Effect of multiple coats of ultra-mild all-in-one adhesives on bond strength to dentin covered with two different smear layer thicknesses.

PURPOSE: To evaluate the effect on bond strength of 1, 2, or 3 coats of two one-step self-etching adhesives on dentin covered with two different smear layer thicknesses. MATERIALS AND METHODS: Flat dentin surfaces from recently extracted third molars were wet ground with 60- or 600-grit SiC paper to produce smear layers of different thicknesses. Adper Easy Bond (3M ESPE) and Clearfil S3 Bond (Kuraray) were applied in 1, 2, or 3 consecutive coats after air drying each coat. ScotchBond Multi Purpose (3M) and Clearfil SE Bond (Kuraray) were used as controls. Composite resin crowns (Filtek Z250, 3M ESPE) were built up, stored for 24 h, and cut in x and y directions. Eight to twelve sticks (0.65 ± 0.05 mm2 of area) from the central area of each tooth were fractured in tension (0.5 mm/min). Sticks from each group were processed for interfacial micromorphological evaluation with SEM. RESULTS: Three-way ANOVA revealed a significant interaction between factors (p < 0.05). Tukey's post-hoc test showed that only when Adper Easy Bond was applied on dentin prepared with 600-grit SiC paper, microtensile bond strength was not significantly affected by the number of coatings. However, the effect of smear layer thickness was only statistically significant when the adhesives were applied in one coat, for both adhesives. When they were applied in two or three coats, smear layer thickness did not significantly affect bond strength (p > 0.05). CONCLUSIONS: The thickness of the smear layer affected the bond strength of both all-in-one adhesives. Additional coats can be beneficial to bond strength, especially with Clearfil S3 Bond.

Post-etching cleaning and resin/ceramic bonding: microtensile bond strength and EDX analysis.

PURPOSE: The aim of this study was to evaluate the microtensile bond strength of a resin composite bonded to two heat-pressed ceramics after performing different post-etching cleaning techniques. MATERIALS AND METHODS: Resin composite specimens were bonded to IPS Empress Esthetic (EE) and IPS Empress 2 (E2) heat-pressed ceramic disks after etching with 10% HF, surface cleaning, silanization and application of an unfilled hydrophobic resin. Resin composite specimens were fabricated using 4-mm (height) Tygon tubes of 0.8 mm diameter and bonded according to the post-etching cleaning technique employed (n = 30): no cleaning (NC); air-water spray for 30 s (AWS); 37% phosphoric acid etching for 30 s (PA); ultrasonic bath in distilled water for 5 min (UB); PA + UB (PAUB); application of a self-etching silane/bonding system Clearfil Silane Kit (CSK). The resin composite specimens were subjected to tensile tension at a crosshead speed of 0.5 mm/min. SEM observation and EDX analysis were performed for each group to determine elemental distribution in the samples. RESULTS: Two-way ANOVA with random effect showed statistically differences between subgroups for E2, in which E2NC only showed bond strength significantly lower than E2AWS and E2BU, as indicated by Student's t-test and a contrast method. For EE, subgroups EENC and EECSK groups showed statistically significant differences between each other and among the other post-etching cleaning technique groups (p < 0.05). CONCLUSION: Air-water spray may be used as a post-etching cleaning technique for both ceramics. The presence of residues did not significantly reduce the bond strength of resin composite to IPS Empress 2 ceramic.

Observational study of adverse reactions related to articaine and lidocaine.

PURPOSE: This study determined the frequency of adverse reactions related to the administration of local dental anesthesia with 4% articaine compared with 2% lidocaine, both associated with epinephrine 1:100,000. The null hypothesis was that there is no difference between the administrations of both dental local anesthesia. METHODS: From a total of 727 patients in an emergency service, 338 and 389 patients were subjected to local anesthesia with lidocaine and articaine, respectively. A questionnaire was completed for each patient that contained patient data, the local anesthesia applied, and any reactions. RESULTS: The overall frequency of adverse reactions was 3.71%, with sweating and pallor being the most frequently observed. There was an association between adverse reactions and the use of daily medication by patients anesthetized with articaine (p = 0.0266). In contrast, in patients anesthetized with lidocaine, there was an association among the duration of the procedure (p = 0.0423), the type of procedure (p = 0.0146), and first anesthesia exposure (p = 0.0448). CONCLUSIONS: The low frequency of adverse reactions with use of articaine and lidocaine led to the conclusion that both solutions are safe for use in dentistry.

