The Effect of Colloidal Silica and Glaze Coatings on the Adhesion of Zirconia with Various Ytrria Concentration.

PURPOSE: This study evaluated the effect of coating traditional and translucent Y-TZP with an industrial nanometric colloidal silica or glaze before or after sintering on the adhesion of zirconia with various ytrria concentration. MATERIALS AND METHODS: Specimens of Y-TZP with 3% and 5% yttria were subdivided into 5 groups (n=10), according to the coating applied and moment of application (before or after Y-TZP sintering): Control (no coating), Colloidal Silica/Sintering, Sintering/Colloidal Silica, Glaze/Sintering, Sintering/ Glaze. Lithium disilicate (LD) was used as positive control. Except for Y-TZP controls, groups were conditioned with silane before cementation with a self-adhesive resin cement. After 24 hours, the shear bond strength and failure analysis were performed. Also, analysis of specimens' surface was accomplished with SEM-EDX. Kruskal-Wallis and Dunn tests were applied to analyze differences between groups (p⟨0.05). RESULTS: Overall, the worst and best values of shear bond strength test were control and glaze after sintering groups. Different morphological and chemical aspects were observed in SEM-EDX analysis. CONCLUSIONS: Coating Y-TZP with colloidal silica showed unsatisfactory results. In 3Y-TZP, the surface treatment associated with the best adhesion values was the application of glaze after zirconia sintering. However, in 5Y-TZP, glaze application can be performed before or after the zirconia sintering to optimize clinical steps.

Influence of thickness and degree of opacity of lithium disilicate on the degree of conversion and bond strength of resin cements.

The aim of this study was to evaluate the influence of various opacities and thicknesses of lithium disilicate on the degree of conversion (DC) of two resin cements and on their bond strength (BS) to the ceramic. Two hundred and forty ceramic samples of lithium disilicate with high translucency (HT), low translucency (LT), and medium opacity (MO) were obtained from IPS e. max CAD in five different thicknesses. Light-cured and dual-cured resin cements were used for DC (n = 9) and BS (n = 8). Cement samples were light-cured under ceramic samples and analyzed using a Raman confocal spectrometer to determine the DC. For BS, resin cement cylinders were fabricated using ceramic samples which were thsen subjected to a microshear bond strength test. The mean values were provided for statistical analysis. The increase in thickness resulted in a decrease in DC for both cements under all experimental conditions, but only affected the BS of the light-cured cement for the MO ceramic. Comparing the opacities, the most translucent ceramics with particular thicknesses exhibited higher DC values than the less translucent ceramics. The LT and MO ceramics with certain thicknesses exhibited the highest BS values than the HT. The dual-cured cement generally showed highest values in both analyses than the light-cured cement. A thicker and more opaque ceramic material can reduce the DC of the cement. The BS decreases with the increasing thickness of the more-opaque ceramics.

An Innovative 3D Printed Tooth Reduction Guide for Precise Dental Ceramic Veneers.

Tooth reduction guides allow clinicians to obtain the ideal space required for ceramic restorations. This case report describes a novel design (CAD) for an additive computer-aided manufactured (a-CAM) tooth reduction guide with channels that permitted access for the preparation and evaluation of the reduction with the same guide. The guide features innovative vertical and horizontal channels that permit comprehensive access for preparation and evaluation of the reduction with a periodontal probe, ensuring uniform tooth reduction and avoiding overpreparation. This approach was successfully applied to a female patient with non-carious lesions and white spot lesions, resulting in minimally invasive tooth preparations and hand-crafted laminate veneer restorations that met the patient's aesthetic demands while preserving tooth structure. Compared to traditional silicone reduction guides, this novel design offers greater flexibility, enabling clinicians to evaluate tooth reduction in all directions and providing a more comprehensive assessment. Overall, this 3D printed tooth reduction guide represents a significant advancement in dental restoration technology, offering clinicians a useful tool for achieving optimal outcomes with minimal tooth reduction. Future work is warranted to compare tooth reductions and preparation time for this guide to other 3D printed guides.

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.

