Effects of light-curing time on the cytotoxicity of a restorative composite resin on odontoblast-like cells

• Autor(a) principal: Aranha, Andreza Maria Fábio
• Data de Publicação: 2010
• Outros Autores: Giro, Elisa Maria Aparecida [UNESP], Hebling, Josimeri, Lessa, Fernanda Campos Rosetti [UNESP], Costa, Carlos Alberto de Souza
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/S1678-77572010000500006; http://hdl.handle.net/11449/226137
• topic: Cultured cells; Cytotoxicity; Dental materials; Dental pulp

This in vitro study evaluated the cytotoxicity of an experimental restorative composite resin subjected to different light-curing regimens. Methods: Forty round-shaped specimens were prepared and randomly assigned to four experimental groups (n=10), as follows: in Group 1, no light-curing; in Groups 2, 3 and 4, the composite resin specimens were light-cured for 20, 40 or 60 s, respectively. In Group 5, filter paper discs soaked in 5 μL PBS were used as negative controls. The resin specimens and paper discs were placed in wells of 24-well plates in which the odontoblast-like cells MDPC-23 (30,000 cells/cm2) were plated and incubated in a humidified incubator with 5% C02 and 95% air at 37°C for 72 h. The cytotoxicity was evaluated by the cell metabolism (MTT assay) and cell morphology (SEM). The data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests (p<0.05). Results: In G1, cell metabolism decreased by 86.2%, indicating a severe cytotoxicity of the non-light-cured composite resin. On the other hand, cell metabolism decreased by only 13.3% and 13.5% in G2 and G3, respectively. No cytotoxic effects were observed in G4 and G5. In G1, only a few round-shaped cells with short processes on their cytoplasmic membrane were observed. In the other experimental groups as well as in control group, a number of spindle-shaped cells with long cytoplasmic processes were found. Conclusion: Regardless of the photoactivation time used in the present investigation, the experimental composite resin presented mild to no toxic effects to the odontoblast-like MDPC-23 cells. However, intense cytotoxic effects occurred when no light-curing was performed.