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1.
Mater Sci Eng C Mater Biol Appl ; 119: 111638, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33321676

RESUMEN

Different crystalline phases in sputtered TiO2 films were tailored to determine their surface and electrochemical properties, protein adsorption and apatite layer formation on titanium-based implant material. Deposition conditions of two TiO2 crystalline phases (anatase and rutile) were established and then grown on commercially pure titanium (cpTi) by magnetron sputtering to obtain the following groups: A-TiO2 (anatase), M-TiO2 (anatase and rutile mixture), R-TiO2 (rutile). Non-treated commercially pure titanium (cpTi) was used as a control. Surfaces characterization included: chemical composition, topography, crystalline phase and surface free energy (SFE). Electrochemical tests were conducted using simulated body fluid (SBF). Albumin adsorption was measured by bicinchoninic acid method. Hydroxyapatite (HA) precipitation was evaluated after 28 days of immersion in SBF. MC3T3-E1 cell adhesion, morphology and spreading onto the experimental surfaces were evaluated by scanning electron microscopy. Sputtering treatment modified cpTi topography by increasing its surface roughness. CpTi and M-TiO2 groups presented the greatest SFE. In general, TiO2 films displayed improved electrochemical behavior compared to cpTi, with M-TiO2 featuring the highest polarization resistance. Rutile phase exhibited a greater influence on decreasing the current density and corrosion rate, while the presence of a bi-phasic polycrystalline condition displayed a more stable passive behavior. M-TiO2 featured increased albumin adsorption. HA morphology was dependent on the crystalline phase, being more evident in the bi-phasic group. Furthermore, M-TiO2 displayed normal cell adhesion and morphology. The combination of anatase and rutile structures to generate TiO2 films is a promising strategy to improve biomedical implants properties including greater corrosion protection, higher protein adsorption, bioactivity and non-cytotoxicity effect.

2.
J Prosthet Dent ; 124(6): 815.e1-815.e7, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33268070

RESUMEN

STATEMENT OF PROBLEM: Exposure of silicone prostheses to environmental factors can alter their properties, affecting longevity. However, whether nonthermal plasma (NTP) can prevent these alterations is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the surface roughness (Ra), sorption, solubility, and color stability (ΔE00) of the MDX4-4210 and A-120 silicones, with and without NTP treatment in accordance with an independent analysis of the use of 2 pigmentations. MATERIAL AND METHODS: One hundred sixty specimens were fabricated and distributed into 16 groups (n=10) as per the silicone, pigmentation, and NTP coating. The NTP was applied, and the Ra, sorption, solubility, and ΔE00 were evaluated before and after accelerated aging. ANOVA was used, and the HSD Tukey test was applied (α=.05). RESULTS: NTP generated an increase in roughness after aging, regardless of pigmentation or silicone. A-120 silicone without NTP showed a reduction in roughness after aging, regardless of pigmentation. For sorption and solubility, the bronze pigmentation (for A-120 and MDX4-4210) presented the smallest results after NTP treatment. For MDX4-4210 with pink pigmentation and NTP, sorption decreased and solubility increased. For A-120 with pink pigmentation and NTP, sorption and solubility increased. Sorption was reduced in all situations, except for A-120 with pink pigmentation, which increased. Regardless of the silicone used, solubility was reduced after NTP for bronze pigmentation. For A-120 and MDX4-4210 with pink pigmentation and NTP, the solubility increased. For both pigmentations, the NTP treatment promoted lower color alteration only for the A-120 silicone after accelerated aging (within the acceptability threshold). CONCLUSIONS: The NTP protocol of this study, which was applied to facial silicones, generated inconsistent results between the evaluated properties. Therefore, the NTP protocol used does not seem to be ideal for the treatment of silicone surfaces after aging.

