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1.
Adv Sci (Weinh) ; 11(24): e2307953, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38582517

RESUMEN

FOXG1 syndrome is a developmental encephalopathy caused by FOXG1 (Forkhead box G1) mutations, resulting in high phenotypic variability. However, the upstream transcriptional regulation of Foxg1 expression remains unclear. This report demonstrates that both deficiency and overexpression of Men1 (protein: menin, a pathogenic gene of MEN1 syndrome known as multiple endocrine neoplasia type 1) lead to autism-like behaviors, such as social defects, increased repetitive behaviors, and cognitive impairments. Multifaceted transcriptome analyses revealed that Foxg1 signaling is predominantly altered in Men1 deficiency mice, through its regulation of the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (Atrx) factor. Atrx recruits menin to bind to the transcriptional start region of Foxg1 and mediates the regulation of Foxg1 expression by H3K4me3 (Trimethylation of histone H3 lysine 4) modification. The deficits observed in menin deficient mice are rescued by the over-expression of Foxg1, leading to normalized spine growth and restoration of hippocampal synaptic plasticity. These findings suggest that menin may have a putative role in the maintenance of Foxg1 expression, highlighting menin signaling as a potential therapeutic target for Foxg1-related encephalopathy.


Asunto(s)
Modelos Animales de Enfermedad , Factores de Transcripción Forkhead , Proteínas del Tejido Nervioso , Proteínas Proto-Oncogénicas , Animales , Ratones , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Factores de Transcripción Forkhead/genética , Factores de Transcripción Forkhead/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Trastorno Autístico/genética , Trastorno Autístico/metabolismo , Encefalopatías/genética , Encefalopatías/metabolismo , Conducta Animal , Masculino
2.
Cell Death Differ ; 29(12): 2417-2428, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-35732922

RESUMEN

Alzheimer's disease (AD) is the most common form of neurodegenerative disease featured with memory loss and cognitive function impairments. Chronic mitochondrial stress is a vital pathogenic factor for AD and finally leads to massive neuronal death. However, the underlying mechanism is unclear. By proteomic analysis, we identified a new mitochondrial protein, cell-cycle exit and neuronal differentiation 1 (CEND1), which was decreased significantly in the brain of 5xFAD mice. CEND1 is a neuronal specific protein and locates in the presynaptic mitochondria. Depletion of CEND1 leads to increased mitochondrial fission mediated by upregulation of dynamin related protein 1 (Drp1), resulting in abnormal mitochondrial functions. CEND1 deficiency leads to cognitive impairments in mice. Overexpression of CEND1 in the hippocampus of 5xFAD mice rescued cognitive deficits. Moreover, we identified that CDK5/p25 interacted with and phosphorylated CEND1 which promoted its degradation. Our study provides new mechanistic insights in mitochondrial function regulations by CEND1 in Alzheimer's disease.


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Enfermedades Neurodegenerativas , Animales , Ratones , Enfermedad de Alzheimer/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Proteómica , Disfunción Cognitiva/genética , Disfunción Cognitiva/metabolismo , Mitocondrias/metabolismo , Péptidos beta-Amiloides/metabolismo , Modelos Animales de Enfermedad , Ratones Transgénicos , Proteínas de la Membrana/metabolismo , Proteínas del Tejido Nervioso/metabolismo
3.
Int J Biochem Cell Biol ; 137: 106026, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-34147653

RESUMEN

Micro/nanotextured topographies (MNTs) can modulate cell-biomaterial interactions mostly by their controllable geometrics. Among them, TiO2 nanotubes, regarded as having a highly controllable nanoscale geometry, have been extensively investigated and applied and significantly affect diameter-dependent cell biological behaviors. In this study, we used five typical MNTs decorated with TiO2 nanotubes with diameters of 30, 50, 70, 100 and 120 nm to explore the optimal nanotube diameter for improving the biofunctional properties and to more deeply understand the underlying mechanisms by which these MNTs affect osteogenic differentiation by revealing the effect of beta1-integrin/Hedgehog-Gli1 signaling on this process. The MNTs affected MG63 osteoblast-like cell spreading, osteogenic gene expression (BMP-2, Runx2 and ALP), mineralization and ALP activity in a diameter-dependent pattern, and the optimal TiO2 nanotube diameter of 70 nm provided the best microenvironment for osteogenic differentiation as well as beta1-integrin/Hedgehog-Gli1 signaling activation. This enhanced osteogenic differentiation by the optimal-diameter TiO2 nanotubes of 70 nm was attenuated via suppression of the beta1-integrin/ Hedgehog-Gli1 signaling, which indicated a significant role of this pathway in mediating the diameter-dependent osteogenic differentiation promotional effect of MNTs with different TiO2 nanotube diameters. These results might provide deeper insights into the signal transduction mechanisms by which different nanoscale geometries influence cellular functions for biomaterial modification and biofunctionalization.


