Three-dimensional finite element analysis of cement flow in abutment margin-crown platform switching / 北京大学学报(医学版)

OBJECTIVE@#To analyze the cement flow in the abutment margin-crown platform switching structure by using the three-dimensional finite element analysis, in order to prove that whether the abutment margin-crown platform switching structure can reduce the inflow depth of cement in the implantation adhesive retention.@*METHODS@#By using ANSYS 19.0 software, two models were created, including the one with regular margin and crown (Model one, the traditional group), and the other one with abutment margin-crown platform switching structure (Model two, the platform switching group). Both abutments of the two models were wrapped by gingiva, and the depth of the abutment margins was 1.5 mm submucosal. Two-way fluid structure coupling calculations were produced in two models by using ANSYS 19.0 software. In the two models, the same amount of cement were put between the inner side of the crowns and the abutments. The process of cementing the crown to the abutment was simulated when the crown was 0.6 mm above the abutment. The crown was falling at a constant speed in the whole process spending 0.1 s. Then we observed the cement flow outside the crowns at the time of 0.025 s, 0.05 s, 0.075 s, 0.1 s, and measured the depth of cement over the margins at the time of 0.1 s.@*RESULTS@#At the time of 0 s, 0.025 s, 0.05 s, the cements in the two models were all above the abutment margins. At the time of 0.075 s, in Model one, the gingiva was squeezed by the cement and became deformed, and then a gap was formed between the gingiva and the abutment into which the cement started to flow. In Model two, because of the narrow neck of the crown, the cement flowed out from the gingival as it was pressed by the upward counterforce from the gingival and the abutment margin. At the time of 0.1 s, in Model one, the cement continued to flow deep inside with the gravity force and pressure, and the depth of the cement over the margin was 1 mm. In Model two, the cement continued to flow out from the gingival at the time of 0.075 s, and the depth of the cement over the margin was 0 mm.@*CONCLUSION@#When the abutment was wrapped by the gingiva, the inflow depth of cement in the implantation adhesive retention can be reduced in the abutment margin-crown platform switching structure.

Prótese overdenture: sistema o'ring / Overdenture prosthesis: o'ring system

Overdenture é uma prótese total que se caracteriza por usar apoios retentivos para que aumente sua estabilidade e retenção na cavidade bucal, gerando assim menor desconforto ao paciente e melhor adaptação. A Prótese overdenture dentossuportada necessita de elementos dentais remanescentes com canais tratados endodonticamente e que possuam suporte periodontal adequado. O objetivo deste relato de caso clínico é expor a sequência de confecção de uma prótese overdenture dentossuportada maxilar associada a uma prótese total convencional mandibular, com os passos clínicos detalhados por meio de uma abordagem teórica e visual. Esse tipo de reabilitação favorece a adaptação do paciente à nova condição, visto que o uso de próteses totais convencionais pode causar certo desconforto ao paciente devido à falta de retenção e estabilidade. Essa manutenção dos dentes remanescentes favorece à manutenção óssea e a futura decisão do paciente em optar pela instalação de implantes dentários, podendo confeccionar próteses implantorretidas (overdentures) ou implantossuportadas (protocolo).O Paciente demonstrou-se satisfeito com o resultado estético e funcional após a instalação da prótese concretizando que o tratamento é viável(AU)

Overdenture is a denture that utilizing retentive supports for increase stability and retention in oral cavity. The tooth-supported overdenture require dental elements with root canal therapy and good periodontal support. The aim of this study is to report the confection of a maxillary tooth-supported overdenture associated with mandibular denture and your clinical steps. This rehabilitation promotes the patient's adaptation the new condition, since the use of conventional dentures may cause discomfort due to lack of retention and stability. The preservation of dental elements promotes bone maintenance and forthcoming decision of the patient in the installation of dental implants that can choose implantretained or implant-supported prosthesis. Patient was satisfied with aesthetic and functional result after installation of prosthesis(AU)

Técnica endocrown como alternativa restauradora para dentes tratados endodonticamente: relato de caso clínico / Endocrown technique as a restorative alternative for endodontically treated teeth: a case report

Este trabalho teve como objetivo apresentar um relato de caso clínico de uma restauração do tipo coroa endocrown cerâmica em um dente molar tratado endodonticamente. Paciente com 45 anos de idade, sexo feminino, procurou a clínica do Centro Universitário da Serra Gaúcha (FSG) relatando a necessidade de reabilitação protética no primeiro molar inferior do lado esquerdo. Com base no exame radiográfico e exame clínico foi constatado um primeiro molar inferior do lado esquerdo com tratamento endodôntico satisfatório, mas uma extensa destruição coronária. Após a aprovação da paciente e indicações para a utilização da técnica, optou-se pela confecção de uma coroa endocrown em cerâmica reforçada por dissilicato de lítio. Foi realizado o preparo do remanescente dentário, envolvendo a câmara pulpar, com ângulos arredondados e expulsivos e, após a moldagem do mesmo com silicone de adição, utilizando a técnica simultânea e duplo fio. O provisório foi realizado com resina quimicamente ativada na cor 62 e, na sessão seguinte a coroa endocrown foi ajustada e polida. Após receber o protocolo de condicionamento adequado da peça, a mesma foi cimentada com cimento autopolimerizável Multilink N. Pode-se concluir que a alternativa restauradora Endocrown é um tratamento conservador e favorável para dentes com extensa destruição coronária, permitindo adequada estética e função(AU)