3.
J Esthet Restor Dent ; 2020 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-33045124

RESUMEN

OBJECTIVE: To evaluate the optical, chemical, and mechanical properties of feldspathic porcelain after handling with different instrument materials. MATERIAL AND METHODS: Feldspathic porcelain was manipulated with different spatula compositions: metal spatula (MS), plastic spatula (PS), and glass spatula (GS) for the fabrication of 30 (n = 10) disks. Contrast ratio (CR), translucency parameter (TP), and surface Knoop microhardness (KHN) were measured. The color change (ΔE00 ) was evaluated using the CIEDE2000 system. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used for surface analysis. Data were analyzed using one-way ANOVA and Tukey test (P < 0.05). RESULTS: All groups presented different morphological surfaces with higher presence of Al on the MS. PS group presented lower Al, Si, K than MS, and GS. Higher CR was observed for PS (0.734; P < 0.043), followed by MS (0.696; P < 0.043) and GS (0.65; P < 0.011). The highest TP (13.06) and KHN (386.27) were presented by GS (P < 0.001). MS and PS presented similar KHN results. The higher ΔE00 were found for plastic/metal comparison. Also, the L* values for the MS group (67.49) were lower than the other groups. CONCLUSION: The use of metal spatula promoted higher color alteration during feldspathic porcelain manipulation than did the other materials. Handling with glass instrument promoted higher microhardness than other spatula materials. CLINICAL SIGNIFICANCE: The effect of the material used for ceramic handling on feldspathic porcelain properties is often ignored. This study shows that the handling spatula material must be carefully chosen to avoid inadvertent changes to the feldspathic porcelain restoration.

4.
J Adhes Dent ; 22(5): 531-538, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33073784

RESUMEN

PURPOSE: To evaluate the roughness, surface energy, and the bond strength of lithium disilicate yielded by two different types of nonthermal plasma (NTP), oxygen- or argon-based, compared to the conventional method. MATERIALS AND METHODS: Ninety-three lithium disilicate (IPS e.max Press) samples were divided into 3 groups: HF (hydrofluoric acid group); ONTP (oxygen-based NTP group); ANTP (argon-based NTP group). Surface energy and roughness analyses were performed before and after surface treatment, and bond strength testing was performed before and after 5000 thermocycles. Scanning electron microscopy (SEM) was used to characterize the surface treatments. Data were submitted to ANOVA and Bonferroni's test with statistical significance set at 5%. RESULTS: The ONTP group presented the highest surface energy values, followed by ANTP and HF. In addition, the ONTP group had higher surface roughness. SEM revealed exposed lithium disilicate crystals in the HF group, but a homogeneous film coverage in both NTP groups. Regarding bond strength, ANTP presented statistically significantly higher values than the other groups before thermocycling, and statistically significantly lower values than the other groups after thermocycling. The HF and ONTP groups presented statistically similar values after thermocycling. CONCLUSION: The bond strength of resin cement to lithium disilicate obtained after oxygen-based NTP was comparable with that obtained after conventional hydrofluoric acid treatment.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Porcelana Dental , Propiedades de Superficie
5.
Mater Sci Eng C Mater Biol Appl ; 117: 111289, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32919650

RESUMEN

Our goal was to create bio-functional chlorhexidine (CHX)-doped thin films on commercially pure titanium (cpTi) discs using the glow discharge plasma approach. Different plasma deposition times (50, 35 and 20 min) were used to create bio-functional surfaces based on silicon films with CHX that were compared to the control groups [no CHX and bulk cpTi surface (machined)]. Physico-chemical and biological characterizations included: 1. Morphology, roughness, elemental chemical composition, film thickness, contact angle and surface free energy; 2. CHX-release rate; 3. Antibacterial effect on Streptococcus sanguinis biofilms at 24, 48 and 72 h; 4. Cytotoxicity and metabolic activity using fibroblasts cell culture (NIH-F3T3 cells) at 1, 2, 3 and 4 days; 5. Protein expression by NIH-F3T3 cells at 1, 2, 3 and 4 days; and 6. Co-culture assay of fibroblasts cells and S. sanguinis to assess live and dead cells on the confocal laser scanning microscopy, mitochondrial activity (XTT), membrane leakage (LDH release), and metabolic activity (WST-1 assay) at 1, 2 and 3 days of co-incubation. Data analysis showed that silicon films, with or without CHX coated cpTi discs, increased surface wettability and free energy (p < 0.05) without affecting surface roughness. CHX release was maintained over a 22-day period and resulted in a significant inhibition of biofilm growth (p < 0.05) at 48 and 72 h of biofilm formation for 50 min and 20 min of plasma deposition time groups, respectively. In general, CHX treatment did not significantly affect NIH-F3T3 cell viability (p > 0.05), whereas cell metabolism (MTT assay) was affected by CHX, with the 35 min of plasma deposition time group displaying the lowest values as compared to bulk cpTi (p < 0.05). Moreover, data analysis showed that films, with or without CHX, significantly affected the expression profile of inflammatory cytokines, including IL-4, IL-6, IL-17, IFN-y and TNF-α by NIH-F3T3 cells (p < 0.05). Co-culture demonstrated that CHX-doped film did not affect the metabolic activity, cytotoxicity and viability of fibroblasts cells (p > 0.05). Altogether, the findings of the current study support the conclusion that silicon films added with CHX can be successfully created on titanium discs and have the potential to affect bacterial growth and inflammatory markers without affecting cell viability/proliferation rates.