Asunto(s)
Proteínas Hedgehog/metabolismo , Integrina beta1/metabolismo , Nanotubos/química , Osteoblastos/citología , Osteogénesis , Titanio/química , Proteína con Dedos de Zinc GLI1/metabolismo , Diferenciación Celular , Proliferación Celular , Proteínas Hedgehog/genética , Humanos , Integrina beta1/genética , Osteoblastos/metabolismo , Propiedades de Superficie , Proteína con Dedos de Zinc GLI1/genética
4.
Cell Death Dis ; 12(4): 294, 2021 03 17.
Artículo en Inglés | MEDLINE | ID: mdl-33731694

RESUMEN

Aberrant expression of splicing factors was found to promote tumorigenesis and the development of human malignant tumors. Nevertheless, the underlying mechanisms and functional relevance remain elusive. We here show that USP39, a component of the spliceosome, is frequently overexpressed in high-grade serous ovarian carcinoma (HGSOC) and that an elevated level of USP39 is associated with a poor prognosis. USP39 promotes proliferation/invasion in vitro and tumor growth in vivo. Importantly, USP39 was transcriptionally activated by the oncogene protein c-MYC in ovarian cancer cells. We further demonstrated that USP39 colocalizes with spliceosome components in nuclear speckles. Transcriptomic analysis revealed that USP39 deletion led to globally impaired splicing that is characterized by skipped exons and overrepresentation of introns and intergenic regions. Furthermore, RNA immunoprecipitation sequencing showed that USP39 preferentially binds to exon-intron regions near 5' and 3' splicing sites. In particular, USP39 facilitates efficient splicing of HMGA2 and thereby increases the malignancy of ovarian cancer cells. Taken together, our results indicate that USP39 functions as an oncogenic splicing factor in ovarian cancer and represents a potential target for ovarian cancer therapy.


Asunto(s)
Proteína HMGA2/metabolismo , Neoplasias Ováricas/genética , Factores de Empalme de ARN/metabolismo , Animales , Línea Celular Tumoral , Femenino , Humanos , Ratones , Ratones Desnudos , Neoplasias Ováricas/patología , Transfección
5.
Biol Psychiatry ; 87(8): 756-769, 2020 04 15.
Artículo en Inglés | MEDLINE | ID: mdl-31955914

RESUMEN

BACKGROUND: Synaptic protein dyshomeostasis and functional loss is an early invariant feature of Alzheimer's disease (AD), yet the unifying etiological pathway remains largely unknown. Knowing that cyclin-dependent kinase 5 (CDK5) plays critical roles in synaptic formation and degeneration, its phosphorylation targets were reexamined in search of candidates with direct global impacts on synaptic protein dynamics, and the associated regulatory network was also analyzed. METHODS: Quantitative phosphoproteomics and bioinformatics analyses were performed to identify top-ranked candidates. A series of biochemical assays was used to investigate the associated regulatory signaling networks. Histological, electrochemical, and behavioral assays were performed in conditional knockout, small hairpin RNA-mediated knockdown, and AD-related mice models to evaluate the relevance of CDK5 to synaptic homeostasis and functions. RESULTS: Among candidates with known implications in synaptic modulations, BAG3 ranked the highest. CDK5-mediated phosphorylation on S297/S291 (mouse/human) destabilized BAG3. Loss of BAG3 unleashed the selective protein degradative function of the HSP70 machinery. In neurons, this resulted in enhanced degradation of a number of glutamatergic synaptic proteins. Conditional neuronal knockout of Bag3 in vivo led to impairment of learning and memory functions. In human AD and related mouse models, aberrant CDK5-mediated loss of BAG3 yielded similar effects on synaptic homeostasis. Detrimental effects of BAG3 loss on learning and memory functions were confirmed in these mice, and such effects were reversed by ectopic BAG3 reexpression. CONCLUSIONS: Our results highlight that the neuronal CDK5-BAG3-HSP70 signaling axis plays a critical role in modulating synaptic homeostasis. Dysregulation of the signaling pathway directly contributes to synaptic dysfunction and AD pathogenesis.


