Avaliação de alumina e carvão ativado conjugados com nanopartículas de prata como pré-tratamentos para nanofiltração visando à redução da incrustação / Evaluation of alumina and activated carbon conjugated to silvernanoparticles as nanofiltration pre-treatments aiming at fouling reduction

RESUMO A má distribuição geográfica de águas em território nacional aliada ao seu desperdício, à poluição dos cursos d'água próximos aos centros urbanos e industriais e à eficiência inadequada de processos de tratamento convencionais faz com que o tratamento e o reúso de água sejam tópicos de crescente importância no Brasil. Um dos métodos de tratamento de água são os processos de separação por membranas, como a nanofiltração. No entanto, esses processos estão sujeitos ao fenômeno de incrustação, que provoca diminuição gradativa de sua eficiência. Sendo assim, o presente trabalho visou à avaliação de diferentes métodos de pré-tratamento de água para mitigação da formação de biofilme em membranas de nanofiltração. Os processos de adsorção em partículas de alumina e desinfecção por meio de carvão ativado impregnado com nanopartículas de prata foram aplicados em uma amostra de um corpo d'água superficial. As amostras com e sem pré-tratamento foram nanofiltradas e a propensão à incrustação de cada uma foi avaliada. As eficiências de remoção de compostos orgânicos dos adsorventes empregados separadamente e em conjunto e as análises de absorção UV/Vis, microscópio eletrônico de varredura e espectroscopia de energia dispersiva do carvão ativado impregnado com nanopartículas de prata mostraram que os materiais empregados no pré-tratamento puderam ser apropriadamente sintetizados. Foi possível também identificar os principais grupos funcionais dos biopolímeros presentes nos biofilmes formados ao longo do tempo. Por fim, pôde-se observar que a adsorção da matéria orgânica é mais eficiente para o controle da incrustação rápida, enquanto o efeito bactericida se destaca no controle a longo prazo.

ABSTRACT The poor geographical distribution of water in the national territory combined with its waste, the pollution of watercourses close to urban and industrial centers, and the inadequate efficiency of conventional treatment processes make the treatment and reuse of water topics of increasing importance in Brazil. One of the advanced water treatment methods is membrane separation processes, such as nanofiltration. However, these processes are subject to fouling phenomenon, which causes a gradual decrease in the efficiency of the process. Therefore, the present work aims to evaluate different methods of pretreatment of water to mitigate the formation of biofilm in nanofiltration membranes. The adsorption processes on alumina particles and disinfection through activated carbon impregnated with silver nanoparticles were applied to a sample of a surface water body. Samples with and without pretreatment were nanofiltered and the propensity to fouling was evaluated. The efficiency of the adsorbents, used both separately and together, in removing organic compounds and the UV/Vis, scanning electron microscope, and Energy-dispersive X-ray spectroscopy analyses of the activated carbon impregnated with silver nanoparticles showed that the materials used in the pre-treatment were properly synthesized. It was also possible to identify the main functional groups of the biopolymers present in biofilms formed over time. Finally, it was observed that the adsorption of organic matter is more efficient for the control of rapid fouling while the bactericidal effect stands out in the long-term fouling control.

Comportamiento termoluminiscente de matrices de alúmina bajo diferentes condiciones de sinterización y dopaje con cerio / Termoluminiscent behavior of alumina matrices under different conditions of sinterization and doping with cerio / Comportamento termoluminiscente de matrizes de alumina sob diferentes condições de sinterização e doping com cerio