This study aimed to present a clinical case report of an endocrown ceramic crown restoration in na endodontically treated molar tooth. A 45-year-old female patient sought the clinic at the Centro Universitário da Serra Gaúcha (FSG), reporting the need for prosthetic rehabilitation on the lower left first molar. Based on the radiographic and clinical examination, the first molar presented satisfactory endodontic treatment, but extensive coronary destruction. After the approval of the patient and indications for the use of the technique, it was decided to make an endocrown with reinforced ceramic by lithium disilicate. The remaining tooth was prepared, involving the pulp chamber, with rounded and expulsive angles and, after the impression with silicone using the simultaneous and double wire technique was taken. The provisional was made with chemically activated resin in color 62 and, in the following session, the endocrown crown was adjusted and polished. After receiving the proper conditioning protocol, it was lutted with Multilink N self-curing cement. It can be concluded that the Endocrown restorative alternative is a conservative and favorable treatment for teeth with extensive coronary destruction, allowing adequate aesthetics and function(AU)

Application evaluation of prefabricated rigid connecting bar in implants immediate impression preparation of edentulous jaw / 北京大学学报(医学版)

OBJECTIVE@#To compare the operation complexity and accuracy of traditional splint impression technique and impression technique with prefabricated rigid connecting bar system for full-arch implants-supported fixed protheses in vitro.@*METHODS@#Standard mandibular edentulous model with six implant analogs was prepared. The implants were placed at the bone level and multiunit abutments screwed into the implants. Two impression techniques were performed: the traditional splint impression technique was used in the control group, and the rigid connecting bar system was used in the test group. In the control group, impression copings were screwed into the multiunit abutments and connected with autopolymerizing acrylic resin. Open tray impression was fabricated with custom tray and polyether. In the test group, cylinders were screwed into the multiunit abutments. Prefabricated rigid bars with suitable length were selected and connected to the cylinders with small amount of autopolymerizing acrylic resin, and open tray impression was obtained. Impression procedures were repeated 6 times in each group. The working time of the two impression methods were recorded and compared. Analogs were screws into the impressions and gypsum casts were poured. The gypsum casts and the standard model were transferred to stereolithography (STL) files with model scanner. Comparative analysis of the STL files of the gypsum casts and the standard model was carried out and the root mean square (RMS) error value of the gypsum casts of the control and test groups compared with the standard model was recorded. The trueness of the two impression techniques was compared.@*RESULTS@#The work time in the test group was significantly lower than that in the control group and the difference was statistically significant [(984.5±63.3) s vs. (1 478.3±156.2) s, P < 0.05]. Compared with the standard model, the RMS error value of the implant abutments in the test group was (16.9±5.5) μm. The RMS value in the control group was (20.2±8.0) μm. The difference between the two groups was not significant (P>0.05).@*CONCLUSION@#The prefabricated rigid connecting bar can save the chair-side work time in implants immediate loading of edentulous jaw and simplify the impression process. The impression accuracy is not significantly different from the traditional impression technology. The impression technique with prefabricated rigid connecting bar system is worthy of clinical application.

Total hip arthroplasty in the public health system of são paulo: comparing types of fixation / Artroplastia total de quadril no sistema público de são paulo: comparando os tipos de fixação

ABSTRACT Brazil lacks registries on the prevalence of primary total hip arthroplasty (THA) fixation methods. Objective: (i) to describe the demographic profile of patients who underwent THA in the public health system of the municipality of São Paulo during the last 12 years and (ii) to compare fixation methods regarding costs, hospital stay length, and death rates. Methods: This is an ecological study conducted with data available on TabNet, a platform belonging to DATASUS. Public data (from the government health system) on THA procedures performed in São Paulo from 2008 to 2019 were extracted. Gender, age, city region, THA fixation method, number of surgeries, costs, hospital stay length, and death rates were analyzed. Results: We analyzed 7,673 THA, of which 6220 (81%) were performed via cementless/hybrid fixation and 1453 (19%), via the cemented technique. Cementless/hybrid fixation had a higher cost (US$ 495.27) than the cemented one (p < 0.001). Nevertheless, hospital stay length was 0.87 days longer for cemented fixation than the cementless/hybrid one. We found no significant difference in death rates between THA fixation methods. Conclusion: THA cementless/hybrid fixation is prevalent in the municipality of São Paulo, which had higher total costs and shorter hospitalizations than cemented fixation. We found no difference between THA fixation methods and death rates. Level of Evidence IV, Case Series.

RESUMO No Brasil, não há registros da prevalência do tipo de fixação da artroplastia total de quadril (ATQ). Objetivo: (i) Descrever perfil demográfico de pacientes submetidos à ATQ no Sistema Único de Saúde de São Paulo durante os últimos doze anos; e (ii) comparar as técnicas de fixação de ATQ quanto aos custos, tempo de internação (TI) e taxa de óbito. Métodos: Estudo ecológico, com dados disponíveis na TabNet do DATASUS. Dados públicos de procedimentos de ATQ eletivos realizados em São Paulo de 2008 a 2019 foram extraídos. Foram analisados: sexo, idade, região municipal, método de fixação em ATQ, número de cirurgias, custo, tempo de internação e óbitos. Resultados: Foram analisadas 7.673 ATQs, sendo 6.220 (81%) não-cimentada/híbridas e 1.453 (19%) cimentadas. A fixação não-cimentada/híbrida teve custo maior em US$ 495,27 do que a cimentada (p < 0,001). Entretanto, TI foi 0,87 dia mais longo na fixação cimentada. Não houve diferença significativa nas taxas de óbito entre os métodos de fixação. Conclusão: A fixação não-cimentada/híbrida na ATQ é prevalente em São Paulo, e apresentou maior custo total, porém menor tempo de internação do que a fixação cimentada. Não houve diferença entre o método de fixação em ATQ e a taxa de óbito. Nível de Evidência IV, Série de Casos.

