Effect of ZrO2 paste, surface treatments, and storage on Weibull characteristics and resin bond strength to zirconia

Abstract The objective is to evaluate the effect of different surface treatments and storage on the shear strength of ultratranslucent zirconia. 36 blocks of ultra-translucent zirconia were fabricated (7x7x2mm) and sintered. Then, divided into 12 groups according to the "surface treatment" (C -Primer; Al -Sandblasting with Al2O3 + Primer; Si -Silicate + Primer; Gl -Glaze + HF + Primer; Z -Zirlink; Zp -Zirlink + Primer) and "storage" factors (ST-with 150 days/37º and without). After surface treatment, five cylinders (Ø=2mm; h=2.0mm) of resin cement (n=15) were constructed in each ceramic block; at the end, the shear strength test was performed (1mm/min, 50Kgf), and analysis of surface failures. 60 additional samples (2x2x2mm) were made for extras analysis (surface roughness, MEV, and EDS). Bond strength and surface roughness data were statistically evaluated by ANOVA (2 factors/1 factor), Tukey test (5%), and Weibull analysis, respectively. ANOVA (2-way) revealed that all factors were statistically significant for bond strength. The silicatization groups (SiST: 30.47AMPa; Si: 29.21AMPa) showed the highest bond strength values, regardless of storage (Tukey's test). While the groups treated with Zirlink (ZST: 2.76FMPa; Z: 5.27EFMPa) showed the lowest values, just similar to the GlST group (5.14EFMPa). The Weibull modulus (m) showed a statistical difference between groups (p=0.000). ANOVA (1 factor) revealed that the "surface treatment" factor (p=0.0000) was statistically significant for surface roughness. Therefore, the application of Zirlink and Glaze on pre-sintered zirconia did not promote efficient adhesion of the ultratranslucent zirconia to the resin cement, even when associated with a primer containing MDP.

Resumo O objetivo é avaliar o efeito de diferentes tratamentos superficiais e do envelhecimento na resistência ao cisalhamento da zircônia ultratranslúcida. Foram confeccionados 36 blocos de zircônia ultratranslúcida (7x7x2mm) e sinterizados. Em seguida, divididos em 12 grupos de acordo com o "tratamento de superfície" (C-Primer; Al-Jateamento com Al2O3+Primer; Si-Silicato+Primer; Gl -Glaze+HF+Primer; Z-Zirlink; Zp-Zirlink+Primer) e fatores de "armazenamento" (ST-com, 150 dias/37º e sem). Após o tratamento superficial, foram construídos cinco cilindros (Ø=2mm; h=2,0mm) de cimento resinoso (n=15) em cada bloco cerâmico; ao final foi realizado o ensaio de resistência ao cisalhamento (1mm/min, 50Kgf) e análise de falhas superficiais. Foram confeccionadas 60 amostras adicionais (2x2x2mm) para análises extras (rugosidade superficial, MEV e EDS). Os dados de resistência de união e rugosidade superficial foram avaliados estatisticamente por ANOVA (2 fatores/1fator), teste de Tukey (5%) e análise de Weibull, respectivamente. ANOVA (2 fatores) revelou que todos os fatores foram estatisticamente significativos para a resistência de união. Os grupos de silicatização (SiST: 30,47AMPa; Si: 29,21AMPa) apresentaram os maiores valores de resistência de união, independente do armazenamento (Tukey). Enquanto os grupos tratados com Zirlink (ZST: 2,76FMPa; Z: 5,27EFMPa) apresentaram os valores mais baixos, apenas semelhantes ao grupo GlST (5,14EFMPa). O módulo de Weibull (m) apresentou diferença estatística entre os grupos (p=0,000). A ANOVA (1 fator) revelou que o fator "tratamento superficial" (p=0,0000) foi estatisticamente significativo para rugosidade superficial. Portanto, a aplicação de Zirlink e do Glaze na zircônia pré-sinterizada não promoveu adesão eficiente da zircônia ultratranslúcida ao cimento resinoso, mesmo quando associada a primer contendo MDP.

Regulación de la implantología dental en México / Regulation of dental implantology in Mexico

Introducción: los implantes dentales se han convertido en uno de los tratamientos odontológicos con mayor demanda en todo el mundo, no sólo por el nivel máximo de funcionalidad y de estética, sino también debido a su estabilidad, osteointegración y facilidad en su rehabilitación. Es incierto si los implantes dentales se encuentran normados formalmente en México, lo que motiva a la revisión del estado actual. Objetivo: evidenciar el estado actual de la legislación de la práctica de la implantología dental en México a través de una revisión en la literatura. Material y métodos: revisión de las legislaciones existentes en México para la aplicación de implantes dentales y su contraparte en el mundo a través de la evaluación de normas expedidas en América y Europa. Resultados: se contabilizó un total de 17 escuelas de implantes dentales que cuentan con el reconocimiento de la Secretaría de Educación Pública, de las cuales tres son públicas y 14 privadas. Se presentó una discrepancia en los planes de estudio que va de 16 a 36 meses. Las escuelas no contaron con un aval normativo. Las normas internacionales para control de calidad y aplicación de la tecnología en implantes se ubicaron en Canadá, Estados Unidos, España, Reino Unido y Francia. Conclusiones: contar con un antecedente normativo establecido por los países de primer mundo y ausente en México permite evidenciar la necesidad de implementar una Norma Oficial Mexicana que regule la fabricación, distribución y almacenamiento de los implantes dentales en México. A la vez, la revisión sugiere que la Secretaría de Educación Pública norme los créditos mínimos necesarios en las instituciones educativas reconocidas para la formación de recursos humanos que ejercen la implantología dental (AU)

Introduction: dental implants have become one of the dental treatments with the highest demand in the world, not only because of the highest level of functionality and aesthetics, but also because of their stability, osseointegration and ease of rehabilitation. It is uncertain if dental implants are formally regulated in Mexico, which motivates the review of the current status. Objective: to demonstrate the current state of the legislation for the practice of dental implantology in Mexico through a review of the literature. Material and methods: review of the existing legislation in Mexico, for the application of dental implants and its counterpart in the world, through the evaluation of standards issued in America and Europe. Results: a total of 17 dental implant schools that have the recognition of the Ministry of Public Education were counted, of which 3 are public and 14 private. There was a discrepancy in the study plans that ranged from 16 to 36 months. Schools will not have regulatory backing. The international standards for quality control and application of technology in implants were located in Canada, the United States, Spain, the United Kingdom and France. Conclusions: having a normative antecedent established by the countries of the first world and absent in Mexico, allows to demonstrate the need for the implementation of an Official Mexican Standard, which regulates the manufacture, distribution and storage of dental implants in Mexico. At the same time, the review suggests that the Ministry of Public Education regulate the minimum necessary credits in recognized educational institutions, for the training of human resources that practice dental implantology (AU)