Resumen Introducción: en la búsqueda de nuevos materiales útiles como dosímetros termoluminiscentes (TL) la alúmina (α-Al2O3) ha adquirido gran atención. La α-Al2O3 posee una sensibilidad TL que es perceptible a las concentraciones de impurezas y a las condiciones térmicas del crecimiento de sus cristales, por lo que encontrar nuevas variaciones del material permitirá aumentar su respuesta TL. Objetivo: analizar las curvas de brillo de matrices de alúmina pura sinterizadas bajo diferentes condiciones de calcinación y dopadas con cerio a concentración 0.1 % p/p (Al2O3:Ce), usando la función asimétrica logística, para calcular sus parámetros cinéticos termoluminiscentes y explicar el comportamiento del material. Materiales y métodos: polvo de alúmina bohemita fue utilizado para preparar muestras puras sintetizadas de bajo diferentes condiciones de calcinación (NALO y ALO). El cerio se introdujo mediante impregnación húmeda utilizando nitrato de cerio hexa-hidratado. El análisis estructural de las matrices se realizó mediante Difracción de Rayos X. La lectura TL se realizó en un TLD 4500. Resultados: la deconvolución obtenida en las curvas de brillo para los grupos ALO y NALO evidencia la presencia de tres y cuatro señales TL respectivamente, y de seis señales TL en la muestra Al2O3:Ce. Conclusión: los tratamientos térmicos aplicados introdujeron un cambio sustancial en la curva de brillo del material y en su cinética TL, en términos del número de trampas y de la cantidad inicial de portadores de carga atrapados. La introducción de impurezas de cerio produjo una modificación fundamental en la curva de brillo de las matrices de alúmina.

Abstract Introduction: in the search for new materials useful as thermoluminescent dosimeters (TL) alumina (α-Al2O3) has acquired great attention. The α-Al2O3 has a sensitivity TL that is perceptível to the concentrations of impurities and to the thermal conditions of the growth of its crystals, so finding new variations of the material will allow to increase its TL response. Objective: analyze the brightness curves of pure alumina matrices sintered under different calcination conditions and doped with cerium at a concentration of 0.1 % p/p (Al2O3:Ce), using the asymmetric logistic function, to calculate its thermoluminescent kinetic parameters and explain the behavior of the material. Materials and methods: boehmite alumina powder was used to prepare pure sintered samples of under different calcination conditions (NALO and ALO). The cerium was introduced by wet impregnation using cerium hexahydrate nitrate. The structural analysis of the matrices was carried out by X-ray diffraction. The TL reading was performed in a TLD 4500. Results: the deconvolution obtained in the brightness curves for the ALO and NALO groups evidences the presence of three and four TL signals respectively, and of six TL signals in the sample Al2O3:Ce. Conclusion: the applied heat treatments introduced a substantial change in the brightness curve of the material and its TL kinetics, in terms of the number of traps and the initial amount of charge carriers trapped. The introduction of cerium impurities produced a fundamental modification in the brightness curve of the alumina matrices.

Resumo Introdução: na busca por novos materiais úteis como dosímetros termoluminescentes (TL), a alumina (α-Al2O3) tem adquirido grande atenção. O α-Al2O3 possui uma sensibilidade TL que é perceptível às concentrações de impurezas e às condições térmicas do crescimento de seus cristais, portanto, encontrar novas variações do material permitirá aumentar sua resposta TL. Objetivo: analisar as curvas de brilho de matrizes de alumina pura sinterizadas sob diferentes condições de calcinação e dopadas com cério na concentração de 0,1 % p/p (Al2O3:Ce), utilizando a função logística assimétrica, para calcular seus parâmetros cinéticos termoluminescentes e explicar a comportamento do material. Materiais e métodos: o pó de alumina boehmite foi usado para preparar amostras de puro sinterizado sob diferentes condições de calcinação (NALO e ALO). O cério foi introduzido por impregnação a úmido com nitrato de cério hexaidratado. A análise estrutural das matrizes foi realizada por difração de raios X. A leitura TL foi realizada em um TLD 4500. Resultados: a deconvolução obtida nas curvas de brilho para os grupos ALO e NALO mostra a presença de três e quatro sinais TL respectivamente, e de seis sinais TL na amostra Al2O3: Ce. Conclusão: os tratamentos térmicos aplicados introduziram uma mudança substancial na curva de brilho do material e sua cinética de TL, em termos do número de armadilhas e da quantidade inicial de portadores de carga aprisionados. A introdução de impurezas de cério produziu uma modificação fundamental na curva de brilho das matrizes de alumina.

