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1.
Future Microbiol ; : 1-11, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38979570

RESUMEN

Aim: To develop a ß-AgVO3 gel and evaluate its physicochemical stability and antifungal activity against Candida albicans. Materials & methods: The gel was prepared from the minimum inhibitory concentration (MIC) of ß-AgVO3. The physicochemical stability was evaluated by centrifugation, accelerated stability (AS), storage (St), pH, syringability, viscosity and spreadability tests and antifungal activity by the agar diffusion. Results: The MIC was 62.5 µg/ml. After centrifugation, AS and St gels showed physicochemical stability. Lower viscosity and higher spreadability were observed for the higher ß-AgVO3 concentration and the minimum force for extrusion was similar for all groups. Antifungal effect was observed only for the ß-AgVO3 gel with 20xMIC. Conclusion: The ß-AgVO3 gel showed physicochemical stability and antifungal activity.


We used silver and vanadium to make a gel that can kill fungi in the mouth. We looked at the color of the gel, it's smell and also checked how well it lasted. The gel turned yellow and had no smell and did not spoil for at least 2 months. When we tested the gel against a type of fungus, it worked as well as another medicine called chlorhexidine, which is sold in pharmacies. But when we compared it with another medicine called nystatin, our gel was not as effective in killing the fungus.

2.
J Environ Manage ; 366: 121658, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39018856

RESUMEN

Higher education institutes (HEIs) are important drivers for the development and implementation of best practices for environmental sustainability. However, reliable indicators are needed to objectively evaluate the environmental performance of HEIs and their policies. The present paper aims at identifying suitable indicators for unbiased comparisons among different HEIs and for the identification of temporal trends in terms of environmental sustainability performance. At this aim, sustainability reports made publicly available by 24 Italian HEIs over a 10-year period were considered. Normalization of sustainability variables such as the annual electrical and thermal energy consumptions, related greenhouse gas emissions, and water consumption, against context-specific factors such as the number of users of each university, latitude, illuminance, heating degree days (HDDs) and cooling degree days allowed identifying the actual possible disturbance of the same variables. HDDs were found to positively affect the thermal energy consumption and the related CO2 emissions. Based on this, a novel indicator was formulated where the actual value of thermal energy consumption and the related CO2 emissions are divided not only by the number of users but also by the HDDs of the HEIs' locations. Indeed, this is a remarkable finding that, prior to confirmation with data from world HEIs, could be implemented in world university green ranking systems for improved and less biased sustainability assessments.


Asunto(s)
Conservación de los Recursos Naturales , Universidades , Italia , Gases de Efecto Invernadero/análisis
3.
ACS Appl Mater Interfaces ; 16(26): 34303-34312, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38885089

RESUMEN

Perovskite nanocrystals hold significant promise for a wide range of applications, including solar cells, LEDs, photocatalysts, humidity and temperature sensors, memory devices, and low-cost photodetectors. Such technological potential stems from their exceptional quantum efficiency and charge carrier conduction capability. Nevertheless, the underlying mechanisms of photoexcitation, such as phase segregation, annealing, and ionic diffusion, remain insufficiently understood. In this context, we harnessed hyperspectral fluorescence microspectroscopy to advance our comprehension of fluorescence enhancement triggered by UV continuous-wave (cw) laser irradiation of CsPbBr3 colloidal nanocrystal thin films. Initially, we explored the kinetics of fluorescence enhancement and observed that its efficiency (φph) correlates with the laser power (P), following the relationship φph = 7.7⟨P⟩0.47±0.02. Subsequently, we estimated the local temperature induced by the laser, utilizing the finite-difference method framework, and calculated the activation energy (Ea) required for fluorescence enhancement to occur. Our findings revealed a very low activation energy, Ea ∼ 9 kJ/mol. Moreover, we mapped the fluorescence photoenhancement by spatial scanning and real-time static mode to determine its microscale length. Below a laser power of 60 µW, the photothermal diffusion length exhibited nearly constant values of approximately (22 ± 5) µm, while a significant increase was observed at higher laser power levels. These results were ascribed to the formation of nanocrystal superclusters within the film, which involves the interparticle spacing reduction, creating the so-called quantum dot solid configuration along with laser-induced annealing for higher laser powers.

