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1.
ACS Appl Mater Interfaces ; 13(27): 31355-31370, 2021 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-34218662

RESUMEN

The development of cancer resistance continues to represent a bottleneck of cancer therapy. It is one of the leading factors preventing drugs to exhibit their full therapeutic potential. Consequently, it reduces the efficacy of anticancer therapy and causes the survival rate of therapy-resistant patients to be far from satisfactory. Here, an emerging strategy for overcoming drug resistance is proposed employing a novel two-dimensional (2D) nanomaterial polysiloxane (PSX). We have reported on the synthesis of PSX nanosheets (PSX NSs) and proved that they have favorable properties for biomedical applications. PSX NSs evinced unprecedented cytocompatibility up to the concentration of 300 µg/mL, while inducing very low level of red blood cell hemolysis and were found to be highly effective for anticancer drug binding. PSX NSs enhanced the efficacy of the anticancer drug doxorubicin (DOX) by around 27.8-43.4% on average and, interestingly, were found to be especially effective in the therapy of drug-resistant tumors, improving the effectiveness of up to 52%. Fluorescence microscopy revealed improved retention of DOX within the drug-resistant cells when bound on PSX NSs. DOX bound on the surface of PSX NSs, i.e., PSX@DOX, improved, in general, the DOX cytotoxicity in vitro. More importantly, PSX@DOX reduced the growth of DOX-resistant tumors in vivo with 3.5 times better average efficiency than the free drug. Altogether, this paper represents an introduction of a new 2D nanomaterial derived from silicane and pioneers its biomedical application. As advances in the field of material synthesis are rapidly progressing, novel 2D nanomaterials with improved properties are being synthesized and await thorough exploration. Our findings further provide a better understanding of the mechanisms involved in the cancer resistance and can promote the development of a precise cancer therapy.


Asunto(s)
Doxorrubicina/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Neoplasias Ováricas/tratamiento farmacológico , Siloxanos/farmacología , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Modelos Animales de Enfermedad , Doxorrubicina/uso terapéutico , Femenino , Humanos , Ensayo de Materiales , Ratones , Nanoestructuras/química , Siloxanos/química
2.
Int J Mol Sci ; 22(11)2021 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-34200185

RESUMEN

Segmented polyurethane ionomers find prominent applications in the biomedical field since they can combine the good mechanical and biostability properties of polyurethanes (PUs) with the strong hydrophilicity features of ionomers. In this work, PU ionomers were prepared from a carboxylated diol, poly(tetrahydrofuran) (soft phase) and a small library of diisocyanates (hard phase), either aliphatic or aromatic. The synthesized PUs were characterized to investigate the effect of ionic groups and the nature of diisocyanate upon the structure-property relationship. Results showed how the polymer hard/soft phase segregation was affected by both the concentration of ionic groups and the type of diisocyanate. Specifically, PUs obtained with aliphatic diisocyanates possessed a hard/soft phase segregation stronger than PUs with aromatic diisocyanates, as well as greater bulk and surface hydrophilicity. In contrast, a higher content of ionic groups per polymer repeat unit promoted phase mixing. The neutralization of polymer ionic groups with silver or zinc further increased the hard/soft phase segregation and provided polymers with antimicrobial properties. In particular, the Zinc/PU hybrid systems possessed activity only against the Gram-positive Staphylococcus epidermidis while Silver/PU systems were active also against the Gram-negative Pseudomonas aeruginosa. The herein-obtained polyurethanes could find promising applications as antimicrobial coatings for different kinds of surfaces including medical devices, fabric for wound dressings and other textiles.


Asunto(s)
Materiales Biocompatibles/farmacología , Transición de Fase , Poliuretanos/farmacología , Pseudomonas aeruginosa/efectos de los fármacos , Plata/química , Staphylococcus epidermidis/efectos de los fármacos , Zinc/química , Ensayo de Materiales , Resistencia a la Tracción
3.
J Biol Regul Homeost Agents ; 35(2 Suppl. 1): 195-204, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34281317

RESUMEN

Graphene-doping procedure represents a useful procedure to improve the mechanical, physical and biological response of several PMMA-derived polymers and biomaterials for dental applications. The aim of the study was to evaluate measure water sorption, water solubility and tolerance trough the rabbit pyrogen testing pyrogen detection of Graphene doped Poly (methyl methacrylate) (PMMA) compared with PMMA as potential materials for dental implant device. A total of 8 aged and unaged samples Graphene doped PMMA and PMMA were tested for water sorption and water solubility of the specimens. The experimental condition was evaluated according to the ISO 20795-1:2013 protocol. The biopolymer tolerance was evaluated in vivo on animals through the pyrogen detection test, acute intracutaneous and systemic irritation test. After wet conditioning both of Graphene doped PMMA and PMMA reported an increase of the weight. All the experimental samples showed a drastic low level of water sorption and solubility. Graphene doped PMMA unaged specimens showed a stability of physical and optical feature after the treatment. The Graphene doped PMMA has not shown pyrogens, an intradermal and systemic irritant effect on animals. The Graphene-doped PMMA satisfy the standard requirements and provide a physical and optical stability of the compound after the treatment. Further in vivo findings are required for future clinical application of the compound.