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)

Enamel Wear of Antagonist Tooth Caused by Dental Ceramics: Systematic Review and Meta-Analysis.

BACKGROUND: This systematic review and meta-analysis aimed to evaluate the wear of the antagonist tooth in ceramic restorations. MATERIAL AND METHODS: This study was carried out based on Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) recommendations; it was also registered in PROSPERO (register number: CRD42022316252). Three databases were consulted in the literature search, Embase, Scopus, and Web of Science. The citation searching was conducted by two researchers independently. The clinical studies that evaluated wear in antagonist teeth concerning ceramic restoration were included. Twelve articles were selected after eliminating duplicates ones and applying the inclusion criteria, and two were chosen through citation. Fourteen articles were considered for the qualitative and quantitative analysis (meta-regression and meta-analysis). RESULTS: The mean linear wear of the antagonist tooth in relation to feldspathic was 8.914 µm, for lithium disilicate it was 0.018 µm, and for zirconia it was 0.257 µm. The mean volumetric wear of the antagonist tooth in relation to feldspathic was 0.273 mm3, for hybrid ceramic it was 0.030 mm3, for lithium disilicate it was 0.018 mm3, and for zirconia it was 0.014 mm3. The mean natural tooth wear was 0.7974 µm per month. Tooth wear caused by zirconia at six months was 31.755 µm, at 12 months it was 24.648 µm, and at 24 months it was 20.662 µm. CONCLUSIONS: Feldspathic produces greater wear of the antagonist tooth from ceramic restorations linearly and volumetrically. In addition, zirconia generates the least wear that will decrease over time, and it will be equal to or less than the natural wear in the tooth.

Two-Year Survival of Ceramic Endocrowns and Partial Coverage Ceramic Restorations with Fiber Post: A 2-Year Double-Blind Randomized Clinical Trial.

PURPOSE: This double-blind randomized clinical trial (RCT) aimed to evaluate the 2-year survival rates of endocrowns and partial coverage ceramic restorations (PCCR) with fiber posts. MATERIAL AND METHODS: Forty (40) participants fulfilled the elegibility criteria, and they were randomly allocated in 2 groups: Endocrown or PCCR+post. The survival rates were assessed based on USPHS modified and radiographic examinations. A Chi-square test was used to assess the distribution of characteristics between groups. Kaplan-Meier and Log-rank tests were used to estimate the survival rate. To evaluate the association between survival of the restorations and the explanatory variables, the Multivariate Cox regression model was used. Only variables presenting p⟨0.20 were maintained in final model (α= 0.05). RESULTS: The highest 2-year survival rates were recorded for the Endocrown group (100%), whereas the PCCR+post group exhibited the lowest performance (66.7%). Most of the restoration failures was due to lack of marginal adaption, fracture, and recurrent caries. Cox Regression unadjusted analysis showed that only type of restoration presented a significant effect (p⟨0.20). Thus, adjusted analysis was not performed. CONCLUSIONS: Endocrowns appear to be a promising conservative restorative option and to be feasible and reliable approach restoring endodontically.

Fatigue behavior and stress distribution of molars restored with MOD inlays with and without deep margin elevation.

OBJECTIVES: This study evaluated the effect of deep margin elevation (DME) and restorative materials (leucite-reinforced glass-ceramics [C] vs. indirect resin composite [R]) on the fatigue behavior and stress distribution of maxillary molars with 2-mm deep proximal margins restored with MOD inlay. METHODS: Fifty-two extracted human third molars were randomly assigned into four groups (n = 13): C; DME + C; R; and DME + R. Inlays were fabricated in CAD-CAM and bonded to all teeth. The fatigue behavior was assessed with the stepwise stress test (10,000 cycles/step; step = 50 N; 20 Hz; initial load = 200 N). Fatigue failure loads and the number of cycles were analyzed with 2-way ANOVA and Tukey's test (p < 0.05) and Kaplan-Meier survival plots. The stress distribution was assessed with finite element analysis. The models were considered isotropic, linear, and homogeneous, and presented bonded contacts. A tripod axial load (400 N) was applied to the occlusal surface. The stress distribution was analyzed with the maximum principal stress criterion. RESULTS: For fatigue, there was no difference for DME factor (p > 0.05). For the material factor, the load and number of cycles for failure were statistically higher in the R groups (p < 0.05). The finite element analysis showed that resin composite inlays concentrated more stress in the tooth structure, while ceramic inlays concentrated more stress in the restoration. Non-reparable failures were more frequent in the resin composite inlays groups. CONCLUSIONS: DME was not negative for fatigue and biomechanical behaviors. Resin composite inlays were more resistant to the fatigue test, although the failure mode was more aggressive. CLINICAL SIGNIFICANCE: DME does not impair mechanical behavior. Resin composite inlays failed at higher loads but with a more aggressive failure mode.