4.
Future Microbiol ; 19(8): 655-665, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38700286

RESUMEN

Aim: To evaluate the biological and mechanical properties of an adhesive with nanostructured silver vanadate (AgVO3). Materials & methods: Specimens in poly(methyl methacrylate) (PMMA) were treated with Ultra Corega Cream (UCCA) denture adhesive with or without AgVO3. Biofilms of Candida albicans, Candida glabrata and Streptococcus mutans were grown and the viable cells counted. Fluorescence microscopy was used. The viability of the VERO cell and adhesive strength were evaluated. Results: All concentrations of AgVO3 reduced the biofilm formation and showed no cytotoxic effect. At 5 min and 24 h, UCCA with 5 and 10% AgVO3 showed better performance, respectively. Conclusion: AgVO3 promoted the antibiofilm activity of the adhesive, with a positive effect on the adhesive strength, and was biocompatible.


What is this summary about? Some people wear false teeth called dentures. They use a special glue to keep these false teeth in their mouths. It is important to clean dentures well and remove the glue every day. If the dentures get dirty, they can cause infections of the gums. Doctors and dentists can help, but sometimes medicines do not work well. This study checked to see whether adding a medicine that can kill bacteria into the glue could stop gum swelling and other illnesses, or make them better.What were the results? The glue containing the medicine killed microbes like fungi and bacteria. It also stuck things together well and was safe to use.What do the results mean? Using this special glue could help people with dentures to avoid illness.


Asunto(s)
Biopelículas , Streptococcus mutans , Vanadatos , Biopelículas/efectos de los fármacos , Vanadatos/farmacología , Animales , Células Vero , Chlorocebus aethiops , Streptococcus mutans/efectos de los fármacos , Materiales Biocompatibles/farmacología , Candida albicans/efectos de los fármacos , Candida albicans/fisiología , Plata/farmacología , Plata/química , Dentaduras/microbiología , Ensayo de Materiales , Polimetil Metacrilato/química , Cementos Dentales/farmacología , Cementos Dentales/química , Adhesión Bacteriana/efectos de los fármacos , Adhesivos/farmacología , Adhesivos/química
5.
Eur J Cardiothorac Surg ; 65(5)2024 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-38663851

RESUMEN

OBJECTIVES: Robotic thymectomy has been suggested and considered technically feasible for thymic tumours. However, because of small-sample series and the lack of data on long-term results, controversies still exist on surgical and oncological results with this approach. We performed a large national multicentre study sought to evaluate the early and long-term outcomes after robot-assisted thoracoscopic thymectomy in thymic epithelial tumours. METHODS: All patients with thymic epithelial tumours operated through a robotic thoracoscopic approach between 2002 and 2022 from 15 Italian centres were enrolled. Demographic characteristics, clinical, intraoperative, postoperative, pathological and follow-up data were retrospectively collected and reviewed. RESULTS: There were 669 patients (307 men and 362 women), 312 (46.6%) of whom had associated myasthenia gravis. Complete thymectomy was performed in 657 (98%) cases and in 57 (8.5%) patients resection of other structures was necessary, with a R0 resection in all but 9 patients (98.6%). Twenty-three patients (3.4%) needed open conversion, but no perioperative mortality occurred. Fifty-one patients (7.7%) had postoperative complications. The median diameter of tumour resected was 4 cm (interquartile range 3-5.5 cm), and Masaoka stage was stage I in 39.8% of patients, stage II in 56.1%, stage III in 3.5% and stage IV in 0.6%. Thymoma was observed in 90.2% of patients while thymic carcinoma occurred in 2.8% of cases. At the end of the follow-up, only 2 patients died for tumour-related causes. Five- and ten-year recurrence rates were 7.4% and 8.3%, respectively. CONCLUSIONS: Through the largest collection of robotic thymectomy for thymic epithelial tumours we demonstrated that robot-enhanced thoracoscopic thymectomy is a technically sound and safe procedure with a low complication rate and optimal oncological outcomes.


