, respectively. RESULTS: The formation of a new copolymer P(GEU-Co-DPEPHA) was evident. The DC and Tg of the P(GEU-Co-DPEPHA) copolymer were greater than the control. DPEPHA in the copolymer at 40 wt.% concentration showed the highest DC and Tg. CONCLUSION: DPEPHA comonomer addition leads to the formation of a new P(GEU-Co-DPEPHA) copolymer with improved DC and Tg. CLINICAL SIGNIFICANCE: The novel P(GEU-Co-DPEPHA) copolymer may improve the physico-mechanical and biological properties of the restorative composite resin. This would improve the quality of restoration and its in vivo serviceability, thereby imparting a good living quality to the entailed population.


Assuntos
Resinas Compostas , Vidro , Teste de Materiais , Metacrilatos , Polimerização , Propriedades de Superfície , Temperatura
16.
J Contemp Dent Pract ; 22(6): 655-664, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34393123

RESUMO

AIM AND OBJECTIVE: The present study assessed the influence of Azadirachta indica (AI) powder on the mechanical, surface, and optical properties of heat-polymerized polymethyl methacrylate (PMMA) denture base material. MATERIALS AND METHODS: A total of 300 heat-polymerized PMMA acrylic resin specimens were fabricated with dimensions of 65 × 10 × 3.3 ± 0.01 mm for flexural strength, 50 × 6 × 4 ± 0.01 mm for impact strength testing, and 15 × 2 ± 0.01 mm for surface roughness, hardness, and translucency testing. The specimens were distributed into six groups (n = 10) based on AI powder concentration: An unmodified control group and AI powder-modified groups with 0.5, 1, 1.5, 2, and 2.5 wt% of acrylic resin powder. Universal testing machine was used to measure flexural strength and Charpy's impact tester for impact strength. Surface roughness, hardness, and translucency were assessed using a profilometer, Vicker hardness tester, and spectrophotometer, respectively. One-way analysis of variance (ANOVA) and posthoc Scheffe's test were utilized; p ≤ 0.05 was considered a statistically significant difference. RESULTS: ANOVA showed no significant differences in terms of impact strength (p = 0.175) and surface roughness (p = 0.371), while significant differences were detected in terms of flexural strength, hardness, and translucency (p = 0.001). According to post hoc Scheffe's test, there was a significant decrease in flexural strength for AI groups (p < 0.001) except 0.5% AI group (p = 0.66), while impact strength had no significant difference between AI groups (p = 0.175). Hardness had an insignificant difference between control and modified groups (p>0.05), with exception of 2.5% AI group (p = 0.001). For translucency, a significant difference was found between control and all modified groups (p<0.05). CONCLUSION: Incorporating AI powder into heat-polymerized denture base material did not significantly alter impact strength, surface roughness, or hardness, except at 2.5% AI concentration, where hardness decreased. On the contrary, flexural strength and translucency were significantly affected. CLINICAL SIGNIFICANCE: This study contributes to establishing a new approach for denture stomatitis disease treatment and prevention with the lowest adverse effect on denture properties.


Assuntos
Azadirachta , Polimetil Metacrilato , Antifúngicos , Bases de Dentadura , Humanos , Teste de Materiais , Propriedades de Superfície
17.
Int J Mol Sci ; 22(16)2021 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-34445543

RESUMO

The current SARS-CoV-2 pandemic causes serious public health, social, and economic issues all over the globe. Surface transmission has been claimed as a possible SARS-CoV-2 infection route, especially in heavy contaminated environmental surfaces, including hospitals and crowded public places. Herein, we studied the deactivation of SARS-CoV-2 on photoactive AgNPs@TiO2 coated on industrial ceramic tiles under dark, UVA, and LED light irradiations. SARS-CoV-2 inactivation is effective under any light/dark conditions. The presence of AgNPs has an important key to limit the survival of SARS-CoV-2 in the dark; moreover, there is a synergistic action when TiO2 is decorated with Ag to enhance the virus photocatalytic inactivation even under LED. The radical oxidation was confirmed as the the central mechanism behind SARS-CoV-2 damage/inactivation by ESR analysis under LED light. Therefore, photoactive AgNPs@TiO2 ceramic tiles could be exploited to fight surface infections, especially during viral severe pandemics.