Effect of ceramic thickness and composite bases on stress distribution of inlays--a finite element analysis.

The purpose of this study was to determine the effect of cavity depth, ceramic thickness, and resin bases with different elastic modulus on von Mises stress patterns of ceramic inlays. Tridimensional geometric models were developed with SolidWorks image software. The differences between the models were: depth of pulpal wall, ceramic thickness, and presence of composite bases with different thickness and elastic modulus. The geometric models were constrained at the proximal surfaces and base of maxillary bone. A load of 100 N was applied. The stress distribution pattern was analyzed with von Mises stress diagrams. The maximum von Mises stress values ranged from 176 MPa to 263 MPa and varied among the 3D-models. The highest von Mises stress value was found on models with 1-mm-thick composite resin base and 1-mm-thick ceramic inlay. Intermediate values (249-250 MPa) occurred on models with 2-mm-thick composite resin base and 1-mm-thick ceramic inlay and 1-mm-thick composite resin base and 2-mm-thick ceramic inlay. The lowest values were observed on models restored exclusively with ceramic inlay (176 MPa to 182 MPa). It was found that thicker inlays distribute stress more favorably and bases with low elastic modulus increase stress concentrations on the internal surface of the ceramic inlay. The increase of ceramic thickness tends to present more favorable stress distribution, especially when bonded directly onto the cavity without the use of supporting materials. When the use of a composite base is required, composite resin with high elastic modulus and reduced thickness should be preferred.

Qualitative and quantitative analysis of Mercury ions on the surface of amalgam restorations after home bleaching / Análise qualitativa e quantitativa de íons Mercúrio na superfície de restaurações de amálgama após o clareamento caseiro

ABSTRACT Objective The bleaching agents may interact with restorative materials, such as dental amalgam, providing an increase mercury ions (Hg) release, whose toxic effect is known. Whereas many patients have amalgam restorations (AR) and seek bleaching treatments, the present study aimed to evaluate in vitro the amount of Hg released from AR made with spherical alloy, after being subjected to different concentrations of carbamide peroxide (CP) for home bleaching. Methods 40 class I AR were prepared in bovine teeth. Afterthe restoration, the samples were randomly allocated into 4 groups (n = 10): C (control group), CP10 (CP 10%) CP15 (CP 15%) CP20 (CP 20%) and its treatments were simulated for 14 days for 6 hours daily. The Hg ions released was measured by energy dispersive X-ray spectroscopy (EDS) and surface changes were assessed in the Scanning Electron Microscope (SEM). Hg levels (percent mass) were recorded and the differences were statistically analyzed using the Kruskal-Wallis test and Dunn's "Post hoc" test. Results Statisticalanalysis showed the bleaching treatment resulted in a higher Hg release (p <0.05), although no visible changes were identified in micrographs when comparing the control group with the other groups (CP10, CP15, CP20). Conclusion Increased Hg release may be observed during simulated home bleaching.

RESUMO Objetivo Os agentes clareadores podem interagir com materiais restauradores, como o amálgama, proporcionando um aumento na liberação de íons de mercúrio (Hg), cujo efeito tóxico é conhecido. Considerando que muitos pacientes possuem restaurações de amálgama (AR) e buscam tratamentos clareadores, o presente estudo teve como objetivo avaliar in vitro a quantidade de Hg liberado a partir da AR confeccionada com liga tipo esférica, após serem submetidas a diferentes concentrações de peróxido de carbamida (PC) para clareamento caseiro. Métodos 40 AR foram confeccionadas em dentes bovinos classe I. Após a restauração, as amostras foram distribuídas aleatoriamente em 4 grupos (n = 10): C (grupo controle), CP10 (PC 10%) CP15 (PC 15%) CP20 (PC 20%) e seus tratamentos foram simulados por 14 dias, por 6 horas diárias. Os íons de mercúrio liberados foram medidos por espectroscopia de energia dispersiva de raios-X (EDS) e as mudanças de superfície foram avaliadas pelo Microscópio Eletrônico de Varredura (MEV). Resultados A análise estatística demonstrou que o tratamento clareador resultou em uma liberação de íons mercúrio (p <0,05), embora nenhuma alteração visível tenha sido identificada nas micrografias quando compara-se o grupo C com os outros grupos (CP10, CP15, CP20). Conclusão Pode-se observar aumento da liberação de mercúrio durante o clareamento caseiro simulado.

