Fit of metal-ceramic crowns: effect of coping fabrication method and veneering ceramic application

Aim: To evaluate the influence of cobalt-chromium (Co-Cr) coping fabrication methods and ceramic application on the marginal and internal fit of metal-ceramic crowns. Methods: Co-Cr copings for metal-ceramic crowns were prepared by lost wax casting or CAD-CAM machining of sintered blocks. The fit was analyzed using the silicone replica technique at four assessment points: marginal gap (MG), axial wall (AW), axio-occlusal (AO) angle, and central occlusal (CO) wall. After the initial analysis, the copings were ceramic-veneered with the layering technique, and the fit was again determined. Data were statistically analyzed by paired and unpaired Student's-t test (α=0.05). Results: Marginal and internal fit before ceramic application according to the coping manufacturing method showed significant differences only at CO (p < 0.001), with milled copings (137.98±16.71 µm) showing higher gap values than cast copings (112.86±8.57 µm). For cast copings, there were significant differences at MG (before 109.13±8.79 µm; after 102.78±7.18 µm) and CO (before 112.86±8.57 µm; after 104.07±10.63 µm) when comparing the fit before and after ceramic firing. For milled copings, there was significant difference only at AO (before 116.39±9.64 µm; after 108.54±9.26 µm). Conclusion: This study demonstrated that the coping fabrication method influenced the internal fit. Ceramic firing maintained or improved the fit of the metal-ceramic crowns. The marginal discrepancy of all restorations, before and after ceramic firing, can be considered clinically acceptable

Metal Alloys in Dentistry: An Outdated Material or Required for Oral Rehabilitation?

ABSTRACT: The present study aims to describe through a literature review, the main types of noble and non-noble alloys in dentistry looking to identify the adhesion mechanisms, compositions and mechanical properties, and its applicability as a rehabilitation resource nowadays. A bibliographic search was conducted in the main health databases PUBMED (www.pubmed.gov) and Scholar Google (www.scholar.google.com.br), in which studies published from 1971 to 2021 were collected. Laboratory studies, case reports, systematic and literature reviews, which were developed in living individuals. Articles that did not deal with metal alloys and its use in dentistry were excluded. Through the review, it was possible to ver ify that all works presented the metal alloys and their main properties, indicating that they are divided into three main types: hi gh noble alloys, noble alloys and base metal alloys differing in their levels of constituent noble metals. Several alloys and meta ls are available for the dental market each presenting advantages and disadvantages, mainly based on its specific composition.Continuous research and development are resulting in the production of new technologies and products, giving dental surgeons even more options in the design and manufacture of restorations using metal alloys and understanding that these resources will still be viable alternatives in oral rehabilitations. However, further studies on metal alloys are needed to better understand this subject.

RESUMEN: El presente trabajo tuvo como objetivo describir a través de una revisión de la literatura, los principales tipos de aleaciones nobles y no nobles utilizados en odontología buscando identificar los mecanismos de adhesión, composiciones y propiedades mecánicas, así como reflejar su aplicabilidad como recurso rehabilitador en la actualidad. Realizamos una búsqueda bibliográfica em las principales bases de datos de salud PUBMED (www.pubmed.gov) y Scholar Google (www.scholar.google.com.br), en la que se recopilaron estudios publicados desde 1971 hasta 2021. Estudios de laboratorio, informes de casos, revisiones sistemáticas y bibliográficas, que se desarrollaron en individuos vivos. Sin embargo, se excluyeron los artículos que no trataban sobre aleaciones metálicas y su uso en odontología. Se pudo observar que todos los trabajos presentaban las aleaciones metálicas y sus principales propiedades indicando que se estas dividen en tres tipos principales: aleaciones altamente nobles, aleaciones nobles y aleaciones de metales base que difierenen sus niveles de metales nobles constituyentes. Hay varias aleaciones y metales disponibles para el mercado dental, cada uno presenta ventajas y desventajas, principalmente en función de su composición específica. La investigación y el desarrollo continuo están dando como resultado la producción de nuevas tecnologías y productos, brindando a los cirujanos dentistas aún más opciones en el diseño y fabricación de las restauraciones, utilizando aleaciones metálicas y, permite concluir que estos recursos seguirán siendo alternativas viables en los tratamientos de rehabilitación. Sin embargo, se necesitan más estudios sobre el tema abordado en el trabajo, para una comprensión más profunda del tema.