A Highly Sensitive Electrochemical Biosensor for Detection of Adenosine Triphosphate Based on Space Block / 分析化学

In this work,a highly sensitive electrochemical biosensor for the detection of trace adenosine triphosphate (ATP) was proposed.The biosensor was based on porous anodic alumina (PAA) and SiO2 nanoparticles combining with several oligonucleotides to construct sandwich structure.It was characterized by scanning electron microscopy,fluorescence microscopy,differential pulse voltammetry and electrochemical impedance spectroscopy,which conformed to the reliability of the biosensor fabrication and the feasibility of the detection.In the presence of ATP,the sandwich structures could be destroyed.The variation of the current was directly corresponding to the amount of the ATP.The application of SiO2nanoparticles could effectively reduce the background and increase the sensitivity of the biosensor.The calibration curve of ATP was obtained in the range of 0.025-0.900 nmol/L with the detection limit of 13 pmol/L (S/N=3).Also,the biosensor exhibited a good specificity.Besides,the sensor was constructed easily and possessed excellent regeneration ability.The proposed biosensor was applied in detection of real sample such as mice blood.Therefore,the proposed ATP-sensing biosensor could be expected to be applied in clinical,pharmaceutical and environmental detection.

Influence of nano alumina coating on the flexural bond strength between zirconia and resin cement

PURPOSE: The purpose of this in vitro study is to examine the effects of a nano-structured alumina coating on the adhesion between resin cements and zirconia ceramics using a four-point bending test. MATERIALS AND METHODS: 100 pairs of zirconium bar specimens were prepared with dimensions of 25 mm × 2 mm × 5 mm and cementation surfaces of 5 mm × 2 mm. The samples were divided into 5 groups of 20 pairs each. The groups are as follows: Group I (C) – Control with no surface modification, Group II (APA) – airborne-particle-abrasion with 110 µm high-purity aluminum oxide (Al2O3) particles, Group III (ROC) – airborne-particle-abrasion with 110 µm silica modified aluminum oxide (Al₂O₃ + SiO2) particles, Group IV (TCS) – tribochemical silica coated with Al2O3 particles, and Group V (AlC) – nano alumina coating. The surface modifications were assessed on two samples selected from each group by atomic force microscopy and scanning electron microscopy. The samples were cemented with two different self-adhesive resin cements. The bending bond strength was evaluated by mechanical testing. RESULTS: According to the ANOVA results, surface treatments, different cement types, and their interactions were statistically significant (P < .05). The highest flexural bond strengths were obtained in nanostructured alumina coated zirconia surfaces (50.4 MPa) and the lowest values were obtained in the control group (12.00 MPa), both of which were cemented using a self-adhesive resin cement. CONCLUSION: The surface modifications tested in the current study affected the surface roughness and flexural bond strength of zirconia. The nano alumina coating method significantly increased the flexural bond strength of zirconia ceramics.

Preparation of adsorbents for selectively removal of heavy metals from Salvia miltiorrhiz extract / 中草药

Objective: Taking molecular sieve as a main component, to develop adsorbents which can selectively remove five kinds of heavy metal in Salvia miltiorrhiz extract solution. Methods: The 13X zeolite powder and active alumina powder were selected to compose adsorbent from four materials including iron red powder, fast powder (activated alumina), 13X molecular sieve powder, and zinc sulfide powder. The adsorbent formula was optimized with uniform design for mixture experiment. Pore-expanding agents, such as Chitisan and EDTA, were added to improve adsorbent pore structure. Results: With uniform design for mixture experiment, adsorbents with 13X zeolite ratio 0.275 6—0.465 5 could effectively remove five heavy metals (Cu, Pb, Cd, Hg, and As) in water solution. The optimal adsorbents from uniform design were hard to remove heavy metal in S. miltiorrhiz extract solution in 4 h, and removal ratios of Cu, Pb, Cd, Hg, and As were 14.4%, 74.5%, 54.6%, 13.4%, and 8.8%, respectively. With the same formula, pore- expanding adsorbents could effectively remove five heavy metals in S. miltiorrhiz extract solution in 4 h, and removal ratios of Cu, Pb, Cd, Hg, and As increased to 21.0%, 91.5%, 97.5%, 60.3%, and 46.8%, respectively. Conclusion: Pore-expanding adsorbents prepared in this study could remove five heavy metals in S. miltiorrhiz extract solution in short time, exhibiting industrial application prospect.

