Concomitant Transcatheter Transfemoral Double Native Valve Replacement for Severe Aortic Stenosis and Severe Mitral Stenosis with Mitral Annular Calcification

Concomitant mitral and aortic valve stenosis in a patient with mitral annular calcification and porcelain aorta poses a unique problem to the surgical team. Transcatheter aortic and mitral valve replacements in native valves offer a viable option for such selected group of patients. We present the case of a 54-year-old male who presented with severe aortic stenosis (AS) and severe mitral stenosis (MS) but was deemed high risk for surgery owing to intense calcification of the aorta and mitral annular calcification, and successfully underwent transcatheter double native valve replacement.

Progress on the application of porcelain veneers in the restoration of dental fluorosis and its influencing factors / 中华地方病学杂志

Due to the cloud-like appearance of the dental surface of dental fluorosis, serious tooth defect may occur, thus affecting the overall beauty of the face. The clinical effect of dental fluorosis is not better than that of normal teeth in the application of repair, which brings some difficulties to the clinicians. The application of porcelain veneers in the restoration of dental fluorosis has been widely concerned by clinicians and researchers due to its advantages of high aesthetics, small amount of tooth tissue abrasion, and good biocompatibility. Therefore, this article comprehensively discusses the application effect and influencing factors of porcelain veneers in the restoration of dental fluorosis, in order to provide some reference for clinical application.

Prediction, analysis and application of learning curve of tooth preparation for all ceramic crowns of maxillary central incisors / 北京大学学报(医学版)

OBJECTIVE@#To predict the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training based on the modified Wright learning curve model, then to analyze and applicate the learning curve.@*METHODS@#Twelve graduate students participating in standardized dental resident training were selected to prepare the resin maxillary central incisors on phantom head simulators for all ceramic crowns 4 times. The results of preparation were evaluated by 3 prosthetic experts with at least 10 years' experience focusing on the reduction, contour, taper, shoulder, finish line, margin placement, adjacent tooth injury, and preparation time for tooth preparation. The learning rate of tooth preparation was calculated by scores of tooth preparation of 4 times. The learning curve of tooth preparation was predicted based on the modified Wright learning curve model. According to the criteria of standardized training skill examinations for dental residents in Beijing, 80 was taken as the qualified standard score. The minimum training times for tooth preparation to satisfy the qualified standard score (80) was calculated, to analyze the characteristics of learning curve and evaluate the effectiveness of tooth preparation.@*RESULTS@#The scores of 4 tooth preparation were 64.03±7.80, 71.40±6.13, 74.33±5.96, and 75.98±4.52, respectively. The learning rate was (106±4)%, which showed the learning curve an upward trend. There were no significant differences between the qualified standard score and the predicted scores of tooth preparation from the 5th preparation to the 13th preparation (P > 0.05). The predicted score of the 14th preparation was higher than the qualified standard score (P < 0.05).@*CONCLUSION@#The trend of the learning curve of tooth preparation for all ceramic crowns of maxillary central incisors on phantom head simulators for graduate students participating in standardized dental resident training is upward, which predicts the minimum training times higher than the qualified standard score is 14 times.

The Effect of Immediate Dentin Sealing on the Marginal Adaptation of LithiumDisilicate Overlay Restorations using different types of luting agents / Efeito do selamento imediato da dentina na adaptação marginal de restaurações overlay de dissilicato de lítio utilizando diferentes tipos de agentes de cimentação: estudo in vitro

Objective:This study evaluated the effect of immediate dentin sealing on the marginal adaptation of lithium disilicate overlays with three different types of resin-luting agents: preheated composite, dual-cure adhesive resin, and flowable composite. Materials and Methods: Forty-eight maxillary first premolars of similar size were prepared with a butt joint preparation design. The teeth were separated into two primary groups, each with twenty-four teeth: Group DDS: Delay dentin sealing (non-IDS) teeth were not treated. Group IDS: dentin sealing was applied immediately after teeth preparation. Each group was subsequently separated into three separate subgroups. Subgroups (DDS+Phc, IDS+Phc): cemented with preheated composite (Enamel plus HRi, Micerium, Italy), Subgroups (DDS+Dcrs, IDS+Dcrs): cemented with dual-cured resin cement (RelyX Ultimate, 3M ESPE, Germany) and Subgroups (DDS+Fc, IDS+Fc): Cemented with flowable composite (Filtek supreme flowable, 3M ESPE, USA). Using a digital microscope with a magnification of 230x, the marginal gap was measured before and after cementation at four different locations from each surface of the tooth, and the mean of measurements was calculated and analyzed statistically using the independent t-test, one-way ANOVA test, Bonferroni correction at a significance level of 0.05. Results: The samples that were immediately sealed with dentin bonding agent showed lower marginal gaps than delayed dentin sealing, both pre-and post-cementation for all subgroups, with a statistically significant difference (p˂0.01). The marginal gap was significantly lower in the IDS+Fc (48.888 ±5.5 µm) followed by the IDS+Dcrs group (53.612 ±5.8 µm) and IDS+Phc (79.19 9±6.9 µm) respectively, while the largest marginal gaps were observed in the DDS+Phc group (86.505 ±5.4 µm). Conclusion: Generally, the teeth with IDS showed better marginal adaptation than teeth without IDS. The marginal gap was smaller with flowable composite and dual-cure resin cement than with preheated composite (AU)

