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1.
Adv Clin Exp Med ; 30(1): 7-15, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33529502

RESUMEN

BACKGROUND: Reduced tooth structure in the pediatric and adolescent population is frequently restored with prefabricated zirconia crowns. On permanent teeth, these restorations may need to be removed and replaced with permanent restorations. OBJECTIVES: To explore and compare the use of 2 high-powered erbium lasers for removing prefabricated zirconia crowns from molar teeth as a non-invasive alternative to rotary instruments. MATERIAL AND METHODS: Twenty-five permanent molars were prepared to dentin and prefabricated all-ceramic zirconia crowns were fitted and cemented with resin modified glass ionomer (RMGI) cement. The teeth were randomly assigned into one of the 2 retrieval treatment groups: the erbium-doped yttrium, aluminum and garnet (Er:YAG) laser group (G1; n = 12) or the erbium, chromium-doped yttrium, scandium, gallium and garnet laser (Er,Cr:YSGG) laser group (G2; n = 13). The laser operating parameters for the Er:YAG laser were 300 mJ, 15 Hz, 4.5 W, and 50-microsecond pulse duration (SSP mode); for the Er,Cr:YSGG laser, they were 4.5 W, 15 Hz, 20 water/20 air, and 5 W, 15 Hz, 50 water/50 air, and 60-microsecond pulse duration (H mode). The experiment was repeated twice. The surface area and the volume of teeth and crowns were measured and the cement space was calculated. The retrieval time and temperature changes were tested and recorded. The data were analyzed with the t-test. The surfaces of the dentin and the crown from each group were further examined using scanning electron microscopy (SEM). RESULTS: The average time for crown removal using the Er:YAG laser was 1 min 32.7 s; for the Er,Cr:YSGG laser it was 3 min 13.9 s (p < 0.0001). The mean temperature changes were 1.41 ±1.36°C for the Er:YAG laser and 2.2 ±0.99°C for the Er,Cr:YSGG laser (p = 0.0321). The SEM examination showed no damage or major structural changes caused by treatment with either erbium-family laser. CONCLUSIONS: Both lasers are effective, non-invasive tools to remove prefabricated zirconia crowns cemented with resin cement and should be considered as viable alternatives to rotary instrumentation.


Asunto(s)
Láseres de Estado Sólido , Coronas , Humanos , Itrio , Circonio
2.
Artículo en Inglés | MEDLINE | ID: mdl-33528455

RESUMEN

The purpose of this study was to evaluate the cleaning and surface treatment techniques in the repair of aged and contaminated yttrium oxide-stabilized tetragonal polycrystalline zirconia (Y-TZP). From a total of 80 specimens of Y-TZP, 60 were subjected to aging simulation in a buccal environment with degradation in an autoclave for 24 hours (127°C/1.5 bar) and contaminated with Streptococcus mutans. The surfaces were cleaned with a triple syringe (air/water jet; n = 20) or isopropyl alcohol (n = 20), or by prophylaxis (n = 20) with pumice and water. The remaining 20 specimens comprised the control group. All specimens were then treated with silicatization (n = 10 per group) or adhesive (n = 10 per group) and repaired with composite resin. Analyses of shear strength, failure mode, and roughness were performed by electron microscopy. Data were analyzed by two-way analysis of variance (ANOVA) and t test (α = .05). Statistical significance was set at P < .05. Two-way ANOVA was significant for aging and surface treatments (P = .049), but was not significant for surface cleaning (P = .05). ANOVA results were statistically significant for surface treatments (P < .0001), with higher resistance for the silicatization groups. The failure mode was mostly adhesive for all specimens. The roughness was not significant for aging and control groups (P > .05). Triple-syringe and prophylaxis cleansing followed by silicatization was the most efficient treatment for the repair of aged and contaminated Y-TZP. There is reduced repair efficiency with the aging of Y-TZP.


Asunto(s)
Resinas Compuestas , Recubrimiento Dental Adhesivo , Anciano , Protocolos Clínicos , Análisis del Estrés Dental , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Cementos de Resina , Resistencia al Corte , Propiedades de Superficie , Itrio , Circonio
3.
Int J Prosthodont ; 34(1): 13-20, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570515