Development of a CLDN18.2-targeting immuno-PET probe for non-invasive imaging in gastrointestinal tumors / 药物分析学报

Claudin18.2(CLDN18.2)is a tight junction protein that is overexpressed in a variety of solid tumors such as gastrointestinal cancer and oesophageal cancer.It has been identified as a promising target and a potential biomarker to diagnose tumor,evaluate efficacy,and determine patient prognosis.TST001 is a recombinant humanized CLDN18.2 antibody that selectively binds to the extracellular loop of human Claudin18.2.In this study,we constructed a solid target radionuclide zirconium-89(89Zr)labled-TST001 to detect the expression of in the human stomach cancer BGC823CLDN18.2 cell lines.The[89Zr]Zr-des-ferrioxamine(DFO)-TST001 showed high radiochemical purity(RCP,＞99％)and specific activity(24.15±1.34 GBq/μmol),and was stable in 5％human serum albumin,and phosphate buffer saline(＞85％RCP at 96 h).The EC50 values of TST001 and DFO-TST001 were as high as 0.413±0.055 and 0.361±0.058 nM(P＞0.05),respectively.The radiotracer had a significantly higher average standard uptake values in CLDN18.2-positive tumors than in CLDN18.2-negative tumors(1.11±0.02 vs.0.49±0.03,P=0.0016)2 days post injection(p.i.).BGC823CLDN18.2 mice models showed high tumor/muscle ratios 96 h p.i.with[89Zr]Zr-DFO-TST001 was much higher than those of the other imaging groups.Immunohistochemistry results showed that BGC823CLDN18.2 tumors were highly positive(+++)for CLDN18.2,while those in the BGC823 group did not express CLDN18.2(-).The results of ex vivo biodistribution studies showed that there was a higher distribution in the BGC823CLDN18.2 tumor bearing mice(2.05±0.16％ID/g)than BGC823 mice(0.69±0.02％ID/g)and blocking group(0.72±0.02％ID/g).A dosimetry estimation study showed that the effective dose of[89Zr]Zr-DFO-TST001 was 0.0705 mSv/MBq,which is within the range of acceptable doses for nuclear medicine research.Taken together,these re-sults suggest that Good Manufacturing Practices produced by this immuno-positron emission tomog-raphy probe can detect CLDN18.2-overexpressing tumors.

Influence of medium-translucency monolithic zirconia thicknesses and light-curing time on the polymerization of dual-cure resin cements

Aim: To investigate and compare the effects of different thicknesses of medium-translucency monolithic zirconia and light curing times on the polymerization of two types of dual-cured resin cement. Methods: A total of 200 cement specimens were prepared from TheraCem and RelyX U200 cement. The specimens were divided into 5 groups: Group I, without interposing zirconia; Group II, 0.50 mm thickness; Group III, 1.00 mm; Group IV, 1.50 mm; and Group V, 2.00 mm thickness. Each group was subdivided into (1) RelyX U200 and (2) TheraCem. Each subgroup was subdivided according to the light-curing time into (a) 20 s and (b) 40 s (n =5). The polymerization was tested using Fourier-transform infrared (FTIR) spectroscopy and a Vickers microhardness tester. The data were statistically analyzed using ANOVA, an independent sample t-test, and Tukey's test at a significance level of 0.05. Results: The control group had the highest values of DC and VMH, followed by 0.50, 1.00, and 1.50 mm, respectively, while the 2.00 mm group showed the lowest values. The specimens irradiated for 40 s had greater DC and VMH than those irradiated for 20 s. RelyX U200 revealed higher values for both parameters compared to TheraCem cement. Conclusion: The polymerization of selfadhesive cement depends on the thickness of the monolithic zirconia, the light curing time, and the composition of the cement. The cement should be irradiated for a longer period than recommended to overcome the light attenuation of zirconia. TEGDMA-based self-adhesive cement showed a higher DC and VMH than BISGMA-based cement

Preparation of 89Zr-labeled mesenchymal stem cells and PET monitoring in mice with systemic lupus erythematosus / 中华核医学与分子影像杂志

Objective:To label mesenchymal stem cells (MSCs) with 89Zr-oxine complex, and assess its characteristics of PET imaging in systemic lupus erythematosus (SLE) model (MRL/lpr mice). Methods:SLE mice were screened by 18F-FDG PET imaging. 89Zr-oxine was prepared and used for labeling MSCs (10 6 MSCs and 1 MBq 89Zr-oxine). 89Zr-oxine-labeled MSCs (0.2 MBq) were injected into MRL/lpr mice and BALB/c mice (each n=5) via tail vein at a dose of 1.2×10 6 cells per mouse, and followed with microPET imaging in vivo at 2 h, 6 h, 1 d, 3 d, 7 d, 10 d and 14 d after injection. The percentage activity of injection dose per gram of tissue (%ID/g) was calculated. Independent-sample t test was used to analyze the data. Results:MSCs was successfully labeled with 89Zr-oxine, with the labeling efficiency of 20% and cell viability >90%. MicroPET imaging showed that MSCs were mainly distributed in lungs and the liver sites at 2 h after injection. The number of MSCs homing to kidneys of MRL/lpr mice ( n=5) increased significantly 24 h after the injection, and the renal uptake of MSCs in MRL/lpr mice was much higher than that in BALB/c mice ((8.28±1.27) vs (4.33±0.94) %ID/g; t=3.54, P=0.024). The renal uptake increased firstly and then decreased and then leveled off, indicating MSCs homing to kidneys. Conclusions:A method for 89Zr-oxine labeling of MSCs is successfully established. 89Zr-labeled MSCs can home to kidneys of SLE mice. PET imaging of 89Zr-labeled MSCs can be effectively used to explore the in vivo distribution and migration behavior of transplanted MSCs during the treatment of diseases such as SLE.