Asunto(s)
Procedimientos Quirúrgicos Robotizados , Timectomía , Neoplasias del Timo , Humanos , Timectomía/métodos , Neoplasias del Timo/cirugía , Masculino , Femenino , Persona de Mediana Edad , Procedimientos Quirúrgicos Robotizados/métodos , Procedimientos Quirúrgicos Robotizados/estadística & datos numéricos , Procedimientos Quirúrgicos Robotizados/efectos adversos , Estudios Retrospectivos , Anciano , Adulto , Resultado del Tratamiento , Complicaciones Posoperatorias/epidemiología , Italia/epidemiología , Neoplasias Glandulares y Epiteliales/cirugía , Neoplasias Glandulares y Epiteliales/patología , Adulto Joven
6.
J Dent ; 145: 104984, 2024 06.
Artículo en Inglés | MEDLINE | ID: mdl-38583645

RESUMEN

OBJECTIVES: To incorporate the nanostructured silver vanadate decorated with silver nanoparticles (AgVO3) into denture base materials: heat-cured (HC) and 3D printed (3DP) resins, at concentrations of 2.5 %, 5 %, and 10 %; and to evaluate the antimicrobial activity in two multi-species biofilm: (1) Candida albicans, Candida glabrata, and Streptococcus mutans, (2) Candida albicans, Pseudomonas aeruginosa, and Staphylococcus aureus, and the wettability. METHODS: The AgVO3 was added to the HC powder, and printed samples were coated with 3DP with AgVO3 incorporated. After biofilm formation, the antimicrobial activity was evaluated by colony forming units per milliliter (CFU/mL), metabolic activity, and epifluorescence microscopy. Wettability was assessed by the contact angles with water and artificial saliva. RESULTS: In biofilm (1), HC-5 % and HC-10 % showed activity against S. mutans, HC-10 % against C. glabrata, and HC-10 % and 3DP-10 % had higher CFU/mL of C. albicans. 3DP-5 % had lower metabolic activity than the 3DP control. In biofilm (2), HC-10 % reduced S. aureus and P. aeruginosa, and HC-5 %, 3DP-2.5 %, and 3DP-5 % reduced S. aureus. 3DP incorporated with AgVO3, HC-5 %, and HC-10 % reduced biofilm (2) metabolic activity. 3DP-5 % and 3DP-10 % increased wettability with water and saliva. CONCLUSION: HC-10 % was effective against C. glabrata, S. mutans, P. aeruginosa, and S. aureus, and HC-5 % reduced S. mutans and S. aureus. For 3DP, 2.5 % and 5 % reduced S. aureus. The incorporation of AgVO3 into both resins reduced the metabolic activity of biofilms but had no effect on C. albicans. The wettability of the 3DP with water and saliva increased with the addition of AgVO3. CLINICAL SIGNIFICANCE: The incorporation of silver vanadate into the denture base materials provides antimicrobial efficacy and can prevent the aggravation of oral and systemic diseases. The incorporation of nanomaterials into printed resins is challenging and the coating is an alternative to obtain the inner denture base with antimicrobial effect.


Asunto(s)
Biopelículas , Candida albicans , Bases para Dentadura , Nanopartículas del Metal , Pseudomonas aeruginosa , Plata , Staphylococcus aureus , Streptococcus mutans , Vanadatos , Humectabilidad , Biopelículas/efectos de los fármacos , Streptococcus mutans/efectos de los fármacos , Candida albicans/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Vanadatos/farmacología , Vanadatos/química , Pseudomonas aeruginosa/efectos de los fármacos , Plata/farmacología , Plata/química , Bases para Dentadura/microbiología , Nanopartículas del Metal/química , Antiinfecciosos/farmacología , Candida glabrata/efectos de los fármacos , Impresión Tridimensional , Ensayo de Materiales , Humanos , Nanoestructuras , Compuestos de Plata/farmacología , Compuestos de Plata/química , Materiales Dentales/química , Materiales Dentales/farmacología
7.
Am J Surg Pathol ; 48(5): 605-614, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38441164