6.
Arch Oral Biol ; 117: 104822, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32592931

RESUMEN

OBJECTIVE: Overcoming substantial shortcomings of soft liners as physico-chemical changes and liner-biofilm-related infections remains a challenge in the rehabilitation treatment. In this study, protective non-thermal plasma (NTP) treatments were developed on the soft liner surface to improve its surface and physico-chemical properties and to reduce fungal colonization after biofilm inhibition challenge. METHODS: Resinous liner specimens (Coe-Soft) were prepared and distributed in 3 groups according to the surface treatments: (1) untreated (control); (2) treated with sulfur hexafluoride-based NTP (SF6); and (3) treated with hexamethyldisiloxane-based NTP (HMDSO). To test the NTP stability and their protective and antimicrobial effect on the liner surface over time, the morphology, chemical composition, roughness, water contact angle, shore A hardness, sorption and solubility were evaluated before and after the specimens were exposed to dual-species biofilm of Candida albicans and Streptococcus oralis for 14 days. Colony forming units and biofilm structure were assessed. Data were submitted to ANOVA and Tukey tests (α = 0.05). RESULTS: Both treatments modified the surface morphology, increased hydrophobicity and roughness of the liner, and were effective to reduce C. albicans adhesion without affecting the commensal health-associated S. oralis. HMDSO presented chemical stability and lower hardness in both periods, whereas SF6 exhibited higher initial hardness than control and the highest sorption; contrarily, similar solubility was noted for all groups. CONCLUSION: HMDSO-based film showed improved physico-chemical properties and inhibited C. albicans biofilm. Thus, it has potential for use to control candida-related stomatitis and improve liner's stability even after being exposed to biofilm inhibition challenge.


Asunto(s)
Antiinfecciosos , Biopelículas , Alineadores Dentales , Gases em Plasma , Antiinfecciosos/farmacología , Candida albicans , Ensayo de Materiales , Gases em Plasma/farmacología , Streptococcus oralis , Propiedades de Superficie
7.
J Clin Exp Dent ; 12(2): e103-e107, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32071690

RESUMEN

Background: Different ceramic surface cleaning methods have been suggested after the acid conditioning. The aim was to evaluate the effect of different protocols used to remove the remaining hydrofluoric acid on the shear bond strength (SBS) between lithium disilicate and resin cement. Material and Methods: Forty-four specimens of lithium disilicate (IPS e.max Press) were divided in 4 groups (n=11): group C (control, no treatment); group HF+S (5% hydrofluoric acid + silane); group HF+US+S (5% hydrofluoric acid + ultrasound cleaning + silane); group HF+PH+S (5% hydrofluoric acid + 37% phosphoric acid + silane). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were performed to characterize the surface morphology. The SBS test was performed on the resin/ceramic interface, and the failure mode was characterized. SBS values were submitted to 1-way ANOVA and the Tukey test (α=.05). The relation between surface treatment and failure modes was analyzed using the chi-squared test (α=.05). Results: The surface treatment type interfered in the shear strength (p<.001) and higher SBS values were observed for the groups HF+US+S (17.87 MPa) and HF+PH+S (16.37 MPa). The surface treatment did not influence the failure mode (p=.713). No fluorsilicate salts were observed after ultrasound cleaning. Conclusions: The utilization of ultrasound cleaning was an effective procedure to remove remaining fluorsilicate salts, promoting the highest SBS values. Key words:Bond strength, ceramics, fluorsilicate, lithium disilicate, resin cement.