Effects of argon plasma and aging on the mechanical properties and phase transformation of 3Y-TZP zirconia

Abstract To evaluate the flexural strength (FS) and flexural modulus (FM) of a commercial 3Y-TZ0P ceramic after artificial aging and either without or with two application times of non-thermal plasma treatments (NTP). In addition, changes in crystalline phase transformation and surface nano-topography after NTP application, during different aging periods, were evaluated. Ninety 3Y-TZP bars (45x4x3 mm) were made for FS and FM testing, and assigned to nine groups (n=10): no NTP/no aging (Control); no NTP/4h aging; no NTP/30h aging; 10s NTP/no aging; 10s NTP/4h aging; 10s NTP/30h aging; 60s NTP/no aging; 60s NTP/4h aging and 60s NTP/30h aging. Artificial accelerated aging was simulated using an autoclave (134º C at 2 bar) for up to 30h. FS and FM were assessed using a universal testing machine and data analyzed using a ANOVA and Tukey test (α=0.05). The volume change in zirconia monoclinic phase (MPV) was evaluated using X-ray diffraction and surface nano-topography was assessed using atomic force microscopy (baseline until 30h-aging). NTP application did not influence the FS and FM of zirconia. Compared to the Control (no NTP/no aging), the FS of zirconia samples treated for 30 hours in autoclave ("no NTP/30h aging" group) increased. Artificial aging for 30 hours significantly increased the FM of zirconia, regardless of NTP application. MPV tended to increase following the increase in aging time, which might result in the surface irregularities observed at 30h-aging. NTP did not alter the zirconia properties tested, but 30h-aging can change the zirconia FS, FM and MPV.

Resumo Avaliar a resistência à flexão (FS) e o módulo de flexão (FM) de uma cerâmica comercial 3Y-TZP após envelhecimento artificial, e com ou sem dois tempos de aplicação de plasma não térmico (NTP). Além disso, a transformação de fase cristalina e a nano-topografia de superfície após a aplicação de NTP, durante diferentes períodos de envelhecimento, foram avaliadas. Noventa barras 3Y-TZP (45x4x3 mm) foram feitas para testes de FS e FM, e distribuídas em nove grupos (n=10): sem NTP/sem envelhecimento (Controle); sem NTP/4h de envelhecimento; sem NTP/30h de envelhecimento; 10sNTP/sem envelhecimento; 10sNTP/4h; 10sNTP/30h; 60sNTP/sem envelhecimento; 60sNTP/4h e 60sNTP/30h. O envelhecimento artificial acelerado foi simulado em autoclave (134º C a 2 bar) por até 30 horas. FS e FM foram avaliados em máquina de ensaio universal e os dados analisados ​​pela ANOVA e teste de Tukey (α = 0,05). A mudança de volume da fase monoclínica de zircônia (MPV) foi avaliada usando difração de raios-X e nano-topografia de superfície foi avaliada utilizando microscopia de força atômica (baseline até 30h). A aplicação do NTP não influenciou a FS e FM da zircônia. Comparado ao Controle ("sem NTP/sem envelhecimento"), a FS das amostras de zircônia tratadas por 30 horas em autoclave ("sem NTP/30h de envelhecimento") aumentou. O envelhecimento artificial por 30 horas aumentou significativamente a FM da zircônia, independente do tempo de aplicação do NTP. O MPV tendeu a aumentar em função do aumento do tempo de envelhecimento para todos os grupos, que pode ter resultado nas irregularidades superficiais observadas com 30 horas de envelhecimento. O NTP não afetou as propriedades da zircônia testadas, mas o envelhecimento por 30 horas pode alterar a FS, FM e MPV da zircônia.

In Vitro Microscopic Evaluation of Metal- And Zirconium-Oxide-Based Crowns' Marginal Fit

ABSTRACT Objective To evaluate the marginal adaptation of computer-aided designing and computer-aided machining (CAD/CAM) fabricated cobalt-chromium and zirconium-oxide-based ceramic crowns compared to those produced by a conventional method. Material and Methods The study consists of three groups; 45 crowns fabricated from cobalt-chromium (CAD-CoCr) and 45 crowns manufactured from zirconium CAD/CAM technology (CAD-Z), and 45 control (C) which consists of conventional metal-ceramic crowns. The marginal discrepancies in vertical dimensions were assessed utilizing a microscope in four surfaces (mesial, distal, vestibular, and oral) for each crown. On completion of the microscopic evaluation, multivariate analysis of variance (MANOVA) was used to study the difference in the four surfaces, considered altogether. Two-way ANOVA revealed the effect of three systems used for gap measurements of each landmark. The differences observed were considered significant at p<0.05. Results There were no differences in the four surfaces revealed by АNOVА in the three groups when considered altogether. Two-way ANOVA of each surface discovered no differences among all groups as well. Conclusion The CAD/CAM crowns revealed a comparable and satisfactory marginal adaptation compared to conventional metal-ceramic crowns.

Preclinical evaluation of 89Zr labeled Daratumumab for imaging diagnosis of multiple myeloma / 中华核医学与分子影像杂志

Objective:To prepare 89Zr labeled Daratumumab and evaluate its feasibility in the imaging diagnosis of multiple myeloma (MM). Methods:According to the principle of 89Y (p, n) 89Zr nuclear reaction, 89Zr was produced by cyclotron solid target system (30 μA, 1.5 h) and automatic purification module. The radionuclide purity, half-life and impurity metal ion concentration were detected. Desferrioxamine (DFO) was coupled with Daratumumab and then chelated with 89Zr to prepare 89Zr-DFO-Daratumumab. The quality control analyses of three consecutive batches were carried out. Pharmacokinetic evaluation and 89Zr-DFO-Daratumumab microPET/CT imaging were performed in normal rabbits and orthotopic myeloma mouse models, respectively. The SUV in situ myeloma and that in normal bone were compared by independent-sample t test. Results:About 560 MBq of 89Zr was obtained, and there were only two characteristic energy peaks of 89Zr (909 keV and 511 keV) by γ spectrometer. The half-life of 89Zr was 78.2 h, and the content of metal impurities was small. 89Zr-DFO-Daratumumab was prepared with pH of 7.2, radiochemical purity of more than 99%, good stability in vitro, and sterility and endotoxin tests were passed. Pharmacokinetic studies in rabbits showed that 89Zr-DFO-Daratumumab was gradually distributed from blood to liver, spleen, kidney and bone joints over time and metabolism. The results of microPET/CT imaging in orthotopic myeloma mouse models showed that the SUVs of 89Zr-DFO-daratumumab in situ myeloma were significantly higher than those in normal bone (2 h: 0.22±0.02 vs 0.06±0.00; 1 d: 0.38±0.01 vs 0.08±0.00; t values: 8.89, 21.90, both P=0.001). Conclusion:89Zr and 89Zr-DFO-daratumumab are successfully prepared, and relevant quality control and biological evaluation in vivo and in vitro are completed, which verify the feasibility of 89Zr-DFO-Daratumumab in the imaging diagnosis of MM, thus laying a foundation for clinical transformation.

