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.

Effect of green tea extract on bonding durability of an etch-and-rinse adhesive system to caries-affected dentin.

OBJECTIVE: Green tea extract has been advocated as a matrix metalloproteinase (MMP) inhibitor; however, its effect on bond durability to caries-affected dentin has never been reported. Thus, the aim of this in vitro study was to evaluate the effect of two MMP inhibitors (2% chlorhexidine and 2% green tea extract), applied after acid etching, on bond durability of an etch-and-rinse adhesive system to caries-affected dentin. MATERIAL AND METHODS: Occlusal enamel was removed from third molars to expose the dentin surface, and the molars were submitted to a caries induction protocol for 15 days. After removal of infected dentin, specimens were conditioned with 37% phosphoric acid (15 seconds) and randomly divided into three groups, according to the type of dentin pretreatment (n=10): NT: no treatment; GT: 2% green tea extract; CLX: 2% chlorhexidine. The etch-and-rinse adhesive system (Adper™ Single Bond 2, 3M ESPE, St. Paul, MN, USA) was applied according to the manufacturer's instructions, and composite resin restorations were built on the dentin. After 24 hours, at 37°C, the resin-tooth blocks were sectioned perpendicularly to the adhesive interface in the form of sticks (0.8 mm2 of adhesive area) and randomly subdivided into two groups according to when they were to be submitted to microtensile bond strength (µTBS) testing: immediately or 6 months after storage in distilled water. Data were reported in MPa and submitted to two-way ANOVA for completely randomized blocks, followed by Tukey's test (α=0.05). RESULTS: After 24 hours, there was no significant difference in the µTBS of the groups. After 6 months, the GT group had significantly higher µTBS values. CONCLUSION: It was concluded that the application of 2% green tea extract was able to increase bond durability of the etch-and-rinse system to dentin. Neither the application of chlorhexidine nor non-treatment (NT - control) had any effect on bond strength after water storage.

Effect of green tea extract on bonding durability of an etch-and-rinse adhesive system to caries-affected dentin

ABSTRACT Objective Green tea extract has been advocated as a matrix metalloproteinase (MMP) inhibitor; however, its effect on bond durability to caries-affected dentin has never been reported. Thus, the aim of this in vitro study was to evaluate the effect of two MMP inhibitors (2% chlorhexidine and 2% green tea extract), applied after acid etching, on bond durability of an etch-and-rinse adhesive system to caries-affected dentin. Material and Methods Occlusal enamel was removed from third molars to expose the dentin surface, and the molars were submitted to a caries induction protocol for 15 days. After removal of infected dentin, specimens were conditioned with 37% phosphoric acid (15 seconds) and randomly divided into three groups, according to the type of dentin pretreatment (n=10): NT: no treatment; GT: 2% green tea extract; CLX: 2% chlorhexidine. The etch-and-rinse adhesive system (Adper™ Single Bond 2, 3M ESPE, St. Paul, MN, USA) was applied according to the manufacturer's instructions, and composite resin restorations were built on the dentin. After 24 hours, at 37°C, the resin-tooth blocks were sectioned perpendicularly to the adhesive interface in the form of sticks (0.8 mm2 of adhesive area) and randomly subdivided into two groups according to when they were to be submitted to microtensile bond strength (μTBS) testing: immediately or 6 months after storage in distilled water. Data were reported in MPa and submitted to two-way ANOVA for completely randomized blocks, followed by Tukey’s test (α=0.05). Results After 24 hours, there was no significant difference in the μTBS of the groups. After 6 months, the GT group had significantly higher μTBS values. Conclusion It was concluded that the application of 2% green tea extract was able to increase bond durability of the etch-and-rinse system to dentin. Neither the application of chlorhexidine nor non-treatment (NT - control) had any effect on bond strength after water storage.

Mudança no processo ensino-aprendizagem nos cursos de graduação em odontologia com utilização de metodologias ativas de ensino e aprendizagem / Learning process modifications in odontology undergraduate courses using actives learning methodologies

Profundas mudanças estão sendo realizadas nos cursos de graduação em odontologia visando formar profissionaisadequados às necessidades de saúde da população brasileira e do Sistema Único de Saúde. Para tanto, torna-se essencial a efetiva articulação das políticas de saúde com a educação. A mudança didáticopedagógica visa a uma aprendizagem ativa, centrada no estudante. Assim, cabe ao professor o papel de facilitador do processo de construção do conhecimento, dando condições ao estudante de desenvolver um pensamento e um discurso próprios, e, inclusive na área da odontologia, utilizar-se de metodologias ativas deensino e aprendizagem. Este artigo apresenta algumas das diferentes metodologias ativas, as quais permitemque o estudante possa trabalhar com problemas reais, assumindo responsabilidades crescentes e interagindo com a população e os profissionais de saúde das áreas afins

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

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...