Asunto(s)
Implantes Dentales , Grafito , Animales , Biopolímeros , Ensayo de Materiales , Metacrilatos , Polimetil Metacrilato , Conejos
4.
J Biol Regul Homeost Agents ; 35(2 Suppl. 1): 241-251, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34281322

RESUMEN

The research is aiming to obtain at room temperature a new ceramic material containing partially stabilized zirconia with different oxides after sintering used for dental and other technological purposes. Our research proposes a new method based on the use of stabilized zirconia with other oxides to obtain optimized dental material with a lower cost price and / or improved properties to allow wider use of these products to an increased number of patients in dental offices. X-ray diffraction, SEM analysis. FTIR spectroscopy, UVVis and density measurements were accomplished for the three ceramic systems. The correlation between the microstructure and the spectroscopic properties of zirconium stabilized by FTIR spectroscopy, UV-Vis helps understanding the mechanisms associated with the formation of high (tetragonal and / or cubic) temperature zirconia. Along with the simple, less costly preparation method and high purity of the ceramic products our study offers a highly desirable product for technological applications.


Asunto(s)
Cerámica , Circonio , Humanos , Ensayo de Materiales , Propiedades de Superficie , Difracción de Rayos X
5.
Int J Mol Sci ; 22(12)2021 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-34199262

RESUMEN

As the number of manned space flights increase, studies on the effects of microgravity on the human body are becoming more important. Due to the high expense and complexity of sending samples into space, simulated microgravity platforms have become a popular way to study these effects on earth. In addition, simulated microgravity has recently drawn the attention of regenerative medicine by increasing cell differentiation capability. These platforms come with many advantages as well as limitations. A main limitation for usage of these platforms is the lack of high-throughput capability due to the use of large cell culture vessels. Therefore, there is a requirement for microvessels for microgravity platforms that limit waste and increase throughput. In this work, a microvessel for commercial cell culture plates was designed. Four 3D printable (polycarbonate (PC), polylactic acid (PLA) and resin) and castable (polydimethylsiloxane (PDMS)) materials were assessed for biocompatibility with adherent and suspension cell types. PDMS was found to be the most suitable material for microvessel fabrication, long-term cell viability and proliferation. It also allows for efficient gas exchange, has no effect on cell culture media pH and does not induce hypoxic conditions. Overall, the designed microvessel can be used on simulated microgravity platforms as a method for long-term high-throughput biomedical studies.


Asunto(s)
Técnicas de Cultivo de Célula/métodos , Microvasos/fisiología , Ingeniería de Tejidos/métodos , Simulación de Ingravidez , Materiales Biocompatibles/farmacología , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Citocinas/metabolismo , Humanos , Mediadores de Inflamación/metabolismo , Células Jurkat , Ensayo de Materiales , Microvasos/efectos de los fármacos , Células THP-1
6.
Molecules ; 26(11)2021 Jun 03.
Artículo en Inglés | MEDLINE | ID: mdl-34205014

RESUMEN

With the trend for green technology, the study focused on utilizing a forgotten herb to produce an eco-friendly coating. Andrographis paniculata or the kalmegh leaves extract (KLE) has been investigated for its abilities in retarding the corrosion process due to its excellent anti-oxidative and antimicrobial properties. Here, KLE was employed as a novel additive in coatings and formulations were made by varying its wt%: 0, 3, 6, 9, and 12. These were applied to stainless steel 316L immersed in seawater for up to 50 days. The samples were characterized and analyzed to measure effectiveness of inhibition of corrosion and microbial growth. The best concentration was revealed to be 6 wt% KLE; it exhibited the highest performance in improving the ionic resistance of the coating and reducing the growth of bacteria.