Zircônia na odontologia: mini-revisão / Zirconia in Dentistry: mini-review

Objetivo: O objetivo deste estudo é fornecer ao cirurgião-dentista conhecimento sobre aspectos gerais da zircônia e abordar a introdução das diferentes gerações. Materiais e métodos: Foi realizada uma pesquisa eletrônica da literatura atual em inglês, incluindo artigos científicos publicados até 2019. Resultados: De acordo com os artigos selecionados, diferenças importantes foram encontradas em relação as novas composições da zircônia, sua microestrutura, diferenças no conteúdo da fase cúbica, e de ítria na fase tetragonal, levando a diferentes propriedades ópticas, mecânicas e de resistência ao envelhecimento. Conclusão: A zircônia é o material mais resistente disponível entre as cerâmicas, com diferenças mecânicas e ópticas entre os materiais disponíveis. A introdução das coroas monolíticas resolveu o problema de lascamento da porcelana de cobertura, mas foram necessárias modificações estruturais para fornecer adequada translucidez.

Purpose: This study aims to provide knowledge to clinicians about general aspects of zirconia and to approach the introduction of different zirconia generations. Methods:An electronic search of the English current literature was conducted including scientific articles published up to 2019. Results: According to the selected articles, important differences were found in terms of the novel compositions of zirconia, microstructures among the materials, differences in cubic phase content and yttria in the tetragonal phase, leading to different optical, mechanical and aging resistance properties. Conclusion: Zirconia is the most resistant material available among ceramics with mechanical and optical differences on available materials. The introduction of the monolithic crowns solving the veneering delamination but struc-tural modifications were necessary to provide adequate translucency

One year clinical evaluation of fracture and marginal integrety of milled biohpp polyetheretherketon (PEEK) versus zirconia veneered single crowns / Avaliação clínica de um ano de fratura e integredade marginal de coroas fresadas à base de biohpp polieteretercetona (PEEK) versus coroas estratificadas de zircônia unitárias (ensaio clínico controlado randomizado)

Objectives: To compare the clinical performance of milled PEEK-based single crowns to zirconia veneered single crowns through evaluation of restoration fracture, margin adaptation, and patient satisfaction. Material and Method: Twenty-four full coverage crowns were fabricated for posterior teeth. The patients were divided into two groups according to crowns' material: Group 1(control group) patients received Zr veneered crowns and Group2 (intervention group) patients received Bio HPP crowns. The preparations were standardized with supra-gingival, chamfer finish line for all teeth. The try-in and provisionalization were performed using CAD/CAM (CAM5-S1) machine with software (Exocad). The restorations were veneered according to manufactures instructions. The restoration surfaces were treated according to the manufacture instructions for each material. Self-adhesive resin cement (by BISCO) was used for both groups for crowns cementation. Fracture, margin integrity and biocompatibility (shade and function) were also evaluated during each recall visit using questionnaire to determine patient satisfaction. These measurements were repeated after two, four, six, eight, ten and twelve months respectively. Results: Fisher's Exact test was used to compare between the two groups; There was no statistically significant difference between the two groups (P-value = 1.000, Effect size = 0.478) for each time period, respectively. Conclusions: Both Zr veneered and Bio HPP crowns revealed successful clinical performance from the clinical performance aspect and patient satisfaction. No significant difference was recorded between the two materials; regarding the clinical performance and patient satisfaction. Therefore, careful checking of the surface of the veneering material one-year post-cementation is recommended (AU)

Objetivo: Comparar o desempenho clínico de coroas unitárias fresadas à base de PEEK com coroas unitárias estratificadas de zircônia por meio da avaliação da fratura da restauração, adaptação marginal e satisfação do paciente. Material e Métodos: Vinte e quatro coroas totais posteriores foram confeccionadas. Os pacientes foram divididos em dois grupos de acordo com o material das coroas: os pacientes do Grupo 1 (grupo controle) receberam coroas estratificadas de Zr e os pacientes do Grupo 2 (grupo de intervenção) receberam coroas BioHPP. Os preparos foram padronizados com linha de término supragengival e chanfro para todos os dentes. O try-in e a provisionalização foram realizados em máquina CAD / CAM (CAM5-S1) com software (Exocad). As restaurações foram estratificadas de acordo com as instruções do fabricante. As superfícies da restauração foram tratadas de acordo com as instruções do fabricante de cada material. O cimento resinoso autoadesivo (BISCO) foi utilizado para a cimentação das coroas em ambos os grupos. Fratura, integridade marginal e biocompatibilidade (tonalidade e função) também foram avaliadas durante cada consulta de retorno usando um questionário para determinar a satisfação do paciente. Essas medições foram repetidas após dois, quatro, seis, oito, dez e doze meses, respectivamente. Resultados: o teste exato de Fisher foi usado para comparação entre os dois grupos; não houve diferença estatisticamente significativa entre os dois grupos (P-valor = 1,000, tamanho do efeito = 0,478) para cada período de tempo, respectivamente. Conclusão: As coroas estratificadas de Zr e BioHPP revelaram um desempenho clínico bem-sucedido do ponto de vista do desempenho clínico e da satisfação do paciente. Nenhuma diferença significativa foi registrada entre os dois materiais; quanto ao desempenho clínico e satisfação do paciente. Portanto, recomenda-se a verificação cuidadosa da superfície do material de estratificação após um ano de cimentação.(AU)