RESUMEN

PURPOSE: To evaluate and compare the occlusal fit of zirconia crowns designed using a digital articulator method and the traditional method in a self-controlled clinical trial. MATERIALS AND METHODS: Two zirconia crowns each were prepared for 12 patients with a single posterior tooth defect using two different methods: a digital articulator method and the traditional method. In the traditional method, casts were scanned using a model scanner, and the relative positions of the maxillary and mandibular arches were determined by the intercuspal occlusion of the casts. In the digital articulator method, casts were mounted on a mechanical articulator and scanned, and the relative positions were determined by their respective positions in the articulator. Additional dynamic occlusal adjustments of the digital articulator crowns were performed. Both groups of zirconia crowns were milled in a five-axis milling machine. The time required for occlusal adjustments, the occlusal contacts, the occlusal contact distributions, the number of occlusal contacts, the relative occlusal forces, and patient satisfaction (visual analog scale score) were evaluated. Wilcoxon test, McNemar test, and paired t test were used to compare the parameters between the two methods. RESULTS: The occlusal adjustment times for the digital articulator and traditional method crowns were 327 ± 226 seconds and 395 ± 338 seconds, respectively (P > .05). There were no significant differences in occlusal contacts, occlusal contact distributions, number of occlusal contacts, relative occlusal forces, or VAS scores between the two methods (P > .05). CONCLUSION: A digital articulator method for single-crown restoration was applied successfully. Crowns fabricated using a digital articulator or the traditional method can achieve acceptable occlusal fit for single-crown restorations.


Asunto(s)
Articuladores Dentales , Diseño de Prótesis Dental , Diseño Asistido por Computadora , Coronas , Humanos , Circonio
4.
Int J Prosthodont ; 34(1): 37-46, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570518

RESUMEN

PURPOSE: To evaluate the 2-year performance of definitive implant- or tooth-supported three-unit fixed dental prostheses made of zirconia-reinforced lithium silicate placed to restore premolars and molars in clinical cases of partial edentulism. MATERIALS AND METHODS: All patients received a three-unit fixed restoration made of monolithic, hot-pressed, zirconia-reinforced lithium silicate glass-ceramic. The restoration was cemented to two natural teeth or attached to two 3.5- or 4.5-mm-diameter square threaded, grit-blasted, acid-etched integrated implants with a Morse taper connection. Peri-implant pocket depth and bone and soft tissue remodeling were recorded for 2 years at each follow-up visit. Esthetic, functional, and biologic United States Public Health Services (USPHS) parameters modified by the World Dental Federation study design were assessed yearly until the final follow-up appointment. At the time of placement of the definitive restorations and at the 2-year follow-up visit, the opposing dentitions were identified by type of restoration and supporting structures. RESULTS: A total of 100 patients were consecutively enrolled in the period between June 2016 and July 2017, and 50 patients each received an implant-supported restoration (Group A) or a tooth-supported restoration (Group B). One (2%) of the 50 implant-supported prostheses fractured after 21 months of function. None of the other prostheses failed or became loose or detached. No significant differences involving probing levels or bone and soft tissue remodeling were found between the follow-up times. No cases of inflammation or infection of the mucosal cuff around the neck of the implants were recorded. The most common issue occurred immediately after placement of the prosthesis, when 3 patients (6%) from Group A and 4 patients (8%) from Group B asked for a modification of tooth shade. CONCLUSION: Implant-supported or tooth-supported three-unit fixed dental prostheses made of zirconia-reinforced lithium silicate can be used to successfully restore cases of posterior partial edentulism. The 2-year results of this report will be studied more in depth in ongoing long-term research.


Asunto(s)
Implantes Dentales , Litio , Diseño de Prótesis Dental , Prótesis Dental de Soporte Implantado , Fracaso de la Restauración Dental , Dentadura Parcial Fija , Estudios de Seguimiento , Humanos , Silicatos , Circonio
5.
Int J Prosthodont ; 34(1): 47-53, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33570519

RESUMEN

PURPOSE: To investigate the impact of high-speed sintering and artificial aging on the fracture load of three-unit zirconia fixed dental prostheses (FDPs). MATERIALS AND METHODS: Three-unit FDPs manufactured from 3Y-TZP (Ceramill Zolid, Amann Girrbach) and 4Y-TZP (Ceramill Zolid HT+, Amann Girrbach; N = 128, n = 64/group) were sintered at 1,580°C (high-speed sintering) or at 1,450°C (control group; n = 32/subgroup). Specimens were bonded to steel abutment models using Multilink Automix (Ivoclar Vivadent), and fracture load was examined without (n = 16/subgroup) and with artificial aging (6,000 thermocycles [5°C/55°C] and 1,200,000 chewing cycles [50 N]; n = 16/subgroup). Univariate analysis of variance, unpaired t test, and Weibull modulus were computed (P < .05). RESULTS: Sintering protocol (P = .944), artificial aging (P = .630), and zirconia material (P = .445) did not show an influence on the fracture load of three-unit FDPs. High-speed sintering led to superior Weibull modulus results for artificially aged 4Y-TZP specimens, while all other groups showed values in the same range. CONCLUSION: The present study shows promising results for the novel high-speed sintering protocol, as it led to comparable fracture load and similar, or even superior, Weibull modulus results compared to the control group. The 4Y-TZP material presented fracture load results similar to the tried-and-tested 3Y-TZP. Artificial aging did not influence zirconia's resistance to fracture for either 3Y-TZP or 4Y-TZP.