RESUMEN

Spread through air spaces (STAS) is a novel invasive pattern of lung cancer associated with poor prognosis in non-small cell cancer (NSCLC). We aimed to investigate the incidence of STAS in a surgical series of adenocarcinomas (ADCs) resected in our thoracic surgery unit and to identify the association of STAS with other clinicopathological characteristics. We retrospectively enrolled patients with stage cT1a-cT2b who underwent resection between 2016 and 2022. For each case, a comprehensive pathologic report was accessible which included histotype, mitoses, pleural invasion, fibrosis, tumor infiltrating lymphocytes, necrosis, inflammation, vascular and perineural invasion, as well as STAS. PD-L1 expression was also investigated. A total of 427 patients with ADCs underwent surgery. Regarding overall survival (OS), no significant difference was observed between the STAS positive (STAS+) and STAS negative (STAS-) groups ( P =0.44). However, vascular invasion (VI) was associated with a poorer survival probability ( P =0.018). STAS+/VI+ patients had tendentially worse survival compared with STAS+/VI- ( P =0.089). ADCs with pathologic evidence of immune system (IS) activation (TILs>10% and PD-L1≥1) demonstrated significantly increased OS compared with ADCs with no IS and VI. In terms of recurrence rate, no statistical differences were found between the STAS+ and STAS- samples ( P =0.2). VI was also linked to a significantly elevated risk of recurrence ( P =0.0048). Our study suggests that in resected early-stage ADCs, STAS+ does not seem to influence recurrence or mortality. VI was instead an adverse pathologic prognostic factor for both survival and recurrence, whereas IS seemed to be protective.


Asunto(s)
Adenocarcinoma del Pulmón , Adenocarcinoma , Neoplasias Pulmonares , Humanos , Adenocarcinoma del Pulmón/cirugía , Adenocarcinoma del Pulmón/patología , Antígeno B7-H1 , Estudios Retrospectivos , Pronóstico , Estadificación de Neoplasias , Invasividad Neoplásica/patología , Recurrencia Local de Neoplasia/patología , Adenocarcinoma/patología , Neoplasias Pulmonares/cirugía
8.
Cancers (Basel) ; 16(3)2024 Jan 26.
Artículo en Inglés | MEDLINE | ID: mdl-38339288

RESUMEN

The accurate selection of the recipient is a crucial aspect in the field of lung transplantation (LTX), especially if patients were previously affected by oncological disease. The aim of this bicentric retrospective study was to evaluate short- and long-term outcomes in patients with previous oncological disease or unknown neoplasia found on native lungs submitted to LTX, compared to a control group. A total of 433 patients were included in the analysis, 31 with malignancies (Group 1) and 402 without neoplastic disease (Group 2). The two groups were compared in terms of short- and long-term outcomes. Patients in Group 1 were older (median age 58 years vs. 50 years, p = 0.039) and mostly affected by idiopathic pulmonary fibrosis (55% vs. 40% p = 0.002). Even though in Group 1 a lower rate of late post-operative complications was found (23% vs. 45%, p = 0.018), the median overall survival (OS) was lower compared to the control group (10 months vs. 29 months, p = 0.015). LTX represents a viable therapeutic option for patients with end-stage lung disease and a history of neoplastic disease. However, every case should be carefully debated in a multidisciplinary setting, considering oncological (histology, stage, and proper disease free-interval) and clinical factors (patient's age and comorbidities). A scrupulous post-transplant follow-up is especially mandatory in those cases.