8.
J Prosthodont ; 28(6): 692-700, 2019 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31125155

RESUMEN

PURPOSE: To investigate the influence of nonthermal plasma (NTP) treatment on the tensile bond strength between heat-polymerized acrylic resin for ocular prostheses and silicone reliner, with and without the use of an adhesive primer. MATERIALS AND METHODS: One-hundred and sixty-four acrylic resin specimens were fabricated and randomly distributed into four groups according to the type of surface treatment: Sofreliner Primer, NTP, Sofreliner Primer + NTP, and NTP + Sofreliner Primer. Two specimens interposed with relining material (Sofreliner) formed one test sample to perform the tensile bond strength tests, before (initial) and after storage (final) in saline solution (37°C, 90 days, n = 10). Surface characterization was performed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The failure type was classified as cohesive, adhesive, or mixed. The data were analyzed statistically using the two-way ANOVA and Tukey test, as well as the chi-squared test (α = 0.05), Bonferroni correction (α = 0.005), and Spearman correlation coefficient (α = 0.05). RESULTS: The SEM and EDS analyses showed the presence of a thin, homogenous organic film in the groups treated with NTP. The NTP + Sofreliner Primer group presented the largest bond strength mean values in the initial period (p < 0.05). Sofreliner Primer and NTP + Sofreliner Primer groups presented the first and second largest tensile bond strength mean values in the final period (p < 0.05), respectively. NTP + Sofreliner Primer group also had the largest number of cohesive (70%, initial) and mixed (90%, final) failures. CONCLUSIONS: The NTP treatment performed before the primer application enhanced the bond between the acrylic resin ocular prosthesis and the Sofreliner silicone-based reliner, even after 90 days of immersion in saline solution.


Asunto(s)
Recubrimiento Dental Adhesivo , Siliconas , Resinas Acrílicas , Cementos Dentales , Análisis del Estrés Dental , Ojo Artificial , Ensayo de Materiales , Propiedades de Superficie , Resistencia a la Tracción
9.
Mater Sci Eng C Mater Biol Appl ; 101: 111-119, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31029304

RESUMEN

The aim of this study was to tailor the deposition parameters of magnetron sputtering to synthetize tantalum oxide (TaxOy) films onto commercially pure titanium (cpTi) surface. The structural and optical properties, morphology, roughness, elemental chemical composition and surface energy were assessed. The impact of TaxOy films on initial Streptococcus sanguinis adhesion was investigated. The morphology and spreading of pre-osteoblastic (MC3T3-E1) cells on a crystalline tantalum oxide film were evaluated. TaxOy films with estimated thickness of 600 nm and different structures (amorphous or crystalline) were produced depending on the various oxygen flow rates and parameters used. X-ray diffraction analysis revealed that the 8 O2 sccm (600 °C/400 W) group showed crystallization corresponding to the ß-Ta2O5 phase. Optical analysis showed that the 4 O2 sccm (200 °C 300 W) to 8 O2 sccm (600 °C 300 W) groups and 10 O2 sccm (200 °C 300 W) group presented regular and large-amplitude interference oscillations, suggesting high optical homogeneity of the films. The crystalline ß-Ta2O5 coating showed higher roughness and surface energy values than the other groups (P < .05) and was biocompatible. Compared with cpTi, the amorphous and crystalline tantalum oxide films did not increase bacterial adhesion (P > .05). By tailoring the deposition parameters, we synthetized a crystalline ß-Ta2O5 coating that improved titanium surface properties and positively affected cell spreading and morphology, making it a promising surface treatment for titanium-based implants.


Asunto(s)
Materiales Biocompatibles/química , Tecnología Biomédica/métodos , Tantalio/química , Animales , Línea Celular , Materiales Biocompatibles Revestidos/química , Ratones , Osteoblastos/citología , Osteoblastos/ultraestructura , Refractometría , Termodinámica , Difracción de Rayos X
10.
J Prosthet Dent ; 119(3): 397-403, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-28689901

RESUMEN

STATEMENT OF PROBLEM: The properties, such as softness and viscoelasticity, of a resinous reliner can deteriorate and extrinsic elements can become incorporated, making surface protection of the reliner material essential. PURPOSE: The purpose of this in vitro study was to evaluate the effect of low temperature plasma on Coe-Soft resinous reliner, submitted to aging in artificial saliva for up to 180 days. Sorption, solubility, Shore A hardness, surface energy, and topographic characteristics were analyzed by scanning electronic microscopy (SEM) and energy-dispersive spectroscopy (EDS). MATERIAL AND METHODS: Forty-four specimens were fabricated and distributed in 2 groups: nonplasma reliner (control group) and reliner with plasma (plasma group). The plasma was applied with a mixture of 70% hexamethyldisiloxane, 20% O, and 10% Ar. Total work pressure was maintained at a constant 20 Pa for 30 minutes of deposition. The specimens were analyzed before and after aging in an incubator with immersion in artificial saliva for 30, 90, and 180 days. The quantitative data were submitted to 2-way ANOVA and the Tukey test (α=.05), while qualitative data were compared visually. RESULTS: The control group presented lower Shore A hardness values only in the initial period, and surface energy increased with aging for both groups until 90 days. Greater sorption percentage values were encountered at 180 days in the plasma group. Greater solubility values were encountered in the control group in all periods. CONCLUSIONS: Plasma is an option for the protection of the material studied because the deposited film remained on the surface of the reliner material after aging.