Objetivo:Esse estudo avaliou o efeito do selamento imediato da dentina na adaptação marginal de overlays em dissilicato de lítio com três tipos diferentes de agentes de cimentação resinosos: resina composta pré-aquecida, adesivo resinoso dual e resina fluida. Materiais e métodos: Quarenta e oito primeiros pré-molares maxilares com tamanho similar foram preparados com término em ombro. O dente foi separado em dois grupos primários, cada um com vinte e quatro dentes: Grupo DDS: retardado selamento da dentina (non-IDS) dente não foi tratado. Grupo IDS: selamento dentinário foi aplicado imediatamente após a preparação do dente. Cada grupo foi separado de modo subsequente em três subgrupos. Subgrupo (DDS+Phc, IDS+Phc): cimentado com resina pré-aquecida (Enamel plus HRi, Micerium, Italy), Subgrupo (DDS+Dcrs, IDS+Dcrs): cimentado com cimento resinoso dual (RelyX Ultimate, 3M ESPE, Germany) e Subgrupo (DDS+Fc, IDS+Fc): cimentado com resina fluida (Filtek supreme flowable, 3M ESPE, USA). Usando um microscópio digital com magnificação de 230x, o gap marginal foi medido antes e após a cimentação em quatro diferentes localizações de cada superfície do dente e a média das medidas foi calculada e estatisticamente analisada através do uso do teste ANOVA um-fator e teste independente de Tukey e correção Bonferroni com nível de significância de 0,05. Resultado: As amostras que foram imediatamente seladas com agente adesivo dentinário apresentaram menores gaps marginais do que o selamento dentinário retardado, ambos pré e pós cimentação para todos os subgrupos apresentaram diferença estatística significante (p˂0.01). O gap marginal foi significativamente menor para IDS+Fc (48.888 ±5.5 µm) acompanhado do IDS+Dcrs group (53.612 ±5.8 µm) e IDS+Phc (79.19 9 ±6.9 µm) respectividamente, enquanto o maior gap marginal foi observado no grupo DDS+Phc (86.505 ±5.4 µm). Conclusão:Geralmente, o dente com IDS apresentou melhor adaptação marginal do que o dente sem IDS. O gap marginal foi menor com resina fluida e cimento resinoso dual do que com a resina composta pré-aquecida (AU)

Influence of number and position of porcelain specimens in the furnace on flexural strength and translucency

The aim of this study was to investigate the influence of the quantity and positioning of feldspathic ceramic specimens inside the furnace on their flexural strength and translucency. The tested hypotheses were that the arrangement of specimens in the furnance would not influence 1) the translucency or 2) the biaxial strength of the porcelain. Methods: Ninety porcelain specimens were made (1.2 mm thickness and 13.5 mm diameter) and assigned into two main groups (n=15): G1 group - 15 firing cycles containing only one specimen each, always at the center of the refractory; and G5 group - 15 firing cycles containing five specimen each, where one specimen was at the center of the refractory and four specimens positioned equidistantly on the periphery. The translucency test was performed using a spectrophotometer, followed by the flexural strength test, according to ISO 6872:2015. T-student test was performed for both the mechanical and optical obtained data. Results: The flexural strength of the porcelain was not affected by the positioning (center x periphery) of the specimens inside the furnace (p =0.08), but the translucency was affected (periphery > center; p =0.009). Regarding to the number of feldspathic ceramic specimens, the biaxial flexural strength was affected (p =0.025), as well as the translucency (p <0.05). Conclusion: A higher quantity of feldspathic ceramic specimens for each firing cycle decreased its biaxial flexural strength and translucency. Also, specimens positioned at the center of the refractory became less translucent than those positioned at the periphery.

Cerâmicas Feldspáticas em Dentes Posteriores pela Técnica CAD/CAM: uma Revisão de Literatura / Feldspatich Ceramics in Posterioes Teeth by CAD/CAM Technique: a Literature Review

O objetivo do presente estudo foi avaliar a indicação do uso das cerâmicas feldspáticas em dentes posteriores, pela técnica CAD/CAM (Computer-aided design [CAD] e computer-aided manufacturing [CAM]) chairside, em uma unidade de alta demanda, por meio de uma revisão de literatura. Uma pesquisa avançada foi realizada a partir da base de dados do PubMed, compreendendo os últimos 15 anos e utilizando os seguintes termos MeSH para pesquisa: "dental crowns", "CAD/CAM system", "porcelain" e "review". Dos 47 artigos levantados inicialmente, 30 foram selecionados para compor a amostra final. A partir do presente estudo foi possível concluir que o uso das cerâmicas feldspáticas desenvolvidas pela técnica CAD/CAM é seguro em dentes posteriores, desde que respeitada a técnica. Esta técnica constitui-se em excelente opção para tratamento odontológico em instituições de alta demanda restauradora que possuem altos níveis de exigência e prontidão, promovendo celeridade, evitando o uso de restaurações provisórias, reduzindo também a quantidade de urgências em próteses.