Asunto(s)
Andrographis/química , Materiales Biocompatibles Revestidos/farmacología , Extractos Vegetales/química , Agua de Mar/química , Acero Inoxidable/farmacología , Antiinfecciosos/química , Antiinfecciosos/farmacología , Antioxidantes/química , Antioxidantes/farmacología , Materiales Biocompatibles Revestidos/química , Corrosión , Tecnología Química Verde , Ensayo de Materiales , Hojas de la Planta/química , Agua de Mar/microbiología , Acero Inoxidable/química
7.
J Contemp Dent Pract ; 22(4): 335-341, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-34266999

RESUMEN

AIM AND OBJECTIVE: The aim and objective of this study is to evaluate the interface between heat-pressed glass-ceramic masses on a Cr-Co metal substrate using a scanning electron microscope and an X-ray energy dispersion spectrometer. MATERIALS AND METHODS: A pressed porcelain-leucite-based ceramic (IPS InLine press-on-metal (PoM); Ivoclar Vivadent AG) was used. Three cylindrical metal specimens cast (diameter 5 mm, height 1.5 mm) in Co-Cr alloy and covered with pressed ceramic (height 1.5 mm), according to the instructions of the manufacturer. All the specimens were covered with conductive carbon and then examined with a scanning electron microscope. The interface areas were studied using projections from an ETD secondary emission detector and a reversing atomic SSD contrast beam at a magnification of 1200× and 2000×, with a voltage 25 kV acceleration and 110 mA climb current. The elemental analysis was done with genesis 3.5 software, without the use of templates. Surface mapping areas and linear line scan projections of elemental distributions during the interface were recorded. RESULTS: The distribution of specific elements in the ceramic coating concludes the existence of ion diffusion from one side of the interface to the other, which leads to an initial conclusion of the development of primary bonds with oxygen bridges. Also, in the interface, there are ledges of the mass of opaquer on the metal substrate, which results in the creation of a mechanical bond. Therefore, the adhesive mechanism must be due to both micromechanical retention and wetting phenomena and is similar to the conventional layering technique. CONCLUSION: The PoM technique can be used as an alternative fabrication method for metal-ceramic restorations. Factors, such as material composition and properties, firing temperatures, cooling rates, operator's skill, porosities, and fabrication process, may affect the quality and strength of the bond between the core and the veneering materials. CLINICAL SIGNIFICANCE: The PoM technique can be used as an alternative fabrication method for metal-ceramic restorations.


Asunto(s)
Recubrimiento Dental Adhesivo , Aleaciones de Cerámica y Metal , Cerámica , Porcelana Dental , Calor , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Estrés Mecánico , Propiedades de Superficie
8.
J Contemp Dent Pract ; 22(4): 342-348, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-34267000

RESUMEN

AIM AND OBJECTIVE: The purpose of this study was to investigate the fracture resistance of marginal ridges restored using different techniques (amalgam, open sandwich technique, and incremental placement) and to compare these with smart dentin replacement (SDR) bulk-fill. MATERIALS AND METHODS: Amalgam, dispersalloy; a nanohybrid resin composite (Tetric N Ceram), a resin-modified glass ionomer cement (RMGIC) base (Fuji II LC), and flowable bulk-fill composites (SureFil SDR) were used. Standardized class II (occluso-distal) OD cavities were prepared on 60 (n = 12) extracted premolars, and five different protocols were used to restore the teeth: group 1, dispersalloy; group 2, dispersalloy with 4 mm Fuji II LC base; group 3, incrementally placed Tetric N Ceram; group 4, Tetric N Ceram with 4 mm Fuji II LC base; and group 5, Tetric N Ceram with SureFil SDR. The restorations were thermocycled then fractured using a universal testing machine, the maximum fracture load of the specimens was measured (N), and the type of fracture was recorded. Statistical analysis was carried out using one-way analysis of variance. RESULTS: Amalgam groups showed the lowest fracture resistance, with no significant difference between the based and nonbased groups. The highest fracture resistance was displayed by Tetric N Ceram with SDR base, and it was significantly higher than all the groups except the Tetric N Ceram nonbased group. The RMGIC based Tetric N Ceram displayed intermediate fracture resistance. The majority of the restorations showed mixed types of fracture except for nonbased amalgam, which mostly failed cohesively through amalgam. SDR-based composite was the only group that showed severe tooth failures. CONCLUSIONS: The use of a 4 mm thick RMGIC base had no detrimental effect on the fracture resistance of class II amalgam and composite restorations. CLINICAL SIGNIFICANCE: Bulk-fill SureFil SDR placed under a conventional resin-based composite had similar fracture resistance to incrementally placed composite but higher than amalgam and composite restorations based on RMGIC.