Asunto(s)
Alineadores Dentales , Ensayo de Materiales , Gases em Plasma/química , Dureza , Humanos , Técnicas In Vitro , Microscopía Electrónica de Rastreo , Saliva Artificial , Siloxanos , Espectrometría por Rayos X
11.
Mater Sci Eng C Mater Biol Appl ; 71: 755-763, 2017 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-27987770

RESUMEN

The material used for interim prostheses fabrication must present excellent physical properties for greater longevity in the face of environmental conditions, which can occur in the oral cavity. The purpose of this study was to evaluate the effect of a photopolymerized glaze on the physical and mechanical properties of polymers used for the fabrication of interim prostheses, before and after thermocycling and immersion in staining solutions. One hundred samples of composite and acrylic resins were fabricated: Dencor chemically activated acrylic resin (CAAR) (n=20) and heat-polymerized acrylic resin (HPAR) (n=20), Charisma (n=20), Structur (n=20), and Protemp (n=20). A mechanical polishing was performed on half of the samples, and a chemical polishing was performed on the remaining samples. Subsequently, all samples were submitted to thermocycling and immersion in coffee staining solution for 21days. Analysis of color and microhardness, as well as atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive x-ray spectrometry (EDS) were performed. The data were submitted to repeated-measures analysis of variance (ANOVA), followed by the Tukey test (α=0.05) and the Student t-test (α=0.05). It was verified that the glaze decreased the chromatic alteration values, and increased the microhardness values of the samples, with the exception of the Charisma resin. The samples that did not receive chemical polishing had the greatest number of surface irregularities. This study concluded that the groups with glaze presented less color alteration. In addition, Charisma and Structur resins exhibited the greatest chromatic stability. As to the microhardness, the values were greater when the samples were treated with the glaze, with the exception of the Charisma group.


Asunto(s)
Luz , Polimerizacion , Polímeros/química , Prótesis e Implantes , Análisis de Varianza , Color , Dureza , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Propiedades de Superficie
12.
Mater Sci Eng C Mater Biol Appl ; 72: 284-292, 2017 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-28024588

RESUMEN

There is no established protocol for bonding zirconia (Y-TZP) with resin cements. Non-thermal plasma (NTP) may be an alternative for the clinical problems related to adhesion. The purpose of the present study was to characterize the surface of Y-TZP exposed to methane (CH4) NTP or coated with a layer of primer for metal alloys and the association between the two methods and to evaluate the effect of NTP treatment on bond strength between Y-TZP and two resin cements. A total of 235 Y-TZP discs (8×2mm) were distributed into five groups: Co (no surface treatment), Pr (primer), NTP (methane plasma), Pr+NTP and NTP+Pr. The effect of the treatment type on the surface free energy, morphology, topography and chemical composition of the Y-TZP discs was investigated. The discs were cemented to composite resin substrates using Panavia F2.0 or RelyX U200. Shear bond strength (n=10) analyses were performed (1mm/min) before and after thermocycling (5-55°C, 2000cycles) on the bonded specimens. The data were analyzed with one and three-way ANOVAs and Bonferroni tests (α=0.05). NTP reduced the surface energy and roughness of the Y-TZP discs. SEM-EDS and XPS analyses showed the presence of the organic thin film, which significantly improved the bond strength results when Rely X U200 was used, whereas the primer treatment was more effective with Panavia F2.0. Thermocycling significantly reduced the bond strength results of the NTP and Pr+NTP groups cemented with Rely X U200 and the Pr and NTP+Pr groups cemented with Panavia F2.0. Nonthermal plasma improves the bond strength between Rely X U200 and Y-TZP and also seems to have water-resistant behavior, whereas Panavia F2.0 showed better results when associated with primer.