Avaliação do tipo de retenção e o uso de diferentes intermediários na adaptação de próteses unitárias sobre implantes / Evaluation of the type of retention and the use of different abutments in the adaptation of single prostheses on implants

Atualmente, devido a perda do elemento dentário e a procura por um tratamento estético e principalmente funcional, a reabilitação com próteses sobre implante tem sido amplamente empregada, com elevada previsibilidade a longo prazo. Com isso, muito tem sido relatado na literatura acerca das possíveis complicações dessa modalidade de tratamento, principalmente relacionado às possibilidades de falhas mecânicas das próteses implantossuportadas. Por isso, o objetivo do presente projeto foi avaliar a influência na adaptação marginal e interna, da utilização do intermediário protético e do tipo de retenção das próteses (parafusada e cimentada) em implantes cone morse submetidos à ciclagem mecânica. Foram confeccionados 40 corpos de prova, no qual cada um tinha a presença de um implante, com as dimensões de 4mm de diâmetro e 11,5mm de comprimento cone morse (n = 40). Dessa forma, foi avaliado a influência da utilização do intermediário e dos sistemas de retenção em cada conexão de maneira específica. Metade dos corpos de prova de cada sistema de conexão foram confeccionados em UCLA (n=20, sendo 10 parafusadas e 10 cimentadas), enquanto que a outra metade foi utilizado um intermediário pré-fabricado (Pilar Universal (n=20, sendo 10 parafusadas e 10 cimentadas). Os corpos de prova foram submetidos à ciclagem mecânica submersos em água destilada simulando um tempo clínico de cinco anos. Além disso, foram avaliados quanto ao torque e destorque (N) e adaptação marginal e interna (µm) antes e após a ciclagem mecânica. Os dados provenientes das mensurações foram organizados em tabela em formato Excel (Microsoft Office Excel, Redmond, WA, Estados Unidos) e submetidos ao software SigmaPlot (SigmaPlot, San Jose, CA, EUA) versão 12.0. Todos os dados foram analisados inicialmente com a utilização da estatística descritiva. Em seguida, os dados para intrusão (valores positivos), extrusão (valores negativos), destorque inicial, destorque final, e descimentação foram analisados em relação a distribuição de normalidade (teste Shapiro-Wilk e igualdade de variância) e, posteriormente, foi adotada a Análise de Variância (ANOVA) a um fator (Grupos diferentes materiais: G1 a G4), quando houve normalidade dos dados, o pós teste de Tukey foi adotado para as comparações múltiplas, quando não foi identificado uma distribuição normal, empregou-se o teste de Kruskall-Wallis e pós-teste de Dunn's ou Tukey, semelhantemente foi realizada a análise específica das variáveis pilares (UCLA e Pilar Universal) e sistemas de retenção (Parafusado e Cimentado). Para todos os testes aplicou-se nível de significância de 5% (α=0,05). A análise gráfica foi considerada através de um gráfico de barras para os dados que apresentaram normalidade com valores de média e desvio padrão, e as demais análises que não apresentaram normalidade foi considerado a confecção de um boxplot para cada grupo comparativo. As próteses sobre implante utilizando pilares em zircônia tem ganhado cada vez mais espaço, além do estudo in vitro, foi realizada uma revisão sistemática para comparar a perda óssea marginal e as complicações próteticas de reabilitações utilizando pilares de zircônia cimentado e parafusado. Em relação as próteses cimentadas e parafusadas, devido as evidências conflitantes e a presença de muitas revisões sistemáticas sobre o tema, foi realizada uma overview de revisões sistemáticas, com o objetivo de compilar as informações disponiveis e avaliar a qualidade metodologica desses estudos a respeito das complicações presentes nas próteses sobre implante cimentadas ou parafusadas(AU)