Asunto(s)
Prótesis Dental , Circonio , Materiales Dentales , Porcelana Dental , Análisis del Estrés Dental , Ensayo de Materiales
6.
Am J Dent ; 34(1): 39-43, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33544987

RESUMEN

PURPOSE: To characterize the color outcome on different zirconia types of various colored titanium backgrounds produced with a newly developed anodized technique. METHODS: Blue, green, pink and gold-colored titanium backgrounds were produced via different anodization voltage values. Non-anodized grey colored titanium was used as a control. A total of 40 disc-shaped zirconia specimens were prepared from four different zirconia types (Cercon HT, Noritake Alliance, Prettau, and Ice Zirkon). The zirconia specimens were placed on different titanium backgrounds to evaluate color differences (ΔE) by recording the L, a and b values. ΔE, ΔL, Δa and Δb values were compared for different titanium backgrounds and zirconia types. To analyze the results, repeated measures ANOVA and Bonferroni adjustments for pairwise comparison were used (α= 0.05). RESULTS: The Cercon HT group had the highest ΔE value, while the Noritake group showed the lowest ΔE value (P< 0.05). ΔL, Δa and Δb values showed significant color changes depending on the color of the titanium background, the sintering procedure of zirconia and the zirconia ingredients (P< 0.05). CLINICAL SIGNIFICANCE: Anodized titanium abutments may improve color in esthetic regions when a ceramic abutment cannot be used. The study showed that the gold-colored titanium produced via anodization was better than other colors at producing a tooth-like color for implant-supported zirconia restorations. Also, by adjusting the color of zirconia restorations, the effect of the background could be altered using the zirconia sintering protocol.


Asunto(s)
Pilares Dentales , Titanio , Color , Ensayo de Materiales , Circonio
7.
Anal Chem ; 93(4): 2090-2096, 2021 02 02.
Artículo en Inglés | MEDLINE | ID: mdl-33435685

RESUMEN

The sensitive detection of coronavirus is of vital importance for the prevention of its rapid spread. Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that causes severe diarrhea and death in neonatal piglets. In this work, a novel PCN-224-based electrochemiluminescence (ECL) system was constructed for PEDV detection with high sensitivity. We found that PCN-224 can be employed as an ECL reporter with a strong signal because of its zirconium-based organic porous frame nanomaterial with a large specific surface area and stable structure. TiO2 nanoparticles were used as an accelerator for the first time to promote the reduction of coreactant potassium peroxydisulfate on the cathode; thus, the initial ECL signal of PCN-224 was significantly amplified. In the presence of PEDV, the ECL signal decreased due to the block effect to electron transfer. As a result, the novel "signal off" biosensor achieved a sensitive detection of PEDV ranging from 1 pg/mL to 10 ng/mL, with a detection limit of 0.4 pg/mL (S/N = 3). Importantly, the PCN-224 nanomaterial enriched the ECL system in biological analysis, and the proposed strategy provided a new route for coronavirus detection.


Asunto(s)
Técnicas Electroquímicas/métodos , Estructuras Metalorgánicas/química , Porfirinas/química , Circonio/química , Técnicas Biosensibles , Luminiscencia , Nanopartículas del Metal/química , Microscopía Electrónica de Transmisión , Titanio/química
8.
Sensors (Basel) ; 21(2)2021 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-33445501

RESUMEN

This research paper is concentrated on the design of biologically compatible lead-free piezoelectric composites which may eventually replace traditional lead zirconium titanate (PZT) in micromechanical fluidics, the predominantly used ferroelectric material today. Thus, a lead-free barium-calcium zirconate titanate (BCZT) composite was synthesized, its crystalline structure and size, surface morphology, chemical, and piezoelectric properties were analyzed, together with the investigations done in variation of composite thin film thickness and its effect on the element properties. Four elements with different thicknesses of BCZT layers were fabricated and investigated in order to design a functional acoustophoresis micromechanical fluidic element, based on bulk acoustic generation for particle control technologies. Main methods used in this research were as follows: FTIR and XRD for evaluation of chemical and phase composition; SEM-for surface morphology; wettability measurements were used for surface free energy evaluation; a laser triangular sensing system-for evaluation of piezoelectric properties. XRD results allowed calculating the average crystallite size, which was 65.68 Å3 confirming the formation of BCZT nanoparticles. SEM micrographs results showed that BCZT thin films have some porosities on the surface with grain size ranging from 0.2 to 7.2 µm. Measurements of wettability showed that thin film surfaces are partially wetting and hydrophilic, with high degree of wettability and strong solid/liquid interactions for liquids. The critical surface tension was calculated in the range from 20.05 to 27.20 mN/m. Finally, investigations of piezoelectric properties showed significant results of lead-free piezoelectric composite, i.e., under 5 N force impulse thin films generated from 76 mV up to 782 mV voltages. Moreover, an experimental analysis showed that a designed lead-free BCZT element creates bulk acoustic waves and allows manipulating bio particles in this fluidic system.