Influência da espessura de restaurações cerâmicas a base de dissilicato de lítio para reabilitação oclusal de dentes posteriores: revisão de literatura / Influence of the thickness of lithium disilicate-based ceramic restorations for occlusal rehabilitation of posterior teeth: literature review

Reabilitações estéticas e funcionais são tratamentos realizados com bastante frequência na clínica diária do Cirurgião Dentista. Para tais intervenções existem diversos materiais citados na literatura, dentre eles, amálgama, ligas metálicas, resinas compostas e cerâmicas odontológicas. As cerâmicas apresentam inúmeras vantagens que integram estética e resistência, além de adesão aos tecidos dentários, todavia é alvo de uma vasta discussão a respeito de sua resistência mecânica quando se trata de trabalhos minimamente invasivos. A utilização das restaurações cerâmicas em dentes anteriores, submetidos a estresse mecânico reduzido, quando em condições oclusais satisfatórias, é vastamente citada na literatura, inclusive em espessuras extremamente conservadoras. Entretanto, quando se trata de dentes posteriores, onde as cargas oclusais são aumentadas, a espessura torna-se fator preponderante na utilização de tais materiais. Para esclarecer tais dúvidas, o presente estudo tem como objetivo realizar uma revisão da literatura a respeito da influência da espessura das cerâmicas a base de dissilicato de lítio em dentes posteriores na resistência a fratura de tais restaurações. Foi realizado levantamento bibliográfico de artigos publicados nas bases de dados PubMed, Lilacs, Medline, Scielo e Portal de Periódicos CAPES nos últimos 10 anos e, após a leitura dos resumos, selecionados os artigos presentes nesse trabalho. Conclui-se que cerâmicas a base de dissilicato de lítio de espessuras reduzidas devem ser utilizadas em dentes posteriores com cautela, haja vista a importância do equilíbrio oclusal e dos possíveis hábitos parafuncionais muito frequentes nos nossos pacientes.

Aesthetic and functional rehabilitations are treatments performed quite frequently in the daily clinic of the Dental Surgeon. For such interventions there are several materials cited in the literature, among them, amalgam, metal alloys, composite resins and dental ceramics. Ceramics have numerous advantages that integrate aesthetics and resistance, in addition to adhesion to dental tissues, however, it is the subject of a vast discussion regarding their mechanical resistance when it comes to minimally invasive works. The use of ceramic restorations in anterior teeth, submitted to reduced mechanical stress, when in satisfactory occlusal conditions, is widely cited in the literature, including in extremely conservative thicknesses. However, when it comes to posterior teeth, where occlusal loads are increased, thickness becomes a preponderant factor in the use of such materials. To clarify these doubts, the present study aims to review the literature regarding the influence of the thickness of lithium disilicate ceramics in posterior teeth on the fracture resistance of such restorations. A bibliographic survey of articles published in PubMed, Lilacs, Medline, Scielo and Portal de Periódicos CAPES in the last 10 years was carried out and, after reading the abstracts, the articles present in this work were selected. It is concluded that reduced thickness lithium disilicate ceramics should be used in posterior teeth with caution, given the importance of occlusal balance and possible parafunctional habits that are very common in our patients.