Asunto(s)
Enfermedad de Alzheimer , Quinasa 5 Dependiente de la Ciclina , Proteínas Adaptadoras Transductoras de Señales , Enfermedad de Alzheimer/genética , Animales , Proteínas Reguladoras de la Apoptosis/metabolismo , Quinasa 5 Dependiente de la Ciclina/genética , Quinasa 5 Dependiente de la Ciclina/metabolismo , Memoria , Ratones , Neuronas/metabolismo , Transducción de Señal
6.
Artif Cells Nanomed Biotechnol ; 46(sup3): S1141-S1151, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30453796

RESUMEN

The hierarchical microtextured/nanotextured topographies have been recognized to have better tissue integration properties, but the underlying mechanisms are only partially understood. Hedgehog signaling plays a pivotal role in developmental and homeostatic angiogenesis. We suppose that the Hedgehog-Gli1 signaling may play a significant role in the response of endothelial cells to microtextured/nanotextured topographies (MNTs). To confirm this hypothesis, we produced the MNTs decorated with TiO2 nanotubes of two different diameters (25 and 70 nm), and the proliferation, apoptosis, angiogenesis-related genes expression and Hedgehog signaling activity of human umbilical vein endothelial cells (HUVECs) grown onto these MNTs were measured. Our results showed that the MNTs induced significantly high expression of Sonic Hedgehog (SHH), Smoothened (SMO) and GLI1 in the HUVECs as well as high activation of Hedgehog-Gli1 signaling, compared to the smooth surface. The HUVECs grown on the MNTs showed significantly high levels of adhesion, proliferation and expression of angiogenesis-related genes, including angiopoietin-1 (ANG-1), vascular endothelial growth factor (VEGFA), vascular endothelial growth factor receptor 2 (VEGFR2) and endothelial nitric oxide synthase (ENOS); these enhancements were attenuated by siRNA-mediated depletion of SMO, which indicated a significant role of Hedgehog-Gli1 signaling in mediating the enhanced effect of the MNTs on the angiogenic potential of HUVECs. This study may contribute to the modification of biomaterial surfaces for better tissue integration and clinical performance.


Asunto(s)
Proliferación Celular/efectos de los fármacos , Proteínas Hedgehog/metabolismo , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Nanotubos/química , Neovascularización Fisiológica/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Titanio , Proteína con Dedos de Zinc GLI1/metabolismo , Regulación de la Expresión Génica/efectos de los fármacos , Células Endoteliales de la Vena Umbilical Humana/citología , Humanos , Propiedades de Superficie , Titanio/química , Titanio/farmacología
7.
Cell Death Differ ; 24(12): 2089-2100, 2017 12.
Artículo en Inglés | MEDLINE | ID: mdl-28800130

RESUMEN

Activation of mammalian target of rapamycin (mTOR) signaling pathway is associated with poor prognosis of epithelial ovarian cancer. The TSC1-TSC2 complex is a critical negative regulator of mTOR signaling. Here, we demonstrated that TSC1 was frequently downregulated in high-grade serous ovarian carcinoma (HGSOC) and low TSC1 expression level is associated with advanced tumor stage. We next identified miR-130a to be a negative regulator of TSC1 by targeting its 3'UTR. miR-130a was overexpressed in HGSOC and could drive proliferation and invasion/metastasis of ovarian cancer cells. miR-130a could also attenuate rapamycin/starvation-induced autophagy. Ectopic TSC1 expression could block the effects of miR-130a on cell proliferation, migration and autophagy. Finally, we found that miR-130a expression could be upregulated by inflammatory factors and was transactivated by NF-κB. Therefore, our findings establish a crosstalk between inflammation and mTOR signaling that is mediated by miR-130a, which might have a pivotal role in the initiation and progression of HGSOC.