Reabilitação com coroas metal free em dentes anteriores traumatizados e com rizogênese incompleta: relato de caso / Rehabilitation with metal free crowns in traumatized anterior teeth with incomplete rhizogenesis: case report

Objetivo: rizogênese incompleta refere-se a dentes permanentes em que não houve a formação completa do ápice radicular, ocasionando perda da vitalidade pulpar e, consequentemente, incapacidade da bainha epitelial de Hertwig para induzir a formação completa da raiz. Devido ao traumatismo e escurecimento dental, se faz necessário em certos casos a confecção de coroas em porcelana pura para reabilitar a paciente em estética e função. O presente trabalho tem como objetivo demonstrar um caso de reabilitação estética e funcional em dente com rizogênese incompleta, onde se consideraram as perdas estruturais e alteração de cor, para que seja possível estabelecer o tratamento mais adequado. Relato de caso: paciente de 16 anos, gênero feminino, atendida na Clínica de Odontologia de uma instituição privada, insatisfeita com a estética do seu dente devido ao escurecimento do elemento 21, pois quando tinha 5 anos o dente foi traumatizado juntamente com o elemento 11. O plano de tratamento adotado para ambos os elementos foi a confecção de peças protéticas em porcelana e cimentação. Considerações finais: esse caso demonstrou que a confecção de coroas estéticas em porcelana é considerada uma boa conduta na rotina clínica em casos de escurecimento dental, devolvendo estética e função para o paciente.(AU)

Objective: incomplete rhizogenesis refers to permanent teeth with incomplete formation of the root apex, causing loss of pulp vitality and the consequent inability of the Hertwig epithelial sheath to induce complete root formation. Due to dental trauma and darkening, some cases require the production of pure porcelain crowns to rehabilitate the aesthetics and function of patients. The present study aims to show a case of aesthetic and functional rehabilitation in a tooth with incomplete rhizogenesis, in which structural losses and color change were considered to establish the most appropriate treatment. Case report: a 16-year-old female patient treated at the Dental Clinic of a private institution. The patient was not satisfied with the aesthetics of her tooth due to the darkening of element 21, because at 5 years old the tooth was traumatized along with element 11. The treatment used for both elements was the production of prosthetic porcelain crowns and cementation. Final considerations: this case showed that the production of aesthetic porcelain crowns is considered a good conduct in the clinical routine in cases of tooth darkening, returning aesthetics and function to the patient.(AU)

Research progress in CoCr metal-ceramic alloy fabricated by selective laser melting / 中华口腔医学杂志

Cobalt-chromium alloys have been applied to dental porcelain fused to metal (PFM) restorations over the past decades owing to their excellent corrosion resistance, good biocompatibility and low price. The production of CoCr metal-ceramic restorations has always been based on traditional lost-wax casting techniques. However, in recent years, selective laser melting (SLM) is becoming more and more highly valued by dental laboratories and dental practitioners due to its individuation, precision and efficiency. This paper mainly reviews the recent researches on the production process of copings, microstructure, mechanical property, metal-ceramic bond strength, fit of copings, corrosion resistance and biocompatibility of SLM CoCr metal-ceramic alloy.

Clinical effect of zirconia all-ceramic crown on repairing the anterior teeth and its influence on the quality of life of patients / 中国基层医药

Objective To investigate the clinical effect of zirconia all -ceramic crown for anterior teeth restoration,and its influence on the quality of life .Methods Eighty-four patients with anterior teeth repair [4 cases were lost during the follow-up,and there were 80 cases (106 teeth)] were selected.According to different surgical methods,they were divided into control group (56 teeth) and study group (50 teeth).The control group used Ni Cr alloy porcelain crown,the study group used two zirconia all -ceramic crown.The patients were followed up for 1 year, the repair effect ,incidence rate of adverse reactions and quality of life score were compared between the two groups .Results After 1 year of crown restoration , the color, integrity, edge coloring in the study group were significantly better than those in the control group(all P<0.05).The incidence rate of adverse reactions such as gingivitis ,peri-odontitis,root fracture,allergies of the study group was 7.5%,which was significantly lower than 45.0%of the control group(χ2 =5.129,P<0.05).There were no statistically significant differences in quality of life scores between the two groups before repair(all P>0.05).The quality of life scores in the study group after repair were significantly higher than those in the control group (t=18.623,22.389,20.724,10.190,all P<0.05).Conclusion The clinical effect of zirconia all-ceramic crown for anterior teeth restoration is better .It can improve the aesthetic effect ,safety and quality of life score of patients .It is worthy of popularizing and application in clinic .