Effect of different separation and purification processes on preparation characteristic of gubi granules powder / 中草药

Objective: To evaluate the optimal separation and purification processes of water extract, the analytic techniques of particle size analysis, powder fluidity testing, and scanning electronic microscope were adopted to compare the influence factor of different separation and purification techniques on microscopic preparation characteristic of intermediate product prepared from water extract of traditional Chinese medicine (TCM) formula purification. Methods: Taking Gubi Granules (GG) which have established the production technology and quality standards in the previous study as an example, three common techniques used for water extract of TCM formula purification, including ethanol precipitation, column chromatogram of macroporous resin, and membrane separation, were applied to preparing the intermediate of GG. Results: Through the comprehensive analysis of fluidity, adhesive property, compressibility, permeability, particle microstructure and particle size distribution, it was found that membrane separation could obtain intermediates with better performance, which was conducive to the subsequent granulation, tabletting, and other process smoothly. The operating conditions for liquid concentration were 0.05 g crude drug/mL, 30 ℃ liquid temperature, 0.15 MPa pressure and 5 m/s flow rate. Conclusion: The different spray dried powders varied greatly. The membrane separation method of 0.2 μm Al2O3 ceramic was selected as the optimal process for separating and purifying of water extract of GG by analyzing the influencing factors of the pharmaceutical properties.

Influence of nano-structured alumina coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements

PURPOSE: The purpose of this study was to evaluate the effect of nano-structured alumina surface coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements. MATERIALS AND METHODS: A total of 90 disk-shaped zirconia specimens (HASS CO., Gangneung, Korea) were divided into three groups by surface treatment method: (1) airborne particle abrasion, (2) tribochemicalsilica coating, and (3) nano-structured alumina coating. Each group was categorized into three subgroups of ten specimens and bonded with three different types of dual-cured resin cements. After thermocycling, shear bond strength was measured and failure modes were observed through FE-SEM. Two-way ANOVA and the Tukey's HSD test were performed to determine the effects of surface treatment method and type of cement on bond strength (P<.05). To confirm the correlation of surface treatment and failure mode, the Chi-square test was used. RESULTS: Groups treated with the nanostructured alumina coating showed significantly higher shear bond strength compared to other groups treated with airborne particle abrasion or tribochemical silica coating. Clearfil SA Luting showed a significantly higher shear bond strength compared to RelyX ARC and RelyX Unicem. The cohesive failure mode was observed to be dominant in the groups treated with nano-structured alumina coating, while the adhesive failure mode was prevalent in the groups treated with either airborne particle abrasion or tribochemical silica coating. CONCLUSION: Nano-structured alumina coating is an effective zirconia surface treatment method for enhancing the bond strength between Y-TZP ceramic and various dual-cured resin cements.

Influence of nano-structured alumina coating treatment on shear bond strength between zirconia ceramic and resin cement / 대한치과보철학회지

PURPOSE: The aim of this study was to investigate whether the application of nano-structured alumina coating to the surface of Y-TZP could enhance the bond strength with resin cement. MATERIALS AND METHODS: A total of 80 zirconia plates were prepared and divided into four groups. : 1) airborne particle abrasion treatment (A) : 2) Rocatec treatment after airborne particle abrasion (R) : 3) nano-structured alumina coating treatment after polishing (PC) and 4) nano-structured alumina coating after airborne particle abrasion (AC). Alumina coating was formed by the hydrolysis of aluminium nitride (AlN) powder and heat treatment at 900℃. Coating patterns were observed with FE-SEM. Resin block was bonded to treated zirconia ceramics using resin cement. The shear bond strengths were measured before and after thermocycling. RESULTS: The FE-SEM images show a dense and uniform nano-structured alumina coating structure, which enhances shear bond strength by increasing micro mechanical interlocking to resin cement. PC and AC groups showed higher shear bond strengths than A and R groups before and after thermocycling. A and R groups displayed significant drops in shear bond strength after thermocycling. However, PC and AC groups did not show any meaningful decreases in shear bond strength after thermocycling. CONCLUSION: Treatment of Y-TZP ceramics with nano-structured alumina coating could significantly increase their shear bond strength.

