Effects of five carbamide peroxide bleaching gels on composite resin microhardness.

• Autor(a) principal: Briso, André Luiz Fraga [UNESP]
• Data de Publicação: 2010
• Outros Autores: Tuñas, Inger T C, de Almeida, Letícia C A G, Rahal, Vanessa, Ambrosano, Glaucia M B
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://www.actaodontologicalat.com/archivo/v23n1/fulltext/articulo5.pdf; http://hdl.handle.net/11449/71872
• topic: drug derivative; peroxide; resin; urea; urea peroxide; dental care; evaluation; gel; hardness; Composite Resins; Gels; Hardness Tests; Peroxides; Tooth Bleaching; Urea

The purpose of this study was to evaluate the effects of five home bleaching products containing 15-16% carbamide peroxide on the microhardness of microhybrid composite resin Z-250 (3M/Espe). A total of 72 specimens were fabricated in cylindrical acrylic matrices (4 x 2 mm), filled with composite resin and photo-activated for 40 seconds. They were divided in 6 study groups (n = 12), according to the bleaching product: Review (SS White), Magic Bleaching (Vigodent), Opalescence (Ultradent), Whiteness Perfect (FGM), Claridex (Biodinâmica), and a control group (not bleached). Specimens were exposed to 1 cc of bleaching gel for 6 hours daily for 2 weeks. The control group specimens were kept in artificial saliva throughout this time. All the specimens were then analyzed in a microhardness tester. Knoop hardness measurements were performed, and the results were submitted to parametric statistical analysis (analysis of variance and Tukey's test). Mean Knoop values and standard deviation were: baseline, 68.52a (4.28); control, 63.42b (7.16); Whiteness Perfect, 57.57c (1.81); Magic Bleaching, 57.22c (3.84); Opalescence, 57.03cd (4.00); Claridex, 53.64de (3.33); Review 51.45e (2.82). Identical letters mean statistical equality according to Tukey's test at the 5% significance level. The products significantly decreased Z-250 (3M/Espe) microhardness.