Currently, due to the loss of the dental element and the search for an aesthetic and mainly functional treatment, rehabilitation with implant prostheses has been widely used, with high long-term predictability. Thus, much has been reported in the literature about the possible complications of this treatment modality, mainly related to the possibility of mechanical failure of implant-supported prostheses. Therefore, the objective of the present project was to evaluate the influence on the marginal and internal adaptation, the use of the prosthetic intermediate and the type of retention of the prostheses (screwed and cemented) in morse taper implants submitted to mechanical cycling. 40 specimens were made, in which each one had an implant, with dimensions of 4 mm in diameter and 11.5 mm in length (n = 40). In this way, the influence of the use of intermediaries and retention systems in each connection was evaluated in a specific way. Half of the specimens of each connection system were made in UCLA (n=20, being 10 screwed and 10 cemented), while the other half was used a prefabricated intermediate (Universal Abutment (n=20, being 10 screwed) and 10 cemented). The specimens were submitted to mechanical cycling submerged in distilled water simulating a clinical time of five years. In addition, they were evaluated for torque and detorque (N) and marginal and internal adaptation (µm) before and after mechanical cycling. Data from measurements were organized in a table in Excel format (Microsoft Office Excel, Redmond, WA, USA) and submitted to SigmaPlot software (SigmaPlot, San Jose, CA, USA) version 12.0. All data were initially analyzed using descriptive statistics. Then, data for intrusion (positive values), extrusion (negative values), initial detorque, final detorque, and debonding were analyzed in relation to dist determination of normality (Shapiro-Wilk test and equality of variance) and, later, the one-way Analysis of Variance (ANOVA) was adopted (Different material groups: G1 to G4), when there was normality of the data, the Tukey post test was adopted for multiple comparisons, when a normal distribution was not identified, the Kruskall-Wallis test and Dunn's or Tukey post-test were used, similarly the specific analysis of the pillar variables (UCLA and Universal Pillar) and systems retainer (Screwed and Cemented). For all tests, a significance level of 5% (α=0.05) was applied. The graphical analysis was considered through a bar graph for the data that presented normality with mean and standard deviation values, and the other analyzes that did not present normality was considered the creation of a boxplot for each comparative group. Implant prostheses using zirconia abutments have gained more and more space, in addition to the in vitro study, a systematic review was performed to compare marginal bone loss and prosthetic complications of rehabilitations using cemented and screwed zirconia abutments. Regarding cemented and screw-retained prostheses, due to conflicting evidence and the presence of many systematic reviews on the subject, an overview of systematic reviews was performed, with the objective of compiling the available information and evaluating the methodological quality of these studies regarding complications present in cemented or screw-retained implant prostheses(AU)

Tasa de supervivencia de prótesis fija unitaria de cerámica feldespática y feldespática reforzada / Survival rate of feldspathic and reinforced feldspathic ceramic single-unit fixed prostheses

Introducción: Gracias a su eficiencia y al uso exclusivo de cerámicas libres de metal, en rehabilitación oral se ha logrado alcanzar los estándares estéticos y mecánicos, manteniendo o, incluso, superando, la calidad de los tratamientos en comparación con las restauraciones metal cerámicas tradicionales. Actualmente los mecanismos de confeccion de cerámica libre están evolucionando cada vez mas hacia las tecnologías maquinadas CAD-CAM y disminuyendo su producción mediante la técnica de Inyeccion PRESS. Objetivo: Comparar la tasa de supervivencia de prótesis fija unitaria realizadas con cerámicas feldespáticas convencionales y reforzadas con disilicato de litio, confeccionadas con sistema CAD/CAM de CEREC® chair-side, en comparación con el método de inyección de laboratorio PRESS convencional de prensión. Métodos: Revisión sistemática realizada a través de búsqueda de evidencia científica en PubMed, PubMed Clinical Queries, Epistemónikos, Tripdatabase, Cochrane Library, recursos electrónicos de la Universidad de los Andes y bibliografía retrógrada, de artículos publicados hasta el año 2019. Se incluyeron todos aquellos estudios referentes a prótesis fija unitaria de cerámicas feldespática convencional y feldespática reforzada con disilicato de litio, confeccionadas mediante CAD/CAM y/o método convencional. Resultados: Un total de 28 artículos cumplieron los criterios de inclusión: 21 estudios observacionales de cohorte, 4 ensayos clínicos aleatorizados y 3 no aleatorizados. A corto y mediano plazo, CAD/CAM de CEREC® registró tasas de supervivencia de 98 por ciento y 91,9 por ciento, respectivamente. El sistema convencional registró tasas de supervivencia de 97,5 por ciento a corto plazo y 93 por ciento a mediano. Conclusiones: A corto plazo se describe en la literatura que CAD/CAM de CEREC® tuvo una tasa de supervivencia ligeramente superior al sistema convencional. Por otro lado, a mediano plazo CAD/CAM de CEREC® presentó una leve disminución respecto al sistema convencional. Aún no hay estudios disponibles para determinar la supervivencia clínica de los tratamientos a largo plazo(AU)

Introduction: Thanks to its efficiency and the exclusive use of metal-free ceramics, in oral rehabilitation it has been possible to achieve aesthetic and mechanical standards, maintaining or even exceeding the quality of the treatments compared to traditional metal-ceramic restorations. Currently, free ceramic manufacturing mechanisms are increasingly evolving towards CAD-CAM machined technologies and decreasing their conventional production through the PRESS Injection technique. Objective: Compare the survival rate of single-unit fixed prostheses made with conventional feldspathic ceramics and reinforced with lithium disilicate by the CEREC® CAD/CAM chairside system, with the conventional PRESS laboratory injection method. Methods: A systematic review was conducted of scientific evidence included in papers published until the year 2019 in PubMed, PubMed Clinical Queries, Epistemonikos, Tripdatabase, Cochrane Library, electronic resources of Los Andes Peruvian University, and retrograde bibliography. The papers selected dealt with conventional and lithium-disilicate reinforced feldspathic ceramic single-unit prostheses made by CAD/CAM and/or the conventional method. Results: A total 28 papers met the inclusion criteria. Of these, 21 were observational cohort studies, four were randomized clinical assays and three were non-randomized assays. Short- and mid-term, CEREC® CAD/CAM achieved survival rates of 98 percent and 91.9 percent, respectively. The conventional system achieved survival rates of 97.5 percent short-term and 93 percent mid-term. Conclusions: As described in the literature, CEREC® CAD/CAM had a slightly higher survival rate than the conventional system in the short term. In the medium term, however, CEREC® CAD/CAM displayed a slight reduction in comparison with the conventional system. No studies are available to determine the clinical survival of the treatments in the long term(AU)