9.
Heliyon ; 10(4): e25525, 2024 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-38384570

RESUMEN

Objective: The aim of this study was to evaluate the roughness, hardness, and color change of pit and fissure sealants of two commercial brands (Fluroshield ™ and Ultraseal XT ™) incorporated with nanostructured silver vanadate nanomaterial decorated with silver nanoparticles (ß-AgVO3) in concentrations (0% - control, 2.5% and 5%). Material and methods: Two commercial brands Fluroshield TM and Ultraseal XT ™ were used to make the samples with dimensions of 6 × 6 × 4 mm. The control group was made according to the manufacturer's instructions and in the groups with the addition of ß-AgVO3, the nanomaterial was added proportionally by mass at percentages of 2.5% and 5%. Roughness properties were evaluated using a 3D Laser Confocal Microscope (n = 10), Knoop microhardness by Microdurometer (n = 10), and color change by Portable Color Spectrophotometer on the CIEDE2000 system (n = 10). Data were evaluated by one-way ANOVA with Bonferroni adjustment and Tukey's mean comparison test at a 5% significance level. Results: Ultraseal XT ™ sealant roughness showed a significant difference between concentrations with the highest mean for the 5% group (P = 0.010). Regarding the hardness, both sealants showed no significant difference between the groups. Fluroshield ™ sealant showed a significant difference in ΔE00 between the control-2.5% 24.93 (3.49) and control-5% 28.41 (2.58). Conclusion: It may be concluded that the incorporation of ß-AgVO3 influenced the increase in roughness for Ultraseal XT ™ pit and fissure sealant, did not interfere with the microhardness of both sealants, and promoted a change in the color of Fluroshield ™ sealant within clinically acceptable limits.

10.
Eur J Cardiothorac Surg ; 65(2)2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38290793

RESUMEN

OBJECTIVES: Benign (laryngo-)tracheal stenosis is a relatively rare pathology and its surgical treatment is performed only at few specialized centres. This study aims to investigate outcomes after (laryngo-)tracheal resection-anastomosis, to explore potential risk factors for postoperative complications and to assess whether, over a 33-year period, there were major changes in surgical indications, techniques or outcomes. METHODS: Retrospective, single-centre review of all consecutive patients who underwent tracheal or laryngo-tracheal resection/anastomosis for benign pathologies from 1990 to 2023. RESULTS: Overall, 211 patients underwent tracheal (149 patients, 70.6%) and laryngo-tracheal (62 patients, 29.4%) resection-anastomosis. Of these, 195 patients (93.8%) were affected by iatrogenic stenosis, while 13 (6.2%) suffered from idiopathic stenosis. The median length of stenosis was 25 mm (interquartile range 1-3, 20-30). The overall morbidity rate was 27.5%, while major morbidity occurred in 10.5% of cases. One patient (0.5%) died in the postoperative period. Glottic oedema (17 patients, 8.1%), granulations (12 patients, 5.7%) and restenosis (10 patients, 4.7%) were the main complications. The only independent risk factor for postoperative complications was the length of the resected airway (P = 0.019). In the latest half of the study period, an older median age was observed, and no patient with idiopathic tracheal stenosis underwent surgery. Postoperative outcomes were comparable between surgical eras. CONCLUSIONS: Surgical treatment of (laryngo-)tracheal stenosis is challenging and should be performed by specialized centres. In our experience, morbidity and mortality rates were satisfactory, and in most cases, patients could breathe without tracheostomy. The length of the stenosis was the most significant risk factor for postoperative complications.


Asunto(s)
Laringoestenosis , Estenosis Traqueal , Humanos , Estenosis Traqueal/cirugía , Estenosis Traqueal/etiología , Constricción Patológica/etiología , Estudios Retrospectivos , Resultado del Tratamiento , Tráquea/cirugía , Laringoestenosis/cirugía , Laringoestenosis/etiología , Anastomosis Quirúrgica/métodos , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología
11.
Medicina (Kaunas) ; 59(12)2023 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-38138182