Asunto(s)
Restauración Dental Permanente , Laboratorios , Diente Premolar , Resinas Compuestas , Materiales Dentales , Cementos de Ionómero Vitreo , Ensayo de Materiales
9.
J Contemp Dent Pract ; 22(4): 353-356, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-34267002

RESUMEN

AIM AND OBJECTIVE: To compare between mineral trioxide aggregate (MTA) mixed with water and water-based gel regarding shear bond strength with resin-modified glass ionomer cement (RMGIC) and composite. METHODS AND MATERIALS: In this study, 40 blocks of cylindrical shape were prepared with acrylic. These blocks were divided into four groups with each group consisting of 10 blocks: group-1A: MTA + distilled water + composite, group-1B: MTA + distilled water + RMGIC, group-2A: MTA + polymer + composite, and group-2B: RMGIC + MTA + polymer. After that, a universal testing machine was used for the measurement of shear bond strength. The acrylic blocks were placed under this machine. A blade with a knife-edge was used to provide a crosshead speed of 1 mm/minute. This was continued till bond of MTA in both forms (distilled water/gel) and restorative material failed. RESULTS: It was observed that a statistically significant difference was found between MTAw + composite and MTAg + composite resin but no statistically significant difference between MTAw + RMGIC and MTAg + RMGIC with p ≥ 0.05. It was found that a statistically significant difference was present between the RMGIC and composite groups within the same MTA type with p ≤ 0.05. CONCLUSION: It was concluded from the present study that MTA with a water-based gel has a better shear bond strength than composite resin and RMGIC materials. CLINICAL SIGNIFICANCE: It has been found that MTA has different properties when it is mixed with polymer and water. Very few studies have been conducted in the past to compare MTA mixed with water and water-based gel regarding the shear bond strength with RMGIC and composite.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Ionómero Vitreo , Compuestos de Aluminio , Compuestos de Calcio , Resinas Compuestas , Combinación de Medicamentos , Ensayo de Materiales , Óxidos , Resistencia al Corte , Silicatos , Agua
10.
J Contemp Dent Pract ; 22(4): 361-364, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-34267004

RESUMEN

AIM AND OBJECTIVE: The present study aims to evaluate the difference in torsional resistance of two reciprocating nickel-titanium (Ni-Ti) rotary files: WaveOne Gold and EdgeOne Fire. MATERIALS AND METHODS: A total of 40 nickel-titanium rotary instruments (n = 40): 20 WaveOne Gold Small (WOGS) and 20 EdgeOne Fire Small (EOFS) were divided into two groups. Each instrument was tested using a torsional resistance device already validated in previous studies to evaluate and compare torsional resistance. The static torsional test was implemented by blocking each instrument at 3 mm from the tip and rotating it until fracture with a reciprocating motion. Torque to fracture (TtF) and fragment length (FL) were measured and statistically analyzed. RESULTS: Statistical analysis of TtF found significant differences between the two groups (p<0.05). The EOFS showed higher TtF if compared to WOGS, with a mean value and a standard deviation of 3.05 ± 0.07 (N cm) against 2.97 ± 0.08 (N cm). Data for FL showed no significant differences (p>0.05) between the two groups. CONCLUSION: According to the results of this study, it is reasonable to assert that EOFS instruments showed a higher torsional resistance if compared to the WOGS. CLINICAL SIGNIFICANCE: As evidenced by this study, EOFS should be considered as a safer solution, in terms of torsional resistance, if compared to WOGS, reducing the risk of intracanal separation due to excessive torsional load.


Asunto(s)
Níquel , Titanio , Aleaciones Dentales , Instrumentos Dentales , Diseño de Equipo , Calor , Ensayo de Materiales , Preparación del Conducto Radicular , Torsión Mecánica
11.
J Contemp Dent Pract ; 22(4): 422-426, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-34267013

RESUMEN

AIM: The aim of this literature review is to determine whether endocrowns are a reliable alternative for endodontically treated teeth with extensive loss of tooth structure, the indications and contraindications of this restorative choice, the principles that should be followed for tooth preparation and which material is most appropriate for endocrown fabrication. BACKGROUND: Rehabilitation of endodontically treated teeth with severe coronal destruction has always been a challenge for the dental clinician. Until recently, the fabrication of a metal-ceramic or all-ceramic full-coverage crown along with a metal or glass fiber post has been the "gold standard" proving its efficacy via numerous clinical studies. With the development of CAD/CAM technology and the evolution of dental materials, new minimally invasive techniques have been introduced with less need for adjustments and less incorporation of structural defects. One of them, the "monoblock technique," proposed by Pissis in 1995, was the forerunner of endocrown restoration, a term used by Bindl and Mörmann to describe an all-ceramic crown anchored to the internal portion of the pulp chamber and on the cavity margins, thus obtaining macromechanical retention provided by the axial opposing pulpal walls and microretention attained with the use of adhesive cementation. REVIEW RESULTS: Endocrowns require a decay-oriented preparation taking advantage of both the adhesion and the retention from the pulp-chamber walls, they are strongly indicated in endodontically treated molars in cases where minimal interocclusal space and curved or narrow root canals are present and they should be manufactured from materials that can be bonded to the tooth structure. CONCLUSION: Endocrowns are a reliable alternative to traditional restorative choices, given that the clinicians respect the requirements and indications describing this technique. CLINICAL SIGNIFICANCE: Traditional restorative techniques demanding tooth substance removal and minimizing the opportunity for reinterventions should be reconsidered.