Stress amplifications in dental non-carious cervical lesions.

This study aims to investigate the influence of the presence, shape and depth of NCCLs on the mechanical response of a maxillary second premolar subjected to functional and non-functional occlusal loadings using 3-D finite element (FE) analysis. A three-dimensional model of a maxillary second premolar and its supporting bone was constructed based on the contours of their cross-sections. From the sound model, cervical defects having either V- or U-shapes, as found clinically, were subtracted in three different depths. The models were loaded with 105 N to simulate normal chewing forces according to a functional occlusal loading (F1) vertically applied and two non-functional loadings (F2 and F3) obliquely oriented. Two alveolar bone crest heights were tested. Ansys™ FE software was used to compute stress distributions and maximum principal stress for each of the models. The presence of a lesion had no effect on the overall stress distribution of the system, but affected local stress concentrations. Non-functional loadings exhibited tensile stresses concentrating at the cervical areas and root surfaces, while the functional loading resulted in homogeneous stress distributions within the tooth. V-shaped lesions showed higher stress levels concentrated at the zenith of the lesion, whereas in U-shaped defect stresses concentrated over a wider area. As the lesions advanced in depth, the stress was amplified at their deepest part. A trend of stress amplification was observed with decreasing bone height. These results suggest a non-linear lesion progression with time, with the progression rate increasing with patient's age (deeper lesions and lower bone support).

Modeling and validation of a 3D premolar for finite element analysis / Modelagem e validação 3D de um premolar para análise de elementos finitos

Introduction: The development and validation of mathematical models is an important step of the methodology of finite element studies. Objective: This study aims to describe the development and validation of a three-dimensional numerical model of a maxillary premolar for finite element analysis. Material and method: The 3D model was based on standardized photographs of sequential slices of an intact premolar and generated with the use of SolidWorks Software (Dassault, France). In order to validate the model, compression and numerical tests were performed. The load versus displacement graphs of both tests were visually compared, the percentage of error calculated and homogeneity of regression coefficients tested. Result: An accurate 3D model was developed and validated since the graphs were visually similar, the percentage error was within acceptable limits, and the straight lines were considered parallel. Conclusion: The modeling procedures and validation described allows the development of accurate 3D dental models with biomechanical behavior similar to natural teeth. The methods may be applied in development and validation of new models and computer-aided simulations using FEM.

Introdução: O desenvolvimento e validação de modelos matemáticos é uma importante etapa da metodologia de estudos de elementos finitos. Objetivo: Este estudo tem o objetivo descrever o desenvolvimento e validação de um modelo numérico tridimensional de um pré-molar superior para análise em elementos finitos. Material e método: Fotografias padronizadas de cortes sequenciais de um pré-molar hígido serviram de referência para o desenvolvimento do modelo 3D, que foi construído por meio do programa SolidWorks (Dassault, França). A fim de validar o modelo testes de compressão e simulação numérica foram realizados. Os gráficos de carga versus deslocamento de ambos os ensaios foram comparados visualmente, a percentagem de erro calculada e homogeneidade dos coeficientes de regressão testada. Resultado: Um modelo 3D preciso foi desenvolvido e validado, uma vez que os gráficos apresentavam-se visualmente semelhantes, o percentual de erro ficou dentro dos limites aceitáveis e as retas foram consideradas paralelas. Conclusão: Os procedimentos de modelagem e validação descritos permitem o desenvolvimento de modelos dentários 3D precisos com comportamento biomecânico semelhante aos dentes naturais. Os métodos podem ser aplicados no desenvolvimento e validação de novos modelos e estudos de simulações computacionais por meio do MEF.