Asunto(s)
Cistadenocarcinoma Seroso/metabolismo , MicroARNs/metabolismo , FN-kappa B/metabolismo , Neoplasias Ováricas/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Animales , Cistadenocarcinoma Seroso/genética , Cistadenocarcinoma Seroso/patología , Femenino , Células HEK293 , Xenoinjertos , Humanos , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , MicroARNs/genética , FN-kappa B/genética , Clasificación del Tumor , Neoplasias Ováricas/genética , Neoplasias Ováricas/patología , Estudios Retrospectivos , Transducción de Señal , Serina-Treonina Quinasas TOR/genética , Transfección , Proteína 1 del Complejo de la Esclerosis Tuberosa , Proteínas Supresoras de Tumor/genética
8.
J Prosthodont ; 26(3): 201-205, 2017 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26375868

RESUMEN

PURPOSE: The focus of this study was to evaluate the effect of reading aloud on masticatory performance and patient satisfaction of patients rehabilitated with conventional complete dentures for the first time. MATERIALS AND METHODS: Sixty-two edentulous patients who received conventional complete denture treatment for the first time were randomly divided into two equal groups. After insertion of the dentures, patients in group I were asked to read a news report three times per day for 4 weeks, while those in group II did not read. The reading duration increased by 5 minutes per week, from 5 minutes in the first week to 20 minutes in the fourth week. The patients' mouth opening during reading aloud was advised to gradually increase throughout the training project. Two and four weeks after insertion of the dentures, masticatory performance was assessed using the sieving method, and patient satisfaction was measured using a visual analogue scale, which combined the patient's perceptions in relation to comfort, esthetics, stability, ability to talk, and ability to chew. RESULTS: There were significant improvements in masticatory performance with reading aloud exercises after the insertion of complete dentures (p < 0.001) at the 2- and 4-week follow-up visits. Masticatory performance also showed significant improvement within each group in the follow-up periods (p < 0.001). No significant differences were found between the two groups in patient satisfaction (p > 0.05) at 2 weeks, but at 4 weeks, patient satisfaction regarding stability, ability to talk, and ability to chew was significantly higher for group I (p < 0.001). CONCLUSIONS: The results of this study suggest that reading aloud exercises significantly improved early masticatory performance and patient satisfaction for denture wearers who were treated with conventional complete dentures for the first time, and may be a useful clinical application for more effective denture treatment.


Asunto(s)
Dentadura Completa , Terapia por Ejercicio/métodos , Boca Edéntula/rehabilitación , Satisfacción del Paciente , Lectura , Anciano , Retención de Dentadura , Estética Dental , Femenino , Humanos , Masculino , Masticación/fisiología , Persona de Mediana Edad , Factores de Tiempo , Resultado del Tratamiento
9.
J Prosthet Dent ; 118(1): 69-75, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27927283

RESUMEN

STATEMENT OF PROBLEM: Cobalt-chromium (Co-Cr) alloys have been widely used for metal-ceramic fixed prostheses and can be fabricated using conventionally cast or new computer-aided technology. However, the effect of different manufacturing methods on the metal-ceramic bond strength needs further evaluation. PURPOSE: The purpose of this in vitro study was to evaluate the metal-ceramic bond strength of a Co-Cr alloy made by casting, milling, and selective laser melting (SLM). MATERIAL AND METHODS: Co-Cr specimens (25×3×0.5 mm) were prepared using a cast, milled, or SLM method and layered with ceramic (8×3×1.1 mm). Metal-ceramic bond strength was measured by a 3-point bend test according to ISO9693. The area fraction of adherence porcelain (AFAP) was determined by measuring the Si content of the specimens with scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The metal-ceramic bond strength and AFAP results were analyzed using 1-way analysis of variance and the Bonferroni post hoc test (α=.05). SEM/EDS and metallurgic microscopy were also used to study the specimens' morphology, elemental composition, and metallurgic structure. RESULTS: No significant differences (P>.05) were found for the bond strength among cast, milled, and SLM Co-Cr alloys. The milled and SLM groups showed significantly more porcelain adherence than the cast group (P<.001). The surface morphologies and oxidation characters of cast, milled, and SLM Co-Cr alloys were similar, whereas the metallurgic structures were different. CONCLUSIONS: The bond strength between ceramics and Co-Cr alloys is independent of the manufacturing method. However, milling- and SLM-produced alloys had better porcelain adherence.