Necrose tecidual causada por alúmen de potássio / Tissue necrosis caused by potassium alumina: case report

O objetivo do presente trabalho foi relatar um caso clínico de necrose tecidual causada por alúmen de potássio. Paciente do sexo feminino realizou procedimento de enxerto de tecido conjuntivo para tratamento de defeito de rebordo classe I. Aos sete dias do período pós-operatório, observou-se extensa necrose da área receptora e do tecido enxertado. A paciente relatou que utilizou bochechos diários de alúmen de potássio para controle de edema e sangramento. O alúmen de potássio interferiu negativamente no processo de reparo tecidual.

The aim of this present study is to describe a case report of tissue necrosis caused by potassium alumina. Subepithelial connective tissue graft was used in the treatment of class I alveolar ridge defect. After seven days an extensive necrosis of the tissue graft and the receptor area was observed. The patient related that used potassium alumina solution as mouthrinse daily to control edema and bleeding. Potassium alumina had a negative influence in the tissue repair process.

Adhesión de cerámicos a resinas poliméricas usadas en odontología / Adhesion of ceramics to polymeric dental resins

Objetivos: evaluar la adhesión cerámico-polímero en materiales usados en restauraciones odontológicas de alta resistencia (alúmina, zirconia) luego del tratamiento de la superficie cerámica. Materiales y métodos: se confeccionaron probetas con un cerámico a base de alúmina y sus superficies fueron modificadas a partir de vidriados y de la posterior formación de microencastres, mediante la sinterización de microesferas o de ataques químicos sobre una capa vítrea previamente sinterizada sobre ellas. Dos de las probetas fueron unidas mediante un adhesivo polimérico, a fin de determinar, bajo tensiones de corte, la resistencia y la tenacidad al despegue y el módulo de corte, en todos los casos, en megapascales y en un mínimo de 15 ensayos por condición experimental. Resultados: se obtuvieron valores medios de resistencia al despegue de entre 7 y 13 MPa; de tenacidad al despegue de entre 3 y 10 MPa, y de módulo de corte entre 5 y 13 MPa. Conclusión: la valoración del desempeño mecánico demuestra que las modificaciones superficiales de los cerámicos generan un comportamiento adhesivo mejorado respecto de lo que ocurre con cerámicos sin modificaciones

Evaluation of inorganic and organic bone components after application of an apatite-coated Al2O3 implants as scaffolds for bone repair

The aim of this work was to study the influence of uncoated and apatite-coated Al2O3 implants on bone regeneration after 30 days of surgery in New Zealand white rabbits. Twelve samples of Al2O3 implants were prepared and half of them (n = 6) were apatite-coated by the modified biomimetic method. Three experimental groups were tested as Group C - control, surgery procedure without cerami c implant, Group Ce - uncoated Al 2O3 implants (n = 6) and Group CeHA - apatite-coated Al2O3 implants (n = 6). The mineralization of the Al2O3 implants was analyzed in bone fragments using FT-Raman spectroscopy. Raman peaks at 959 cm-1 and 2940 cm-1 evaluated the inorganic and organic bone content, respectively. In vivo citotoxicity was analyzed using micronucleus test. Inorganic and organic content were higher in CeHA samples than in Ce and C (CeHA > Ce > C). FT-Raman spectroscopy showed that the higher the deposition of the organic matrix, more mineralization occurred. The micronucleus test showed that the uncoated and apatite-coated Al2O3 implants were non-cytotoxic and safe to in vivo applications.