Screwed and cement implant prosthesis: current clinical considerations / Prótese sobre implante cimentada e parafusada: considerações clínicas atuais

ABSTRACT Introduction: There is no consensus as to which cemented or screwed retention system is best to avoid bone loss around the implant from a fixed implant-supported restoration. Objective: To evaluate the prosthesis retention systems on screw and cemented implants, regarding: bone loss, survival and failure rate, biological complications and microbiological analysis. Methods: A search was made for scientific articles that contemplated the subject through the databases Pubmed and SciELO, without period restriction. The titles, abstracts and then access to the full text has been verified. Results: It was found that excess cement may play an important role in the development of peri-implant disease. Technical failures are most seen in prosthesis retained by screws, and biological complications in cemented crowns. The success rate for both restraint systems is high, and retention-independent implant prosthesis treatment provides predictability. Conclusion: The appropriate retention system for the patient depends on several factors, including indication, advantages and disadvantages, retention provided, aesthetics and clinical performance.

RESUMO Introdução: Não há consenso sobre qual sistema de retenção, cimentado ou parafusado, é o melhor para evitar perda óssea ao redor do implante de uma restauração fixa implanto-suportada. Objetivo: Avaliar os sistemas de retenção de próteses sobre implantes parafusadas e cimentadas, quanto aos fatores: perda óssea, taxa de sobrevivência e de falhas, complicações biológicas e análises microbiológicas. Métodos: Foi realizada uma busca por artigos científicos que contemplassem o tema através das bases de dados Pubmed e SciELO, sem restrição de período. Os títulos, resumos e em seguida o acesso ao texto completo foi verificado. Resultados: Foi observado que o excesso de cimento pode desempenhar um papel importante no desenvolvimento da doença peri-implantar. Falhas técnicas são mais observadas em próteses retidas por parafusos e complicações biológicas em coroas cimentadas. A taxa de sucesso para os dois sistemas de retenção é alta e o tratamento com próteses sobre implantes independente da retenção oferece previsibilidade ao caso. Conclusão: O sistema de retenção apropriado para o paciente depende de diversos fatores, incluindo a indicação, vantagens e desvantagens, retenção fornecida, estética e desempenho clínico.

Estudo in vitro da influência de diferentes plugs coronários sobre o remanescente da obturação, após preparo para pino, na retenção de pinos metálicos fundidos / In vitro assessment of the influence of different protection plugs over obturation remnant space, after post preparation, on the retention of cast metal posts

Objetivo: Avaliar a influência de diferentes plugs de proteção, acomodados sobre o remanescente da obturação após preparo para pino, na retenção de pinos metálicos fundidos. Métodos: Cinquenta dentes bovinos foram decoronados, manualmente instrumentados até a lima manual Kerr #80 e obturados. A desobturação parcial de 10mm do conduto foi realizada com uma broca Largo e os grupos foram divididos de acordo com os diferentes materiais utilizados como plugs (n=10): Grupo I (Controle, sem plug); Grupo II (plug de Coltosol®); Grupo III (plug, em consistência de massa, de Sealapex® + óxido de zinco); Grupo IV (plug de etil-cianoacrilato); e Grupo V (plug de fosfato de zinco). Uma camada de 1mm de espessura dos diferentes plugs (Grupos II, III, IV ou V) foi acomodada sobre a obturação remanescente. Os espécimes foram selados e armazenados em 100% de umidade, por 7 dias. Após moldagem do conduto, foram confeccionados pinos metálicos fundidos e cimentados com fosfato de zinco. Os espécimes permaneceram em câmara úmida por 45 dias antes do teste de tração, realizado em uma máquina universal de ensaios. Os valores foram expressos em Mega pascal (MPa) e submetidos aos testes ANOVA e Tukey (p<0,05). Resultados: O etilcianoacrilato diminuiu a retenção dos pinos metálicos fundidos (p<0,01). Não houve diferença entre os outros grupos (p>0,05), semelhante- mente ao controle. Conclusão: A proteção da obturação com plugs confeccionados com etil-cianoacrilato prejudica a retenção de pinos metálicos fundidos cimentados com fosfato de zinco, enquanto Sealapex® acrescido de óxido de zinco, fosfato de zinco endurecido ou Coltosol® não interferem na adesividade (AU).

A new retaining method of cement-retained restoration with linguo-horizontal insertion of fiber post / 대한치과보철학회지

The retaining methods of implant prosthesis were classified into a screw-retained and a cement-retained type. A screw-retained prosthesis has many advantages, such as retrievability, preventing residual cement, while their disadvantages include the possibility of screw loosening and fracture, on the contrary advantages of cement-retained prosthesis are relatively low cost, but they are difficult to retrieve. To combine the advantages of both type, screw-cement retained prosthesis (SCRP) type have been introduced. But they still require ideal implant placement. So we introduce fiber post retained prosthesis without residual cement for preventing soft tissue trouble due to excessive cement.