Assuntos
Cerâmica/química , Nanopartículas Metálicas/química , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/efeitos da radiação , Titânio/química , Antivirais/farmacologia , COVID-19/virologia , Humanos , Luz , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/efeitos da radiação , Pandemias , Tamanho da Partícula , SARS-CoV-2/metabolismo , Propriedades de Superfície , Inativação de Vírus/efeitos dos fármacos , Inativação de Vírus/efeitos da radiação
18.
Int J Oral Maxillofac Implants ; 36(4): 650-659, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34411204

RESUMO

PURPOSE: To evaluate whether a hydrophilic surface treatment compared with a hydrophobic implant surface can enhance osseointegration by analysis of calcium deposition, bone-to-implant contact (BIC), bone volume (BV), and upregulation of genes involved in bone formation. MATERIALS AND METHODS: Sixty implants (n = 60) with a hydrophobic (SAE) or hydrophilic (SAE-HD) surface treatment were placed bilaterally in each femur of 3-month-old male mice (n = 30). Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were utilized for quantifying the presence of calcium on the implant surface 7 days after implant placement. The specimens were analyzed after 14 and 21 days for BIC and BV by Nano CT scanning followed by histologic evaluation. Additionally, 1, 3, and 7 days postsurgery, femurs were harvested, implants were explanted, and gene expression (Sp7, Bsp, Sost, IL-1α, and IL-10) by quantitative real-time polymerase chain reaction was studied. Moreover, implants were characterized for surface roughness area. Data were statistically analyzed with two-way analysis of variance (ANOVA) followed by the Tukey test (P < .05). RESULTS: The amount of calcium on the surface was higher for SAE-HD after 7 days. Nano CT revealed significantly more BV in the SAE-HD than the SAE surface. The histologic assessment showed increased BIC in SAE-HD in comparison to SAE. SAEHD showed significantly increased levels of genes involved in bone formation. CONCLUSION: Both surfaces were able to modulate bone responses toward osteoblast differentiation. SAE-HD presented a better response compared with SAE.


Assuntos
Implantes Dentários , Titânio , Animais , Implantes Experimentais , Masculino , Camundongos , Microscopia Eletrônica de Varredura , Osseointegração , Propriedades de Superfície
19.
Gen Dent ; 69(5): 46-51, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34424212

RESUMO

The aim of this study was to evaluate the effects of different polishing techniques on the surface roughness and gloss of various composites. A total of 360 composite cylinders (6 mm in diameter and 2 mm in thickness) were made using a silicone matrix and 1 of the following 6 restorative materials (n = 60): Admira Fusion, GrandioSO, Filtek Supreme, Filtek Z250, TPH Spectra ST, and Herculite Classic. The composite specimens were cured and then immersed in water for 24 hours. The baseline roughness was standardized with 600-grit silicon carbide paper used in a polishing device for 30 seconds. The specimens were divided into 6 subgroups (n = 10) according to the polishing technique: abrasive discs (Sof-Lex); abrasive discs (Sof-Lex) and diamond paste (Diamond Excel); abrasive rubber point (Dimanto); silicon carbide polishing brush (OptiShine); rubber spiral wheels (Sof-Lex Spiral Wheels - Diamond Polishing System); or sequential application of polishing pastes (Diamond ACI and ACII). After polishing was completed, the surface roughness and gloss were measured, and the data underwent 2-way analysis of variance and the Tukey test (P < 0.05). Statistically significant differences were observed for roughness (P < 0.001) and gloss (P < 0.001) for both factors analyzed (composite material and polishing technique). Admira Fusion exhibited the highest roughness and lowest gloss values of all of the composites, and Filtek Supreme exhibited the lowest roughness and highest gloss values. Sof-Lex Spiral Wheels and OptiShine polishing brush exhibited lower roughness and higher gloss than the other polishing techniques. The effects of different polishing techniques were material dependent, but all systems tested provided clinically acceptable results. The use of a single polishing technique for all types of composite materials might result in undesirable clinical outcomes.


Assuntos
Materiais Dentários , Polimento Dentário , Humanos , Teste de Materiais , Propriedades de Superfície
20.
Phys Chem Chem Phys ; 23(33): 18001-18011, 2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34382985

RESUMO

A hydrophobic heptapeptide, with sequence AFILPTG, as part of a phage capsid protein binds effectively to silica particles carrying negative charge. Here, we explore the silica binding activity of the sequence as a short polypeptide with polar N and C terminals. To describe the structural changes that occur on binding, we fit experimental infrared, Raman and circular dichroism data for a number of structures simulated in the full configuration space of the hepta-peptide using replica exchange molecular dynamics. Quantum chemistry was used to compute normal modes of infrared and Raman spectra and establish a relationship to structures from MD data. To interpret the circular dichroism data, instead of empirical factoring of optical activity into helical/sheet/random components, we exploit natural transition orbital theory and specify the contributions of backbone amide units, side chain functional groups, water, sodium ions and silica to the observed transitions. Computed optical responses suggest a less folded backbone and importance of the N-terminal when close to silica. We further discuss the thermodynamics of the interplay of charged and hydrophobic moieties of the polypeptide on association with the silica surface. The outcomes of this study may assist in the engineering of novel artificial bio-silica heterostructures.


Assuntos
Oligopeptídeos/química , Dióxido de Silício/química , Teoria da Densidade Funcional , Interações Hidrofóbicas e Hidrofílicas , Nanopartículas/química , Desdobramento de Proteína , Dióxido de Silício/síntese química , Propriedades de Superfície
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