Effect of Ceramic Thickness and Composite Bases on Stress Distribution of Inlays - A Finite Element Analysis

The purpose of this study was to determine the effect of cavity depth, ceramic thickness, and resin bases with different elastic modulus on von Mises stress patterns of ceramic inlays. Tridimensional geometric models were developed with SolidWorks image software. The differences between the models were: depth of pulpal wall, ceramic thickness, and presence of composite bases with different thickness and elastic modulus. The geometric models were constrained at the proximal surfaces and base of maxillary bone. A load of 100 N was applied. The stress distribution pattern was analyzed with von Mises stress diagrams. The maximum von Mises stress values ranged from 176 MPa to 263 MPa and varied among the 3D-models. The highest von Mises stress value was found on models with 1-mm-thick composite resin base and 1-mm-thick ceramic inlay. Intermediate values (249-250 MPa) occurred on models with 2-mm-thick composite resin base and 1-mm-thick ceramic inlay and 1-mm-thick composite resin base and 2-mm-thick ceramic inlay. The lowest values were observed on models restored exclusively with ceramic inlay (176 MPa to 182 MPa). It was found that thicker inlays distribute stress more favorably and bases with low elastic modulus increase stress concentrations on the internal surface of the ceramic inlay. The increase of ceramic thickness tends to present more favorable stress distribution, especially when bonded directly onto the cavity without the use of supporting materials. When the use of a composite base is required, composite resin with high elastic modulus and reduced thickness should be preferred.

O objetivo do estudo foi avaliar o efeito da profundidade da cavidade, da espessura da cerâmica e da presença de bases de resina, com os diferentes módulos de elasticidade na distribuição de tensões de von Mises em inlays cerâmicos. Modelos geométricos tridimensionais foram desenvolvidos com o software SolidWorks. As diferenças entre os modelos foram: a profundidade da parede pulpar, a espessura da cerâmica e a presença de bases de resina composta com diferentes espessuras e módulos de elasticidade. Os modelos geométricos foram engastados nas superfícies proximais e base do osso maxilar e uma carga de 100 Newton foi aplicada. O padrão de distribuição de tensões foi analisado com diagramas de tensão de von Mises. O valor de tensão máxima de von Mises foi variável entre os modelos e situou-se na faixa entre 176 e 263 MPa. O maior valor foi encontrado nos modelos restaurados com bases de resina composta de 1 mm e inlay cerâmico de 1 mm de espessura. Valores intermediários (249-250 MPa) ocorreram nos modelos com bases de resina composta de 2 mm e inlays de 1 mm de espessura e nos modelos com bases de resina composta de 1 mm e inlays de 2 mm. Os menores valores foram observados nos modelos restaurados exclusivamente com inlay cerâmico (176-182 MPa). Verificou-se que inlays com maior espessura distribuem o estresse de forma mais favorável e bases com baixo módulo de elasticidade aumentam a concentração de tensões na superfície interna do inlay de cerâmica. O aumento da espessura do material cerâmico tende a apresentar uma distribuição de tensões mais favorável, principalmente quando cimentadas diretamente sobre o preparo cavitário, sem a existência de materiais intermediários. Em situações em que o emprego de materiais de base é necessária, deve-se preferir resinas compostas com alto módulo de elasticidade e espessura reduzida.

Slow progression of dentin bond degradation during one-year water storage under simulated pulpal pressure.

OBJECTIVES: To evaluate the dentin bond durability of simplified adhesives after one-year (1 y) under water storage and simulated pulpal pressure. METHODS: Class I cavities were prepared in sixty human third molars with the pulpal wall located in mid-coronal dentin. The roots were cut off to expose the pulpal chamber, and the teeth were assembled in a pulpal pressure simulator device. A two-step etch-and-rinse adhesive (Single Bond 2/SB), a two-step self-etch adhesive (Clearfil SE Bond/CSE), a three-step self-etch adhesive (Adper Scotchbond SE/SSE) and three all-in-one adhesives (Adper Easy Bond/EB, Clearfil S(3) Bond/S3 and Adhese One/AO) were applied according to manufacturers instructions. No enamel pre-etching was used for the self-etch systems. The cavities were filled with a composite (Z250, 3M ESPE) in four to five horizontal increments and individually cured. Immediately after the final cure, pulpal pressure was set to 15 cm H(2)O. After 24 h and 1 y under simulate pulpal pressure the teeth were cut following a 'nontrimming' microtensile test technique (n=30) and tested in tension. Kruskall-Wallis and post hoc multiple comparisons were used at alpha=0.05. Weibull statistics was applied to SB, CSE and EB. Fractographic analysis of debonded specimens was performed using scanning electron microscopy. RESULTS: At 24 h and 1 y periods, SB showed higher bond strength means than all the others adhesives tested. CSE was not statistically different from EB at 24 h and from EB and SB at 1 y. EB showed bond strength statistically higher than the other three self-etch adhesives, which were not statistically different from each other at 24 h. AO showed significantly lower bond strength than all tested materials after 1 y. For all adhesives the mean bond strength at 1 y were not statistically different from the values measured at 24 h (p>0.05). Shifts in failure mode patterns and Weibull modulus decrease indicate some degree of bond degradation after the 1 y storage period. CONCLUSION: One-year of simulated pulpal pressure did not affect dentin bond strength of simplified adhesives in Class I restorations. Signs of degradation were only revealed by fractographic analysis and reliability parameters.