Asunto(s)
Aleaciones/química , Gases em Plasma/química , Cementos de Resina/química , Circonio/química , Metano/química , Microscopía Electrónica de Rastreo , Espectroscopía de Fotoelectrones , Resistencia al Corte , Espectrometría por Rayos X , Propiedades de Superficie
13.
PeerJ ; 4: e2756, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-28028459

RESUMEN

Exceptionally well-preserved three-dimensional insects with fine details and even labile tissues are ubiquitous in the Crato Member Konservat Lagerstätte (northeastern Brazil). Here we investigate the preservational pathways which yielded such specimens. We employed high resolution techniques (EDXRF, SR-SXS, SEM, EDS, micro Raman, and PIXE) to understand their fossilisation on mineralogical and geochemical grounds. Pseudomorphs of framboidal pyrite, the dominant fossil microfabric, display size variation when comparing cuticle with inner areas or soft tissues, which we interpret as the result of the balance between ion diffusion rates and nucleation rates of pyrite through the originally decaying carcasses. Furthermore, the mineral fabrics are associated with structures that can be the remains of extracellular polymeric substances (EPS). Geochemical data also point to a concentration of Fe, Zn, and Cu in the fossils in comparison to the embedding rock. Therefore, we consider that biofilms of sulphate reducing bacteria (SRB) had a central role in insect decay and mineralisation. Therefore, we shed light on exceptional preservation of fossils by pyritisation in a Cretaceous limestone lacustrine palaeoenvironment.

14.
Mater Sci Eng C Mater Biol Appl ; 69: 995-1003, 2016 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-27612795

RESUMEN

The effect of a photopolymerized glaze on different properties of acrylic resin (AR) for ocular prostheses submitted to accelerated aging was investigated. Forty discs were divided into 4 groups: N1 AR without glaze (G1); colorless AR without glaze (G2); N1 AR with glaze (G3); and colorless AR with glaze (G4). All samples were polished with sandpaper (240, 600 and 800-grit). In G1 and G2, a 1200-grit sandpaper was also used. In G3 and G4, samples were coated with MegaSeal glaze. Property analysis of color stability, microhardness, roughness, and surface energy, and assays of atomic force microscopy, scanning electron microscopy, and energy-dispersive spectroscopy were performed before and after the accelerated aging (1008h). Data were submitted to the ANOVA and Tukey Test (p<0.05). Groups with glaze exhibited statistically higher color change and roughness after aging. The surface microhardness significantly decreased in groups with glaze and increased in groups without glaze. The surface energy increased after the aging, independent of the polishing procedure. All groups showed an increase of surface irregularities. Photopolymerized glaze is an inadequate surface treatment for AR for ocular prostheses and it affected the color stability, roughness, and microhardness. The accelerated aging interfered negatively with the properties of resins.


Asunto(s)
Resinas Acrílicas/química , Ojo Artificial , Luz , Polimerizacion , Dureza , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Factores de Tiempo
15.
Toxicol In Vitro ; 36: 180-185, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27521695

RESUMEN

The aim of this study was to evaluate the influence of pigment incorporation on the cytotoxicity of ocular prosthesis N1 color acrylic resin. Nine samples were manufactured by heat-polymerization in water bath and divided into 3 groups: acrylic resin without pigment incorporation (group R), acrylic resin with pigment incorporation (group RP), and acrylic pigment (group P). Eluates formed after 72h of sample immersion in medium were incubated with conjunctival cell line (Chang conjunctival cells) for 72h. The negative control group consisted in medium without samples (group C). The cytotoxic effect from the eluates was evaluated using MTT assay (cell proliferation), ELISA assay (quantification of IL1ß, IL6, TNF α and CCL3/MIP1α) and RT-PCR assay (mRNA expression of COL IV, TGF ß and MMP9). Data were submitted to ANOVA with Bonferroni post-tests (p<0.05). All groups were considered non-cytotoxic based on cell proliferation. However, resin with pigment incorporation showed significant IL6 quantity increase. Resin without pigment incorporation exhibited higher mRNA expression of COL IV, MMP9 and TGF ß, however it was also observed for the negative control group. The materials exhibited divergent biological behavior. Despite the pigment incorporation that resulted in an increase of IL6, no cytotoxicity was observed based on cell proliferation.


Asunto(s)
Resinas Acrílicas/toxicidad , Colorantes/toxicidad , Conjuntiva/citología , Ojo Artificial , Línea Celular , Proliferación Celular/efectos de los fármacos , Colágeno Tipo IV/genética , Humanos , Metaloproteinasa 9 de la Matriz/genética , ARN Mensajero/metabolismo , Factor de Crecimiento Transformador beta/genética
16.
J Prosthet Dent ; 115(6): 780-7, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26803181