An evaluation of the effect of different veneer materials on fracture resistance of zirconia core / Avaliação dos diferentes efeitos de materiais de revestimento na resistência à fratura do núcleo de zircônia

Objectives: this in vitro study was done to evaluate the effect of packable P60 composite and Tetric N-Ceram composite veneer material on fracture strength of zirconia cores. Material and Methods:Twenty four zirconium cores (Vita, Germany) with 0.7 mm thickness were fabricated by CAD/CAM technology and then subjected to air abrasion with 50 µm of Al2O3. Cores were randomly divided into three groups according to veneering material (group A: control group sandblasted with 50 µm Al2O3 veneered by IPS E-max Ceram porcelain, group C: sandblasted with 50 µm Al2O3, etching with hydrofluoric acid and veneered with P60 composite, group E: sandblasted with 50 µm Al2O3, etching with hydrofluoric acid and veneered with Tetric N-Ceram composite). All crowns were subjected to fracture strength test in the testing machine, with load application by steel ball indenter and 0.5 mm/min. cross head speed. Results: statistical analysis was carried out utilizing one-way ANOVA, LSD. The results of fracture strength value test showed the highest mean value was registered for group (A), and the lowest mean for group (E). One-way ANOVA test represented that, there was a statistically high significant different among all groups. LSD results showed a high significant difference increase in fracture resistance for Group A at p value (*p < 0.001 High significant). Conclusions: Within the limitation of this study, sandblasting zirconia core with 50 µm Al2O3 and veneering with conventional ceramic produced restoration with acceptable fracture resistance value (AU)

Objetivo: o objetivo desse estudo in vitro foi avaliar o efeito dos compósitos P60 compactáveis e material laminado de compósitos Tetric-N Ceram na resistência à fratura de núcleos de zircônia. Material e métodos:Vinte e quatro núcleos de zircônia (Vita, Germany) com 0.7 mm de espessura fabricados por tecnologia de CAD/CAM e sinterizados em alta temperatura (1450ºC por 60 min) de acordo com as instruções do fabricante. Núcleos totalmente de zircônias foram submetidos a abração com 50 µm de Al2O3. Os núcleos de zircônia foram divididos de forma randomiza em três grupos de acordo com o material de revestimento (grupo A: grupo controle jateado com 50 µm Al2O3 folheado com porcelana IPS E-max Ceram, grupo C: jateado com 50 µm Al2O3 , coberto com concentração 9,5% de ácido fluorídrico e folheado com resina composta compatível, grupo E: jateado com 50 µm Al2O3 coberto com concentração 9,5% de ácido fluorídrico e folheado com porcelana IPS E-max Ceram. Todos os espécimes (coroas) foram submetidos a teste de resistência a fratura com máquina de teste universal, essa máquina utilizou para aplicação de carga bola de aço com 6mm de diâmetro 0,5 mm/min de velocidade da cruzeta. Resultados: análise estatística foi realizada utilizando One-way ANOVA, LSD. O resultado da resistência a fratura mostra que o maior valor médio foi registrado no grupo A e a menor média para o grupo E. O resultado do teste One-Way ANOVA representaram que houve uma diferença estatisticamente alta e significante entre todos os grupos. LSD foi executada para mostrar a fonte de significância. Os resultados do LSD mostraram um aumento da diferença significativa alta na resistência à fratura para o grupo A no valor de p (p < 0.001 signicancia alta). Conclusão: Dentro das limitações desse estudo o uso convencional de jateamento com 50 µm Al2O3 e estratificação com cerâmica convencional produziu restauração com valor aceitável de resistência a fratura (AU)

Patient Satisfaction and Pink Esthetics of PEEK Versus Zirconium Abutments in the Esthetic Zone (A Randomized Controlled Trial) / Satisfação do paciente e estética rosa dos pilares PEEK versus Zircônia na zona estética (um ensaio clínico randomizado)

Objective: This study was performed to evaluate the use of PEEK abutments versus zirconium abutments with lithium disilicate superstructure on the esthetic acceptance and peri-implant clinical parameters. Zirconium abutments were found to have high surface roughness even after polishing. This causes a remarkable collapse of the soft tissue papilla that is a primary factor in the Pink Esthetic Score(PES), resulting in failed esthetic restoration in the anterior esthetic zone. Material and Methods:Twenty patients who needed a single implant restoration in the esthetic zone were included in this study. Eighteen patients completed screening, baseline, three-month, six-month, and twelve-month follow-up visits. At the screening visit, the patients were randomly allocated into two groups: Zirconia abutments (A) Group, and PEEK abutments (B) Group, both of which were restored with IPS e.max CAD superstructure. Patients Satisfaction was assessed by visual analogue scale (VAS). Pink esthetics score (PES), modified plaque index (mPI) and modified gingval index (mGI) were also assessed. Results: All implants were successfully osseo-integrated with a 100% survival rate over one year. Patient satisfaction was significantly higher for the PEEK group than the zirconium group. The pink esthetic score showed no statistical significance between both groups. The modified plaque index was significantly lower for the PEEK group than the zirconium group. The modified gingival index showed no statistical difference between both groups. Conclusion: PEEK revealed to be a versatile material to replace zirconium for implant abutments, due to its lower plaque affinity and higher patient satisfaction (AU)

Objetivo: Este estudo foi realizado para avaliar o uso de pilares PEEK versus pilares de zircônia com estrutura de dissilicato de lítio quanto a aceitação estética e parâmetros clínicos peri-implantares. Os pilares de zircônia apresentam alta rugosidade superficial, mesmo após o polimento. Isso causa um colapso notável da papila do tecido mole, que é um fator primário no índice estético rosa (Pink Esthetic Score - PES), resultando em falha na restauração estética na zona estética anterior. Materiais e Métodos:Vinte pacientes que precisavam de um implante unitário na zona estética foram incluídos neste estudo. Dezoito pacientes completaram a triagem, a consulta inicial e as visitas de acompanhamento de três, seis e doze meses. Durante a triagem, os pacientes foram aleatoriamente divididos em dois grupos: Grupo Pilares de Zircônia (A) e Grupo de Pilares PEEK (B), ambos foram restaurados com IPS e.max CAD. A satisfação dos pacientes foi avaliada pela escala visual analógica (VAS). O PES, o índice de placa modificado (mPI) e o índice gengival modificado (mGI) também foram avaliados. Resultados: Todos os implantes foram osseointegrados com sucesso, com uma taxa de sobrevivência de 100% ao longo de um ano. A satisfação do paciente foi significativamente maior para o grupo PEEK quando comparado com o grupo de pilares de zircônia. O índice da estética rosa não apresentou significância estatística entre os dois grupos. O índice de placa modificado foi significativamente menor para o grupo PEEK quando comparado com o grupo de pilares de zircônia. Conclusão: O PEEK revelou-se um material versátil para substituir a zircônia em pilares de implante, devido a sua menor afinidade de placa e maior satisfação do paciente. (AU)