The present study aims to evaluate the indication of the use of feldspathic ceramics in posterior teeth, by the CAD/CAM technique (Computer-aided design [CAD] and computer-aided manufacturing [CAM]), in a public institution, through a literature review. An advanced search was carried out in the PubMed database, covering the last 15 years and using the following MeSH search terms: "dental crowns", "CAD/CAM system", "porcelain" and "review". Thirty out of the 47 articles initially surveyed were selected to compose the final sample. From the present study, it was possible to conclude that the use of feldspathic ceramics developed by the CAD/CAM technique is safe in posterior teeth, whether the technique is respected. This technique is an excellent option for dental treatment in institutions of high restorative demand that have high levels of demand and readiness, promoting celerity, avoiding the use of temporary restorations, also reducing the number of urgencies in prosthesis.

The effect of adding nanoparticles to dental porcelain on the fracture resistance and bond strength to zirconia core

Background: Porcelain combined with zirconia core substructure has low fracture toughness. Nanoparticles are incorporated into the porcelain to boost its mechanical properties. Aims: To evaluate the effect of the incorporation of silver oxide and titanium oxide nanoparticles into porcelain powder on the bond strength of porcelain veneer to zirconia core. The flexural strength of nanoparticles?modified porcelain was also evaluated. Materials and Methods: The flexural strength of feldspathic porcelain was measured (according to ISO specifications number 6872) after the incorporation of silver and titanium oxide nanoparticles. For measuring the bond strength at the porcelain?zirconia interface, 70 bars (4 × 4 × 12 mm) of zirconia were cut and fired in a furnace. The control and nanoparticles?modified porcelain powders were built up on the zirconia bars and fired to create veneers of 3 mm height, 4 mm width and 4 mm thickness. The porcelain veneers were de?attached from the zirconia core by the universal testing machine. The failure load was recorded to calculate the bond strength. Statistical Analysis: The data were analysed with one?way analysis of variance followed by Tukey’s test. Results: The addition of 0.5–1.5% silver oxide nanoparticles to feldspathic porcelain increased the flexural strength. The addition of 1.0–4.0% titanium oxide nanoparticles to feldspathic porcelain increased the flexural strength. Either 0.5–1.0% silver oxide or 3.0–4.0% titanium oxide nanoparticles in feldspathic porcelain increased the shear bond strength to zirconia core. Conclusion: The flexural strength of porcelain veneer and the bond strength at porcelain?zirconia interface can be improved by adding either 0.5% silver oxide nanoparticles or 4% titanium oxide nanoparticles to porcelain powder.

Preparation and antibacterial properties of Cu-ZnO-loaded dental veneering porcelain / 口腔疾病防治

Objective@#To investigate the antibacterial properties, biocompatibility and mechanical properties of Cu-ZnO-loaded dental veneering porcelain to provide an experimental basis for the development of new dental veneering porcelain. @*Methods@#Cu-ZnO nanoparticles were added to IPS E.max Ceram for restorative veneer porcelain at different mass percentages of 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and 6 wt% using ball milling in ceramic powder. A cylindrical specimen with a diameter of 20 mm and a thickness of 2 mm was prepared by high-temperature sintering. Scanning electron microscopy was used to observe the surface morphologies of nano-Cu-ZnO and the specimens. The antibacterial effect of Escherichia coli (E. coli) was quantitatively studied by the plate colony counting method. The CCK-8 method was used to evaluate in vitro the cytotoxicity of the tested piece to mouse fibroblasts (L929). Live and dead cells were observed by fluorescence microscopy. The mechanical properties of modified IPS E. Max Ceram veneering porcelain were tested by a three-point bending strength test. @* Results @# Under the scanning electron microscope, Cu-ZnO appears with a block-like structure and can be seen dispersed in the veneering porcelain. When the nano Cu-ZnO loading was 1 wt%, 2 wt%, 3 wt%, and 4 wt%, the antibacterial rates of the specimens were 24.85%, 67.94%, 96.92%, and 99.99%, respectively, and the difference between the experimental groups and the control group was statistically significant (F = 23.308,P = 0.001). The relative growth rate of each group was greater than 80% after coculture with mouse fibroblast cells (L929) for 1 day and 3 days, and there was no significant difference between the groups. The morphology of L929 cells was normal after coculture for 24 hours. With the increase in the Cu-ZnO concentration, the flexural strength of the specimen exhibited an increasing trend followed by a decreasing trend. The bending strength of the specimen loaded with 3 wt% nano Cu-ZnO reached the maximum value (84.728 ± 6.82) MPa, and there was no statistically significant difference between groups (F = 0.633,P = 0.702).@*Conclusion@#The antibacterial rate of IPS E. max Ceram veneering porcelain loaded with 3 wt% nano Cu-ZnO was more than 96% against E. coli after high-temperature sintering at 750 ℃. The bending strength reached the maximum (84.728 ± 6.82) MPa, and there was no obvious cytotoxicity.