Avaliação da resistência de união e comportamento em fadiga de laminados cerâmicos recimentados após remoção com laser Er: YAG / Evaluation of bond strength and fatigue behavior of rebonding ceramic laminates after removal with Er: YAG laser

Este trabalho teve como finalidade avaliar a resistência de união adesiva e o comportamento em fadiga de laminados cerâmicos recimentados após sua remoção utilizando laser Er:YAG. 62 amostras foram divididas em dois grupos: controle (C), e Er:YAG (L). Incisivos centrais bovinos (N=62), foram fixados com resina acrílica no interior de tubos de PVC, com a face vestibular do esmalte exposta. Estas foram polidas, em máquina de polimento semiautomática com lixas de granulação 600, 800, 1200 e 2500 para obtenção de uma superfície plana. Discos de cerâmica vítrea reforçada por cristais de leucita (Empress CAD, Ivoclar Vivadent) foram confeccionados em duas dimensões, 10 mm x 1 mm destinados ao teste de fadiga (n=30), e 3 mm x 1 mm para o teste de resistência de união por cisalhamento (n=32). Os discos foram polidos em máquina de polimento semiautomática com lixas de granulação 600, 800, 1200 e 2500 e cimentados sob as superfícies de esmalte, utilizando cimento resinoso fotopolimerizável (Variolink Esthetic LC, Ivoclar Vivadent). Os conjuntos obtidos foram mantidos em estufa a 37°C por 7 dias. As amostras dos grupos Controle passaram pelos testes de cisalhamento e fadiga logo após este período. As dos grupos Er:YAG, foram submetidas a aplicação do laser (3.6W - 18 Hz x 200 mJ - 2940 nm) sobre a superfície cerâmica, a fim de promover seu descolamento. Em seguida, as superfícies foram submetidas ao processo de limpeza adequado, e recimentadas sob o mesmo protocolo anterior. Para o teste de cisalhamento foi utilizado um dispositivo em forma de faca, com célula de carga de 1000 kgf (1 mm/min) e a análise estatística obtida através dos testes ANOVA e Tukey (95%). Para a classificação dos modos de falha, as amostras foram observadas em estereomicroscópio óptico. A análise do comportamento em fadiga se deu através do método Stepwise stress, com carga inicial de 300 N (5.000 ciclos), steps incrementais de 100 a 700 N (10.000 ciclos/step), seguido de steps de 50 N (10.000 ciclos/step). Para a análise estatística, os testes Kaplan-Meier e Mantel-Cox, seguidos da comparação múltipla aos pares (5%), foram empregados. Os dados obtidos no teste de cisalhamento demonstraram não haver significância estatística para o fator laser (p=0.444), porém, no fator envelhecimento o valor foi significativamente menor (p=0.031). As amostras do grupo laser apresentaram valores significativamente menores em relação ao teste de resistência a fadiga quando comparadas as do grupo controle (p=0,007), que apresentou maiores valores de falha em carga (FFL) e número de ciclos (CFF). Entretanto, o módulo de Weibull para FFL e CCL não foi estatisticamente significante entre os grupos. Com base nos resultados obtidos pode-se concluir que, a resistência de união não foi afetada enquanto sobreviência em fadiga foi significativamente reduzida em laminados cerâmicos recimentados após exposição ao laser Er:YAG (AU)