Asunto(s)
Acústica/instrumentación , Materiales Biocompatibles/química , Cerámica/química , Circonio/química , Bario/química , Electroforesis/métodos , Diseño de Equipo , Glicerol/química , Plomo , Microscopía Electrónica de Rastreo , Aceite de Oliva/química , Espectrometría por Rayos X , Espectroscopía Infrarroja por Transformada de Fourier , Difracción de Rayos X
9.
Toxicol Lett ; 339: 32-38, 2021 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-33370593

RESUMEN

Metal-organic frameworks (MOFs) have shown promising properties for removal of chemical warfare agents, in particular for material decontamination and functionalized fabrics. The MOF-properties could also be beneficial for skin decontamination, especially when exposed to highly toxic and low volatile nerve agents. In such exposures, efficient decontamination is crucial for adequate medical management. In the present study, seven zirconium-based MOFs were evaluated for their ability to degrade VX and subsequently tested in vitro for decontamination of VX on human dermatomed skin. Of the MOFs evaluated, MOF-808 showed the greatest ability to degrade VX in an alkaline buffer with complete degradation of VX within 5 min. PCN-777, Zr-NDC and NU-1000 displayed degradation half-lives of approximately 10 min. When including MOF-808 in a skin friendly carrier with slightly acidic pH, a decreased agent degradation rate was observed, requiring over 24 h to reach complete degradation. In skin decontamination experiments, MOF-808 enhanced the efficacy compared to the carrier alone, essentially by improved agent absorption. Adding MOF-808 to Reactive Skin Decontamination Lotion (RSDL) did not improve the high effectiveness of RSDL alone. The present study showed that including MOF in skin decontamination lotions could be beneficial. Further studies should include optimizing the particulates and formulations.


Asunto(s)
Sustancias para la Guerra Química/toxicidad , Descontaminación/métodos , Estructuras Metalorgánicas/uso terapéutico , Agentes Nerviosos/toxicidad , Compuestos Organotiofosforados/toxicidad , Piel/efectos de los fármacos , Circonio/uso terapéutico , Células Cultivadas/efectos de los fármacos , Sustancias para la Guerra Química/metabolismo , Humanos , Agentes Nerviosos/metabolismo , Compuestos Organotiofosforados/metabolismo , Crema para la Piel
10.
Chemosphere ; 262: 128317, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33182083

RESUMEN

The development of industrialization and agricultural activities have carried various negative impacts to living organisms in recent decades and also, the frequent problem of inorganic pollution have been environmental anxiety to the community. Among these, Cr6+ and F- are priority poisonous pollutants from many industries. In this work, we present a low-cost synthesis procedure to obtain biocompatible zirconium incorporated chitosan-gelatin composite (CS-Zr-GEL) were fabricated and explored for the adsorptive removal of toxic Cr6+ and F- from water. The adsorption mechanism of toxic Cr6+ and F- was done by batch mode as a function of contact time, solution pH and co-existing ions. The obtained materials were extensively studied by several physico-chemical techniques to access their properties by X-ray diffraction (XRD), scanning electron microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) analysis. Additionally, the fabricated adsorbent is highly dependent on solution pH. The kinetic and isotherm data were fitted using pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity for CS-Zr-GEL is 138.89 and 12.13 mg/g at 323K for Cr6+ and F- respectively. These findings demonstrate that the CS-Zr-GEL adsorbent represents a promising candidate that would have a practical influence on water/wastewater treatments.


Asunto(s)
Quitosano/química , Cromo/análisis , Fluoruros/análisis , Gelatina/química , Contaminantes Químicos del Agua/análisis , Purificación del Agua/métodos , Circonio/química , Adsorción , Concentración de Iones de Hidrógeno , Cinética , Aguas Residuales/química
11.
Chemosphere ; 263: 127938, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32829222

RESUMEN

The urgent need for eutrophication control motivated the development of many novel adsorbents for enhanced phosphate polishing removal. Among these, zirconium-based nanomaterial was regarded as an effective kind because of its ability to bind phosphate specifically via inner-sphere complexation. In this study, we proposed a new strategy to improve the efficiency of zirconium oxides (HZO) nanoparticles by immobilizing them onto a gel-type anion exchange resin covalently attached with ammonium groups, denoted as HZO@N201. A previously developed macro-porous polymeric nanocomposite HZO@D201 was used for comparison. The immobilized nanoparticles in HZO@N201 were well dispersed in the gel matrix, manifesting smaller particle size and richer surface hydroxyl groups in comparison to HZO@D201. As a result of the structural merits in collective, HZO@N201 not only exhibited superior phosphate adsorptive capacity and affinity towards phosphate to HZO@D201, but also facilitate phosphate diffusion, based on isotherm, pH and kinetic tests. Mechanistic study by XPS and 31P SS-NMR substantiated the selective phosphate adsorption pathway as the formation of inner-sphere complexes by HZO@N201, which exhibited enhanced reactivity than HZO@D201. Lastly, fixed-bed runs of HZO@N201 was conducted, achieving an effective treatable volume of 2000 BV, which was 600 BV more than HZO@D201. Additional adsorption-regeneration cycle confirmed its reusability and potential for practical application. We believe the gel-type polymeric host could facilitate the formation and dispersion of smaller sized nanoparticles, exposing more surface hydroxyl groups highly accessible to phosphate. The results of this paper offer insights to a new strategy for immobilization of functional nanoparticles aiming at enhanced adsorptive removal of phosphate.