RESUMEN

Background and objectives: VATS segmentectomy has been proven to be effective in the treatment of stage I NSCLC, but its technical complexity remains one of the most challenging aspects for thoracic surgeons. Furthermore, 3D-CT reconstruction images can help in planning and performing surgical procedures. In this paper, we present our personal experience of 11 VATS anatomical resections performed after accurate pre-operative planning with 3D reconstructions. Materials and methods: A 3D virtual model of the lungs, airways, and vasculature was obtained, starting from a 1.25 mm 3-phase contrast CT scan, and the original images were used for the semi-automatic segmentation of the lung parenchyma, airways, and tumor. Results: Six males and five females were included in this study. The median diameter of the pulmonary lesion at the pre-operative chest CT scan was 20 mm. The surgical indication was confirmed in seven patients: in three cases, a lobectomy, instead of a segmentectomy, was needed due to intraoperative findings of nodal metastasis. Meanwhile, only in one case, we performed a lobectomy because of inadequate surgical resection margins. Skin-to-skin operative average time was 142 (IQR 1-3 105-182.5) min. The median post-operative stay was 6 (IQR 1-3 3.5-7) days. The mean value of the closest surgical margin was 13.7 mm. Conclusion: Image-guided reconstructions are a useful tool for surgeons to perform complex resections in order to spare healthy parenchyma and to ensure disease-free margins. Nevertheless, human skill and surgeon experience still remain fundamental for the final decisions regarding the proper resection to perform.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Masculino , Femenino , Humanos , Neoplasias Pulmonares/diagnóstico por imagen , Neoplasias Pulmonares/cirugía , Neoplasias Pulmonares/patología , Neumonectomía , Imagenología Tridimensional/métodos , Pulmón/patología , Carcinoma de Pulmón de Células no Pequeñas/cirugía , Estudios Retrospectivos
12.
J. health sci. (Londrina) ; 21(2): https://seer.pgsskroton.com/index.php/JHealthSci/article/view/5956, 19/06/2019.
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1051240

RESUMEN

The incorporation of antimicrobial agents may influence the mechanical properties of acrylic resins. Thus, the use of these agents only in regions of dental prostheses subject to greater contamination may be an alternative. This study evaluates the effect of thermomechanical fatigue on the bond strength between a conventional and an experimental acrylic resin incorporated with nanostructured silver vanadate decorated with silver nanoparticles (AgVO3). 60 specimens (Ø13mm x 23mm height) in self-curing resin were obtained and divided into groups according to the experimental resin incorporated with AgVO3 (Ø4mm x 6mm height): G1­Conventional x Conventional, G2­Conventional x 2.5% of AgVO3, G3­Conventional x 5% of AgVO3. Ten samples of each group were subjected to bond strength analysis after manufacture, and 10 were previously submitted to 1.200.000 cycles with 98N load and 2Hz/second frequency and alternating baths of 5 ºC, 37ºC and 55 ºC. The fracture area was analyzed. The data were submitted to analysis of variance of two-factors with Bonferroni adjustment for post hoc comparisons (α=0.05) was used. The fatigue did not affect the bond strength (p=0.416), however, there was influence of the AgVO3 concentration on the bond strength between the resins (p=0.013). Mixed failures with adhesive predominance were observed in samples without AgVO3 and cohesive failures in samples with the nanomaterial. The use of AgVO3 can improve or maintain the bond strength between resins with no thermomechanical fatigue influence. (AU).


A incorporação de agentes antimicrobianos pode influenciar nas propriedades mecânicas de resinas acrílicas. Desta forma, o uso destes agentes apenas em regiões das próteses dentárias sujeitas a maior contaminação pode ser uma alternativa. Este estudo avalia o efeito da fadiga termomecânica na resistência de união entre uma resina acrílica convencional e uma experimental incorporada com vanadato de prata nanoestruturado decorado com nanopartículas de prata (AgVO3). Foram obtidos 60 espécimes (Ø13mm x 23mm de altura) em resina autopolimerizável, divididos em grupos de acordo com a resina experimental incorporada com AgVO3 (Ø4mm x 6mm de altura): G1-Convencional x Convencional, G2-Convencional x 2,5% de AgVO3, G3 -Convencional x 5% de AgVO3. Dez amostras de cada grupo foram submetidas à análise de resistência à união após a confecção e 10 foram submetidas previamente a 1.200.000 ciclos com carga de 98 N e frequência de 2Hz/segundo e banhos alternados de 5 ºC, 37 ºC e 55 ºC. A área de fratura foi analisada. Os dados foram submetidos à análise de variância de dois fatores com ajuste de Bonferroni para comparações pos hoc (α = 0,05). A fadiga não afetou a força de união (p=0,416), no entanto, houve influência da concentração de AgVO3 na resistência de união entre as resinas (p=0,013). Falhas mistas com predominância adesiva foram observadas nas amostras sem AgVO3 e falhas coesivas nas amostras contendo o nanomaterial. O uso de AgVO3 pode melhorar ou manter a resistência da união entre as resinas sem influência da fadiga termomecânica.