Stability of the prosthetic screws of three types of craniofacial prostheses retention systems

OBJECTIVES: This study aimed to evaluate the stability of prosthetic screws from three types of craniofacial prostheses retention systems (bar-clip, ball/O-ring, and magnet) when submitted to mechanical cycling. MATERIALS AND METHODS: Twelve models of acrylic resin were used with implants placed 20 mm from each other and separated into three groups: (1) bar-clip (Sistema INP, São Paulo, Brazil), (2) ball/O-ring (Sistema INP), and (3) magnet (Metalmag, São Paulo, Brazil), with four samples in each group. Each sample underwent a mechanical cycling removal and insertion test (f=0.5 Hz) to determine the torque and the detorque values of the retention screws. A servo-hydraulic MTS machine (810-Flextest 40; MTS Systems, Eden Prairie, MN, USA) was used to perform the cycling with 2.5 mm and a displacement of 10 mm/s. The screws of the retention systems received an initial torque of 30 Ncm and the torque values required for loosening the screw values were obtained in three cycles (1,080, 2,160, and 3,240). The screws were retorqued to 30 Ncm before each new cycle. RESULTS: The sample was composed of 24 screws grouped as follows: bar-clip (n=8), ball/O-ring (n=8), and magnet (n=8). There were significant differences between the groups, with greater detorque values observed in the ball/O-ring group when compared to the bar-clip and magnet groups for the first cycle. However, the detorque value was greater in the bar-clip group for the second cycle. CONCLUSION: The results of this study indicate that all prosthetic screws will loosen slightly after an initial tightening torque, also the bar-clip retention system demonstrated greater loosening of the screws when compared with ball/O-ring and magnet retention systems.

Onde se encontra o travamento posterior da maxila de uma prótese total superior? / Where is the postpalatal seal in a complete upper denture?

Na confecção de uma prótese total superior, a delimitação correta do travamento posterior é uma responsabilidade do clínico. Para evidenciá-lo, esse deve basear-se em referências anatômicas e fatores fisiológicos individuais de cada paciente.

During the fabrication of a complete denture the practitioner is responsible for a proper postpalatal seal. Thus it must be based on anatomic structures and physiologic aspects of each patient.

Tratamento de infecção após artroplastia total de joelho / Treatment of infection after total knee arthroplasty

Objetivos: Comparar as taxas de sucesso das modalidadesterapêuticas utilizadas no tratamento de infecções associadas aartroplastia total de joelho (ATJ), e avaliar o desfecho funcionale de dor nas modalidades por meio de escores de qualidadede vida. Métodos: Avaliamos todos os indivíduos que desenvolveraminfecção após ATJ em nosso serviço, entre 1º de janeirode 2008 e 31 de dezembro de 2010. Resultados: Neste período,29 pacientes com ATJ tiveram infecção, e 12 deles foram submetidosa desbridamento e retenção da prótese (D+R), sete acirurgia de troca da prótese em dois estágios, seis a cirurgia emum estágio, e quatro receberam terapia antibiótica supressivapor não poderem ser submetidos a nova cirurgia. Conclusão: Astaxas de sucesso de D+R, da revisão em um, e em dois está-gios foi de 75%, 83,3% e 100%, respectivamente. Os melhoresresultados referente à qualidade de vida e função ocorreramnos pacientes submetidos a D+R. Em contraste, os piores resultadosforam observados em pacientes tratados com cirurgiade revisão em dois estágios. Nível de Evidência II, EstudosPrognósticos- Investigação do Efeito de Característica deum Paciente Sobre o Desfecho da Doença.

Objectives: To identify and compare the rate of success of therapeuticmodalities applied in surgeries for the treatment of infectionsassociated with total knee arthroplasty (TKA), and to evaluate thefunctional outcome and pain in different therapeutic modalities bymeans of quality of life scores. Methods: We evaluated all patientswho developed periprosthetic infection after TKA for primary orsecondary osteoarthritis, in the period from January 1st, 2008 toDecember 31st, 2010. Results: In the study period, 29 patients withTKA had infection, and 12 of these underwent debridement andretention of the prosthesis (D+R), seven received two-stage and sixone-stage exchange arthroplasties, and four patients were treatedwith suppressive antibiotic therapy because they could not undergoanother surgical procedure. Conclusion: The D+R , one-stagerevision and two-stage revision success rates were 75%, 83.3%,and 100%, respectively. The best results of quality of life (QoL) andfunction occur in patients undergoing D+R. In contrast, the worstQoL and functional results were obtained in patients treated withtwo-stage revision arthroplasty. Level of Evidence II, PrognosticStudies - Investigating the Effect of a Patient Characteristicon the Outcome of Disease.

Masticatory performance with different types of rehabilitation of the edentulous mandible

Abstract Aim: To compare the masticatory performance associated with different rehabilitation strategies for patients with edentulous mandibles. Methods: one portion of the test food "Optocal" was provided to groups: Natural Dentition (n = 15), Mandibular Fixed Implant-Supported Prosthesis with Maxillary Fixed Prosthesis (n = 8), Mandibular Fixed Implant-Supported Prosthesis with Maxillary Removable Prosthesis (n = 14), Mandibular Implant-Retained Overdenture with Maxillary Removable Prosthesis (n = 16), and Complete Dentures (n = 16). The portion was collected after 40 chewing strokes, and then passed through a stack of eight sieves with decreasing apertures. Masticatory performance was determined by weighing the portion of food on each sieve. Results: the masticatory performance was: 71.00% for Natural Dentition, 41.57% for Mandibular Fixed Implant-Supported Prosthesis with Maxillary Fixed Prosthesis, 31.44% for Mandibular Fixed Implant-Supported Prosthesis with Maxillary Removable Prosthesis, 27.70% for Mandibular Implant-retained Overdenture, and 14.33% for Complete Dentures. The data were statistically compared using Student's t-test (p < 0.05). Natural Dentition and Complete Denture groups were statistically different from all other groups, with the Natural Dentition and Complete Denture groups exhibiting the highest and lowest masticatory performance values, respectively. Conclusions: Osseointegrated implants improved the masticatory performance of all implant-supported groups compared to the Complete Dentures group.