This work aimed to evaluate the adhesive bond strength and fatigue behavior of cemented ceramic laminates after their removal using Er:YAG laser. 62 samples were divided into two groups: control (C), and Er:YAG (L). Bovine central incisors (N=62) were fixed with acrylic resin inside of PVC tubes, with the buccal surface of the enamel exposed. These were polished in a semi-automatic polishing machine with #600, 800, 1200 and 2500 grit sandpaper to obtain a flat and polished surface. Discs of a leucite reinforced glass ceramic (Empress CAD, Ivoclar Vivadent) were made in two dimensions, 10 mm x 1 mm for the fatigue test (n=30), and 3 mm x 1 mm for the shear bond strength test (n=32). The discs were polished in a semiautomatic polishing machine with #600, 800, 1200 and 2500 grit sandpaper and cemented on the enamel surfaces using a light-curing resin cement (Variolink Esthetic LC, Ivoclar Vivadent). The sets obtained were stored at 37°C for 7 days. The samples from the Control groups underwent the shear and fatigue tests shortly after this period. The Er:YAG groups were submitted to laser application (3.6W - 18 Hz x 200 mJ - 2940 nm) on the ceramic surface, in order to promote its debonding. Then, the surfaces were subjected to the appropriate cleaning process, and re-cemented following the same previous protocol. For the shear bond strength test, a knifeshaped device was used, with a load cell of 1000 kgf (1 mm/min) and the statistical analysis was obtained through the ANOVA and Tukey tests (95%). For the classification of failure modes, the samples were observed in an optical stereomicroscope. The analysis of fatigue behavior was performed using the Stepwise stress method, with an initial load of 300 N (5,000 cycles), incremental steps from 100 to 700 N (10,000 cycles/step), followed by 50 N steps (10,000 cycles/step). For statistical analysis, the Kaplan-Meier and Mantel-Cox tests, followed by multiple pairwise comparisons (5%), were used. The data obtained in the shear bond strength test showed no statistical significance for the laser factor (p=0.444), however, the aging factor the value was significantly lower (p=0.031). In the fatigue test, laser group showed significantly lower values in relation to the control group (p=0.007), which showed higher values of failure under load (FFL) and number of cycles (CFF). However, the Weibull modulus for FFL and CCL was not statistically significant between groups. Based on the results obtained, it can be concluded that the bond strength was not affected while fatigue survival was significantly reduced in ceramic laminates re-cemented after exposure to Er:YAG laser (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.

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).

Ceramic Laminate Veneers Luted with Preheated Resin Composite: A 10-Year Clinical Report.

Resin cement and preheated restorative resin composite may be used for luting laminate veneers. The main advantage of resin composite is increased wear resistance, which could lead to better marginal performance in long term. This article reports a clinical treatment with feldspar laminate veneers luted to the maxillary teeth with preheated resin composite in a private practice. Case was finalized in May 2009 and followed by 10 years. Excellent clinical service and remarkable long-lasting marginal integrity were observed after 123 months. Scanning electron microscopy analysis showed no wear, gaps, or ditching at the margins. Restorative margins showed a smooth transition between ceramic and tooth with no signs of degradation. Preheated resin composite for luting ceramic laminate veneers may be considered an excellent clinical option.

Incorporation of Hybrid Nanomaterial in Dental Porcelains: Antimicrobial, Chemical, and Mechanical Properties.

Biofilm formation on biomaterials is a challenge in the health area. Antimicrobial substances based on nanomaterials have been proposed to solve this problem. The aim was to incorporate nanostructured silver vanadate decorated with silver nanoparticles (ß-AgVO3) into dental porcelains (IPS Inline and Ex-3 Noritake), at concentrations of 2.5% and 5%, and evaluate the surface characteristics (by SEM/EDS), antimicrobial activity (against Streptococcus mutans, Streptococcus sobrinus, Aggregatibacter actinomycetemcomitans, and Pseudomonas aeruginosa), silver (Ag+) and vanadium (V4+/V5+) ions release, and mechanical properties (microhardness, roughness, and fracture toughness). The ß-AgVO3 incorporation did not alter the porcelain's components, reduced the S. mutans, S. sobrinus and A. actinomycetemcomitans viability, increased the fracture toughness of IPS Inline, the roughness for all groups, and did not affect the microhardness of the 5% group. Among all groups, IPS Inline 5% released more Ag+, and Ex-3 Noritake 2.5% released more V4+/V5+. It was concluded that the incorporation of ß-AgVO3 into dental porcelains promoted antimicrobial activity against S. mutans, S. sobrinus, and A. actinomycetemcomitans (preventing biofilm formation), caused a higher release of vanadium than silver ions, and an adequate mechanical behavior was observed. However, the incorporation of ß-AgVO3 did not reduce P. aeruginosa viability and increased the surface roughness of dental porcelains.