Comparison of the applicatied effect of two kinds of post core porcelain fused to metal crown for restoration of residual crown of first molar / 中国基层医药

Objective To compare the applicatied effect of two kinds of post core porcelain fused to metal crown for restoration of residual crown of first molar .Methods 52 patients with residual crowns of first molars (98 teeth) were selected.According to the random numerical table method ,they were divided into group A[post core crown of metal casting in 27 cases ( 49 teeth ) ] and group B [ post core crown of screw thread amalgam in 25 cases (49 teeth)].After a year of follow -up,the success rate of the two groups was compared .Results Metal casting core crown pile was broken at 0 in group A and at 3 in group B,the success rate of group A was 93.88％,and the success rate of group B was 79.59％,the difference was statistically significant between the two groups (χ2 =4.346, P<0.05).Conclusion The retention,resistance and durability of post core crown of metal casting is far superior to post core crown of screw thread amalgam ,and it is a more ideal repair method .

Dissilicato de lítio: como potencializar a tenacidade a fratura clinicamente? / Lithium disilicate: how to potentiate fracture toughness clinically?

As restaurações indiretas metalocerâmicas têm um largo tempo de acompanhamento clínico com alta taxa de sucesso. Contudo, a mudança na escala de valores dos conceitos estéticos e o apelo por um comportamento socioeconômico que transmita maior confiança e autoestima têm procurado substituir tais materiais. O grande problema da infraestrutura metálica é o chamado "sorriso metalocerâmico" que expõe a cinta metálica após recessão da margem gengival, constituindo-se fator indesejável. Visando contornar esse problema, aprimoramentos técnico-científicos têm procurado substitutos, tais como as coroas com ombros cerâmicos "colar-less"1,2, 3, até o aprimoramento de novos sistemas vitro-cerâmicos com aumento do conteúdo de cristais que visam impedir a propagação de trincas, aumentando a tenacidade dessas estruturas e melhorando sua resistência mecânica. Entre os novos sistemas cerâmicos, os que empregam o dissilicato de lítio voltaram a ser explorados pela gama de aplicações clínicas, principalmente nos fragmentos cerâmicos e lentes de contato tão em moda. Sendo a tenacidade à fratura componente importante na escolha do sistema cerâmico, este trabalho tem o objetivo de esclarecer os reais mecanismos envolvidos na escolha do dissilicato de lítio como opção clínica para a confecção de restaurações indiretas contemporâneas

The metal-ceramics indirect restorations have a square time of clinical attendance with high success rates. However, the change in the scale of values of aesthetic concepts and the appeal for a socioeconomic behavior that transmits larger trust and selfconfidence have been trying to substitute such materials. The great problem of the metallic infrastructure is the called "metal-ceramic smile" that exposes the metallic colar after gingival margin recession, being constituted undesirable factor. Aiming to outline that problem, technician-scientific improvements have been seeking substitutes such as: the crowns with ceramic shoulders "colar-less" 1, 2, 3, until the improvement of new systems glass-ceramics with increase of crystals content to impede cracks propagation, increasing the fracture toughness values of those structures and improving their mechanical resistance. Among new ceramic systems, those that use lithium disilicate were explored by the range of clinical applications again, mainly in ceramic fragments and dental veneers so in fashion. Being the fracture toughness to important component in the choice of ceramic system, this work has the objective to explain the real mechanisms involved in the choice lithium disilicate as clinical option to make contemporary indirect restorations

Degradação Adesiva de um Compósito Auto Aderente aos Substratos da Técnica Indireta / Bonding Degradation of a Self-Adhering Composite to Substrates used in Indirect Technique

O objetivo desse estudo foi avaliar a resistência de união - RU ao cisalhamento de um compósito fluido auto aderente em quatro substratos utilizados na técnica indireta, com uma semana e um ano de armazenamento em água destilada. Quarenta e oito amostras (5 mm largura / 15 mm comprimento / 2 mm espessura) foram preparadas em laboratório protético: 12 amostras do(a) cerômero Adoro/AD, cerâmica/leucita Empress Esthetic/EE, cerâmica/zircônia ZirCAD/ZI (Ivoclar Vivadent), mais a liga Fit Cast SB/ME (Talladium do Brasil), sendo as amostras divididas em dois grupos para cada período de tempo (uma semana e um ano). Dois compósitos fluidos (Controle / FF-Filtek Z350XT Flow / 3M ESPE e o auto aderente / DF-Dyad Flow / Kerr) foram unidos aos quatro substratos. Quatro matrizes Tygon foram posicionadas sobre as amostras, as quais foram preenchidas com os compósitos FF e DF (fotopolimerização 20s). As matrizes foram removidas para expor os corpos de prova (12 por grupo) e as amostras foram armazenadas em água destilada/ 37±2 °C por uma semana e um ano. Após estes períodos, cada amostra foi conectada a uma máquina de ensaios para realização dos ensaios de RU a uma velocidade de 1,0 mm/min, até a falha. Os resultados foram analisados por ANOVA e teste de Tukey (p<0,05). Nos ensaios de uma semana, os substratos leucita e metal apresentaram as maiores médias de RU para ambos os compósitos. Nos ensaios de um ano, os substratos não apresentaram diferença estatística nas médias de RU para ambos os compósitos, com exceção da zircônia que apresentou resultado nulo. Os valores médios de RU, no entanto, foram significativamente menores quando comparados com os resultados dos ensaios de uma semana.(AU)