Effects of heat treatment on the bonding strength of pure titanium processed via selective laser melting and porcelain / 口腔疾病防治

Objective@# To evaluate the effect of heat treatment on the bonding strength of pure titanium formed by selective laser melting (SLM) and porcelain.@*Methods@#Ninety-six pure titanium specimens were laser machined to meet ISO 9693 standards. The specimens were divided into a heat treated group (A) and a nonheat treated group (B). According to the porcelain type, the specimens in groups A and B were divided into Super Ti22 (a), Titankeramik (b), and Triceram (c) groups. Then, according to sandblasting pressures of 0.25 MPa (1) and 0.45 MPa (2), they were further divided into Aa1, Aa2, Ab1, Ab2, Ac1, Ac2, Ba1, Ba2, Bb1, Bb2, Bc1, and Bc2 groups. The surface morphology and roughness of the sandblasted specimens were assessed using a laser scanning confocal microscope. After the porcelain was fused, the three-point bending titanium-porcelain bonding strength was tested. A stereomicroscope was used to characterize the titanium-porcelain interfaces and determine the mode of failure.@* Results@# The Vickers hardness of group A specimens (188.21 ± 11.94) was significantly lower than that of group B specimens (204.48 ± 6.32) HV (P<0.05). The roughness value in group A1 (2.90 ± 0.32) μm was significantly lower than that in group A2 (3.43 ± 0.43) μm (P<0.05). Specimens in group B1 (2.62 ± 0.08) μm were significantly smaller than those in group B2 (3.01 ± 0.06) μm (P<0.05). The bonding strength in group Aa1 was (33.75 ± 2.31) MPa, group Aa2 was (36.32 ± 1.44) MPa, group Ab1 was (39.82 ± 2.28) MPa, group Ab2 was (33.74 ± 1.53) MPa and group Ac2 was (38.63 ± 1.36) MPa, which was significantly higher than that in the corresponding groups Ba1 (29.65 ± 1.10) MPa, Ba2 (27.17 ± 2.24) MPa, Bb1 (27.29 ± 1.61) MPa, Bb2 (23.85 ± 0.97) MPa, and Bc2 (35.75 ± 1.93) MPa (P<0.05). With increasing sandblasting pressure, the bonding strength of the titanium ceramic in group Aa2 was significantly higher than in group Aa1, while that in group Ab2 was significantly lower than that in group Ab1 (P<0.05). In groups A, Bc1 and Bc2, the fracture model showed mixed failure, while in groups Ba1, Ba2, Bb1, and Bb2, the model showed interfacial failure.@* Conclusion @# The Vickers hardness of SLM titanium can be significantly reduced by heat treatment. SLM pure titanium after heat treatment is beneficial to combination of the three porcelain types and titanium. The titanium-porcelain bonding strength may be affected by sandblasting pressure.

Influência da espessura e diferentes graus de opacidade do dissilicato de lítio no grau de conversão e resistência de união de cimentos resinosos / Influence of thickness and different degrees of opacity of lithium disilicate on the degree of conversion and bond strength of resin cements

O objetivo desse trabalho foi avaliar a influência de diferentes graus de opacidade e espessuras do dissilicato de lítio no grau de conversão de dois cimentos resinosos e na resistência de união dos mesmos à cerâmica. Duzentos e quarenta amostras cerâmicas de dissilicato de lítio (6x6 mm) foram obtidos a partir de blocos de IPS E-max CAD (Ivoclar Vivadent, Schaan, Liechtensten), nas opacidades HT (alta translucidez), LT (baixa translucidez) e MO (média opacidade), nas espessuras de 0,3 mm, 0,7 mm, 1,2mm, 1,7 mm, 2,0 mm. Para as análises do grau de conversão (n=9) e resistência de união (n=8) foram utilizados um cimento de ativação física (Variolink Esthetic LC) e um cimento dual (Multilink N). Para análise do grau de conversão, as amostras de cimento foram fotoativadas sob as amostras de cerâmica e levadas a um espectrômetro Raman confocal. Para o teste de resistência de união foram confeccionados cilindros de cimento resinoso sobre as amostras cerâmicas e submetidos ao ensaio de microcisalhamento. Os resultados mostraram que o aumento das espessuras causou diminuição no grau de conversão dos dois cimentos em todas as condições estudadas, porém só influenciou negativamente a resistência de união do cimento Variolink Esthetic LC quando unido à cerâmica na opacidade MO. Na comparação entre as opacidades, de maneira geral, a cerâmica de maior translucidez HT apresentou maiores valores de grau de conversão em comparação às outras opacidades. Já para resistência de união, em algumas espessuras as cerâmicas LT e MO apresentaram os maiores valores. O cimento dual Multilink N apresentou os maiores valores nas duas análises comparado ao cimento fotoativado Variolink Esthetic LC. Portanto, o aumento da espessura e da opacidade do material cerâmico podem promover uma diminuição no grau de conversão do cimento. A resistência de união também sofre uma diminuição com o aumento da espessura de cerâmicas mais opacas. No entanto, a maior translucidez do material não garante valores mais altos dessa mesma propriedade(AU)