Asunto(s)
Fosfatos/química , Poliestirenos/química , Contaminantes Químicos del Agua/química , Circonio/química , Adsorción , Resinas de Intercambio Aniónico/química , Concentración de Iones de Hidrógeno , Inmovilización , Nanocompuestos/química , Nanopartículas , Óxidos , Polímeros , Contaminantes Químicos del Agua/análisis
12.
Chemosphere ; 268: 129155, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33352508

RESUMEN

The metal-organic framework (MOF) UiO-66 is made of zirconium clusters coordinated with 1,4-benzenedicarboxylate linkers that is stable in water and is highly tolerant to extremely acidic or basic environments. Conversely, the zirconium clusters are affine to nucleophiles so the crystalline structures of UiO-66 can be converted into amorphous derivatives. In a mineral acid solution both protons and coordinating nucleophile are present. This study for the first time revealed that it is the strong nucleophile instead of proton deteriorate the crystalline structures of UiO-66. Also, the so-produced amorphous mesoporous matrix, if not totally dissolved, can be applied as an efficient adsorbent. The noted adsorption capabilities of Cu(II) and nucleophiles by these amorphous mesoporous matrix did not correlate with the structural crystallinity or the internal surface area; conversely, the doped nucleophiles were noted to contribute to the adsorption tendencies towards Cu(II) and phosphate species via electrostatic interactions and hydrogen bonding, respectively. Conversion of sacrificing UiO-66 template to amorphous matrix can be applied as an effective way to fabricate specific adsorbent with resistance to extreme pH and strong nucleophile challenges.


Asunto(s)
Estructuras Metalorgánicas , Contaminantes Químicos del Agua , Purificación del Agua , Adsorción , Circonio
13.
Food Chem ; 337: 127974, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-32920274

RESUMEN

Facile enrichment and determination of trace organophosphorus pesticides (OPPs) in foods has been a constantly pursuing goal in food safety field. Herein, Zr4+-immobilized covalent organic frameworks (Fe3O4@COF@Zr4+) have been first constructed and utilized as the powerful adsorbents for magnetic solid-phase extraction (MSPE) of OPPs. Owing to the π-π stacking interaction, hydrogen bonding and Zr4+-phosphate coordination reaction, the composites exhibited excellent selectivity and superior affinity to OPPs. Under optimized conditions, the proposed MSPE method coupled with GC-FPD showed good linearity (R2 ≥ 0.9990) and yielded low limits of detection (0.7-3.0 µg kg-1) for OPPs. Moreover, the developed method was successfully employed for the quantitation of OPPs in spiked vegetable samples and obtained satisfactory recoveries in the range of 87-121% with the relative standard deviations (RSDs) ≤ 8.9%. These results demonstrated that the prepared nanoparticles hold unique advantages for trace OPPs analysis in foodstuffs.


Asunto(s)
Estructuras Metalorgánicas/química , Organofosfatos/análisis , Plaguicidas/análisis , Extracción en Fase Sólida/métodos , Verduras/química , Compuestos de Anilina/química , Análisis de los Alimentos/instrumentación , Análisis de los Alimentos/métodos , Contaminación de Alimentos/análisis , Hierro/química , Límite de Detección , Fenómenos Magnéticos , Nanocompuestos/química , Extracción en Fase Sólida/instrumentación , Circonio/química
14.
Evid Based Dent ; 21(4): 138-139, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33339976