The aim of this study was to evaluate the shear bond strength (SBS) of a self-adhering flowable composite on four substrates used in indirect technique, for a week and one year of storage in distilled water. Forty eight samples (5 mm wide / 15 mm length / 2 mm thick) were prepared at dental prosthetic laboratory: 12 samples of the ceromer Adoro/AD, leucite ceramic IPS Empress Esthetic/EE, zirconia ceramic ZirCAD/ZI (Ivoclar Vivadent) and the metal ceramic alloy Fit Cast SB/ME (Talladium do Brasil). Samples of each substrate were divided into two groups for each time (a week and one year). Two flowable composites (Control/FF-Filtek Z350 XT Flow/3M ESPE, and the self-adhering/DF-Dyad Flow/Kerr) were bonded to four substrates. Four Tygon tubing were positioned over each sample, which were filled in with the composites FF and DF, and visible light-cured for 20s. The tubings were removed to expose the specimens (12 per group) in format of cylinders, and the samples were stored in distilled water at 37 ± 2°C for one week and one year. After these periods, each sample was attached to testing machine and the specimens were submitted to the shear bond strength test at speed of 1.0mm/min, until failure. The results were analyzed by ANOVA and Tukey test (p<0.05). To one week tests, the substrates leucite and metal showed the highest SBS means, to both composites. For the one-year experiments, the substrates did not show differences in the SBS averages for both composites, except for zirconia that showed null result. However, the SBS averages were lower when compared to one week tests.(AU)

Masking ability of opaque thickness on layered metal-ceramics

This study evaluated the masking ability of two opaques applied in different thicknesses. Eighty NiCr metal discs 16 mm in diameter and 1.0 mm thick were prepared. The disks were divided into 8 groups (n = 10). Ceramic opaque in paste (groups 1 to 4) or powder (groups 5 to 8) presentations were applied. They were machined with aluminum oxide burs to the following thicknesses: G1 and G5 = 0.10 mm; G2 and G6 = 0.15 mm; G3 and G7 = 0.20 mm and G4 and G8 = 0.30 mm. Dentin ceramic 0.7 mm thick was applied over these discs, sintered and glazed according manufacturer’s instructions. Color was assessed with a Minolta CR10 spectrocolorimeter on the CIELab scale. Powder opaque had higher values on (L) and (ΔE) variables, and lower values on (a) and (b) variables compared to paste opaque. For opaque thickness, 0.10 mm had higher ΔE than all other thicknesses. L values were higher for 0.20 mm and 0.30 mm. Lowest and highest a* values were observed for 0.10 mm and 0.30 mm, respectively. No difference was observed for b* values. There were differences between paste and powder opaque types; 0.10 mm thickness behaves differently from the other thicknesses, with higher ΔE, while 0.15 mm does not differ statistically from thicker layers.

O objetivo deste estudo foi avaliar a capacidade de mascara mento de duas cerâmicas opacas para metalocerâmicas aplicadas em espessuras diferentes. Foram confeccionados 80 discos metálicos de NiCr (High Bond) com 16 mm de diâmetro e 1,0 mm de espessura. Os discos foram divididos em 8 grupos (n=10) e aplicadas as cerâmicas opacas (Noritake) em pasta (grupos de 1 a 4) e em pó (grupos de 5 a 8). Estas foram usinadas com pontas de óxido de alumínio até atingir as seguintes espessuras: G1 e G5 = 0,10 mm; G2 e G6 = 0,15 mm; G3 e G7 = 0,20 mm e G4 e G8 = 0,30mm de espessura. A cerâmica de dentina opaca foi aplicada (0,7 mm) e realizado o glazeamento. A cor foi avaliada com Espectrocolorímetro (Minolta CR10) e foi aplicada análise de variância com para p<5%. Resultados: O opaco em pó apresentou valores maiores estaticamente significantes nas variáveis (L*) e (ΔE), ocorrendo o inverso nas outras duas variáveis. Quanto à espessura de opaco, os valores podem ser agrupados da seguinte forma, segundo os testes complementares aplicados: variável (L*): (0,10 = 0,15) < (0,20 = 0,30); variável (a*): (0,10) < (0,15 = 0,20) < (0,30); variável (b*): não houveram diferenças estatisticamente significantes; variável (ΔE): (0,10)< (0,15 = 0,20 = 0,30). Conclui-se que houve diferença entre os tipos de opaco em pasta e em pó e que todas as espessuras testadas, exceto a de 0,10 mm, podem ser usadas sem alteração significativa da cor.