Asunto(s)
Coronas , Diente no Vital , Porcelana Dental , Fracaso de la Restauración Dental , Análisis del Estrés Dental , Humanos , Ensayo de Materiales
12.
Indian J Dent Res ; 32(1): 98-103, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34269245

RESUMEN

Objective: This study aimed to evaluate the effects of Coca-Cola®, Sprite®, and Maaza® on Microleakage, shear bond strength (SBS) and adhesive remnants underneath orthodontic brackets. Materials and Methods: A total of 192 human premolar teeth were used in this study. The sample was divided into four groups: Artificial saliva (control) [Group 1], Coca-Cola [Group 2], Sprite [Group 3] and Maaza [Group 4]. All the samples were stored in artificial saliva and immersed in their respective testing media (except the control group) for 15 minutes 3 times a day, separated by intervals of 8 hours. The immersion cycle was repeated for 15 days. After the immersion cycle, 24 teeth from each group were tested for SBS and adhesive remnant index subsequently. The remaining 24 teeth from each group underwent dyeing with methylene blue and were analyzed stereomicroscopically to evaluate microleakage underneath the brackets. Kolmogorov-Smirnov and Shapiro normality tests were performed and homogeneity of variance was tested with the Levene test. One-way ANOVA and Kruskal-Wallis tests were carried out separately for SBS, ARI and microleakage. Statistical analyses were performed using SPSS 20 for Windows (SPSS Inc., Chicago) software. Results: Coca-Cola showed a significant reduction in SBS and microleakage (p < 0.05) compared to the other groups. ARI did not show any significant differences between any groups (p > 0.05). The mean microleakage scores were higher for the gingival side of the brackets compared to the incisal side. Both Sprite and Maaza showed significant differences compared to artificial saliva, despite the SBS not being statistically significant (p > 0.05). Conclusions: A significant reduction of SBS was observed in Coca-Cola while increased microleakage was seen in all three drinks compared to artificial saliva.


Asunto(s)
Recubrimiento Dental Adhesivo , Soportes Ortodóncicos , Bebidas Gaseosas , Cementos Dentales , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Soportes Ortodóncicos/efectos adversos , Resistencia al Corte , Propiedades de Superficie
13.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artículo en Inglés | MEDLINE | ID: mdl-34207917

RESUMEN

Osteoarthritis is a major concern in the United States and worldwide. Current non-surgical and surgical approaches alleviate pain but show little evidence of cartilage restoration. Cell-based treatments may hold promise for the regeneration of hyaline cartilage-like tissue at the site of injury or wear. Cell-cell and cell-matrix interactions have been shown to drive cell differentiation pathways. Biomaterials for clinically relevant applications can be generated from decellularized porcine auricular cartilage. This material may represent a suitable scaffold on which to seed and grow chondrocytes to create new cartilage. In this study, we used decellularization techniques to create an extracellular matrix scaffold that supports chondrocyte cell attachment and growth in tissue culture conditions. Results presented here evaluate the decellularization process histologically and molecularly. We identified new and novel biomarker profiles that may aid future cartilage decellularization efforts. Additionally, the resulting scaffold was characterized using scanning electron microscopy, fluorescence microscopy, and proteomics. Cellular response to the decellularized scaffold was evaluated by quantitative real-time PCR for gene expression analysis.


Asunto(s)
Diferenciación Celular , Condrogénesis , Cartílago Auricular/química , Matriz Extracelular/química , Ensayo de Materiales , Andamios del Tejido/química , Animales , Línea Celular , Humanos , Porcinos
14.
Int J Nanomedicine ; 16: 4239-4250, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34194227

