RESUMO
This study evaluated the surface microhardness of four glass ionomer cements and a composite resin (Fuji IX, Ketac Molar, Vidrion R, Vitromolar and Z 250). Ten specimens of each glass ionomer cement with 8.0 mm diameter and 5.0 mm high dimensions were made and Vicker's microhardness measurements were taken at 1 day and 1 week after initial setting reaction. The results were analyzed using Student's T test and Tukey test (p < 0.05) and demonstrated that the values of microhardness increased after 1 week, with the exception of Fuji IX. Resin composite Z250 presented the greatest values for microhardness.
Assuntos
Resinas Compostas/química , Cimentos de Ionômeros de Vidro/química , Dureza , Testes de Dureza , Técnicas In Vitro , Manufaturas , Fatores de TempoRESUMO
The purpose of this study was to evaluate the surface roughness of two glass-ionomer cements (Vitremer and Chelon-Fil), and one compomer (Dyract) when submitted to different finishing/polishing procedures at different times. A hundred 80-sample discs were made of each material and randomly divided into six finishing/polishing groups: mylar strip (control); Sof-Lex discs; diamond burs; diamond burs/Sof-Lex discs; 30-fluted carbide bur; 30-fluted carbide bur/Sof-Lex discs. These procedures were carried out immediately after preparation of the samples, after 24 and 168 h. Average surface roughness (Ra) was measured with a profilometer and the values were compared using anova (P < 0.05). The smoothest surface for all materials was obtained when cured in contact with the mylar strip. All other tested products increased surface roughness of restorative materials, but Sof-lex discs lead to better results. The worst results were verified with diamond burs. The finishing/polishing procedures, when performed immediately, can improve the roughness of glass-ionomer cements but not of the compomer tested.
Assuntos
Compômeros/química , Polimento Dentário/métodos , Cimentos de Ionômeros de Vidro/química , Análise de Variância , Resinas Compostas/química , Restauração Dentária Permanente , Desenho de Equipamento , Humanos , Teste de Materiais , Propriedades de SuperfícieRESUMO
The present study was designed to analyse the average depth of the microporosity of a nickel-chromium (Ni-Cr) system alloy (Verabond II). The metal surface was subject to one of the following surface treatment: (i) Electrolytic etching in nitric acid 0.5 N at a current density of 250 mA cm(-2); (ii) chemical etching with CG-Etch etchant; and (iii) Sandblasting with alumina particles 50 microm. Half of the samples were polished before the surface treatments. The depth of porosity was measured through photomicrographs (500x) with a profilometer, and the data were statistically analysed using an analysis of variance (anova) followed by Tukey's test. The conclusions were (i) Differents surface treatment of the Ni-Cr system alloy lead to different depths of microporosity; (ii) The greatest depth of porosity was observed in non-polished alloy; (iii) The greatest and identical depth of microporosity was observed following electrolytic etching and chemical etching; (iv) The least and identical depth of microporosity was observed with chemical etching and sandblasting with alumina particles 50 microm, and (v) Chemical etching showed an intermediary depth.
Assuntos
Condicionamento Ácido do Dente/métodos , Ligas de Cromo/análise , Colagem Dentária , Resinas Compostas , Técnica de Fundição Odontológica , Prótese Parcial Fixa , HumanosRESUMO
The present study was designed to analyse the average depth of the microporosity of a nickel-chromium (Ni-Cr) system alloy (Verabond II). The metal surface was subject to one of the following surface treatment? (i) Electrolytic etching in nitric acid 0ú5 N at a current density of 250 mA cm-²; (ii) chemical etching with CG-Etch etchant/ and (iii) Sandblasting with alumina particles 50 µm. Half of the samples were polished before the surface treatments. The depth of porosity was measured through photomicrographs (500) with a profilometer, and the data were statistically analysed using an analysis of variance (anova) followed by Tukey`s test. The conclusions were (i) Differents surface treatment of the Ni-Cr system alloy lead to different depths of microporosity/ (ii) The greatest depth of porosity was observed in non-polished alloy/ (iii) The greatest and identical depth of microporosity was observed following electrolytic etching and chemical etching/ (iv) The least and identical depth of microporosity was observed with chemical etching and sandblasting with alumina particles 50 µm, and (v) Chemical etching showed an intermediary depth