Fracture resistance and strain analysis of zirconia copings with vertical knife edge and three horizontal finish line designs; chamfer, deep chamfer and shoulder with two cementation techniques / Resistência à fratura e análise de deformação de copings de zircônia com término cervical em lâmina de faca e três términos horizontais; chanfro, chanfro largo e ombro com duas técnicas de cimentação

Objective: The purpose of this in vitro study is to evaluate the effect of four finish line configurations and two cement types on the fracture resistance of zirconia copings. Material and Methods: Forty yttrium tetragonal zirconia polycrystals copings were manufactured on epoxy resin dies with four preparation designs: knife edge, chamfer, deep chamfer 0.5, 1 mm and shoulder 1 mm. The copings were cemented with two cement types (glass ionomer and resin cement); (n = 5). Two strain gauges were attached on each coping before they were vertically loaded till fracture with a universal testing machine. Data were analyzed by 2-way analysis of variance ANOVA (p < .05). Fractured specimens were examined for mode of failure with digital microscope. Results: Knife edge showed the highest mean fracture resistance (987.04 ± 94.18) followed by Chamfer (883.28 ± 205.42) followed by Shoulder (828.64 ± 227.79) and finally Deep chamfer finish line (767.66 ± 207.09) with no statistically significant difference. Resin cemented copings had higher mean Fracture resistance (911.76 ± 167.95) than glass ionomer cemented copings (821.55 ± 224.24) with no statistically significant difference. Knife edge had the highest strain mean values on the buccal (374.04 ± 195.43) and lingual (235.80 ± 103.46) surface. Shoulder finish line showed the lowest mean strain values on the buccal (127.47 ± 40.32) and lingual (68.35 ± 80.68) with no statistically significant difference. Resin cemented copings had higher buccal (295.05 ± 167.92) and lingual (197.38 ± 99.85) mean strain values than glass ionomer copings (149.14 ± 60.94) and (90.27 ± 55.62) with no statistically significant difference. Conclusion: Vertical knife edge finish line is a promising alternative and either adhesive or conventional cementation can be used with zirconia copings (AU)

Objetivo: O objetivo deste estudo in vitro é avaliar o efeito de quatro configurações de términos cervicais e dois tipos de cimentos na resistência à fratura de copings de zircônia. Material e Métodos: Quarenta copings de zircônia tetragonal policristalina estabilizada por ítrio foram confeccionados em matrizes de resina epóxi com quatro tipos de términos cervicais: lâmina de faca, chanfro, chanfro largo 0,5, 1 mm e ombro 1 mm. Os copings foram cimentados com dois tipos de cimento (ionômero de vidro e cimento resinoso); (n = 5). Dois extensômetros foram fixados em cada coping antes de serem carregados verticalmente até a fratura com uma máquina de teste universal. Os dados foram analisados por análise de variância ANOVA 2 fatores (p < 0,05). Os espécimes fraturados foram examinados quanto ao modo de falha com microscópio digital. Resultados: A Lâmina de faca apresentou a maior média de resistência à fratura (987,04 ± 94,18) seguida pelo Chanfro (883,28 ± 205,42), pelo Ombro (828,64 ± 227,79) e finalmente o Chanfro largo (767,66 ± 207,09), sem diferença estatisticamente significativa. Os copings cimentados com cimento resinoso apresentaram maior média de resistência à fratura (911,76 ± 167,95) em relação aos copings cimentados com ionômero de vidro (821,55 ± 224,24), sem diferença estatisticamente significativa. A lâmina de faca apresentou os maiores valores médios de deformação na superfície vestibular (374,04 ± 195,43) e lingual (235,80 ± 103,46). O término em ombro apresentou os menores valores médios de deformação na superfície vestibular (127,47 ± 40,32) e lingual (68,35 ± 80,68), sem diferença estatisticamente significativa. Os copings cimentados com resina apresentaram maiores valores médios de deformação na superfície vestibular (295,05 ± 167,92) e lingual (197,38 ± 99,85) do que os copings cimentados com ionômero de vidro (149,14 ± 60,94) e (90,27 ± 55,62), sem diferença estatisticamente significativa. Conclusão: O término cervical em lâmina de faca é uma alternativa promissora e a cimentação adesiva ou convencional pode ser usada na cimentação de copings de zircônia. (AU)

MicroPET imaging studies of 89Zr-labeled EGFR and HER2 antibodies in gastric mucinous adenocarcinoma / 中华核医学与分子影像杂志