Asunto(s)
Aleaciones de Cromo/química , Recubrimiento Dental Adhesivo , Técnica de Colado Dental , Porcelana Dental/química , Rayos Láser , Aleaciones de Cerámica y Metal/química , Cerámica/química , Humanos , Ensayo de Materiales , Fenómenos Mecánicos , Microscopía Electrónica de Rastreo , Docilidad , Espectrometría por Rayos X , Estrés Mecánico , Propiedades de Superficie , Resistencia a la Tracción
10.
Tumour Biol ; 37(7): 8721-9, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26738868

RESUMEN

Ovarian cancer is the most lethal gynecological malignancy. Patients usually have poor prognosis because of late diagnosis, relapse, and chemoresistance. It is pressing to seek novel agent for the treatment of ovarian cancer. Neferine is a bisbenzylisoquinoline alkaloid isolated from the embryos of lotus (Nelumbo nucifera). In this study, we investigated the antitumor effect of neferine on ovarian cancer cells. We found that neferine exhibited growth-inhibitory effect on human ovarian cancer cells, whereas showing less cytotoxic to non-malignant fallopian tube epithelial cells. Furthermore, we demonstrated that neferine induced autophagy and inactivated the mTOR pathway. Finally, we found that both p38 MAPK and JNK signaling pathways were activated by neferine treatment and contributed to the induction of autophagy in ovarian cancer cells. In conclusion, our findings showed that neferine induced autophagy of human ovarian cancer cells via p38 MAPK/JNK activation. Neferine may be explored as a promising antitumoral agent in ovarian cancer.


Asunto(s)
Autofagia/efectos de los fármacos , Bencilisoquinolinas/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Neoplasias Ováricas/tratamiento farmacológico , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo , Antineoplásicos/farmacología , Línea Celular Tumoral , Femenino , Humanos , Nelumbo/química , Neoplasias Ováricas/metabolismo , Extractos Vegetales/farmacología , Serina-Treonina Quinasas TOR/metabolismo
11.
J Prosthet Dent ; 114(5): 715-24, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26213266

RESUMEN

STATEMENT OF PROBLEM: The effects of different heat treatments on the internal oxidation and metal-ceramic bond in Pd-Ag alloys with different trace elements require further documentation. PURPOSE: The purpose of this in vitro study was to determine whether heat treatment affects the metal-ceramic bond strength of 2 Pd-Ag alloys containing different trace elements. MATERIAL AND METHODS: Thirteen cast specimens (25×3×0.5 mm) from each of 2 Pd-Ag alloy groups (W-1 and Argelite 61+3) were allocated to heat treatments before porcelain application: heating under reduced atmospheric pressure of 0.0014 MPa and 0.0026 MPa and heating under normal atmospheric pressure. Bond strengths were evaluated using a 3-point bending test according to ISO9693. Results were analyzed using 2-way ANOVA and Tukey HSD test (α=.05). Visual observation was used to determine the failure types of the fractured specimens. Scanning electron microscopy and energy dispersive spectroscopy were used to study morphologies, elemental compositions, and distributions in the specimens. RESULTS: The W-1 group had a mean bond strength significantly higher than that of Argelite 61+3 (P<.001). Heating under reduced atmospheric pressures of 0.0014 MPa and 0.0026 MPa resulted in similar bond strengths (P=.331), and both pressures had significantly higher bond strengths than that of heating under normal atmospheric pressure (P=.002, P<.001). Heating under different air pressures resulted in Pd-Ag alloys that contained either Sn or In and Ga, with various degrees of internal oxidation and different quantities of metallic nodules. CONCLUSIONS: Heating under reduced atmospheric pressure effectively improved the bond strength of the ceramic-to-Pd-Ag alloys.