RESUMEN

STATEMENT OF PROBLEM: Nonthermal plasma (NTP) treatment is an alternative technique for promoting the adhesion of resin cement to lithium disilicate ceramic. However, no study has evaluated whether the surface modifications are affected by atmospheric air aging. PURPOSE: The purposes of this in vitro study were to characterize the lithium disilicate surface after depositing an organosilicon film with NTP treatment and to verify the surface energy before and after atmospheric air aging up to 30 days. MATERIAL AND METHODS: Sixteen lithium disilicate disks (10×3 mm) were prepared, and their surfaces were treated with a mixture of hexamethyldisiloxane and argon, followed by oxygen plasma treatment, both for 30 minutes. The lithium disilicate surface was characterized through scanning electron microscopy, energy-dispersive spectroscopy, and atomic force microscopy. Surface energy analysis was performed before (T0) and immediately after NTP treatment (T1) and after atmospheric air aging for 7 (T2), 15 (T3), and 30 days (T4). Data were submitted to analysis of variance followed by the Tukey HSD test (α=.05). RESULTS: Carbon, oxygen, and silicon were identified on the disilicate surface after NTP treatment, suggesting organosilicon film adhesion. Air aging did not modify the film morphology. At T1, the surface energy was significantly higher compared with other periods, and the water contact angle on the disilicate surface was reduced to 0 degrees. Similar surface energy was observed for T0, T2, T3, and T4. CONCLUSIONS: On the basis of the results of this in vitro study, NTP treatment can promote bonding to lithium disilicate surfaces because of its high surface wettability. However, after air aging, the wettability was not durable.


Asunto(s)
Cerámica , Materiales Dentales , Porcelana Dental , Atmósfera , Recubrimiento Dental Adhesivo/métodos , Técnicas In Vitro , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Propiedades de Superficie
17.
Mater Sci Eng C Mater Biol Appl ; 60: 37-44, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26706504

RESUMEN

The effect of nonthermal plasma on the surface characteristics of commercially pure titanium (cp-Ti), and on the shear bond strength between an autopolymerizing acrylic resin and cp-Ti was investigated. A total of 96 discs of cp-Ti were distributed into four groups (n=24): Po (no surface treatment), SB (sandblasting), Po+NTP and SB+NTP (methane plasma). Surface characterization was performed through surface energy, surface roughness, scanning microscopy, energy dispersive spectroscopy, and X-ray diffraction tests. Shear bond strength test was conducted immediately and after thermocycling. Surface treatment affected the surface energy and roughness of cp-Ti discs (P<.001). SEM-EDS showed the presence of the carbide thin film. XRD spectra revealed no crystalline phase changes. The SB+NTP group showed the highest bond strength values (6.76±0.70 MPa). Thermocycling reduced the bond strength of the acrylic resin/cp-Ti interface (P<.05), except for Po group. NTP is an effective treatment option for improving the shear bond strength between both materials.


Asunto(s)
Resinas Acrílicas/química , Titanio/química , Porcelana Dental/química , Ensayo de Materiales , Cementos de Resina/química , Resistencia al Corte , Propiedades de Superficie
18.
J Adhes Dent ; 17(5): 413-9, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26525005

RESUMEN

PURPOSE: The purpose of this study was twofold: 1) to characterize the zirconia (Y-TZP) surfaces through scanning electronic microscopy associated with energy-dispersive spectroscopy and atomic force microscopy after the deposition of a thin organosilicon film by nonthermal plasma (NTP) treatment, and 2) to determine the zirconia surface hydrophilicity, before and after aging, through surface energy analysis. MATERIALS AND METHODS: Surfaces of 16 zirconia disks (10 x 3 mm) were treated for 30 min each with hexamethyldisiloxane and argon plasmas, followed by oxygen plasma. Disks were analyzed before NTP treatment, immediately after NTP treatment, and after aging for 7, 15, and 30 days. The surface energy of the Y-TZP disks was measured with a goniometer. Quantitative data were submitted to statistical analysis using ANOVA and Tukey's test (p < 0.05). RESULTS: Immediately after NTP treatment, the surface energy of the zirconia disks was significantly higher than at any other tested period (p < 0.001), and the water contact angle on the zirconia disks was reduced to 0 degrees. Similar surface energy results were obtained before NTP treatment and after 15 or 30 days of aging (p > 0.05; Tukey's test). Energy-dispersive spectroscopy results revealed the presence of carbon, oxygen, and silicon on the surface after NTP treatment. CONCLUSION: NTP treatment was useful for treating the zirconia surface for cementation procedures, as it produced a high level of hydrophilicity on the zirconia surface. However, this high level of hydrophilicity did not persist after aging.