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)

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.

Influence of the Application and Light-Curing of Bonding Adhesives Inside Lithium Disilicate Ceramic Crowns.

This in vitro study evaluated the effect of the application and previous photoactivation of bonding adhesives in lithium disilicate ceramics. This was achieved by analyzing the bond strength of the cement-ceramic interface, nanohardness and elastic modulus of bonding adhesives and resin cements. The bonding adhesives used were Scotchbond Multi-Purpose (SBMP); Scotchbond Multi-Purpose light-cured (SBMP+LC); Single Bond 2 (SB2); Single Bond 2 light-cured (SB2+LC); Single Bond Universal (SBU) and Single Bond Universal light-cured (SBU+LC). After luting the ceramic in composite resin blocks, all specimens were subjected to 10,000 thermocycles. Sticks were obtained for the microtensile bonding strength test and the nanohardness and elastic modulus of the bonding adhesive and resin cements. Data were submitted to one-way ANOVA and Fishers tests (α =0.05). The results indicated that the bonding strength and mechanical properties were influenced by the interaction of the bonding adhesive and resin cement. For the mechanical properties analyzed, no statistically significant differences were observed between the groups. Single Bond Universal was the only system that was effective with or without previous light activation. For the other adhesive systems, Scotchbond Multi- Purpose and Single Bond 2, the previous light activation was necessary to optimize the bonding strength of the adhesive interface.

Avaliação da taxa de sucesso e de sobrevivência de restaurações cerâmicas realizadas com o sistema CAD-CAM CEREC após 5 anos: projeto piloto / Evaluation of the success rate and survival rate of ceramic restorations performed with the CAD-CAM CEREC system after 5 years: pilot project

O presente estudo teve como objetivo fazer uma avaliação da taxa de sucesso e sobrevivência de restaurações indiretas, realizadas pelo sistema CEREC AC Bluecam após 5 anos. Trata-se de um estudo piloto, com a inclusão de 102 pacientes e um total de 113 restaurações. As restaurações foram feitas a partir de blocos pré-fabricados de cerâmica feldspática (CEREC Blocs). Os prontuários de todos os pacientes foram avaliados. Um total de 36 restaurações foram avaliadas clinicamente usando-se os critérios USPHS e FDI modificados. Além disso, foi criada uma ficha clínica com um questionário abrangendo uma série de informações clínicas relevantes. A taxa de satisfação do paciente foi avaliada através da escala analógica visual. A taxa de sucesso e sobrevivência para as restaurações avaliadas dentro do critério adotado foi de 80,6% e 0,9% respectivamente. Um total de 19 (18,5%) de falhas foi encontrado. A principal razão das falhas foi a fratura da cerâmica, sendo significativamente maior para dentes não vitais. Restaurações indiretas feitas a partir do sistema CEREC AC tiveram um sucesso clínico considerável com taxa de sucesso de 80,6% após 5 anos. A taxa de satisfação dos pacientes frente a esse tipo de tratamento foi bem alta para todos os parâmetros avaliados, chegando a uma média de 96%(AU)

The present study aimed to evaluate the success and survival rate of indirect restorations performed by the CEREC AC Bluecam system after 5 years. This is a pilot study with the inclusion of 102 patients and a total of 113 restorations. The restorations were made from prefabricated feldspar ceramic blocks (CEREC Blocs). The medical records of all patients were evaluated. A total of 36 restorations were clinically evaluated using the modified USPHS and FDI criteria. In addition, a clinical record was created with a questionnaire covering a range of relevant clinical information. Patients' satisfaction rate was assessed using the visual analogue scale. The success and survival rate for the restorations evaluated according to the adopted criteria was 80.6% and 0.9% respectively. A total of 19 (18.5%) failures were found. The main reason for the failures was ceramic fracture, being significantly higher for non vital teeth. Indirect restorations made from the CEREC AC system have had considerable clinical success with a success rate of 80.6% after 5 years. The patients' satisfaction rate regarding this type of treatment was very high for all parameters evaluated, reaching an average of 96%(AU)