This research aims to evaluate the influence of different degrees of opacity and thicknesses of lithium disilicate on the degree of conversion of two resin cements and on their bond strength to the ceramic. Two hundred and forty lithium disilicate ceramic samples (6x6 mm) were obtained from IPS E-max CAD (Ivoclar Vivadent, Schaan, Liechtensten), in HT, LT and MO opacities, with thicknesses of 0.3 mm, 0.7 mm, 1.2 mm, 1.7 mm, 2.0 mm. For degree of conversion (n=9) and bond strength analysis (n=8) a light cured (Variolink Esthetic LC) and a dual cured resin cement (Multilink N) were used. To analyze the degree of conversion, the cement samples were light cured under the ceramic samples and taken to a confocal Raman spectrometer. For the bond strength test, resin cement cylinders were made on the ceramic samples that were later subjected to a microshear. The results showed that the increase in thickness caused a decrease on degree of conversion of both cements in all the conditions studied, but it only had an influence on bond strength of Variolink LC cement for MO ceramic. Comparing the opacities, for the degree of conversion, the most translucent ceramics had higher conversion values compared to the less translucent ones in some thicknesses. As for bond strength, in some thicknesses the LT and MO ceramics showed the highest values. The dual cement Multilink showed the highest values of conversion degree and bond strength compared to Variolink Esthetic LC light-cured cement. The Multilink dual cement showed the highest values in both analyzes compared to the Variolink LC light-cured cement. Therefore, increasing the thickness and opacity of the ceramic material can promote a decrease in the degree of cement conversion. The bond strength also suffers a decrease with increasing thickness of more opaque ceramics and the greater translucency of the material does not guarantee higher values of this same property(AU)

Determination of Shear Bond Strength of Nanocomposite to Porcelain and Metal Alloy

Abstract Objective: To compare porcelain and metal repair done with both nanocomposite and conventional composite. Material and Methods: A total of 30 cylinders were fabricated from Porcelain (I), Porcelain fused to metal (II), and metal (III) substrate each. Control group (A) was bonded with conventional micro-hybrid composite and experimental group (B) was bonded with nanocomposite in a 2 mm thickness. All specimens were thermocycled and stored in distilled water at 37 °C for 7 days. A universal testing machine was used to measure the Shear bond strength (SBS). The difference between bond strengths of the groups was compared using an independent t-test. Results: In all three groups, the SBS was higher in the experimental group as compared to the control group. The use of nanocomposite of metal alloy presented maximum shear bond strength, followed by samples of porcelain fused to metal and finally porcelain, showing the lowest values of SBS. Conclusion: Porcelain and alloys bonded with nanocomposite exhibit enhanced adhesiveness as well as aesthetic and mechanical properties. This subsequently would translate into providing higher clinical serviceability and durability and hence a cost-effective and accessible repair option for human welfare (AU).

The Effect of Coloring Beverages on Color Stability of Hybrid Ceramics with Different Surface Treatments

ABSTRACT Objective To assess the effects of coloring beverages on the color stability of two types of hybrid ceramics with different surface treatments. Material and Methods 180 specimens of two hybrid ceramics (Vita Enamic and Mazic Duro) and a feldspathic ceramic (Vita Mark II) were prepared (n=60 in each group). Half of the discs in each group were glazed while the other was polished. The specimens were then divided into three subgroups and immersed in distilled water, carrot juice, and coffee. The overall color difference (∆E) was calculated based on CIE L*a*b* color space. Data were analyzed using three-way and one-way ANOVA; Tukey's honest significant difference was also done for pairwise comparisons (α=0.05). Results Vita Mark II specimens revealed less overall color changes compared to other groups. The ∆E of the glazed Vita Enamic specimens was greater than polished specimens following immersion in distilled water (p=0.03) and coffee (p=0.001), but it was not significant for carrot juice. The same results were obtained for polished Mazic Duro specimens. Relatively similar amounts of ∆E were recorded in polished and glazed subgroups of Vita Mark II. Conclusion The ∆E of hybrid ceramics was higher than Vita Mark II. Polishing could be recommended for surface treatment of hybrid ceramics instead of glazing, saving time and facilitating the process.

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.

CAD-FEA modeling and fracture resistance of bilayer zirconia crowns manufactured by the rapid layer technology