Correlation between clinical performance and degree of conversion of resin cements: a literature review

AbstractResin-based cements have been frequently employed in clinical practice to lute indirect restorations. However, there are numerous factors that may compromise the clinical performance of those cements. The aim of this literature review is to present and discuss some of the clinical factors that may affect the performance of current resin-based luting systems. Resin cements may have three different curing mechanisms: chemical curing, photo curing or a combination of both. Chemically cured systems are recommended to be used under opaque or thick restorations, due to the reduced access of the light. Photo-cured cements are mainly indicated for translucent veneers, due to the possibility of light transmission through the restoration. Dual-cured are more versatile systems and, theoretically, can be used in either situation, since the presence of both curing mechanisms might guarantee a high degree of conversion (DC) under every condition. However, it has been demonstrated that clinical procedures and characteristics of the materials may have many different implications in the DC of currently available resin cements, affecting their mechanical properties, bond strength to the substrate and the esthetic results of the restoration. Factors such as curing mechanism, choice of adhesive system, indirect restorative material and light-curing device may affect the degree of conversion of the cement and, therefore, have an effect on the clinical performance of resin-based cements. Specific measures are to be taken to ensure a higher DC of the luting system to be used.

Parafusamento transverso em prótese sobre implante: aspectos inovadores no design e na aplicação do sistema / Cross-pinning in implant-supported prosthesis: innovative design and approach

Reabilitações com próteses implantossuportadas são usadas frequentemente para resolver casos de edentulismo. Elas podem ser retidas por de meio de parafusos ou agentes de cimentação. No entanto, nos casos de alinhamento inadequado dos implantes ou fragilidade pelo desenho final da estrutura protética, o sistema de parafusamento convencional não pode ser utilizado. Um método alternativo para se manter a reversibilidade da peça protética é o parafusamento transverso. Este consiste em um sistema tubo/parafuso de dimensões reduzidas que possibilita o parafusamento em uma área palatina ou lingual. Entretanto, aperfeiçoamentos nos sistemas existentes comercialmente eram necessários para se suprirem dificuldades como custo, técnica de confecção e dimensões dos componentes. O presente artigo apresenta o desenvolvimento de um produto adequado para este método, para suprir as desvantagens dos sistemas anteriores, apresenta a técnica de confecção clínica e laboratorial, e discute os aspectos fundamentais no planejamento desse sistema...

Implant-supported prostheses are frequently used in oral rehabilitation to solve cases of edentulism. They may be screw-retained or cement-retained. However, sometimes conventional screw-retained systems can not be used in cases of improper alignment of implants or compromised structural integrity of the prosthesis. An alternative method to maintain reversibility of the rehabilitation is cross-pinning. This system consists of a tube/screw with reduced dimensions which enables screwing in a palatal or lingual area. However, improvements in the commercially existing systems have been necessary to overcome difficulties such as costs, manufacturing technique and component dimensions. This paper presents the development of an appropriate product for this method, allowing to overcome the disadvantages of previous systems and analyzes the clinical and laboratory steps discussing the fundamental aspects of planning when using this system...

Clinical common problems after restoration with telescopic crown-retained removable partial dentures / 中国组织工程研究

BACKGROUND:Telescopic crown-retained removable partial dentures are characterized as pick to wear voluntarily, convenient to clean, smal foreign body sensation of the fixed denture, and good functional recovery, and have been widely used in recent years. However, there are also some problems existing. OBJECTIVE:To review the common problems of the telescopic crown-retained removable partial dentures and to raise the countermeasures. METHODS: A computer-based search of CNKI and PubMed (1980-2013) was performed for relevant articles addressing the telescopic crown using the keywords of “cone sleeve crown, abutment, clinical observation” in Chinese and English, respectively. RESULTS AND CONCLUSION:Telescopic crown-retained removable partial dentures are an ideal method for repair of dentition defects associated with periodontal disease. In summary, the telescopic crown-retained removable partial dentures have good clinical effects, but how to maintain the long-term stability is the main chalenge. In recent years, a variety of ways have been developed to improve the long-term stability, such as changing the inner crown material, which obtains the most prominent achievements, but these methods need to be further observed in clinical applications. Common complications for telescopic crown-retained removable partial dentures include abutment fracture, inner crown shedding, denture fracture, periodontal problems, and reduced retention force, which generaly cannot influence the application of telescopic crown-retained removable partial dentures through repair.

Loosening torque of Universal Abutment screws after cyclic loading: influence of tightening technique and screw coating

PURPOSE: The purpose of this study was to evaluate the influence of tightening technique and the screw coating on the loosening torque of screws used for Universal Abutment fixation after cyclic loading. MATERIALS AND METHODS: Forty implants (Titamax Ti Cortical, HE, Neodent) (n=10) were submerged in acrylic resin and four tightening techniques for Universal Abutment fixation were evaluated: A - torque with 32 Ncm (control); B - torque with 32 Ncm holding the torque meter for 20 seconds; C - torque with 32 Ncm and retorque after 10 minutes; D - torque (32 Ncm) holding the torque meter for 20 seconds and retorque after 10 minutes as initially. Samples were divided into subgroups according to the screw used: conventional titanium screw or diamond like carbon-coated (DLC) screw. Metallic crowns were fabricated for each abutment. Samples were submitted to cyclic loading at 106 cycles and 130 N of force. Data were analyzed by two-way ANOVA and Tukey's test (5%). RESULTS: The tightening technique did not show significant influence on the loosening torque of screws (P=.509). Conventional titanium screws showed significant higher loosening torque values than DLC (P=.000). CONCLUSION: The use of conventional titanium screw is more important than the tightening techniques employed in this study to provide long-term stability to Universal Abutment screws.