RESUMEN

Source of funding This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectorsType of study/design Randomised controlled trial (RCT) with parallel design.Subjects This RCT was conducted at the Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Centre of Dental Medicine, University of Zurich, Zurich, Switzerland. Ten patients, six women and four men, with a mean age of 62 years and an age range of 49-77 years, requiring posterior tooth-supported 3-unit fixed partial dentures (FPDs) were included in this RCT. The abutment teeth were six molars and six premolars in the maxilla and five molars and three premolars in the mandible. The patients fulfilled the following inclusion criteria: they all were >18 years, with a full mouth plaque score <25% and a full mouth bleeding score <25%. They all needed a posterior tooth-supported FPD, in which the third molar was not an abutment tooth. Only abutments with no extensive pretreatment were eligible. Adjacent and opposing teeth should be healthy or adequately restored.Treatment Three intraoral digital scanning systems (Lava C.O.S.; 3M [Lava], iTero; Align Technology Inc [iTero], Cerec Bluecam; Dentsply Sirona [Cerec]) and conventional light/regular body polyether impression in a stock tray were made on each of the included participants by the same clinician. The opposing arch impression was made in alginate. The sequence of the four techniques was computer generated and concealed in opaque sealed envelopes. Three calibrated experienced clinicians were involved in the treatment. They followed the published guidelines for preparing abutments that receive CAD/CAM ceramic FPDs. After interim prosthesis removal and double retraction cord application, the digital or the conventional impression procedure was started as dictated by the random sequence. Scans were done according to the manufacturer's guidelines, whereby Lava and Cerec required powdering of the teeth by titanium oxide and iTero did not.Main outcome Time needed for obtaining a scan or an impression was calculated. For digital scans it consisted of the time required for powdering, scanning and occlusal registration, while in conventional impression it started from the beginning of impression mixing till tray removal. The number of impression or scan remakes required until results fulfilling the quality criteria were obtained was also recorded. Visual analogue scale (VAS) was used to rate the perception of both, clinicians and patients for the procedures. Patients were asked to rate their comfort with the procedure, while clinicians rated both difficulty and comfort, where 0 indicated uncomfortable and simple and 100 difficult and comfortable. Subjective assessment of the time as judged by the clinicians and the patients was also reported.Main results Generally speaking, conventional impression was better than the three complete arch digital scans, regarding time required in seconds, difficulty for clinicians, comfort and time perception of both patients and clinicians. Number of remakes were highest in iTero (7), followed by Lava, conventional impression and finally Cerec (0). The time required for each technique differed significantly Polyether = 658 (95%CI 528-782) Cerec = 1776 (95%CI 804-2386) iTero = 1107 (785 - 2091). A significant difference was found neither among the three digital impressions, nor between the conventional impression and Lava (µ = 1091, 95%CI [717-1465]). The same findings were reported regarding difficulty for the clinicians. A significant difference was reported between conventional impression (µ = 15, 95%CI [7-24]) and both Cerec (µ = 67, 95%CI [58-77]) and iTero (µ = 43, 95%CI [25-62]). No significant difference was reported among the studied techniques regarding patients' comfort and time perceptions of both clinicians and patients except for a difference in the patients' time perception of Cerec and conventional impression, where P = .035. Regarding the clinicians' comfort a significant difference was only found between conventional impression (µ = 82, 95%CI [69-94]) and Cerec (µ = 32, 95%CI [18-46]).Conclusion Within the limitations of this RCT, it can be concluded that complete arch conventional impression is objectively less time consuming and subjectively preferred by both clinicians and patients when compared to digital scanning. Digital scanning techniques, requiring powdering, are more difficult for the clinicians than powderless ones and conventional impression.


Asunto(s)
Materiales de Impresión Dental , Técnica de Impresión Dental , Anciano , Cerámica , Dentadura Parcial Fija , Femenino , Humanos , Masculino , Persona de Mediana Edad , Suiza , Flujo de Trabajo , Circonio
15.
J Biomed Nanotechnol ; 16(7): 1144-1159, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-33308381

RESUMEN

Oxidative stress is one of the principal causes of hypoxia-induced kidney injury. The ceria nanoparticle (CNP) is known to exhibit free radical scavenger and catalytic activities. When zirconia is attached to CNPs (CZNPs), the ceria atom tends to remain in a Ce3+ form and its efficacy as a free radical scavenger thus increases. We determined the effectiveness of CNP and CZNP antioxidant activities against hypoxia-induced acute kidney injury (AKI) and observed that these nanoparticles suppress the apoptosis of hypoxic HK-2 cells by restoring autophagy flux and alleviating mitochondrial damage. In vivo experiments revealed that CZNPs effectively attenuate hypoxia-induced AKI by preserving renal structures and glomerulus function. These nanoparticles can successfully diffuse into HK-2 cells and effectively counteract reactive oxygen species (ROS) to block hypoxia-induced AKI. This suggests that these particles represent a novel approach to controlling this condition.


Asunto(s)
Lesión Renal Aguda , Nanopartículas , Antioxidantes , Apoptosis , Autofagia , Humanos , Hipoxia , Estrés Oxidativo , Especies Reactivas de Oxígeno , Circonio
16.
Int J Nanomedicine ; 15: 9891-9907, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33328732