Abstract In the RLT (Rapid Layer Technology), veneering ceramic and framework are fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) and then cemented to obtain the restoration. This study aimed to evaluate the effect of the thickness of veneering ceramic manufactured by the RLT technique on the fracture resistance (FR) of bilayer crowns with zirconia frameworks. Twenty zirconia frameworks and twenty feldspathic posterior crowns with two different veneering ceramic occlusal thicknesses (1mm=TF1; 2mm=TF2) were manufactured using CAD/CAM system. The specimens were luted to an epoxy resin abutment with resin cement and mechanically cycled (200N and 4.5×105 Pa, 37°C, 2×106 cycles, 3Hz). The FR test was performed (10kN, 0.5mm/min), and the specimens were analyzed in a stereomicroscope. For the stress analysis (finite element analysis, FEA), a 10kN load was equal to the in vitro test, and the principal stress was evaluated. The FR data were analyzed by Student's t-test and Weibull's analysis. The thickness influenced the FR of bilayer crowns. The FR was higher in the TF2 than in the TF1 group. The TF2 group presented the highest characteristic strength compared to the group TF1. The predominant type of failure was delamination. The FEA showed higher stress concentrations below the loading application point at the veneering cement interface in the 1-mm-thick model. The bilayer crowns manufactured using the approach of 2mm of veneering ceramic promoted higher FR compared to the group with 1mm veneering ceramic. Also, the FEA showed that the veneer ceramic thickness has an effect on stress distribution in zirconia-based bilayer crowns.

Resumo Na RLT (Rapid Layer Technology), a cerâmica de cobertura e infraestrutura são fabricados pelo Computer-Aided Design / Computer-Aided Manufacturing (CAD / CAM) e cimentados para obter a restauração. Este estudo teve como objetivo avaliar o efeito da espessura da cerâmica de cobertura fabricada pela técnica RLT na resistência à fratura (RF) de coroas bilaminadas com infraestrutura de zircônia. Vinte infraestruturas de zircônia e vinte coroas posteriores feldspáticas com duas espessuras oclusais da cerâmica de cobertura (1mm = TF1; 2mm = TF2) foram fabricadas usando o sistema CAD / CAM. Os espécimes foram cimentados em preparos de resina epóxi com cimento resinoso dual e ciclados mecanicamente (200N e 4,5×105 Pa, 37° C, 2×106 ciclos, 3Hz). O teste de RF foi realizado (10kN, 0,5mm / min) e, posteriormente, os espécimes foram analisados em estereomicroscópio. Para a análise de tensão (análise de elementos finitos, FEA), uma carga de 10kN foi aplicada igual ao teste in vitro, e a tensão principal foi avaliada. Os dados de RF foram analisados pelo teste t de Student e análise de Weibull. A espessura mostrou forte influência na RF das coroas bilaminadas. A RF foi maior em TF2 do que no grupo TF1. O grupo TF2 apresentou a maior resistência característica em relação ao grupo TF1. O tipo de falha predominante foi a delaminação. O FEA mostrou maiores concentrações de tensões abaixo do ponto de aplicação da carga, na interface cimento e cerâmica de cobertura no modelo de coroa de 1 mm de espessura. As coroas de bilaminadas confeccionadas com 2 mm de cerâmica de cobertura promoveram maior RF em comparação ao grupo com cerâmica de cobertura de 1 mm. Além disso, a FEA mostrou que a espessura da cerâmica de cobertura tem um efeito na distribuição de tensões em coroas bilaminadas à base de zircônia.

Effect of ceramic materials on the optical properties of porcelain veneers for tetracycline-stained teeth / 华西口腔医学杂志

OBJECTIVES@#To analyze the chromatic properties and translucency of porcelain veneers made from different ceramic materials against the background of tetracycline-stained teeth.@*METHODS@#Porcelain specimens (A1, A3, B2, B4) measuring 0.50 mm in thickness were prepared by heat-press casting and layering. The L*, a*, and b* values of the specimens against simulated tetracycline tooth and black-and-white backgrounds were measured by a spectrophotometer, and color differences ΔE@*RESULTS@#The ΔE@*CONCLUSIONS@#When changing the color of tetracycline-stained teeth, 0.50 mm-thick IPS d.SIGN feldspathic veneers with an opaque layer provide better chromatic properties than IPS e.max Press LT glass ceramic veneers. However, the translucency of feldspathic veneers is generally poorer than that of glass ceramic veneers.

Effect of different treatments of highly translucent zirconia on the bonding strength between zirconia and veneering porcelain / 口腔疾病防治

Objective @# To evaluate the effect of different surface treatments on the bonding strength between highly translucent zirconia and veneering porcelain and to provide a research basis for improving the zirconium porcelain bond strength between zirconium and ceramic material.@*Methods @# Thirty cylindrical zirconia blocks with 10-mm diameter and 10-mm height were prepared and divided into four groups (n=7), labeled as control group (C), sandblasting group (S), bonding group (B), and sandblasting and bonding group (SB). The surface morphology of zirconia before and after sandblasting was observed in the remaining two specimens. Group C was veneered (2 mm in height and 5 mm in diameter) with porcelain powder by layering after grinding. Group S was sandblasted after grinding. Group B was veneered with a thin layer of porcelain powder as bond coating. Group SB was sandblasted and veneered with a thin layer of porcelain powder. After sintering, the shear specimens were embedded, and a shear bond strength test was conducted. Statistical analysis was conducted to analyze the data. Fracture surface analysis was also performed to determine the failure modes by stereomicroscopy.@*Results @# The bonding strength of group C was 21.86 ± 3.18 MPa. For group S, it was 22.12 ± 3.06 MPa. For group B, it was 19.19 ± 1.46 MPa. Finally, for group SB, it was 27.76 ± 1.95 MPa. There was no significant difference in shear strength between group C, group S and group B. There was a significant difference in shear strength between each group and group SB (P < 0.05). Under a stereomicroscope, the observed fracture modes of each group were mainly mixed failure.@*Conclusion@#Sandblasting cannot significantly increase the bonding strength between zirconia and veneering porcelain. Veneering with a thin layer of porcelain powder as the bond coating has no obvious effect on the bonding strength. Sandblasting and veneering with a thin layer of porcelain powder as a bond coating can significantly improve the bonding strength between zirconia and veneering porcelain.