Objective:To screen 89Zr-labeled anti-epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2) monoclonal antibody molecular probes suitable for monitoring the gastric mucinous adenocarcinoma bearing mouse models with low glucose metabolism. Methods:The expression of EGFR and HER2 in the MGC803 gastric cancer cell line was verified by analyzing cell slides and xenograft tumor sections. 89Zr-Deferoxamine (DFO)-Cetuximab and 89Zr-DFO-Pertuzumab were prepared and the radiochemical purity was detected. Cell binding experiments and blocking experiments were performed to verify the binding ability and specificity of the probes. Twelve gastric mucinous adenocarcinoma bearing mouse models were divided into 3 groups ( n=4 in each group): 89Zr-DFO-Cetuximab group (7.4 MBq/mouse, 74 μg/mouse), 89Zr-DFO-Pertuzumab group (7.4 MBq/mouse, 70 μg/mouse) and 18F-fluorodeoxyglucose (FDG) group (7.4 MBq/mouse). MicroPET imaging was performed at 4, 24 and 48 h ( 18F-FDG group underwent imaging at 1 h only) post-injection. The biodistribution study of 89Zr-DFO-Cetuximab and 89Zr-DFO-Pertuzumab was conducted in 2 groups ( n=4 in each group) 48 h after the injection. The independent sample t test was used for data analysis. Results:The immunofluorescent staining demonstrated EGFR expression was significantly higher than HER2 expression in MGC803 gastric cancer cell line. The radiochemical purity of 89Zr-DFO-Cetuximab and 89Zr-DFO-Pertuzumab were both more than 95%, and the specific activities were 100 and 95 MBq/mg, respectively. The two probes had good stability in normal saline and fetal bovine serum, with the radiochemical purity higher than 80% at 72 h. MicroPET imaging showed that the uptake of 89Zr-DFO-Cetuximab in the MGC803 tumor was significantly higher than that of 18F-FDG and 89Zr-DFO-Pertuzumab. The biodistribution study demonstrated the 89Zr-DFO-Cetuximab uptake (percentage activity of injection dose per gram of tissue, %ID/g) of tumors at 48 h was significantly higher than that of 89Zr-DFO-Pertuzumab (56.3±12.0 vs 22.0±3.6; t=4.31, P<0.05). Conclusion:Compared with 89Zr-DFO-Pertuzumab, 89Zr-DFO-Cetuximab has a better potential for non-invasive monitoring of gastric mucinous adenocarcinoma with low glucose metabolism.

Ciencia y evolución del dióxido de zirconio, de la prioridad mecánica a la necesidad estética / Science and evolution of zirconium dioxide, from mechanical priority to aesthetic need

RESUMEN En la actualidad, los procedimientos de alta tecnología enfocados a las restauraciones en base a cerámicas dentales han permitido la evolución y perfeccionamiento de distintas formas de manufactura de restauraciones, iniciándose así, la utilización de cerámicas como el dióxido de zirconio. Objetivo : Identificar las publicaciones recientes de los materiales de restauración a base de dióxido de zirconio que incluyan estudios clínicos, propiedades mecánicas, físicas y estéticas, así como su evolución, manufactura y diversas aplicaciones en la práctica clínica diaria. Material y métodos : La búsqueda sistemática de la literatura se realizará en las bases de datos de PubMed y Ebsco, se considerarán publicaciones del 2010- 2019 y que fueran investigaciones clínicas, laboratoriales y todas aquellas que mostraban la evolución en el tiempo del dióxido de zirconio, así como su aplicabilidad y diversificación. Resultados: Se revisaron 48 artículos que cumplieron con los criterios de selección para la revisión bibliográfica. Se encontró que todas las restauraciones protésicas a base de dióxido de zirconio, indistintamente a su forma de utilización, mostraron un desempeño clínico muy similar a los tres años, después de ese tiempo, dependerá del tipo de utilización, composición y elección del caso. Conclusiones: El éxito clínico de las restauraciones en base a dióxido de zirconio, es debido a las múltiples ventajas mecánicas y, con las recientes modificaciones estructurales, sumadas al agregado de aditivos para su estabilización, se perfila como un material idóneo para el trabajo tanto en zonas estéticas como en áreas de necesidad de soporte mecánico con carga funcional elevada.

SUMMARY At present, high-tech procedures focused on restorations based on dental ceramics have allowed the evolution and improvement of different forms of manufacturing restorations, thus initiating the use of ceramics such as zirconium dioxide. Objective: To identify recent publications of zirconium dioxide based restoration materials that include clinical studies, mechanical, physical and aesthetic properties, as well as their evolution, manufacturing and various applications in daily clinical practice. Materials and methods: The systematic search of the literature will be carried out in the databases of PubMed and Ebsco, publications from 2010-2019 will be considered and that they were clinical, laboratory research and all those that showed the evolution in time of zirconium dioxide , as well as its applicability and diversification. Results: 48 articles were reviewed that met the selection criteria for the literature review. It was found that all prosthetic restorations based on zirconium dioxide, regardless of their use, showed a clinical performance very similar to three years, after that time, will depend on the type of use, composition and choice of case. Conclusions: The clinical success of restorations based on zirconium dioxide is due to the multiple mechanical advantages and, with the recent structural modifications, added to the addition of additives for stabilization, is emerging as an ideal material for work both aesthetic areas as in areas of need for mechanical support with high functional load.

Determining Efficacy and Minimum Inhibitory Concentrations of a Denture Adhesive Containing Particles and Nanoparticles of Zirconium against Candida albicans.

Candidiasis as a common complication in patients who wear dentures. Zirconia particles and nanoparticles have antimicrobial properties. This study aimed to investigate the effect of adding zirconia particles and nanoparticles, to denture adhesive on candidiasis.METHODSA total of 46 wells in 6 columns and 6 rows were selected from a cell culture plate. Equal amounts of Candida albicans and denture adhesive were added to all wells. Zirconia was then added to the first three rows at different concentrations of particles and the second three rows received different concentrations of nanoparticles, so that the concentrations were half the previous column. After 24 hours, by adding one type of Thiazolyl Blue Tetrazolium Bromide (MTT) to all the wells, the growth or lack of growth of C. albicans was investigated. Finally, the death or survival (merely lack of growth) of C. albicans was studied by sampling the wells with no growth.RESULTSC. albicans growth was seen in all concentrations of zirconia particles. However, it did not grow in all three rows of nanoparticles up to 31 µgr/mL concentration. Further, all wells with no growth continued to grow after removal of nanoparticles from the medium. Zirconium particles may have anti-candida properties at concentrations above 250 µgr/mL. However, nanoparticles with a minimum concentration of 31 µgr/mL inhibit the growth of C. albicans but do not cause death of these microorganisms.

Hyperkalemia in chronic kidney disease

SUMMARY Hyperkalemia is a frequent finding in patients with chronic kidney disease (CKD). This increase in serum potassium levels is associated with decreased renal ion excretion, as well as the use of medications to reduce the progression of CKD or to control associated diseases such as diabetes mellitus and heart failure. Hyperkalemia increases the risk of cardiac arrhythmia episodes and sudden death. Thus, the control of potassium elevation is essential for reducing the mortality rate in this population. Initially, the management of hyperkalemia includes orientation of low potassium diets and monitoring of patients' adherence to this procedure. It is also important to know the medications in use and the presence of comorbidities to guide dose reduction or even temporary withdrawal of any of the potassium retention-related drugs. And finally, the use of potassium binders is indicated in both acute episodes and chronic hyperkalemia.