RESUMEN

Purpose: Pore-forming toxins (PFTs) perform important functions during bacterial infections. Among various virulence-targeting therapies, nanosponges (NSs) have excellent neutralization effects on multiple PFTs. To enhance treatment efficacy, NSs tend to be incorporated into other biomaterials, such as hydrogels. Methods: In the present work, red blood cell (RBC) vesicles were harvested to wrap polymer nanoparticles, leading to the formation of NSs, and the optimal Pluronic F127 hydrogel concentration was determined for gelation. Then, a novel detoxification system was constructed by incorporating NSs into an optimized Pluronic F127 hydrogel (NS-pGel). Next, the system was characterized by rheological and sustained release behavior as well as micromorphology. Then, the in vitro neutralization effect of NS-pGel on various PFTs was examined by a hemolysis protocol. Finally, therapeutic and prophylactic detoxification efficiency was evaluated in a mouse subcutaneous infection model in vivo. Results: A thermosensitive, injectable detoxification system was successfully constructed by loading NSs into a 30% Pluronic F127 hydrogel. Characterization results demonstrated that the NS-pGel hybrid system sustained an ideal fluidity and viscosity at lower temperatures but exhibited a quick sol-gel transition capacity near body temperature. In addition, this hybrid system had a sustained release behavior accompanied by good biocompatibility and biodegradability. Finally, the NS-pGel system showed neutralization effects similar to those of NSs both in vitro and in vivo, indicating a good preservation of NS functionality. Conclusion: In conclusion, we constructed a novel temperature-sensitive detoxification system with good biocompatibility and biodegradability, which may be applied to the clinical treatment of PFT-induced local lesions and infections.


Asunto(s)
Antibacterianos/administración & dosificación , Antibacterianos/química , Hidrogeles/administración & dosificación , Hidrogeles/química , Poloxámero/química , Animales , Proteínas Bacterianas , Materiales Biocompatibles , Eritrocitos/química , Proteínas Hemolisinas , Hemólisis/efectos de los fármacos , Masculino , Ensayo de Materiales , Ratones Endogámicos ICR , Nanopartículas/química , Pruebas de Neutralización , Reología , Staphylococcus aureus/patogenicidad , Temperatura , Vibrio vulnificus/patogenicidad , Viscosidad
15.
J Adhes Dent ; 23(4): 287-296, 2021 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-34269539

RESUMEN

PURPOSE: To systematically review the literature to evaluate whether the bond strength of resin-based materials to enamel is affected by deproteinizing agents. MATERIALS AND METHODS: This systematic review and meta-analysis was conducted according to the PRISMA statement. PubMed, ISI Web of Science, Cochrane Library, SciELO, Scopus, LILACS, IBECS, and BVS databases were screened up to December 2020. Eligibility criteria included in vitro studies that reported the effect of a deproteinizing agent applied before or after acid etching on the immediate or long-term bond strength of resin-based materials to enamel. The meta-analysis was carried out using Review Manager (version 5.3.5). A global comparison was performed with the standardized mean difference based on random-effect models at a significance level of α = 0.05. RESULTS: A total of 23 studies were included in the meta-analysis. In all the studies, only the immediate bond strength was evaluated. The bond strength of the materials was improved by the application of NaOCl or papain prior to enamel etching with phosphoric acid (p ≤ 0.006). None of the deproteinizing agents had a significant effect when applied after etching with phosphoric acid (p ≥ 0.27). CONCLUSIONS: Based on in vitro studies, deproteinization with sodium hypochlorite or papain-based agents increases the immediate bond strength of resin-based materials to enamel only when used prior to phosphoric-acid etching.


Asunto(s)
Grabado Ácido Dental , Recubrimiento Dental Adhesivo , Esmalte Dental , Ensayo de Materiales , Ácidos Fosfóricos , Cementos de Resina , Resistencia al Corte , Hipoclorito de Sodio , Propiedades de Superficie
16.
J Adhes Dent ; 23(4): 309-318, 2021 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-34269541

RESUMEN

PURPOSE: Thanks to adhesive techniques and strengthened glass ceramics, ultrathin bonded occlusal veneers have been recently introduced. However, since a universally accepted thickness limit for ultrathin ceramics has yet to be established, their resistance to fracture needs to be better investigated. The purpose of this in vitro study was to evaluate the effect of dentin bonding on the flexural properties (ie, fracture load and flexural strength) of a lithium-disilicate (LD) glass ceramic when used in thicknesses equal to or less than the manufacturer's recommendations for occlusal restorations. MATERIALS AND METHODS: A total of 96 dentin slices (2.0 mm thick and 15 mm long) were obtained by sectioning bovine teeth along their long axes. LD slices of different thicknesses (1.5 mm/1.3 mm/1.0 mm/0.8 mm/0.6 mm) and 15 mm in length were cut from CAD/CAM LD blocks (IPS e.max CAD-C16). In each of 5 experimental groups, 16 dentin slices were adhesively luted to 16 LD slices (n = 16) of the same thickness, in order to create 16 bi-layered dentin-LD bonded assemblies. In the control group, the 16 remaining dentin slices were conventionally cemented to 1.5-mm-thick LD slices (n = 16) using a resin-modified glass-ionomer cement (FujiCEM 2). All dentin-LD assemblies were cut perpendicularly to their joint interface, in order to obtain 1-mm-wide, 15-mm-long bi-layered prismatic beams, having the following final thicknesses: for the 5 experimental groups, 2 mm (dentin layer) + 1.5 mm/ 1.3 mm/1.0 mm/0.8 mm/0.6 mm (LD layer); for the control group, 2 mm (dentin layer) + 1.5 mm (LD layer). All prismatic beams were subjected to a three-point bending test (14-mm span, load applied on the LD side). Fracture loads (N) and flexural strengths (MPa) were recorded. Data were analyzed using one-way ANOVA on ranks tests (α = 0.05). The correlations between the recorded flexural strengths and the dentin:LD thickness ratio and between the flexural strength and the luting strategy were also investigated. The failure modes were observed and classified. RESULTS: No statistically significant differences were recorded between the conventionally luted control group (LD thickness 1.5 mm; fracture load 35.26 N; flexural strength 60.44 MPa) and the thinnest adhesively luted experimental group (LD thickness 0.6 mm; fracture load 28.97 N; flexural strength 90.01 MPa) in terms of fracture load and flexural strength. A fracture involving both the dentin and the LD of the bi-layered prismatic beam, but without any debonding between the LD and the dentin substrates of the broken specimen, was the most common failure mode observed on the adhesively luted samples. CONCLUSION: Compared to conventional cementation, when LD is bonded to dentin, the flexural properties of the whole system are improved, and the two different substrates seem to behave like a single unit. Once adhesively luted, 0.6-mm-thick LD has the same fracture load and flexural strength as that of the conventionally luted 1.5-mm-thick LD.