Effect of nano-aIumina on mitophagy in primary corticaI neuronaI ceIIs from Wistar newborn rats / 中国药理学与毒理学杂志

OBJECTIVE To study the effect of nano-alumina(nano-Al2 O3 )on mitophagy in primary cortical neuronal cells from Wistar newborn rats. METHODS The purity of neuronal cells was detected by immunohistochemistry,and the lactate dehydrogenase(LDH)assay was performed to determine the viability of the cells treated with 13 nm nano-Al2 O3 0.5 mmol·L-1 for 12,24 and 48 h,respectively. The mitochondrial membrane potential(MMP)was detected by flow cytometry analysis . The ultrastructure of mitochondria and mitophagy vacuoles was observed by transmission electron microscopy(TEM). Auto-phagic vacuoles were observed by dansylpentanediamine(MDC)staining and the expression of autoph-agy related protein Beclin1 and LC3Ⅱ/ Ⅰ was determined by Western blotting. Mitophagy was observed by Lysotracker and Mitotracker staining respectively. RESULTS More than 95% cells were neuronal cells. The activity of LDH in the supernatant liquid exposed to nano-Al2 O3 for 12 and 24 h groups was sig-nificantly increased compared with the control group(P﹤0.05). After exposure to nano-Al2 O3 ,the mito-chondrial membrane potential was significantly decreased compared with the control group( P ﹤0.01). The results of TEM displayed mitochondrial swelling and the formation of vacuoles and mitophagy in nano-Al2 O3 groups. MDC positive fluorescence particles were observed and the expression of autophagy related protein Beclin1 and LC3Ⅱ/ Ⅰ was increased in nano-Al2 O3 groups compared with the control group( P ﹤ 0. 05 ). The result of Lysotracker and Mitotracker colocalization showed the fusion of mitochondria and lysosomals. CONCULSION Nano-Al2 O3 may induce autophagy and mitochondria damage in neuronal cells while the damaged mitochondria may be removed by mitophagy.

An Invitro Evaluation of The Effect of Zirconia Surface Treatment on Shear Bond Strength to A Resin Cement.

Statement Of Problem;Developments in ceramic core materials such as lithium disilicate, aluminium oxide, and zirconium oxide have allowed more widespread application of all-ceramic restorations over the past 10 years. However, establishing a reliable bond of resin cement to zirconia based materials has been proven to be difficult, which is the major limitation against fabricating zirconia restoration , and there is no clear recommendation in the literature regarding surface treatment before bonding. Purpose; This study evaluated the effect of zirconia surface treatments namely Airborne Particle Abrasion, Hydrofluoric acid etching, Hydrofluoric acid etching followed by silanation and Primer application on shear bond strength to a self etch dual cure resin cement bonded to dentin specimens. Material And Methods; Twenty zirconia rods (3 x 2.5 mm) were prepared from zirconia blocks and assigned into 5 groups. Each group were subjected to the following surface treatments. (1) group I - Control ( C ) no treatment , (2) group II - airborne-particle abrasion (APA), (3) group III – hydrofluoric acid etching ( HF ), (4) group IV - hydrofluoric acid etching followed by silanation ( HF/S ), and (5) group V - application of zirconia primer ( Z ) . Dentin specimens were prepared from extracted molars stored in 0.5% chloramine-T. Zirconia rods were bonded to dentin using a resin cement (Multilink Speed), then light polymerized. The specimens were loaded to failure with the notched shear bond test method in a universal loading apparatus. Results were analyzed using 1-way ANOVA (alpha=.05). Results;ANOVA showed significant differences in bond strength among the different surface treatments ( p value 0.001). The highest values were obtained with group V (Z) ( 8.66 Mpa) followed by group II (APA) (6.71 Mpa ), group IV (HF/S) (4.41 Mpa) . The least values were obtained for group III (HF) (3.88 Mpa ) and there were no significant difference ( p value 0.53 ) between group III (HF) ( 3.88 Mpa ) and group I (C) (3.70 Mpa).Conclusion:The resin bond to Y-TZP was improved by surface treatment. Zirconia Primer application is practically a reliable surface treatment . Airborne Particle Abrasion , although not so reliable , is also an effective treatment while bonding zirconia to a resin cement .