Bonding performance of a self-adhering flowable composite to indirect restorative materials

Introduction: Simplified restorative materials may be a logical next step for dental manufacturers. Objective: The aim of this study was to evaluate the shear bond strength of a self-adhering flowable composite to four substrates used in indirect technique. Material and methods: Twenty-four samples (5 mm wide, 15 mm length and 2 mm thick / six blocks each substrate) were prepared in the dental prosthetic laboratory. The following materials were used: ceromer (SR Adoro/AD, Ivoclar Vivadent), leucite ceramic (IPS Empress Esthetic/EE, Ivoclar Vivadent), zirconia ceramic (ZirCAD/ZI, Ivoclar Vivadent); metal ceramic alloy (Fit Cast SB/ME, Talladium do Brasil). Samples of each substrate were divided into two groups (n = 3). Two flowable composites (Control/FF - Filtek Z350 XT Flow/3M ESPE, and the self-adhering/DF - Dyad Flow/Kerr) were bonded to the four substrates. Four Tygon tubings were positioned over each sample, which were filled in with the composites FF and DF, and visible light-cured for 20 s. The tubings were removed to expose the specimens (12 per group) in format of cylinders and samples were stored in distilled water at 37±2°C for one week. After this period, each sample was attached to testing machine and the specimens were submitted to the shear bond strength test at speed of 1.0 mm/min, until failure. The results were analyzed by two-way ANOVA and Tukey test (p < 0.05). Results: The means (SD) were (in MPa): AD + FF = 34.4 ± 4.9; AD + DF = 28.2 ± 4.2; EE + FF = 29.7 ± 5.8; EE + DF = 32.3 ± 6.9; ZI + FF = 23.2 ± 5.4; ZI + DF = 8.5 ± 1.5; ME + FF = 28.9 ± 4.2; ME + DF = 31.7 ± 4.5. Conclusion: The efficacy of flowable composites is material-dependent. The self-adhering composite provided lower bond strength only to zirconia ceramic. Comparing with the control group, Dyad Flow showed lower bond strength to the ceromer and zirconia ceramic.

Prótese metalocerâmica associada à prótese metaloplástica implantossuportada em paciente desdentado total / Full maxillary, metal-ceramic implant-supported prosthesis against a complete, mandibular, acrylic implant-supported prosthesis: a case report

A utilização de diferentes métodos e materiais deve ser considerada durante o planejamento de próteses implantossuportadas. Complicações, como fraturas da base de resina acrílica, desgaste e fratura dos dentes, podem ocorrer com frequência, gerando a necessidade de um planejamento cuidadoso para cada paciente, o que pode tornar a seleção do tipo de tratamento mais complexa. Diante disso, este artigo descreve a reabilitação oral de um paciente totalmente edêntulo, portador de prótese tipo protocolo bimaxilar, que apresentava queixa estética, perda de dimensão vertical e fratura em dentes de resina acrílica do arco superior. Após o restabelecimento da dimensão vertical, realizou-se a substituição de suas próteses antigas por uma nova prótese tipo protocolo bimaxilar, sendo que a cerâmica foi utilizada como material de cobertura para o arco superior, e resina como material de cobertura para o arco inferior. Ao final do tratamento, o paciente recebeu placas oclusais lisas bimaxilares para proteger os dentes e implantes de possíveis hábitos parafuncionais. A forma como o tratamento foi conduzido permitiu uma resolução rápida e eficaz, com resultado estético e funcional muito favorável para o paciente.

The use of different methods and materials should be considered during the planning of implant-supported prostheses. Complications such as fractures of the acrylic resin base, wear and fracture of teeth can occur frequently, creating the need for careful planning for each patient, which can make the selection of the type of treatment more complex. Thus, this article describes the oral rehabilitation of a completely edentulous patient with bimaxillary fixed implant-supported prosthesis, with complaints on aesthetics, loss of vertical dimension and fracture of acrylic resin teeth of the upper arch. After the restoration of vertical dimension, his dentures were replaced with new bimaxillary implant-supported fixed prostheses, ceramic and acrylic resin were used as veneering material for maxilla and mandible, respectively. At the end of the treatment, the patient received bimaxillary flat occlusal splints to protect the teeth and implants of possible parafunctional habits. The approach for the treatment allowed a quick and effective resolution, with aesthetic and functional outcomes very favorable for the patient.