Maxillary complete denture rehabilitation of a patient with marked maxillomandibular discrepancy: a clinical case report / Confecção de prótese total superior em paciente com acentuada discrepância maxilomandibular: relato de caso clínico

Dentistry is constantly concerned with enabling better living conditions for patients, as well as providing comfort so that functions such as chewing, speaking, and swallowing may be executed properly and esthetically satisfactory. In edentulous patients, many of these functions are lost, but can be restored by prosthodontics. Within this context, the present article seeks to report a clinical case in which a maxillary complete denture was made for a patient presenting with maxillomandibular discrepancy and marked maxillary prognathism.

Uma constante preocupação da odontologia é de possibilitar melhores condições de vida aos pacientes, oferecendo-lhe conforto para que funções como mastigação, fonação e deglutição possam ser exercidas de maneira adequada e que apresente uma estética satisfatória. Com a perda dentária, muitas destas funções são perdidas, mas podem ser restabelecidas através do uso de prótese. Neste contexto, o presente artigo visa descrever a execução de um caso clínico onde foi confeccionada uma prótese total superior em paciente com discrepância maxilomandibular apresentando projeção acentuada da maxila em relação à mandíbula.

Efeito da altura do pilar, de diferentes cimentos e das ciclagens térmica e mecânica sobre a resistência máxima à tração de infraestruturas metálicas cimentadas / Effect of abutment height, different cements, thermocycling and cyclic loading on the ultimate tensile strength of cement-retained/implant-supported cast restorations

Este estudo avaliou (1) o efeito da altura do pilar, dos diferentes cimentos e da termociclagem e (2) o efeito dos diferentes cimentos e da ciclagem mecânica sobre a resistência máxima à tração (RMT) de restaurações implantossuportadas cimentadas. Pilares de titânio (UCLA), com alturas de 4,0 e 6,0 mm (1), ou 4,0 mm (2), foram torqueados com 32 N.cm a análogos de implantes HI. Infraestruturas em Co-Cr, jateadas com óxido de alumínio 50 µm foram cimentadas com: Fosfato de Zinco- FZ; RelyX Luting 2- RXL2; C & B Cement- C&B; RelyX U100- RXU100 e RelyX Temp NE- RXTNE. Os conjuntos foram submetidos aos ensaios de tração (0,5 mm/min) após: 1- armazenagem em saliva artificial a 37 ºC durante 24 h (controle), 2- termociclagem (10.000 ciclos, 5,0 e 55 °C, 30 s de imersão), ou 3-ciclagem mecânica (106 ciclos, 140 N, 15 Hz). Os dados foram analisados por (1) 3-way ANOVA e Dunnett, e (2) 2-way ANOVA e Tukey HSD (α=0,05). Independentemente da altura do pilar, não houve diferença nos resultados dos grupos sem termociclagem (p≥0,05). Após termociclagem, houve aumento (p<0,05) na RMT nos pilares de 6,0 mm. Após ciclagem mecânica, houve diminuição (p<0,05) nos resultados de RMT produzidos por RXL2. A altura do pilar influenciou os resultados do RXL2, que produziu RMT mais elevada com os pilares de 6,0 mm. Com exceção do RXL2, a ciclagem mecânica não comprometeu a RMT das infraestruturas cimentadas. Em determinadas condições, o RXTNE produziu RMT semelhante à alguns cimentos finais

This study evaluate (1) the effect of abutment height, different cements and thermocycling, and (2) the effect of different cements and cyclic loading on the ultimate tensile strength (UTS) of cement-retained/implant-supported cast restorations. UCLA-type abutments with 4.0 and 6.0-mm height (1), or 4.0-mm height (2) were torqued to with 32 N.cm to internal hexagon dental implant replicas. Copings casted in Co-Cr, sandblasted with 50-µm aluminum oxide particles were cemented with: Zinc Phosphate- ZP; RelyX Luting 2- RXL2; C & B Cement- C&B; RelyX U100-RXU100 and RelyX Temp NE- RXTNE. The assemblies were submitted to the tensile test (0.5 mm/min) after: 1- storage in artificial saliva at 37 °C for 24 h (control), 2-thermocycling (10,000 cycles, 5.0 and 55 ºC, 30-s dwell time), or 3- cyclic loading (106 cycles, 140 N, 15 Hz). Data were analyzed by (1) 3-way ANOVA and Dunnett tests, and (2) 2-way ANOVA and Tukey HSD tests (α=0.05). Regardless of the abutments' heights, no significant differences were found among the UTS of the nonthermocycled groups (p≥0.05). After thermocycling, an increasing in the UTS was observed for the 6.0-mm abutments (p<0.05). After cyclic loading, the UTS values produced by RXL2 were decreased (p<0.05). The abutment's heights used affected the RXL2 results, which produced higher results with the 6.0-mm abutments. With the exception of RXL2, cyclic loading did not detrimentally affect the UTS of the cemented castings. In some conditions, the provisional cement RXTNE produced similar UTS to some definitive cements