Early Results of Cementless Total Hip Arthroplasty Using a Third Generation Alumina-on-Alumina Bearing Surface / 대한정형외과학회잡지

PURPOSE: The purpose of this study is to evaluate the early results and occurrence of complications of cementless total hip arthroplasty (THA) using an alumina-on-alumina articulation with a minimum follow up period of three years. MATERIALS AND METHODS: We prospectively followed 108 patients (121 hips) who underwent cementless THA using an alumina-on-alumina articulation. The mean age of the patients was 50.7 years (range, 20-80 years) and mean the follow up period was 48 months (range, 36-60 months). Preoperative diagnoses included osteonecrosis of the femoral head in 90 hips; secondary osteoarthritis due to hip dysplasia in 24 hips; secondary osteoarthritis after acetabular fracture in four hips; acute femoral neck fracture in three hips. Clinical evaluation was performed using Harris hip score (HHS) and radiographic evaluation was performed in terms of the fixation of components and the prevalence of osteolysis. In addition, we observed complications, including the occurrence of sound or fracture of the alumina head or liner. RESULTS: Mean HHS improved from 62.4 points to 94 points at final follow-up. Thigh discomfort was found in six hips and mild inguinal discomfort was found in eight hips. Both had disappeared within one year after operation. A clicking sound was detected in two patients. One hip had become dislocated and an alumina liner fracture had occurred in one hip. Loosening of component or osteolysis was not observed in any hip. The radiographic wear was not measurable. CONCLUSION: Early results of cementless THA using an alumina-on-alumina articulation were favorable, with osseointegration of the components and absence of periprosthetic osteolysis. However, longer-term follow up for a hip clicking sound and fracture of an alumina fracture are necessary.

Porcelanas dentales, 2da parte: clasificación según el método de elaboración de la restauración / Dental porcelains, 2nd part: classification according to the elaboration method of the restoration

Las restauraciones elaboradas con porcelana ocupan un lugar central en la odontología restauradora y rehabilitadora estética. Las propiedades físicas y estéticas, indicaciones clínicas y técnica de trabajo de las porcelanas dentales están íntimamente relacionadas con su composición y estructura. Su comprensión se convierte en decisiva para el exitoso trabajo del clínico.

Análise da resistência flexural e microdureza de dois sistemas de cerâmica aluminizada infiltrada por vidro / Analysis of flexural strength and microhardness of two alumina glass infiltrated ceramic systems

O estudo avaliou in vitro a resistência flexural e a microdureza de dois sistemas de cerâmica aluminizada infiltrada por vidro: In-Ceram Alumina (Vita) e Alglass (Celmat). Foram testados corpos de prova em forma de barra, conforme a ISO 6872-1998, foram testados em ensaios de resistência flexural de três pontos e microdureza Vickers, por indentação. Analisou- se a superfície de fratura dos corpos por MEV. In-Ceram Alumina apresentou maior resistência à flexão (441,7 ± 54,1 MPa) que o Alglass (287,8 ± 53,6 MPa). Os sistemas não apresentaram diferença estatística para microdureza: 1210,4 ± 90,0 HV e 1135,6 ± 117,5 HV, respectivamente. In-Ceram Alumina apresentou na superfície de fratura maior homogeneidade e menor número de poros que o Alglass. O Alglass, com custo reduzido comparado ao In-Ceram Alumina, atendeu à ISO 6872-1998 podendo ser empregado clinicamente