Clinical study of onlay treatment of cracked teeth with vital pulp / 重庆医学

Objective To investigate the effect of cobalt chromium alloy onlay on the direct repair of cracked vital pulp teeth with the resin compostie filling and porcelain-fused-to-metal (PFM ) crown repair as the control .Methods 201 cracked vital pulp teeth from 201 cases were randomly divided into 3 groups according to the clinical symptoms :mild discomfort at occlusion (group A) ,pain at occlusion accompanied with transient pain to cold or hot stimulation (group B) and pain at occlusion accompanied with continuous pain to cold or hot stimulation(group C) .The cracked teeth directly were restored by the resin composite filling ,cobalt chromium alloy onlay and PFM crown repair and the effective rate in each group was observed after 2-year follow up .Results The effective rate of the group A ,B and C were statistically significant different from each other (P<0 .05) .The effective rate of the co-balt chromium alloy onlay and the PFM crown was statistically significant higher than that of resin composite (P<0 .05) .Conclusion The direct repair with cobalt chromium alloy onlay is an effective repair method for the cracked vital pulp teeth with mild discomfort at occlusion and mild pain accompanied with transient pain to cold or hot stimulation .

A comparative study on the bond strength of porcelain to the millingable Pd-Ag alloy

PURPOSE: The porcelain fused to gold has been widely used as a restoration both with the natural esthetics of the porcelain and durability and marginal fit of metal casting. However, recently, due to the continuous rise in the price of gold, an interest towards materials to replace gold alloy is getting higher. This study compared the bond strength of porcelain to millingable palladium-silver (Pd-Ag) alloy, with that of 3 conventionally used metal-ceramic alloys. MATERIALS AND METHODS: Four types of metal-ceramic alloys, castable nonprecious nickel-chrome alloy, castable precious metal alloys containing 83% and 32% of gold, and millingable Pd-Ag alloy were used to make metal specimens (n=40). And porcelain was applied on the center area of metal specimen. Three-point bending test was performed with universal testing machine. The bond strength data were analyzed with a one-way ANOVA and post hoc Scheffe's tests (alpha=.05). RESULTS: The 3-point bending test showed the strongest (40.42 +/- 5.72 MPa) metal-ceramic bond in the nonprecious Ni-Cr alloy, followed by millingable Pd-Ag alloy (37.71 +/- 2.46 MPa), precious metal alloy containing 83% of gold (35.89 +/- 1.93 MPa), and precious metal alloy containing 32% of gold (34.59 +/- 2.63 MPa). Nonprecious Ni-Cr alloy and precious metal alloy containing 32% of gold showed significant difference (P<.05). CONCLUSION: The type of metal-ceramic alloys affects the bond strength of porcelain. Every metal-ceramic alloy used in this study showed clinically applicable bond strength with porcelain (25 MPa).

Reparación intraoral de una prótesis parcial fija metal-cerámica de seis unidades con resina compuesta: relato del caso / Repair of a six-unit fixed partial denture metal-ceramics with composite resin: case report

Múltiples son los factores que pueden desencadenar fracturas de porcelana en una prótesis parcial fija metal-cerámica, aunque esta situación no siempre determina un reemplazo. La reparación de porcelana mediante el uso de resina compuesta es una alternativa con ventajas de una fácil manipulación y bajo costo. El objetivo del presente artículo es presentar a la resina compuesta como una opción con resultados considerables en la reparación de prótesis metal-cerámicas fracturadas, con alto compromiso estético. Se presenta un caso clínico de reparación intraoral de una prótesis fija metal-cerámica de seis unidades en el sector anterior superior. El tratamiento realizado incluyó fresado de la superficie de porcelana, aislamiento absoluto, grabado ácido con fluoruro de fosfato acidulado, microarenado con óxido de aluminio, silanización, aplicación del adhesivo convencional y tres tipos de resinas compuestas, resina opaca, microhíbrida y resina de nanorelleno. A los 8 meses se evaluó la adaptación de la reparación mediante un explorador e inspección visual, secando con una jeringa triple donde no se observó signos de percolación alguna. Basado en los resultados se puede considerar a esta combinación de resinas compuestas como una alternativa útil en la reparación de porcelana fracturada.

There are multiple factors that can trigger a fracture of porcelain in a metal-ceramic fixed partial denture, although a replacement is not always required. The porcelain repair using composite resin is an alternative with advantages such as easy handling and low cost. The aim of this paper is to present the composite as an option with significant results in the repair of fractured metal-ceramic prostheses, with a high aesthetic commitment. We report a case of intraoral repair of a six-unit metal-ceramic fixed prosthesis in the anterior superior sector. The treatment provided included milling of the surface of porcelain, absolute isolation, acid etching with acidulated phosphate fluoride, aluminium oxide sandblasting, silanization, conventional adhesive application and three types of composite resins: opaque resin, micro-hybrid resin and nanofilled resin. After 8 months we assessed the adaptation of the repair using a surface explorer and visual inspection, drying with a triple syringe. No signs of seepage were observed. Based on the results, this combination of composite resins can be considered as a useful alternative in the repair of broken porcelain.