RESUMEN

Purpose: The aim of this study was to investigate the effect of various mass fractions of 10-methacry-loyloxydecyl dihydrogen phosphate (MDP)-conditioned or unconditioned zirconia nano- or micro-particles with different initiator systems on the mechanical properties of nanohybrid resin composites. Methods: Both light-cured (L) and dual-cured (D) resin composites were prepared. When the mass fraction of the nano- or micro-zirconia fillers reached 55 wt%, resin composites were equipped with dual-cured initiator systems. We measured the three-point bending-strength, elastic modulus, Weibull modulus and translucency parameter of the nanohybrid resin composites containing various mass fractions of MDP-conditioned or unconditioned zirconia nano- or micro-particles (0%, 5 wt%, 10 wt%, 20 wt%, 30 wt% and 55 wt%). A Cell Counting Kit (CCK)-8 was used to test the cell cytotoxicity of the experimental resin composites. The zirconia nano- or micro-particles with MDP-conditioning or not were characterized by transmission electron microscopy (TEM), Fourier infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). Results: Resin composites containing 5-20 wt% MDP-conditioned or unconditioned nano-zirconia fillers exhibited better three-point bending-strength than the control group without zirconia fillers. Nano- or micro-zirconia fillers decreased the translucence of the nanohybrid resin composites. According to the cytotoxicity classification, all of the nano- or micro-zirconia fillers containing experimental resin composites were considered to have no significant cell cytotoxicity. The FTIR spectra of the conditioned nano- or micro-fillers showed new absorption bands at 1719 cm-1 and 1637 cm-1, indicating the successful combination of MDP and zirconia particles. The XPS analysis measured Zr-O-P peak area on MDP-conditioned nano- and micro-zirconia fillers at 39.91% and 34.89%, respectively. Conclusion: Nano-zirconia filler improved the mechanical properties of nanohybrid resin composites, but cannot be the main filler to replace silica filler. The experimental dual-cured composites can be resin cements with better opacity effects and a low viscosity.


Asunto(s)
Fenómenos Mecánicos , Nanopartículas/química , Circonio/química , Resinas Compuestas/química , Módulo de Elasticidad , Ensayo de Materiales , Metacrilatos/química , Fosfatos/química , Dióxido de Silicio/química , Propiedades de Superficie
17.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(6): 647-651, 2020 Dec 01.
Artículo en Chino | MEDLINE | ID: mdl-33377341

RESUMEN

OBJECTIVE: This study aimed to investigate the effect of occlusal thickness design on fracture resistance of endocrowns restored with lithium disilicate ceramic and zirconia. METHODS: A total of 24 artificial first mandibular molars were randomly divided into four groups with six teeth in each group as follows: group lithium disilicate ceramic-2 mm (lithium disilicate ceramic, with an occlusal thickness of 2 mm and a retainer length of 4 mm); group lithium disilicate ceramic-4 mm (lithium disilicate ceramic, with an occlusal thickness of 4 mm and a retainer length of 2 mm); group zirconia-2 mm (zirconia, with an occlusal thickness of 2 mm and a retainer length of 4 mm); and group zirconia-4 mm (zirconia, with an occlusal thickness of 4 mm and a retainer length of 2 mm). After adhesive cementation (RelyX Ultimate Clicker), all specimens were subjected to thermocycling (10 000 cycles). The specimens were subjected to fracture resistance testing at a 135° angle to the teeth at a crosshead speed of 0.5 mm·min⁻¹ in a universal testing machine. Data were analyzed with ANOVA and Tukey's HSD test by SPSS 15.0. The failure modes were classified. RESULTS: The fracture resistances of groups lithium disilicate ceramic-2 mm, lithium disilicate ceramic-4 mm, zirconia-2 mm, and zirconia-4 mm were (890.54±83.41), (2 320.87±728.57), (2 258.05±557.66), and (3 847.70±495.99) N respectively. Group zirconia-4 mm had the highest fracture resistance, whereas group lithium disilicate ceramic-2 mm had the lowest. CONCLUSIONS: The fracture resistance of molar endocrown with zirconia is higher than that with lithium disilicate ceramic. Increasing the occlusal thickness can improve the fracture resistance but increase the risk of fracture of abutment.


Asunto(s)
Coronas , Fracaso de la Restauración Dental , Cerámica , Porcelana Dental , Análisis del Estrés Dental , Ensayo de Materiales , Circonio
18.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 55(11): 885-890, 2020 Nov 09.
Artículo en Chino | MEDLINE | ID: mdl-33171563

RESUMEN

Objective: To observe the changes of peri-implant tissue around the individualized abutment that was grinded from zirconia provisional crown in one year. Methods: In this research, a prosthodontic-driven virtual implant planning and immediate provisionalization were conducted in computer assisted design software. And computer-aided design/computer-aided manufacturing (CAD/CAM) techniques were used to fabricate the zirconia provisional crown and surgical guide template before surgery. The implant was accurately placed with the surgical guide, and the zirconia provisional crown was immediately delivered after surgery. Three months later, the implant osseointegration was completed, and zirconia provisional crown was prepared intraorally to generate customized zirconia abutment for final prosthesis. The study included 30 patients with single anterior tooth loss, including 18 males and 12 females, aged from 26 to 50 years old, and the mean age was (36.2±6.1) years old. The patients were from the Center of Oral Implantology, The First Affiliated Hospital of Zhejiang University Medical College from January 2017 to February 2018. After cementation of the final prosthesis, the cases were followed up at 6 and 12 months time intervals. Implant survival rate, probing depth, bleeding on probing, marginal bone level loss and papilla index score (PIS) were recorded in every appointment. Results: The survival rate of 30 implants was 100%, and the probing depths were less than 5 mm. The bone resorption at 6 and 12 months follow-up after the final delivery was 0 (0, 0) mm and 0 (-0.2, 0) mm, respectively, and the difference was not statistically significant (P>0.05). The PIS was 3.0 (2.0, 4.0), 3.0 (2.8, 4.0) and 3.0 (3.0, 4.0) on the final delivery, 6 and 12 months after final delivery, respectively. Conclusions: Marginal bone level and bone loss were stable with this new implant clinical protocol at the one-year follow-up.