Asunto(s)
Materiales Dentales/efectos de la radiación , Calor , Aleaciones de Cerámica y Metal/efectos de la radiación , Paladio/efectos de la radiación , Resistencia al Corte/efectos de la radiación , Plata/efectos de la radiación , Materiales Dentales/química , Calefacción , Ensayo de Materiales , Aleaciones de Cerámica y Metal/química , Microscopía Electroquímica de Rastreo , Espectrometría por Rayos X , Estrés Mecánico
12.
Eur J Oral Sci ; 123(4): 297-304, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26104804

RESUMEN

There is a dearth of dental scientific literature on the effect of different oxidation heat treatments (OHTs) (as surface pretreatments) on the bonding performance of cast and milled cobalt-chromium (CoCr) alloys. The objective of this study was to evaluate the effect of different OHTs on the bond strength between a ceramic and cast and milled CoCr alloys. Cobalt-chromium metallic specimens were prepared using either a cast or a milled method. Specimens were subjected to four different OHT methods: without OHT; OHT under normal atmospheric pressure; OHT under vacuum; and OHT under vacuum followed by sandblasting. The metal-ceramic bond strength was evaluated using a three-point bending test according to ISO9693. Scanning electron microscopy and energy-dispersive spectroscopy were used to study the specimens' microstructure and elemental composition. The bond strength was not affected by the CoCr manufacturing method. Oxidation heat treatment performed under normal atmospheric pressure resulted in the highest bond strength. The concentration of oxygen on the alloy surfaces varied with the different pretreatment methods in the following order: OHT under normal atmospheric pressure > OHT under vacuum > without OHT ≈ OHT under vacuum followed by sandblasting.


Asunto(s)
Aleaciones de Cromo/química , Recubrimiento Dental Adhesivo , Porcelana Dental/química , Aleaciones de Cerámica y Metal/química , Aluminio/análisis , Óxido de Aluminio/química , Presión Atmosférica , Cromo/análisis , Cobalto/análisis , Diseño Asistido por Computadora , Revestimiento para Colado Dental/química , Grabado Dental/métodos , Calor , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oxidación-Reducción , Oxígeno/análisis , Oxígeno/química , Docilidad , Silicio/análisis , Espectrometría por Rayos X , Estrés Mecánico , Propiedades de Superficie , Tungsteno/análisis , Vacio
13.
J Dent ; 42(3): 319-28, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24316343

RESUMEN

OBJECTIVES: The purpose of this study was to evaluate the efficacy of surface treatments on the bonding properties between a metal and ceramic. METHODS: Sixty metal specimens were divided equally into four groups of 15 samples each. These groups received different treatments (Gr1: 250µm Al2O3+preoxidation; Gr2: 250µm Al2O3+degassing; Gr3: 120µm Al2O3+preoxidation; Gr4: 120µm Al2O3+degassing). Bond strengths were evaluated using a three-point bending test. The results were analyzed using 2-way ANOVA and Tukey's test. Scanning electron microscopy and energy dispersive spectroscopy were used to observe the microscopic features, elemental compositions and distributions, and diffusion in the specimens. Mechanical profiler was used to measure the roughness of metal surface. RESULTS: The bond strengths of the four groups ranged from 45.00±3.63MPa to 51.61±5.91MPa, with significant differences (P<.05). The specimen that received the pretreatment of 250µm Al2O3 air-particle abrasion+degassing had the highest bond strength. Heating under different oxygen partial pressures caused the final Pd-Ag alloys to have varying degrees of internal oxidation and different quantities of metallic nodules. None of the elements in either the ceramic or the Pd-Ag alloy layer diffused into the other layer. CONCLUSIONS: The metal-ceramic specimen subjected to air-particle abrasion with 250µm Al2O3 and degassed before porcelain firing had significantly higher bond strength than specimens treated differently.


Asunto(s)
Recubrimiento Dental Adhesivo , Grabado Dental/métodos , Porcelana Dental/química , Aleaciones de Oro/química , Aleaciones de Cerámica y Metal/química , Paladio/química , Óxido de Aluminio/química , Materiales Dentales/química , Difusión , Calor , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Oxidación-Reducción , Oxígeno/química , Presión Parcial , Tamaño de la Partícula , Docilidad , Espectrometría por Rayos X , Estrés Mecánico , Propiedades de Superficie
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