Effect of Finish Line on Marginal Fit of Sintered Gold Copings

The aim of this study was to evaluate the vertical marginal gap of sintered gold copings and metal-ceramic crowns with different finish line preparations: a beveled round shoulder (BRS) and a beveled long chamfer (BLC), testing the null hypotheses that there are no differences in marginal gap regardless of finish line and phase of restoration (coping or crown). Stainless steel master models were fabricated to simulate tooth preparation for metal-ceramic crowns with different finish lines (BRS and BLC). Ten dies were obtained from each model. Preparations were coated with 2 layers of spacer to 1 mm from the margin. Sintercast gold copings were prepared, sintered and adjusted to the dies. The copings (n=10) were placed onto the master model and the marginal gap was measured in 24 equidistant points using optical microscopy (X230). An opaque and two body ceramic layers were subsequently applied to the copings and the same measuring procedure was performed for the crowns. The data were analyzed statistically using paired and unpaired Student's t-test (α=0.05). Mean marginal gap values (µm) for the copings and crowns were, respectively: 113.6 and 117.1 for the BRS; and 58.2 and 74.3 for the BLC preparation. Significantly greater marginal gaps (p=0.0307) were found for restorations with BRS than with BLC finish line, which also showed statistically significant differences in the gap size between coping and crown (p=0.001). In conclusion, marginal gap is influenced by ceramic application on copings fabricated on BLC preparation, and greater marginal gaps were found for restorations with BRS finish line, rejecting the experimental null hypotheses.

O objetivo deste estudo foi avaliar a fenda marginal vertical de copings de ouro sinterizado e coroas metalo-cerâmicas com diferentes tipos de término de preparo: ombro arredondado biselado (OAB) e chanfro longo biselado (CLB), testando a hipótese nula de que não há diferenças na adaptação marginal quando se compara o tipo de término ou a fase da restauração (coping ou coroa). Modelos de aço inoxidável foram confeccionados simulando preparos dentais com diferentes términos (OAB e CLB). Dez modelos de gesso foram confeccionados a partir de cada preparo. Duas camadas de espaçador foram passadas em cada preparo, a 1 mm da margem. Os copings de Sintercast confeccionados, sinterizados e ajustados ao modelo de gesso. Os copings (n=10) foram colocados no modelo de aço e a fenda marginal foi medida em 24 pontos equidistantes por meio de microscópio óptico (×230). Uma camada de opaco e duas de porcelana feldspática foram aplicadas sobre os copings e o mesmo processo de mensuração de fenda foi utilizado para as coroas. Os dados foram analisados estatisticamente usando o teste t Student pareado e não-pareado (α=0,05). Os valores médios de fenda marginal (µm) para os copings e coroas foram, respectivamente: 113,6 e 117,1 para OAB; e 58,2 e 74,3 para CLB. Fendas marginais significantemente maiores (p=0,0307) foram observadas nas restaurações com términos OAB quando comparados ao término CLB, o qual mostrou diferenças estatísticas na comparação entre coping e coroa (p=0,001). Em conclusão, a fenda marginal é influenciada pela aplicação de cerâmica em copings fabricados com términos CLB, e fendas marginais maiores foram observadas para restaurações com término OAB, rejeitando-se as hipóteses nulas.

Integração multidisciplinar nas reabilitações estéticas adesivas / Multidisciplinary integration in adhesive esthetic rehabilitations

A crescente valorização de um sorriso esteticamente agradável faz com que profissionais e pacientes busquem cada vez mais alternativas de tratamento para modificar a aparência dental. Diversas situações clínicas que necessitam de resistência e estética, e que antigamente só eram resolvidas com tratamentos protéticos invasivos, hoje podem ser solucionadas perfeitamente com materiais restauradores adesivos de última geração. A multidisciplinaridade permite que as diversas áreas da odontologia, dentro da mesma filosofia, trabalhem e alcancem os objetivos desejados, devolvendo não só a estética almejada pelo paciente, mas principalmente garantindo a função e a longevidade do resultado. O presente trabalho tem como objetivo descrever a importância de uma abordagem interdisciplinar na reabilitação oral de pacientes, assim como revisar o estágio atual dos materiais restauradores adesivos.

The increasing appreciation of an aesthetically pleasant smile has encouraged professionals and patients to search new treatment alternatives to modify the appearance of the teeth. Several clinical situations that require resistance and esthetics, and that could only be solved with invasive prosthetic treatments in the past, can today be perfectly solved with state-of-the-art adhesive restorative materials. The multidisciplinary integration allows for several areas of Dentistry to work under the same philosophy to reach the desired objectives: to restore the esthetics desired by the patient along with function and long-term durability of the treatment. This paper aims to describe the importance of an interdisciplinary approach in the oral rehabilitation of patients, as well as to review the current stage of adhesive restorative materials.