13.
Braz. dent. j ; 24(6): 599-604, Nov-Dec/2013. tab, graf
Artículo en Inglés | LILACS | ID: lil-697650

RESUMEN

The aim of this study was to investigate the influence of accelerated artificial aging (AAA) on the microstructure and mechanical properties of the Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma and Filtek Z100. composite resins. The composites were characterized by Fourier-transform Infrared spectroscopy (FTIR) and thermal analyses (Differential Scanning Calorimetry - DSC and Thermogravimetry - TG). The microstructure of the materials was examined by scanning electron microscopy. Surface hardness and compressive strength data of the resins were recorded and the mean values were analyzed statistically by ANOVA and Tukey's test (α=0.05). The results showed significant differences among the commercial brands for surface hardness (F=86.74, p<0.0001) and compressive strength (F=40.31, p<0.0001), but AAA did not affect the properties (surface hardness: F=0.39, p=0.53; compressive strength: F=2.82, p=0.09) of any of the composite resins. FTIR, DSC and TG analyses showed that resin polymerization was complete, and there were no differences between the spectra and thermal curve profiles of the materials obtained before and after AAA. TG confirmed the absence of volatile compounds and evidenced good thermal stability up to 200 °C, and similar amounts of residues were found in all resins evaluated before and after AAA. The AAA treatment did not significantly affect resin surface. Therefore, regardless of the resin brand, AAA did not influence the microstructure or the mechanical properties.


A influência do sistema de envelhecimento artificial acelerado (EAA) na microestrutura e nas propriedades mecânicas das resinas compostas Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma e Filtek Z100 foi investigada. Os compósitos foram caracterizados por espectroscopia de infravermelho com transformada de Fourier (FTIR) e análises térmicas (calorimetria exploratória diferencial - DSC e termogravimetria - TG). A microestrutura dos materiais foi analisada por microscopia eletrônica de varredura. Os dados de dureza superficial e resistência à compressão foram registados para as resinas e os valores médios foram submetidos ao teste de Kolmogorov-Smirnov (p>0,05), ANOVA e teste de Tukey (α=0,05). Os resultados mostraram diferenças significativas entre as marcas comerciais em termos de dureza (F=86,74, p<0,0001) e resistência à compressão (F=40,31, p<0,0001), mas o EAA não afetou as propriedades (dureza superficial: F=0,39, p=0,53, resistência à compressão: F=2,82, p=0,09) de qualquer uma das resinas. FTIR, DSC e análise de TG revelou que a polimerização da resina foi completa, e não houve diferenças entre os espectros e os perfis de curva térmica dos materiais obtidos, antes e depois de EAA. TG mostrou a ausência de compostos voláteis e evidenciou uma boa estabilidade térmica até 200 °C, e quantidades similares de resíduos foram encontradas em todas as resinas avaliadas, antes e depois de EAA. O tratamento de EAA não afetou significativamente a superfície das resinas. Portanto, independentemente do tipo de resina, o EAA não influenciou a microestrutura e as propriedades mecânicas.


Asunto(s)
Resinas Compuestas/química , Fuerza Compresiva , Análisis del Estrés Dental , Dureza , Técnicas In Vitro , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Polimerizacion , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de Superficie , Dióxido de Silicio/química , Termogravimetría , Factores de Tiempo , Rayos Ultravioleta , Circonio/química
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