Asunto(s)
Implantes Dentales de Diente Único , Implantes Dentales , Adulto , Coronas , Prótesis Dental de Soporte Implantado , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Resultado del Tratamiento , Circonio
19.
Indian J Dent Res ; 31(4): 537-545, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33107453

RESUMEN

Purpose of the Study: To comparatively evaluate the wear resistance of two different posterior indirect restorative materials against human enamel. Materials and Methods: Two different posterior indirect restorative materials of ten in each Group-I (Monolithic zirconia) (n = 10) and Group-II (Cast cobalt chromium) (n = 10) were formed into disc and used as a substrate for the wear test. Freshly extracted mandibular first premolars were used as a pin (antagonist) (n = 20). Pin-on-disc wear testing machine was used to simulate the masticatory parameters and evaluation of the wear parameters was done after 1,20,000 cycles, with load of 40N for specific duration. Data related to wear testing procedure were tabulated and evaluated. Results were statistically analyzed using Mann-Whitney test and Wilcoxon signed rank test. Results: Mean surface roughness value (Ra value) obtained for Group-I disc test samples showed no statistical significance (P value < 0.05). Mean wear rate value of test disc samples was statistically significant between Group-I and Group-II (P value < 0.05). Mean surface roughness value was statistically significant between Groups-I and II before and after wear test (P value < 0.05). Conclusion: From the results obtained, it was found that the Group-I (Monolithic zirconia) exhibited higher wear resistance than Group-II (cast cobalt chromium) and causes less wear to the opposing enamel antagonist.


Asunto(s)
Aleaciones de Cromo , Porcelana Dental , Diseño Asistido por Computadora , Esmalte Dental , Humanos , Ensayo de Materiales , Propiedades de Superficie , Circonio
20.
Artículo en Inglés | MEDLINE | ID: mdl-33093772

RESUMEN

Background: Forms of interstitial pneumonia secondary to exposure to an air-contaminant are varied and so far, insufficiently described. Objectives/Methods: We report here a case of a 57-year-old patient managed in our department for the exploration of MRC grade 2 dyspnoea and interstitial pneumonia. He mentioned multiple occupational and domestic exposures such as hens' excrements, asbestos and metal particles; he also had a previous history of smoking. Results: High-resolution computed tomography showed ground glass opacities predominating in posterior territories and surrounding cystic lesions or emphysematous destruction. The entire etiological assessment revealed only macrophagic alveolitis with giant multinucleated cells on the bronchoalveolar lavage. A surgical lung biopsy allowed us to refine the diagnosis with evidence of desquamative interstitial pneumonia and pulmonary granulomatosis. Finally, the analysis of the mineral particles in the biopsy revealed abnormally high rates of Zirconium and Aluminium. We were therefore able to conclude to a desquamative interstitial pneumonia associated with pulmonary granulomatosis linked to metal exposure (Aluminium and Zirconium). The clinical, functional and radiological evolution was favorable after a systemic corticosteroid treatment with progressive decay over one year. Conclusion: This presentation reports the first case to our knowledge of desquamative interstitial pneumonitis related to exposure to Zirconium and the third one in the context of Aluminium exposure. The detailed analysis of the mineral particles present on the surgical lung biopsy allows for the identification of the relevant particle to refine the etiological diagnosis, to guide the therapeutic management and to give access to recognition as an occupational disease. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (1): 79-84).


Asunto(s)
Aluminio/efectos adversos , Granuloma del Sistema Respiratorio/inducido químicamente , Exposición por Inhalación/efectos adversos , Enfermedades Pulmonares Intersticiales/inducido químicamente , Pulmón/efectos de los fármacos , Circonio/efectos adversos , Corticoesteroides/administración & dosificación , Aluminio/análisis , Biopsia , Granuloma del Sistema Respiratorio/diagnóstico , Granuloma del Sistema Respiratorio/tratamiento farmacológico , Granuloma del Sistema Respiratorio/metabolismo , Humanos , Pulmón/química , Pulmón/diagnóstico por imagen , Pulmón/patología , Enfermedades Pulmonares Intersticiales/diagnóstico , Enfermedades Pulmonares Intersticiales/tratamiento farmacológico , Enfermedades Pulmonares Intersticiales/metabolismo , Masculino , Persona de Mediana Edad , Resultado del Tratamiento , Circonio/análisis
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