RESUMO
To investigate the interaction between dentin and self-etching systems with different pH characteristics. Midcoronal occlusal dentin of 12 extracted human molars was exposed and the specimens were randolmly divided into four groups according to the adhesive system used: Scotchbond Multipurpose Plus (SB) - control; Optibond Solo Plus Self-Etch (OP) - pH 1.5; Adper Prompt L Pop (PR) - pH 1.0; Clearfil SE Bond (CL) - pH 2.0. The specimens were examinated by scanning electron microscopy (SEM) to compare the typical structures of resin-dentin interaction using a metrical scale draw on the images. The adhesive systems applied produced statistical different hybrid layer thickness (p = 0.049), and the mean values (µm) were: SB = 6.13, OP = 1.6, PR = 2.04 and CL = 0.82. The resin tags formation and hybrid layer extension relationship were: SB = 1/9.2 µm, OP = 1/8.2 µm, PR = 1/13.1 µm and CL = 1/7.6 µm. The average thickness of hybrid layer was in the inverse ratio to the pH of the adhesive systems studied. The acidity of self-etching adhesives may be considered one of the many factors responsible for the resin-dentin interactions characteristics observed by SEM
Assuntos
Humanos , Dentina , Concentração de Íons de Hidrogênio , Dente MolarRESUMO
PURPOSE: To assess the effects of three different dental adhesive systems on the formation of secondary root caries, in vitro, with a standardized interfacial gap in a filled cavity model. METHODS: 40 sound human molars were selected and randomly assigned to four experimental groups: Clearfil SE Bond (CSEB), Xeno III (X-III), Scotchbond Multi-Purpose Plus (SBMP) and negative control (NC) without an adhesive system. After the standardized Class V cavity preparations on the buccal and lingual surfaces, restorations were placed with resin composite (Filtek Z250) using a standardized interfacial gap, using a 3 x 2 mm piece of 50 microm metal matrix. The teeth were sterilized with gamma irradiation and exposed to a cariogenic challenge using a bacterial system with Streptococcus mutans. Depth and extension of wall lesions formed and the depth of outer lesions were measured by software coupled with light microscopy. RESULTS: For wall lesion extension the ANOVA test showed differences between groups except between X-III and SBMP (P=0.294). The Tukey's test of confidence intervals indicated smaller values for the CSEB group than for the others. For wall lesion depth the CSEB group also presented the smallest mean values of wall lesion depth when compared to the others (P<0.0001) for all comparisons using Tukey's test. Regarding outer lesion depth, all adhesives showed statistically similar behavior. SEM evaluation of the morphologic appearance of caries lesions confirmed the statistical results showing small caries lesion development for cavities restored with CSEB adhesive system, which may suggest that this adhesive system interdiffusion zone promoted a good interaction with subjacent dentin protecting the dental tissues from recurrent caries.
Assuntos
Resinas Compostas , Restauração Dentária Permanente/métodos , Cimentos de Resina , Cárie Radicular/prevenção & controle , Análise de Variância , Adesivos Dentinários , Humanos , Dente Serotino , Cárie Radicular/microbiologia , Estatísticas não Paramétricas , Streptococcus mutansRESUMO
Introdução - O dente humano apresenta fluorescência quando irradiado por luz ultravioleta. Para a obtenção da estética com restaurações diretas de resina composta é necessário que este material se assemelhe ao dente em diferentes situações, inclusive quando submetido à incidência de diversos tipos de luz. Métodos - Nesta pesquisa, avalia-se a emissão de fluorescência de algumas marcas comerciais de resina composta anterior/posterior quando submetidas apenas à iluminação por lâmpadas emissoras de radiação ultravioleta. Dez avaliadores calibrados classificaram em níveis de fluorescência (alta, média e baixa) os 33 corpos de prova, dispostos aleatoriamente em um ambiente escuro desprovido de luz natural e apenas sob o efeito da luz ultravio1eta. Resultados - Devido à amostra obtida não ser normal nem homogênea, os escores conferidos pelos avaliadores foram submetidos ao Teste de Friedman. A distribuição das diversas marcas comerciais entre 11 grupos permitiu identificar o comportamento de cada amostra. Conclusões - Houve uma grande diferença entre as vârias marcas comerciais de resinas compostas que foram identificadas como de alta, média e baixa fluorescência. Geralmente as marcas comerciais de cada fabricante apresentavam valores de fluorescência semelhantes. As resinas compostas de uma mesma marca comercial, indicadas para reproduzir a dentina, o esmalte ou a borda incisal apresentaram fluorescências iguais.