| Revista: | Materials research |
| Base de datos: | PERIÓDICA |
| Número de sistema: | 000312710 |
| ISSN: | 1516-1439 |
| Autores: | Discacciati, Jose Augusto Cesar1 Pimenta, Flavio Juliano Garcia Santos Sander, Herbert Haueisen Neves, Alisson Discacciati2 Orefice, Rodrigo Lambert3 |
| Instituciones: | 1Universidade Federal de Minas Gerais, Faculdade de Odontologia, Belo Horizonte, Minas Gerais. Brasil 2Universidade Estadual de Montes Claros, Montes Claros, Minas Gerais. Brasil 3Universidade Federal de Minas Gerais, Departamento de Engenharia Metalurgica e de Materiais, Brasil |
| Año: | 2004 |
| Periodo: | Abr-Jun |
| Volumen: | 7 |
| Número: | 2 |
| Paginación: | 313-318 |
| País: | Brasil |
| Idioma: | Inglés |
| Tipo de documento: | Nota breve o noticia |
| Enfoque: | Experimental |
| Resumen en inglés | Polymerization shrinkage is a critical factor affecting the longevity and acceptability of dental composite resins. The aim of this work was to evaluate the effect of light intensity and irradiation time on the polymerization process of a photo cured dental composite resin by measuring the Vickers hardness number (VHN) and the volumetric polymerization shrinkage. Samples were prepared using a dental manual light-curing unit. The samples were submitted to irradiation times of 5, 10, 20 and 40 s, using 200 and 400 mW.cm-2 light intensities. Vickers hardness number was obtained at four different moments after photoactivation (immediate, 1 h, 24 h and 168 h). After this, volumetric polymerization shrinkage values were obtained through a specific density method. The values were analyzed by ANOVA and Duncan's (p = 0.05). Results showed increase in hardness values from the immediate reading to 1 h and 24 h readings. After 24 h no changes were observed regardless the light intensities or activation times. The hardness values were always smaller for the 200 mW.cm-2 light intensity, except for the 40 s irradiation time. No significant differences were detected in volumetric polymerization shrinkage considering the light intensity (p = 0.539) and the activation time (p = 0.637) factors. In conclusion the polymerization of the material does not terminate immediately after photoactivation and the increase of irradiation time can compensate a lower light intensity. Different combinations between light intensity and irradiation time, i.e., differ |
| Disciplinas: | Medicina, Ingeniería, Química |
| Palabras clave: | Odontología, Ingeniería de materiales, Química de polímeros, Resinas compuestas, Polimerización, Irradiación, Propiedades mecánicas, Dureza |
| Keyword: | Medicine, Engineering, Chemistry, Dentistry, Materials engineering, Polymer chemistry, Composite resins, Polymerization, Irradiation, Mechanical properties, Hardness |
| Texto completo: | Texto completo (Ver HTML) |