Asunto(s)
Resistencia Flexional , Litio , Animales , Bovinos , Cerámica , Diseño Asistido por Computadora , Porcelana Dental , Análisis del Estrés Dental , Dentina , Ensayo de Materiales , Propiedades de Superficie
17.
J Adhes Dent ; 23(4): 319-326, 2021 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-34269542

RESUMEN

PURPOSE: To compare the effect of different methods of cleaning residual composite cement from the surface of lithium-disilicate glass-ceramic on its bond strength. MATERIALS AND METHODS: Blocks of lithium-silicate glass-ceramic (e.max CAD) were coated with composite cement. Blocks in a positive control (CO+) group received no cement; negative controls (CO-) received composite cement. After water storage (24 h), specimens were cleaned as follows (n = 20/group): BUR: grinding with a fine-grit diamond bur (20 s); ALUM: air abrasion with 50-µm alumina (10 s); GLASS: air abrasion with 50-µm glass beads (10 s); FURN: firing in ceramic furnace and cleaning with ethanol; SULF: immersion in sulfonic acid solution (1 h); HYFL: no additional treatment. All specimens were etched with hydrofluoric acid, aside from the CO- group, and treated with silane. A 1.5-mm diameter cement-filled tube was affixed to the specimens and light polymerized. Specimens were stored in 37°C water for 24 h (n = 10) or 90 days (n = 10). Shear bond strength was tested. Two-way ANOVA and post-hoc Tukey tests were performed. Specimens from each group were examined with SEM. RESULTS: Bond strength significantly differed according to surface cleaning method (p < 0.01) and storage time (p < 0.01), but their interaction was not significant (p = 0.264). Longer storage time decreased the bond strength. BUR, ALUM, GLASS, and FURN did not differ statistically significantly from CO+, but were significantly greater than CO-. SULF and HYFL did not differ statistically significantly from CO- and were significantly lower than CO+. CONCLUSIONS: Cleaning composite cement with BUR, ALUM, GLASS, and FURN restored bond strengths to that of the positive control. However, only GLASS and FURN did not roughen the surface of the underlying lithium-silicate glass-ceramic.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Abrasión Dental por Aire , Cerámica , Porcelana Dental , Litio , Ensayo de Materiales , Propiedades de Superficie
18.
J Adhes Dent ; 23(4): 327-334, 2021 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-34269543

