RESUMO
In order to evaluate its application as a dental prosthesis material, a CoCrW alloy was subjected to in vitro cytotoxicity test, surface characterization and electrochemical studies performed in artificial saliva and 0.15 mol.L-1 NaCl medium. The used techniques were: anodic polarization curves, chronoamperometric measurements, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) analysis and X-ray photoelectron spectroscopy (XPS). Cytotoxicity test was also performed. The electrochemical behavior of CoCrW alloy was compared in both studied media, from corrosion potential (Ecorr) to a 600 mV anodic overvoltage. From the electrochemical measurements it was observed that the CoCrW alloy in both media presents only generalized corrosion. SEM and EDS analysis showed that the alloy presents carbide niobium and silicon and manganese oxides as nonmetallic inclusions. XPS results indicated that cobalt does not significantly contribute to the passivating film formation. Cytotoxicity test showed no cytotoxic character of CoCrW alloy. These results suggest that the CoCrW alloy can be used as biomaterial to be applied as prosthesis in dental implants.
Assuntos
Ligas Dentárias/química , Saliva Artificial/química , Técnicas In Vitro , Propriedades de SuperfícieRESUMO
Abstract In order to evaluate its application as a dental prosthesis material, a CoCrW alloy was subjected to in vitro cytotoxicity test, surface characterization and electrochemical studies performed in artificial saliva and 0.15 mol.L-1 NaCl medium. The used techniques were: anodic polarization curves, chronoamperometric measurements, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) analysis and X-ray photoelectron spectroscopy (XPS). Cytotoxicity test was also performed. The electrochemical behavior of CoCrW alloy was compared in both studied media, from corrosion potential (Ecorr) to a 600 mV anodic overvoltage. From the electrochemical measurements it was observed that the CoCrW alloy in both media presents only generalized corrosion. SEM and EDS analysis showed that the alloy presents carbide niobium and silicon and manganese oxides as nonmetallic inclusions. XPS results indicated that cobalt does not significantly contribute to the passivating film formation. Cytotoxicity test showed no cytotoxic character of CoCrW alloy. These results suggest that the CoCrW alloy can be used as biomaterial to be applied as prosthesis in dental implants.
Resumo Estudos eletroquímicos, caracterização de superfície e teste de citotoxicidade in vitro foram realizados da liga CoCrW em meios de saliva artificial e NaCl 0,15 mol.L-1, com o objetivo de avaliar a sua aplicação como material de prótese dentária. Foram usadas como técnicas, curvas de polarização anódica, medidas cronoamperométricas, espectroscopia de impedância eletroquímica (EIE), microscopia eletrônica de varredura (MEV), espectroscopia por energia dispersiva de raios X (EDS) e espectroscopia fotoeletrônica de raios X (XPS). O teste de citotoxicidade também foi realizado. O comportamento eletroquímico da liga CoCrW foi comparado nos dois meios estudados desde o potencial de corrosão (Ecorr) até uma sobretensão anódica de 600 mV. Foi observado, a partir de medidas eletroquímicas, que a liga CoCrW se encontra passivada em uma ampla faixa de potencial e que a sobretensões mais elevadas apresenta apenas corrosão generalizada nos dois meios. Análises por MEV e EDS mostraram que a liga apresenta inclusões não metálicas de carbeto de nióbio, de óxidos de silício e de manganês. Os resultados de XPS indicaram que o cobalto não contribui significativamente para a formação do filme passivo. O teste de citotoxicidade mostrou que a liga CoCrW não se apresenta citotóxica. Estes resultados sugerem que a liga estudada pode ser usada como biomaterial a ser aplicado como prótese sobre implantes dentários.
Assuntos
Ligas Dentárias/química , Saliva Artificial/química , Técnicas In Vitro , Propriedades de SuperfícieRESUMO
Statement of Problem. The chemical or topographic modification of the dental implant surface can affect bone healing, promote accelerated osteogenesis, and increase bone-implant contact and bonding strength. Objective. In this work, the effects of dental implant surface treatment and fibronectin adsorption on the adhesion of osteoblasts were analyzed. Materials and Methods. Two titanium dental implants (Porous-acid etching and PorousNano-acid etching followed by fluoride ion modification) were characterized by high-resolution scanning electron microscopy, atomic force microscopy, and X-ray diffraction before and after the incorporation of human plasma fibronectin (FN). The objective was to investigate the biofunctionalization of these surfaces and examine their effects on the interaction with osteoblastic cells. Results. The evaluation techniques used showed that the Porous and PorousNano implants have similar microstructural characteristics. Spectrophotometry demonstrated similar levels of fibronectin adsorption on both surfaces (80%). The association indexes of osteoblastic cells in FN-treated samples were significantly higher than those in samples without FN. The radioactivity values associated with the same samples, expressed as counts per minute (cpm), suggested that FN incorporation is an important determinant of the in vitro cytocompatibility of the surfaces. Conclusion. The preparation of bioactive titanium surfaces via fluoride and FN retention proved to be a useful treatment to optimize and to accelerate the osseointegration process for dental implants.