RESUMO A hiperpotassemia é um achado frequente em pacientes com doença renal crônica (DRC). Esta elevação do nível sérico de potássio está associada à diminuição da excreção renal do íon, assim como ao uso de medicações para retardar a progressão da DRC ou para controlar doenças associadas, como diabetes mellitus e insuficiência cardíaca. A hiperpotassemia aumenta o risco de episódios de arritmia cardíaca e morte súbita. Assim, o controle da elevação de potássio é essencial para a diminuição da taxa de mortalidade nessa população. O manejo da hiperpotassemia inclui, inicialmente, orientação de dietas com baixo teor de potássio e acompanhamento da aderência dos pacientes a esse procedimento. Também é importante conhecer as medicações em uso e a presença de comorbidades, a fim de orientar a redução de doses ou até mesmo a suspensão temporária de alguma das drogas relacionadas à retenção de potássio. E, finalmente, o uso de quelantes de potássio é indicado tanto em episódios agudos como nos casos de hiperpotassemia crônica.

Grinding of composite cores using diamond burs with different grit sizes: the effects on the retentive strength of zirconia crowns

Aim: To evaluate the retention of Y-TZP crowns cemented in aged composite cores ground with burs of different grit sizes. Methods: Sixty composite resin simplified full-crown preparations were scanned, while 60 Y-TZP crowns with occlusal retentions were milled. The composite preparations were stored for 120 days (wet environment-37°C) and randomly distributed into three groups (n=20) according to the type of composite core surface treatment. The groups were defined as: CTRL (control: No treatment), EFB (extra-fine diamond bur [25µm]), and CB (coarse diamond bur [107µm]). The grinding was performed with an adapted surveyor standardizing the speed and pressure of the grinding. The intaglio surfaces on the crowns were air-abraded with silica-coated alumina particles (30 µm) and then a silane was applied. The crowns were cemented with self-adhesive resin cement, thermocycled (12,000 cycles; 5/55°C), stored (120 days) and submitted to a retention test (0.5mm/min). The retentive strength data (MPa) were analyzed using one-way analysis of variance and Tukey test, as well as Weibull analysis. Failures were classified as 50C (above 50% of cement in the crown), 50S (above 50% of cement in the substrate) and COE (composite core cohesive failure). Results: No statistical difference was observed among the retention values (p=0.975). However, a higher Weibull modulus was observed in the CTRL group. The predominant type of failure was 50S (above 50% of cement in the substrate composite). Conclusion: The retention of zirconia crowns was not affected by grinding using diamond burs with different grit sizes (coarse/extra-fine) or when no grinding was performed

Gingival fibroblasts behavior on bioactive zirconia and titanium dental implant surfaces produced by a functionally graded technique

Abstract Adding a biological apatite layer to the implant surface enhances bone healing around the implant. Objective This study aimed to characterize the mechanical properties and test human gingival fibroblasts behavior in contact with Zirconia and Titanium bioactive-modified implant materials. Methodology 6 groups were considered: Titanium (Ti6Al4V), Ti6Al4V with 5% HA and 5% ßTCP, Zirconia (YTZP), YTZP with 5% HA and 5% ßTCP. For each group, we produced discs using a novel fabrication method for functionally graded materials, under adequate conditions for etching and grit-blasting to achieve equivalent surface microroughness among the samples. Surface roughness (Ra, Rz), water contact angle, shear bond strength, and Vickers hardness were performed. Human gingival fibroblasts immortalized by hTERT gene from the fourth passage, were seeded on discs for 14 days. Cell viability and proliferation were assessed using a resazurin-based method, and cellular adhesion and morphology using field emission gun scanning electron microscopy (FEG-SEM). After 3 days of culture, images of fluorescent nucleic acid stain were collected by confocal laser scanning microscopy (CLSM). Results Results were presented as mean ± standard deviation (SD). We compared groups using one-way ANOVA with Tukey's post-hoc test, and significance level was set at p<0.05. After 14 days of culture, cell viability and proliferation were significantly higher in YTZP group than in other groups (p<0.05). Samples of YTZP-ßTCP presented significantly higher wettability (p<0.05); yet, we observed no improvement in cell behavior on this group. Fibroblast spreading and surface density were more evident on YTZP specimens. Adding calcium-phosphate bioactive did not alter the tested mechanical properties; however, Ti6Al4V material shear bond strength was statistically higher than other groups (p<0.05). Conclusion Adding bioactive materials did not improve soft-tissue cell behavior. When compared to other zirconia and titanium groups, pure zirconia surface improved adhesion, viability and proliferation of fibroblasts. Cell behavior seems to depend on surface chemical composition rather than on surface roughness.

Does the metal artifact reduction algorithm activation mode influence the magnitude of artifacts in CBCT images?

PURPOSE: This study was conducted to assess the effectiveness of a metal artifact reduction (MAR) algorithm activated at different times during cone-beam computed tomography (CBCT) acquisition on the magnitude of artifacts generated by a zirconium implant.MATERIALS AND METHODS: Volumes were obtained with and without a zirconium implant in a human mandible, using the OP300 Maxio unit. Three modes were tested: without MAR, with MAR activated after acquisition, and with MAR activated before acquisition. Artifacts were assessed in terms of the standard deviation (SD) of gray values and the contrast-to-noise ratio (CNR) in 6 regions of interest with different distances (10 to 35 mm, from the nearest to the farthest) and angulations (70° to 135°) from the implant region.RESULTS: In the acquisitions without MAR, the regions closer to the implant (10 and 15 mm) had a higher SD and lower CNR than the farther regions. When MAR was activated (before or after), SD values did not differ among the regions (P>0.05). The region closest to the implant presented a significantly lower CNR in the acquisitions without MAR than when MAR was activated after the acquisition; however, activating MAR before the acquisition did not yield significant differences from either of the other conditions.CONCLUSION: Both modes of MAR activation were effective in decreasing the magnitude of CBCT artifacts, especially when the effects of the artifacts were more noticeable.