Application of polymeric porcelain color-masking cast posts in the aesthetic repair of anterior teeth: a case report / 华西口腔医学杂志

Many patients with large-area tooth defect need cast post-core crown restoration. However, the color defect of the cast post-core will affect the final restorative result, especially that of the anterior teeth. A new technology of color masking by applying CERAMAGE polymeric porcelain to the cast metal post-core surface improves the color of a full-ceramic restoration of anterior teeth and may provide a new alternative for the aesthetic repair of anterior teeth with a large area of defective tooth.

Influência do material cerâmico, cimento e tipo de substrato na qualidade estética de restaurações indiretas / Influence of ceramic material, resin cement and type of substrate in the aesthetic quality of indirect restorations

O objetivo deste estudo foi avaliar a influência do material cerâmico, cimento e tipo de substrato na qualidade estética de restaurações indiretas. A pesquisa científica foi dividida em duas partes. Na primeira análise, a alteração de cor e luminosidade de restaurações cerâmicas à base de dissilicato de lítio (e.max CAD), monossilicato de lítio (Celtra Duo) e cerâmica híbrida (Vita-Enamic CAD) foram analisadas quando sobrepostas em diferentes substratos (esmalte bovino, metal e zircônia), após a aplicação de pastas de prova "try-in" e após a cimentação com diferentes tipos de cimentos resinosos (RelyX Veneer, Variolink Esthetic LC e RelyX Ultimate). As análises foram realizadas em espectrofotômetro de reflexão UVVisivel (n=6). Os resultados mostraram que o tipo de substrato influenciou de maneira mais significante a estabilidade de cor e luminosidade das cerâmicas, independente da cor e tipo de material de cimentação. No segundo projeto, o objetivo foi avaliar a alteração cromática e a transmitância de diferentes restauraçoes cerâmicas: dissilicato de lítio (e.max CAD), monossilicato de lítio (Celtra Duo) e cerâmica híbrida (Vita-Enamic CAD) em oito diferentes espessuras (0,3mm à 2,0mm), com variação da potência do fotopolimerizador (1000mW/cm2 e 3200mW/cm2 ) e submetidos ao envelhecimento UV. As análises da alteração cromática foram realizadas em espectrofotômetro de reflexão UV-Visivel (n=8), enquanto que a análise da transmitância das cerâmicas foi realizada medindo-se a radiação de luz transmitida pelos diferentes materiais com um medidor de potência. Os resultados obtidos mostraram que os materiais cerâmicos estudados apresentam comportamentos diferentes quanto a estabilidade de cor das peças cimentadas. As diferentes espessuras influenciaram na cor do conjunto após o envelhecimento UV em todos os materiais estudados, sendo que a cerâmica de dissilicato de lítio e a cerâmica híbrida apresentaram influência nas espessuras mais delgadas. A transmitância dos materiais foi influenciada pela sua espessura e composição. A variação da potência do fotopolimerizador não influenciou na estabilidade de cor de todos os materiais analisados nas diferentes espessuras(AU)

The aim of this study was to evaluate the influence of ceramic material, resin cement and type of substrate in the aesthetic quality of indirect restorations. The research was divided into two chapters. In the first analysis, the color difference and luminosity of lithium disilicate (e.max CAD), zirconia-reinforced lithium silicate (Celtra Duo) and polymer infiltrated ceramic network (Vita Enamic CAD) were analyzed on different substrates (bovine enamel, metal and zirconia), after try-in pastes placed between the ceramics and substrates and after luting with different resin cements (RelyX Veneer, Variolink Esthetic LC e RelyX Ultimate) (n=6). The results showed that the type of substrate had more influence on the color stability and luminosity of ceramics, independent of the color and resin cement used. In the second study, the aim was to evaluate the color difference and transmittance of different ceramic restorations: lithium disilicate (e.max CAD), zirconia-reinforced lithium silicate (Celtra Duo) and polymer infiltrated ceramic network (Vita Enamic CAD) in eight thickness (0.3mm to 2.0mm), using light-emitting diode Valo Cordless (Standard and Xtra power modes) submitted to UV aging (n=8). The transmittance was done measuring the light transmitted through the materials with a power meter. The results showed that the ceramic materials showed different behavior in the color stability, especially for the thinner lithium disilicate and polymer infiltrated ceramic network materials. The transmittance was influenced by the thickness and composition of the materials. The variation in the power intensity of the lightemitting diode did not influence the color stability of the materials, independent of its thickness(AU)