Fracturing of revision of a cobalt-chrome femoral head after fracturing of a ceramic femoral head, with diffuse metallosis. Case report

We presente a case of a fracture of a cobalt-chrome femoral head after revision of a hip total prosthesis with ceramic femoral head fracture. During surgery we found the cobalt-chrome femoral head fracture, wear of the polyethylene and massive metallosis in muscular and cartilaginous tissue. Both femoral stem and acetabular cup were stable and without apparent wearing. After surgical debridement, we promoted the substitution of the femoral head and the acetabular polyethylene by similar ones. After 12 months of follow-up, the patient has no pain complaints, function limit or systemic signs associated with malign metallosis.

Odontologia estética: integração entre prótese, dentística e periodontia: relato de caso clínico / Esthetic dentistry: relationship between prosthodontics, restorative dentistry and periodontics: a case report

O tratamento restaurador deve restabelecer a função mastigatória e conferir bom resultado estético, a fim de proporcionar ao paciente sorriso agradável. Um planejamento multidisciplinar que envolva as especialidades favorece a obtenção de melhor resultado clínico. Este artigo tem por objetivo relatar um caso clínico em que se integraram a dentística, a periodontia e a prótese dentária, na reabilitação de incisivos superiores, com remodelação dos dentes 12 e 22 em resina composta e coroas totais ametálicas nos dentes 11 e 21, precedidas de clareamento dental.

The restorative treatment should reestablish the masticatory function, provide satisfactory esthetic results and a pleasant smile to the patient. A multidisciplinary planning comprising specialties favors the achievement of desirable clinical outcomes. The aim of this case report is to present a situation where Restorative Dentistry, Periodontics and Prosthodontics were integrated for the rehabilitation of four maxillary incisors. The laterals were restored with composite resin and the centrals were restored with a all-ceramic system, after tooth bleaching therapy.

Reconstrução unitária posterior com coroas endocrown: relato de caso / Single-unit reconstructions using endocrown restorations: a case report

Há crescente demanda de pacientes que solicitam restaurações em que se utilizam materiais estéticos, dentre eles, os principais são as resinas compostas e as cerâmicas. Quando se tratar de cavidades extensas, a cerâmica deve ser indicada, pela maior possibilidade de obtenção de bons resultados em longo prazo. Dentes tratados endodonticamente geralmente possuem grandes cavidades, e as restaurações do tipo endocrown são uma opção bastante conservadora em relação aos pinos intrarradiculares associados às coroas totais. Este artigo descreve uma sequência clínica e técnica de uma coroa adesiva indireta do tipo endocrown em dente posterior, utilizando-se cerâmica como material restaurador, por meio de um sistema CAD/CAM para confecção.

There is an increasing demand for esthetic restorations using composite and ceramic materials. Ceramics should be the material of choice when restoring large posterior cavities, due to its higher long-term predictability. Endodontically-treated posterior teeth usually presente wide cavities, and endocrowns are a safe alternative when compared to posts associated to full-coverage crowns. This article is a clinical report using an endocrown fabricated with a CAD/CAM ceramic system.

Mechanical properties of cobalt-chromium alloys containing different proportion of once-used alloys after recasts / 中国组织工程研究

BACKGROUND:There are numerous studies about mechanical changes of recast cobalt-chromium ceramic al oys. However, little is reported on the mechanical properties of cobalt-chromium ceramic al oys containing once-used al oys after recasts. OBJECTIVE:To study the effects of different proportion of once-used al oys to recasting cobalt-chromium al oys on their mechanical properties, including tensile strength, yield strength, elongation and hardness. METHODS:Cobalt-chromium al oys cast samples were prepared and recast for three times (40%once-used al oys were added per time). The tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness of each specimen were measured. In addition, microscopic metal ographic observation was done. RESULTS AND CONCLUSION:Being recast for three times, cobalt-chromiun al oys showed no significant differences on their tensile strength, 0.2%yield strength, percentage of elongation, flexural strength and Vickers hardness. GenerationⅠal oy samples had uniform size, smal diameter and smal carbide size distributing along the grain boundary, mainly exhibiting spherical and irregular wormlike forms. Generations Ⅱ and Ⅲ samples were uniform in shape, but crystal grains were coarsened a little. Carbide from Generation IV samples began to be coarsened, irregular wormlike carbides were increased in amount, and a few of non-metal ic inclusions could be found in grains. Cobalt-chromium al oys can be recast after addition of 40%once-used al oys for three times at least in air environment, without decrease of the mechanical properties.