Asunto(s)
Aire , Materiales Biocompatibles Revestidos/química , Gases em Plasma/química , Itrio/química , Circonio/química , Argón/química , Carbono/análisis , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Ensayo de Materiales , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Oxígeno/análisis , Oxígeno/química , Silicio/análisis , Siloxanos/química , Espectrometría por Rayos X , Propiedades de Superficie , Tensión Superficial , Factores de Tiempo , Humectabilidad
19.
Am J Dent ; 28(3): 174-80, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26201230

RESUMEN

PURPOSE: To analyze whether immersion in sodium fluoride (NaF) solutions and/or common acidic beverages (test solutions) would affect the surface roughness or topography of lithium disilicate ceramic. METHODS: 220 ceramic discs were divided into four groups, each of which was subdivided into five subgroups (n = 11). Control group discs were immersed in one of four test beverages for 4 hours daily or in artificial saliva for 21 days. Discs in the experimental groups were continuously immersed in 0.05% NaF, 0.2% NaF, or 1.23% acidulated phosphate fluoride (APF) gel for 12, 73, and 48 hours, respectively, followed by immersion in one of the four test beverages or artificial saliva. Vickers microhardness, surface roughness, scanning electron microscopy (SEM) associated with energy dispersive spectroscopy, and atomic force microscopy (AFM) assessments were made. Data were analyzed by nested analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS: Immersion in the test solutions diminished the microhardness and increased the surface roughness of the discs. The test beverages promoted a significant reduction in the Vickers microhardness in the 0.05% and 0.2% NaF groups. The highest surface roughness results were observed in the 0.2% NaF and 1.23% APF groups, with similar findings by SEM and AFM. Acidic beverages affected the surface topography of lithium disilicate ceramic. Fluoride treatments may render the ceramic surface more susceptible to the chelating effect of acidic solutions.


Asunto(s)
Bebidas , Cariostáticos/química , Porcelana Dental/química , Fluoruros/química , Fluoruro de Fosfato Acidulado/química , Bebidas Gaseosas , Citrus sinensis , Café , Microanálisis por Sonda Electrónica , Frutas , Dureza , Humanos , Concentración de Iones de Hidrógeno , Ensayo de Materiales , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Saliva Artificial/química , Fluoruro de Sodio/química , Propiedades de Superficie , Factores de Tiempo , Vino
20.
J Prosthet Dent ; 112(5): 1156-63, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24928773

RESUMEN

STATEMENT OF PROBLEM: Surface transformation with nonthermal plasma may be a suitable treatment for dental ceramics, because it does not affect the physical properties of the ceramic material. PURPOSE: The purpose of this study was to characterize the chemical composition of lithium disilicate ceramic and evaluate the surface of this material after nonthermal plasma treatment. MATERIAL AND METHODS: A total of 21 specimens of lithium disilicate (10 mm in diameter and 3 mm thick) were fabricated and randomly divided into 3 groups (n=7) according to surface treatment. The control group was not subjected to any treatment except surface polishing with abrasive paper. In the hydrofluoric acid group, the specimens were subjected to hydrofluoric acid gel before silane application. Specimens in the nonthermal plasma group were subjected to the nonthermal plasma treatment. The contact angle was measured to calculate surface energy. In addition, superficial roughness was measured and was examined with scanning electron microscopy, and the chemical composition was characterized with energy-dispersive spectroscopy analysis. The results were analyzed with ANOVA and the Tukey honestly significant difference test (α=.05). RESULTS: The water contact angle was decreased to 0 degrees after nonthermal plasma treatment. No significant difference in surface roughness was observed between the control and nonthermal plasma groups. Scanning electron microscopy and energy-dispersive spectroscopy images indicated higher amounts of oxygen (O) and silicon (Si) and a considerable reduction in carbon (C) in the specimens after nonthermal plasma treatment. CONCLUSIONS: Nonthermal plasma treatment can transform the characteristics of a ceramic surface without affecting its surface roughness. A reduction in C levels and an increase in O and Si levels were observed with the energy-dispersive spectroscopy analysis, indicating that the deposition of the thin silica film was efficient.


Asunto(s)
Cerámica/química , Porcelana Dental/química , Gases em Plasma/química , Grabado Ácido Dental/métodos , Argón/química , Carbono/análisis , Pulido Dental/instrumentación , Calor , Humanos , Ácido Fluorhídrico/química , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oxígeno/análisis , Distribución Aleatoria , Silanos/química , Silicio/análisis , Dióxido de Silicio/química , Siloxanos/química , Espectrometría por Rayos X , Propiedades de Superficie , Tensión Superficial , Factores de Tiempo , Humectabilidad
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