The aim of this work was to evaluate, in vitro, the microhardness, mechanical properties and fracture surface morphology of two different systems of glass infiltrated dental ceramic: In-Ceram Alumina (Vita) and Alglass (Celmat) systems. Both materials were used to prepare bar-shaped specimens according to ISO 6872-1998. Three point flexural strength and Vickers microhardness through indentation tests were used to evaluate the samples. The samples surface fracture was achieved through SEM. The Results showed that In-Ceram Alumina presented higher flexural strength values (441.7 ± 54.1 MPa) than Alglass (287.8 ± 53.6 MPa). There was no significant statistic difference in microhardness Vickers results (1210,4 ± 90,0 HV; 1135,6 ± 117,5 HV) between two groups, respectively. In-Ceram Alumina had more homogeneity and less pores at fracture surface than the Alglass. However, Alglass has reduced costs in relation to In-Ceram Alumina and reached the ISO 6872-1998 standard requirements, by this mean this material can be considered to be used clinically used

Minimum 5-Year Results of Titanium Tapered Stem with Alumina Bearing in Cementless Total Hip Arthroplasty Using a Modified Direct Lateral Approach / 대한정형외과학회잡지

PURPOSE: The purpose of the current study is to evaluate the clinical and radiographic outcomes of primary total hip arthroplasty (THA) using a single titanium tapered stem with alumina bearing, which was performed through a modified direct lateral approach. MATERIALS AND METHODS: One hundred twenty consecutive primary THAs were performed in 102 patients, and retrospectively reviewed. There were 53 men and 49 women of mean age 54 years, and all patients were followed for a minimum follow-up period of 5 years (range, 5-8.1 years). Clinical outcomes assessment consisted of calculation of the Harris hip score (HHS), and evaluation of the presence of thigh pain or limp. Sequential radiographs were evaluated for implant migration, osteolysis, reactive line, cortical hypertrophy, or evidence of component loosening. RESULTS: At the final follow-up, the mean preoperative HHS of 46 points improved to 94 points; and activity-related thigh pain occurred in two hips, and mild limps in four hips. There was no evidence of implant migration, osteolysis, or component loosening. Audible squeaking was present in two hips, without pain and radiographic abnormality. Dislocation occurred in three hips. CONCLUSION: The minimum 5-year results of titanium tapered stem with alumina bearing in cementless primary THA, using a modified direct lateral approach, were encouraging.

A comparative study on the fracture behavior of zironia, glass infiltrated alumina and PFM full crown system / 대한치과보철학회지

PURPOSE: The purpose of this study was to compare the fracture behavior of Zironia, glass infiltrated Alumina and PFM full crown system. MATERIALS AND METHODS: Fifteen crowns for each of 3 experimental groups (Zironia, glass infiltrated Alumina and PFM full crown) were made by the conventional method. The crowns mounted on the testing jig were inclined in 30 degrees to the long axis of the tooth and the universal testing machine was used to measure the fracture strength. RESULTS: 1. The mean fracture strengths were 588.3 +/- 49.6 MPa for zirconia system, 569.1 +/- 61.8 MPa for PFM system and 551.0 +/- 76.5 MPa for glass-infiltrated alumina system (P>.05). 2. The mean shear bond strengths were 25.5 +/- 5.6 MPa for zirconia system, 38.9 +/- 5.0 MPa for Ni-Cr alloy system and 39.4 +/- 5.1 MPa for glass-infiltrated alumina system. 3. The chemical bonding was observed at interfaces between PFM or glass-infiltrated alumina and veneering porcelain, however, no chemical bonding was observed at interface between zirconia and veneering porcelain. CONCLUSION: With the study, the fracture strengths of PFM crown system had a higher fracture strength than conventional zirconia system crown and glass-infiltrated alumina crowns. and than the shear bond strengths glass-infiltrated alumina system had a higher shear bond strength than conventional PFM system and zirconia system.

Porcelanas dentales / Dental porcelains

Las restauraciones elaboradas con porcelana ocupan un lugar central en la odontología restauradora y rehabilitadora estética. Las propiedades físicas y estéticas, las indicaciones clínicas y la técnica de trabajo de las porcelanas dentales están íntimamente relacionads con su composición y estructura. Su comprensión se convierte en decisiva para el exitoso trabajo del clínico.

Metal Free Prosthodontics.

Metal free or All –ceramic restorations are the term for restorations consisting solely of ceramics without any metal support . They are highly esthetic . This article reviews some of the common metal free ceramics and their application