Pinos de fibras de carbono para a restauração de dentes tratados endodonticamente / Carbon fiber posts for the restoration of endodontically treated teeth

A restauração de dentes tratados endodonticamente utilizando os sistemas de pinos e núcleos ainda é um procedimento realizado com frequência na clínica odontológica. Os diferentes sistemas de pinos e núcleos que são comercializados apresentam diferença em suas propriedades dependendo do comportamento mecânico do material utilizado para a confecção desses sistemas. Por esta razão, Assif et al., Freedman e Duret et al. acreditam que alguns tipos de fraturas radiculares estão associadas com a presença de pinos intra-radiculares que possuem o módulo de elasticidade diferente ao da dentina, logo, podem concentrar tensões na estrutura radicular. Como o módulo de elasticidade dos pinos de fibra de carbono tem sido descrito como semelhante ao da dentina, este estudo se propõe a apresentar, por meio de uma revisão de literatura, as características dos pinos de fibra de carbono para a restauração de dentes tratados endodonticamente

Excelência estética com implantes osseointegrados unitários: relato de caso clínico / Esthetic excellence with osseointegrated implants for single-tooth replacement: a case report

É grande a demanda por um sorriso de aparência natural nos consultórios odontológicos. Nesse aspecto, os implantes osseointegrados têm se destacado como alternativa previsível na reposição de elementos perdidos em regiões de alta exigência estética. No entanto, em algumas situações, a espessura do tecido gengival torna o uso de componentes protéticos metálicos tradicionais problemático, devido à transparência da cor acinzentada do metal no colo do elemento protético reposto. Neste caso clínico, utilizou-se um pilar protético cerâmico associado a uma coroa de porcelana pura, para otimizar os resultados estéticos, favorecendo a harmonia entre o pilar, a coroa e os tecidos moles circundantes.

Principais causas de fratura em dentes tratados endodonticamente / Main reasons for fracture in endodontically treated teeth

Um problema freqüentemente associado a dentes tratados endodonticamente é a fratura de dentes. Devido ao prognóstico duvidoso de dentes fraturados, este trabalho verificou na literatura quais seriam as principais causas de fratura em dentes tratados endodonticamente, para que estes fatores possam ser contornados e a restauração destes dentes possa ser executada de forma mais favorável. Entre as principais causas citadas na literatura, a diminuição da quantidade de estrutura dentária parece ser a mais significativa e a utilização de pinos intra-radiculares deve ser feita com cautela. Fatores como alteração das propriedades mecânicas e do conteúdo de água, técnica de condensação lateral e corrosão de pinos intra-radiculares apresentaram importância secundária...

Planejamento de implantes osseointegrados: associação do guia cirúrgico à tomografia computadorizada / Osseointegrated implants treatment planning: the association of the surgical stent to the computerized tomography

O advento da osseointegração proporcionou ao desdentado total ou parcial a possibilidade de reabilitação estética e funcional de forma eficaz e segura. Entretanto, a utilização desta tecnologia de maneira precisa e previsível exige da equipe profissional um diagnóstico correto e um planejamento detalhado. A seleção do número, tamanho e inclinação dos implantes deve ser baseada nas condições anatômicas do paciente e no resultado protético final que se pretende alcançar. Sendo assim, a tomografia computadorizada associada ao guia cirúrgico torna-se o meio mais adequado para estabelecer com precisão uma continuidade lógica entre a restauração planejada e as fases cirúrgicas. Este trabalho tem como objetivo ilustrar, através de uma situação clínica pré-operatória, a importância da utilização desta técnica no planejamento protético-cirúrgico da reabilitação através de implantes osseointegrados. Quando a condição existente não é capaz de garantir um prognóstico previsível e durável, então a condição intrabucal do paciente ou o planejamento protético devem ser modificados