In-vitro efficacy of two spectrophotometer-based shade matching systems for color matching of ceramics after artificial accelerated aging / Eficácia in vitro de dois espectrofotômetros baseados em escalas de cor para avaliação de cor de cerâmicas após envelhecimento artificial acelerado

Objective: The objective of the present in-vitro study was to verify the efficacy of two spectrophotometer-based shade matching systems for color matching of ceramics after artificial accelerated aging (AAA). Material and Methods: The ceramics used were porcelain laminated veneers. Seventy standard-shaped discs (thickness x diameter: 0.5 mm x 10 mm) of B1 shades were used. Based upon the type of resin cement used, the specimens were divided into seven groups (10/group). The following light-cured cements were used: RelyX-Veneer (L-RV), Variolink-Veneer (L-VV), and Variolink-Esthetic (L-VE). The dual-cured cements were: RelyX Ultimate (D-RU), RelyX-Unicem (D-RC), and Variolink-Esthetics DC (D-VE). The control group consisted of ceramic only. All specimens were thermocycled in water for 3,500 cycles between 5 oC -55 oC, with dwell times of 30 s in each bath and a transfer time of 10 s between baths. All specimens were thermocycled in water for 3,500 cycles between 5 oC and 55 oC, and color measurement was done using the VITA Easyshade and ColorEye spectrophotometers. Baseline color reading was performed 24-hours after cementation. Differences in color (DE) of EasyShade and ColorEye before and after AAA were determined and compared statistically. Group comparisons were done using the paired t-tests. Level of significance was set at P< 0.05. Results: The mean differences in color (ΔE) values obtained from EasyShade spectrophotometer for light- and dual-cured cements, were 0.843±0.89 (L-RV ), 4.11±0.69 (L-VV) and 0.833±0.47 (L-VE); and 2.22±0.64 (D-RU), 3.37±0.83 (D-RC) and 0.38±0.92 (D-VE), respectively. The mean differences in color (ΔE) values obtained from ColorEye spectrophotometer for light- and dual-cured cements, were 0.68±0.86 (L-RV ), 4.55±0.83 (L-VV) and 2.68±0.26 (L-VE); and 2.06±0.84 (D-RU), 1.8±1.08 (D-RC) and 0.96±0.71 (D-VE), respectively. There was no significant difference in the mean DE values among the groups. Conclusion: The VITA Easyshade and ColorEye shade matching systems are comparable in terms of their efficacy for color matching of cerammics after AAA.(AU)

Objetivos: O objetivo do presente estudo in vitro foi verificar a eficácia de dois espectrofotômetros baseados em escalas de cor para avaliação de cor de cerâmicas após envelhecimento artificial acelerado (EAA). Material e Métodos: As cerâmicas utilizadas foram laminados cerâmicos. Foram usados setenta discos de formato padrão (0,5mm de espessura x 10 mm de diâmetro) de tonalidades B1. Com base no tipo de cimento resinoso utilizado, os corpos-de-prova foram divididos em sete grupos (10 / grupo). Foram utilizados os seguintes cimentos fotopolimerizáveis: RelyX-Veneer (L-RV), Variolink-Veneer (L-VV) e Variolink-Esthetic (L-VE). Os cimentos de cura dual foram: RelyX Ultimate (D-RU), RelyX-Unicem (D-RC) e Variolink-Esthetics DC (D-VE). O grupo controle consistia apenas de cerâmica. Todos os corpos-de-prova foram termociclados em água por 3.500 ciclos entre 5oC-55oC, com tempos de permanência de 30s em cada banho e um tempo de transferência de 10s entre os banhos. A medição da cor foi feita usando os espectrofotômetros VITA Easyshade e ColorEye. A leitura da cor inicial foi realizada 24 horas após a cimentação. As diferenças na cor (ΔE) do EasyShade e ColorEye antes e depois do EAA foram determinadas e comparadas estatisticamente. As comparações dos grupos foram feitas usando o teste t pareados. O nível de significância foi estabelecido em p <0,05. Resultados: os valores médios de diferenças na cor (ΔE) obtidos no espectrofotômetro EasyShade para cimentos fotopolimerizáveis e duais foram de 0,843 ± 0,89 (L-RV), 4,11 ± 0,69 (L-VV) e 0,833 ± 0,47 (L-VE ); e 2,22 ± 0,64 (D-RU), 3,37 ± 0,83 (D-RC) e 0,38 ± 0,92 (D-VE), respectivamente. os valores médios de diferenças na cor (ΔE) obtidos no espectrofotômetro ColorEye para cimentos fotopolimerizáveis e duais foram de 0,68 ± 0,86 (L-RV), 4,55 ± 0,83 (L-VV) e 2,68 ± 0,26 (L-VE); e 2,06 ± 0,84 (D-RU), 1,8 ± 1,08 (D-RC) e 0,96 ± 0,71 (D-VE), respectivamente. Não houve diferença significativa nos valores médios de ΔE entre os grupos. Conclusão: Os sistemas de combinação de cores VITA Easyshade e ColorEye são comparáveis em termos de eficácia para avaliação de cores de cerâmicas após EAA. (AU)

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.