Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

• Autor(a) principal: de Paula, Andréia Bolzan
• Data de Publicação: 2010
• Outros Autores: Tango, Rubens Nisie [UNESP], Sinhoreti, Mário Alexandre Coelho, Alves, Marcelo Corrêa, Puppin-Rontani, Regina M.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1590/S0103-64402010000200005; http://hdl.handle.net/11449/71823
• topic: Composite resin; Dental materials; Hardness; Resin cements; Filtek Z250; resin; resin cement; tooth cement; analysis of variance; animal; cattle; chemistry; dental bonding; dental equipment; dental surgery; drug effect; enamel; hardness; methodology; nonparametric test; Analysis of Variance; Animals; Cattle; Composite Resins; Curing Lights, Dental; Dental Bonding, Light-Cured; Dental Cements; Dental Enamel; Dental Restoration, Permanent; Resin Cements; Statistics, Nonparametric

This study evaluated the Knoop hardness and polymerization depth of a dual-cured resin cement, light-activated at different distances through different thicknesses of composite resin. One bovine incisor was embedded in resin and its buccal surface was flattened. Dentin was covered with PVC film where a mold (0.8-mm-thick and 5 mm diameter) was filled with cement and covered with another PVC film. Light curing (40 s) was carried out through resin discs (2, 3, 4 or 5 mm) with a halogen light positioned 0, 1, 2 or 3 mm from the resin surface. After storage, specimens were sectioned for hardness measurements (top, center, and bottom). Data were subjected to split-plot ANOVA and Tukey's test (α=0.05). The increase in resin disc thickness decreased cement hardness. The increase in the distance of the light curing tip decreased hardness at the top region. Specimens showed the lowest hardness values at the bottom, and the highest at the center. Resin cement hardness was influenced by the thickness of the indirect restoration and by the distance between the light-curing unit tip and the resin cement surface.