RESUMEN

PURPOSE: The effect of surface moisture on bur-cut dentin on the microtensile bond strength (µTBS) of universal adhesives with various contents of 2-hydroxyethyl methacrylate (HEMA) and methacrylamide monomers was evaluated. MATERIALS AND METHODS: Flat mid-coronal dentin surfaces of human molars were exposed, and a standardized smear layer was prepared using a fine-grit diamond bur. The surfaces were either left wet or air dried for 10 s before bonding with Clearfil Universal Bond Quick (UBQ), experimental UBQ without an amide monomer (UBQexp), Scotchbond Universal (SBU), Prime&Bond Universal (PBU), or BeautiBond Universal (BBU). The specimens were built up with resin composite, sectioned into sticks and subjected to the µTBS test after 24 h or 10,000 thermal cycles. The µTBS data were analyzed using three-way ANOVA followed by pairwise comparisons with Bonferroni's correction (α = 0.05). RESULTS: The level of dentin moisture did not significantly affect µTBS of UBQ and BBU (p > 0.05). HEMA-containing UBQ, UBQexp, and SBU exhibited higher µTBS to dry dentin, while HEMA-free PBU and BBU showed higher µTBS to wet dentin. Thermocycling significantly decreased the µTBS of UBQexp (p < 0.01) and BBU (p < 0.001) irrespective of dentin moisture level, while SBU was significantly affected only on dry dentin (p < 0.001). Thermocycling had no significant effect on UBQ and PBU containing methacrylamide monomers (p > 0.05). CONCLUSION: Dry surfaces enabled obtaining optimal bonding for HEMA-containing adhesives to bur-cut dentin, while wet surfaces enabled optimal bonding for HEMA-free adhesives. Methacrylamide monomers could contribute to the improvement of the initial and long-term bonding performance of universal adhesives to bur-cut dentin.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios , Acrilamidas , Adhesivos , Resinas Compuestas , Cementos Dentales , Dentina , Humanos , Ensayo de Materiales , Metacrilatos , Cementos de Resina , Resistencia a la Tracción
19.
J Adhes Dent ; 23(4): 335-345, 2021 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-34269544

RESUMEN

PURPOSE: The pretreatment of glass-ceramic before adhesive cementation can be performed with hydrofluoric acid (HF)/silanization (S) or with an ammonium polyfluoride-containing primer (APF). It can be modified by application of a silane-containing universal adhesive (UA) and/or additional silanization. The aim of this study was to evaluate the bond strength of composite cements to two different glass ceramics after different pretreatments and aging. MATERIALS AND METHODS: Disks of leucite-reinforced glass-ceramic or lithium-disilicate glass-ceramic were pretreated with HF+S, HF+UA, HF+S+UA, APF, or APF+S, bonded in pairs with composite cement and sectioned into microsticks (n = 96/group). The microtensile bond strength was determined either after 24 h (n = 48) or after aging for 6 months in water (n = 48). Fracture patterns were analyzed at 50X magnification. Statistical evaluation was performed using the Kruskal-Wallis test, pairwise comparisons with Bonferroni's correction, and the chi-squared test (p < 0.05). RESULTS: Pretreatment with HF+UA or APF led to significantly lower bond strength compared to HF+S. Additional silanization after application of UA or APF resulted in a significant increase in bond strength. After aging, HF+UA groups showed significantly lower bond strengths, independent of additive silanization. Aging did not affect APF-pretreated leucite-reinforced glass-ceramic; for lithium-disilicate glass-ceramic, the bond strength dropped significantly. Additional silanization improved aging resistance for the respective groups. CONCLUSION: Bond strength and its long-term stability depend on the ceramic used and on the pretreatment. An ammonium polyfluoride-containing primer seems to be a promising option compared to conventional pretreatment with hydrofluoric acid. Additive silanization improves the long-term stability of the microtensile bond strength.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Grabado Ácido Dental , Cerámica , Porcelana Dental , Ácido Fluorhídrico , Ensayo de Materiales , Silanos , Silicatos , Propiedades de Superficie , Resistencia a la Tracción
20.
J Adhes Dent ; 23(4): 347-356, 2021 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-34269545

RESUMEN

PURPOSE: To evaluate the effect of different concentrations of ethylene-diamine-tetra acetic acid (EDTA) on bond strength (BS) and nanoleakage (NL) of fiber posts bonded into root canals. MATERIALS AND METHODS: Seventy-two single roots were endodontically treated and divided into six groups (n = 12), according to the combination of the following factors: surface treatment (no irrigation [control], 17% EDTA, or 24% EDTA), and composite cement applied with an adhesive used in a self-etch mode (Single Bond Universal/RelyX Ultimate [SB], 3M Oral Care; Ambar Universal/Allcem [AM], FGM). After fiber post cementation, six 1-mm-thick disks were obtained for each root. Push-out bond strength (BS) was evaluated using 8 specimens per group, and the other 4 specimens were used to examine nanoleakage (NL). Data from BS and NL of each adhesive were evaluated by two-way ANOVA (surface treatment vs root region) and Tukey's test (α = 0.05). RESULTS: The application of 17% and 24% EDTA did not influence the bond strengths of either adhesive. In general, the application of 17% and 24% EDTA increased NL values for both adhesives. CONCLUSION: Pre-treatment with different concentrations of EDTA was not able to improve the adhesion of fiber posts into root canals with universal adhesives..


Asunto(s)
Recubrimiento Dental Adhesivo , Técnica de Perno Muñón , Cementos Dentales , Cavidad Pulpar , Dentina , Ácido Edético , Ensayo de Materiales , Cementos de Resina
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